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close this bookJournal of the Network of African Countries on Local Building Materials and Technologies - Volume 3, Number 4 (HABITAT, 1995, 46 p.)
View the document(introduction...)
View the documentThe aim of the network and its journal
View the documentForeword
View the documentEnergy efficiency in the production of building materials*
View the documentEnergy conservation for cost reduction in Indian cement industry - NCB's initiatives*
View the documentEnergy efficient method of portland slag cement grinding**
View the documentPlant audit and energy management***
View the documentEvents
View the documentPublications review

(introduction...)

United Nations Centre for Human Settlements (Habitat)
Nairobi, 1995


Rice husk incinerator

The aim of the network and its journal

The Network of African Countries on Local Building Materials and Technologies has the objective of strengthening local technological capacity through facilitating information flow, regional cooperation and transfer of appropriate technologies in low-cost and innovative building materials sector in African countries.

The Journal of the Network, currently published biannually, aims at providing a channel for information that is available and could be used by professionals, technicians, researchers, scientists as well as policy and decision-makers. It is a medium for information exchange and facilitator for acquiring suitable technologies and know-how by needy countries.

Efforts are made to compile, process and publish articles and technical papers originating, mainly from the African region. However, as deemed appropriate and subject to availability, research findings and technological information from countries outside the African region are also included to stimulate interregional cooperation as well.

CONTRIBUTIONS TO THE JOURNAL

This Journal welcomes information or articles on low-cost innovations in building-materials technology. Information in the form of technical and policy papers, illustrations, news items and announcements of events can be sent from individuals or institutions in the private or public sector, from within and outside the African region. All correspondence on the Journal should be addressed to the Chief, Building and Infrastructure Technology Section, Research and Development Division, UNCHS (Habitat), P.O. Box 30030, Nairobi Kenya.

The views expressed in this Journal do not necessarily reflect those of the United Nations. Mention of firm names and commercial products do not imply the endorsement of UNCHS (Habitat). The reprinting of any of the material in this publication is welcome, provided that the source is mentioned and one copy sent to UNCHS (Habitat).

National Network Institutions
Housing and Architecture Department
Ministry of Town Planning and Housing
Yaounde, Cameroon

Department of Civil Engineering
University of Addis Ababa
Ethiopia

Building and Road Research Institute (BRRI)
Kumasi University
Ghana

Housing and Building Research Institute (HABRI)
College of Architecture and Engineering
University of Nairobi, Kenya

Lesotho Housing and Land
Development Cooperation
Maseru, Lesotho

Department of Civil Engineering
The Polytechnic
University of Malawi, Malawi

Department of Architecture and Civil Engineering
University of Malta, Malta

School of Industrial Technology
University of Mauritius, Mauritius

Ministry of Local Government and Housing
Windhok, Namibia

Nigerian Building and Road Research Institute (NBRRI)
Lagos, Nigeria

Faculty of Engineering
Fourah Bay College
University of Sierra Leone
Freetown, Sierra Leone

Centre Technique des Materiaux de Construction
de la Ceramique et du Verre
CTMCCV
Tunis, Tunisia

Ministry of Lands, Housing and Urban Development
Kampala, Uganda

Building Research Unit (BRU)
Dar-es-Salaam
United Republic of Tanzania

National Housing Authority
Lusaka, Zambia

Ministry of Public Construction and National Housing
Harare
Zimbabwe

Editor-in-Chief:

Kalyan Ray

Editor:

Baris Der-Petrossian

Foreword

Economic development and human settlements development, consist largely of harnessing increasing amounts of energy for productive purposes in general, and shelter construction in particular. This can occur either by increasing the amount of energy resources - if availability of such resources is unrestricted - or by making more efficient use of available energy resources.

In the building-materials sector, energy is consumed mainly for extracting raw materials, manufacturing of finished products and in transportating building materials to the site. The relative amount of energy used in each of these areas vary depending on local conditions. However, the highest energy consumption occurs in the production process of building materials.

The building-materials industries as a whole, rely to a large extent on high temperature processes and are among the most energy-intensive industries. For example, the cost of energy in the production of cement or clay bricks/tiles accounts for 50 to 70 per cent of the direct cost of manufacturing. It is, therefore, important that the use of energy in the production process is optimized so that the overall cost of housing construction is reduced and the polluting impact of the excessive use of fossil fuel is arrested.

Various studies have revealed that many building-materials industries, particularly in developing countries, use outdated technologies which are inefficient in terms of use of energy. Eventhough the task of reducing use of energy, while maintaining high quality and quantity of outputs, is rather difficult, measures could be taken to monitor and optimize the use of energy in the production processes. Ultimately, the most promising approach would be to increase the use of low energy-content materials and apply energy-efficient and low-polluting technologies in the construction. It is in light of this situation that the Habitat Agenda adopted by the second United Nations Conference on Human Settlements (Habitat II) has emphasized the need for Governments and stakeholders "to encourage and promote the application of low energy, environmentally-sound and safe manufacturing technologies in the building materials and construction sector".

This issue of the Journal is devoted to energy efficiency in the production of building materials. It is hoped that the readers will find the contents of this issue interesting and useful to their work. The contribution of Mr. Baris Der-Petrossian of UNCHS (Habitat)'s Research and Development Division in drafting, compiling and editing the articles included in this Journal is thankfully acknowledged.



Dr. Wally N'Dow
Assistant Secretary-General
UNCHS (Habitat)


Mud-straw building blocks are both low-cost and low-energy building materials, courtesy Sean Sprague/Earth Scan

Energy efficiency in the production of building materials*

By Baris Der-Pelrossian, UNCHS (Habitat). This article has been produced based on in-house research conducted earlier.

INTRODUCTION

Most developing countries have realized the significance of expanding the capacity of domestic production of building materials and have adopted or are in the course of adopting necessary policies to that effect. However, translating these policies into reality will depend first and foremost on the availability of the basic resource inputs for the production of a variety of basic building materials. The main inputs required for the production of building materials are:

(a) raw materials;
(b) labour;
(c) capital items such as machinery and tools; and
(d) energy.

All these inputs play vital roles in the production process and inadequate supply of any of them will jeopardize the success of any enterprise producing building materials. Yet, there are certain building materials - such as cement, lime and burnt-clay bricks - for which energy alone is an exceptionally crucial factor of production - in fact, so crucial that these materials can easily be classified as energy-intensive building materials. For instance, in the production of fired-clay bricks, the energy input is the only means of transforming the properties of the raw material (clay) into the desirable building brick which should possess certain characteristics in terms of strength, durability and resistance to water absorption. Similarly, in the production of lime and cement, energy is the only input which transforms the limestone into a material with cement properties.

In most developing countries, energy-dependent building materials are the key materials in the construction sector. Portland cement is the single most strategic material and, almost invariably, where there are near substitutes such as low-strength binders, they all tend to be energy-dependent. For the purpose of low-income housing, opportunities to expand the availability of walling materials beyond the range of cement-based materials are often restricted to another energy-dependent building material - tired-clay bricks. Roofing materials pose another problem of high-cost and scarcity but, unlike walling materials, the options are limited to a few energy-intensive materials: aluminium sheets, galvanized-iron sheets and asbestos-cement sheets. One material which can be explored to improve the availability of roofing materials to the low-income population is fired-clay tiles - another energy-intensive material.

Energy is probably the single most crucial factor required to improve the production of building materials in developing countries, yet it remains scarce, prohibitive in cost or not available. The main reason for this setback is obvious. The sharp increases in crude oil prices in the 1970s have since sustained a devastating trend in the energy situation, with the oil-importing developing countries being the most disadvantaged. The negative cycle in cost and supply of crude oil has had a similar effect on alternative forms of energy such as coal, firewood and electricity. The cost of energy in the production of a typical energy-intensive building material such as cement comprises 60 to 75 per cent of the direct manufacturing cost (1) - that is, if the source of energy is ever available at all.

In recent times, attention has continuously focused on ways and means of improving the energy situation to enhance the building-materials sector. Efforts in this direction are being made in both developing and industrialized countries, with outstanding achievements from the latter. Finland, for example, with minimal investments in ventilation technology has achieved about 30 to 75 per cent savings in energy consumption in the concrete industry. Hungary has achieved a 50 per cent reduction in energy consumption in the brick industry by renewing dryers and stoves and promoting efficiency in heat recovery (2). A few energy-saving technologies have also emerged in India and elsewhere. Thus, there is sufficient evidence that the negative trend in the energy sector is reversible. The purpose of this article is, therefore, to take account of the useful innovations towards improvement of the energy situation and, in particular, to stimulate research and development activities in an effort to ensure wide-scale production of local-building materials for the low-income population.

I. Energy Consumption in the Building-Materials Sector

Energy sources in the production of building materials can be classified as either primary sources - such as oil, coal, gas, other fuels and electricity, or as secondary sources - consisting of waste-heat which is generated during the production process.

While both sources of energy are important in the search for energy-efficiency in building materials production, the primary sources of energy are fundamental to the energy crisis and, perhaps, deserve more attention. There is a distinction between thermal energy resources, which are responsible for the main energy transformation process in the production cycle, vis-a-vis energy for electrical power to run machines for ventilation, grinding of raw materials and similar functions. Thermal-energy consumption normally outweighs that of electrical power. For instance, in cement manufacture, fuel consumption accounts for about 75 to 90 percent of the total primary energy used in a plant while electrical power accounts for the remaining 10 to 25 per cent(3). In some small-scale technologies for production of lime and fired-clay bricks, energy requirements could sometimes be accounted for only by fuel consumption in the firing process.

Comparison between various building materials in terms of their energy-consumption patterns should take into consideration variations between countries and even within one country; consideration should also be given to variations between production technologies for the same building material. This is a very complex task and, in the absence of comprehensive universal data in this areas, an attempt has been made in table 1 to provide an indication of relative energy consumption for selected building materials in India.

Table 1. Energy consumption in the manufacture of building materials in India

Classification of material

Energy consumption in MJ/kg of material

I

Burnt-clay tiles

3.00

II

Burnt-clay bricks

1.43


Hollow-concrete blocks

1.20


Sand-lime blocks

1.03

III

Reinforced concrete

2.00-8.00


Unreinforced concrete

1.20


Aerated concrete

2.89

IV

Portland cement

6.70


Hydrated lime

4.21


Gypsum plaster

1.52


Calcined-clay pozzolana

1.39

V

Steel

26.00


Aluminium

144.00

VI

Wood products

3.00

Source: Fog, M. H. and Nadkarni, K. L., reference No. 1

The energy values given in table 1 can only be meaningful if comparisons are made between materials with similar functions in construction. For instance, cement, lime and gypsum are comparable within the limits to which they can be used in construction for identical purposes. This phenomenon is illustrated in tables 2 and 3, using walling materials and binders as examples. These consumption values become even more meaningful when translated into cost values relative to total cost of production as indicated in table 4.

Table 2. Energy consumption in materials for walling

Element

Energy content of 1 sq. m in MJ

Wall made of

bricks:

118.0 kg

278.5

hollow-clay bricks,

cement:

2.5 kg

10.0

18 cm × 10 cm × 30 cm

lime:

6.4 kg

57.6

21 cm thick

sand:

0.043m

314.2




360.3

Wall made of

bricks:

73.1 kg

172.5

hollow-clay bricks,

cement:

2.0 kg

8.0

8 cm × 18 cm × 30 cm

lime:

5.2 kg

46.8

13 cm thick

Sand:

0.035m3

11.5



238.8;

Wall made of

bricks:

127.0 kg

660.4

solid-clay bricks,

cement:

1.8 kg

7.2

12 cm × 16 cm × 25 cm

lime:

4.5 kg

40.5

15 cm thick

sand:

0.03 m3

9.9



718.0

Wall made of

bricks:

255.0 kg

1326.0

solid-clay bricks,

cement:

4.4 kg

17.6

12 cm × 16 cm × 25 cm

lime:

11.1 kg

99.9

30 cm thick

sand:

0.074m3

24.4



1467.9

Wall made of adobe,

adobe:

800.0 kg

1.5

40 cm × 10 cm × 20 cm

cement:

1.6 kg

6.4

43 cm thick

lime:

4.2 kg

37.8

sand:

0.028m3

9.4



55.1

Wall made of adobe,

adobe:

400.0 kg

0.75

20 cm × 40 cm × 40 cm

cement:

1.6 kg

6.4

23 cm thick

lime:

4.2 kg

37.8

sand:

0.028m3

9.3



54.25

Wall made of concrete

cement:

52.4 kg

209.6

blocks, 20 cm × 20 cm

lime:

7.0 kg

71.1

× 40 cm 23 cm thick

sand:

0.159m3

52.5

stone:

0.107m3

35.3



368.5

Source: Rai, M. Energy Conservation in the Development and Production of Building Materials, reference No. 7

Table 3. Energy consumption of selected binders (basis 1m3 wet mortar)

Composition of binder

Energy requirement as percentage of 1:6 cement-sand mortar

Cement: sand (1:6)

100

Cement: lime: sand (1:1:6)

135

Lime: burnt-clay pozzolana (1:2)

172

Lime: burnt-clay pozzolana: sand (1:1:1)

133

Lime: flyash or rice-husk ash (1:2)

94

Lime kiln reject: flyash or rice-husk ash (1:2)

25

Source: Rai, M. Energy Conservation in the Development and production of Building Materials, reference No. 7

Table 4. Cost of energy relative to production cost of selected materials

Material

Energy cost as percentage of total material cost

Cement

43.0 - 53.0

Lime

47.9 - 59.5

Gypsum products

11.1 - 16.6

Bricks and tile

29.7 - 36.5

Other structural

23.7

Clay products

35.2

Concrete blocks

3.6 - 6.5

Timber sawmills

2.2 - 4.1

Source: UNIDO - The building materials industry in developing countries, an analytical appraisal, sectoral studies series No. 16 vol. 1, Vienna 1985 p. 98.

Another important but often neglected component in energy consumption in the building- materials sector is in relation to transportation or distribution of the finished product for construction. Building materials are produced solely for construction so that their energy consumption computations can only be finalized at the point of use. In fact, there are some developing countries where the cost of transporting building materials outweighs the actual cost of production. In Botswana, Honduras and Sudan, after 100 miles, the cost of transporting cement is higher than the manufacturing cost(4).

II. Prevailing energy-inefficient production systems

Despite the high cost and scarcity of energy, there is a considerable degree of wastefulness in the use of energy in the production of building materials, especially regarding energy-dependent building materials. To some extent, energy loss in this context can be attributed to basic human error or negligence in the production process. However, a fundamental reason for wastefulness in energy utilization can be attributed to two related factors:

(a) production technology; and
(b) scale of production.

The extent to which the choice of technology determines the efficiency of energy utilization can be illustrated with the following examples:

(a) Cement production

Cement production is basically a choice between rotary kiln technology and vertical shaft kiln technology. The rotary kiln is more popular, due to several technical advantages. However, on account of energy consumption alone, the shaft kiln is more efficient - as illustrated in table 5.

Table 5. Typical energy consumption patterns of cement manufacturing processes in Europe (fossil fuel only)

Type of kiln

Energy consumption in kcal/kg of clinker

Shaft kiln

750

Rotary kiln types

Dry (long kiln)

860

Wet (long kiln)

1300

Dry (suspension pre-heater)

790

Source: Spence, R.J.S. Small-scale Production of Cementitious Materials, I.T. Publications Ltd., London, 1980.

In a similar development in India, it was established that while a vertical shaft kiln consumed around 750 kcal/kg of clinker, a rotary kiln consumed up to 2000 kcal/kg of clinker. In addition to the advantage of low-fuel consumption, the vertical shaft kilns are known to have operated efficiently on a variety of solid fuels, sometimes with an ash content as high as 50 per cent (5). Even within the rotary kiln technology, there are variations between the wet process and the dry process, with implications for energy-efficiency. For instance, a wet process could consume 1400 kcal/kg of cement compared to 750 kcal/kg of cement energy consumption in the dry process - a difference of about 86 per cent (6).

(b) Lime production

Fuel consumption in alternative technologies for production of hydrated lime tends to show the importance of choice of technology in achieving energy efficiency. Using the case-study of the Federal Republic of Germany in table 6, an energy saving of about 40 per cent is achieved when rotary kiln technology is adopted in place of a traditional vertical kiln. A similar trend applies to India, where energy efficiency of the CBRI improved shaft kiln has been achieved through the principles of uniformity of heat distribution over the cross section of the kiln plus the provision of a good draught system. In detail, the CBRI kiln is a tall cylindro-conical structure constructed of masonry material with an internal lining of fired-clay bricks. The effective height of this kiln for a 10 tonne per day capacity is 11 m and the calcining zone maintains a temperature of 950°C to 1100°C (7).

Table 6. Fuel consumption in lime production using different technologies

Country

Type of kiln

Proportion of production cost

Primary energy consumption MJ/kg quicklime


Traditional vertical kiln

35

4.760

Federal Republic of Germany

Ring annular kiln

22

4.865


Rotary kiln

20

6.715


Traditional kiln

-

12.60

India

Conventional

-

9.03


Improved shaft kiln (CBRI)

-

6.24

Source: UNCHS (Habitat), Technical note No. 12, 1987

(c) Fired-clay bricks

The theoretical energy requirement for firing clay bricks in small-scale kilns is about 20 to 35 per cent of the actual energy consumption in production practice. Thus, most existing brick production technologies are by definition energy-inefficient. Despite this trend, large-scale kilns are more efficient in energy consumption than traditional kilns as exemplified in table 7.

Since transportation of bricks from the point of production to the point of use accounts for a significant amount of energy consumption, it could be argued that the scale of production is a crucial determinant of efficiency in energy utilization. Building materials, by their nature, tend to have a low value-to weight ratio so that they are excessively costly to transport even over short distances. This situation is worsened in most developing countries where the scarcity and prohibitive cost of oil are rampant and where the infrastructure or facilities for transportation are under-developed. Large-scale production technologies predetermine high-energy consumption for distribution of building materials because a single plant often has a wide catchment zone, sometimes an entire country. Large-scale brick industry is an example of prevailing error in choice of scale of technology as far as energy-efficiency in transportation is concerned.

III. Innovations for energy-efficient building materials production technologies

There are at least four ways in which the building materials sector can realize improvements in terms of energy-efficiency. These are:

(a) extensive use of those building materials which can be produced with hardly any expenditure on thermal energy or electrical power;

(b) innovative technologies to improve or minimize fuel consumption in energy-intensive building materials production;

(c) innovations related to use of cheap and renewable forms of energy as fuel or electrical power; and

(d) promotion of small-scale technologies to minimize energy consumption in transportation of materials.

The four strategies outlined above are interrelated rather than independent. Thus a comprehensive approach to the energy crisis may require the implementation of all four approaches concurrently.

The following parts of this article show the specific merits of each.

(a) No-energy building materials

In principle, building materials which can be produced without the use of any type of thermal energy and electrical power should form the cornerstone of the building materials sector in countries facing scarcities and high cost of energy. Unfortunately, there are only a limited number of such building materials. Typical examples are unstabilized soil blocks, fibre-reinforced soil blocks, manually produced bamboo walling and thatch roofing.

Table 7. Energy consumption in brick-making technologies

Technology

Scale of production
(No. of bricks)

Labour required (man-hr for 1000 solid bricks)

Over-all energy consumpion (MJ/1000 solid bricks)

Small-scale production, all manual methods, clamps, scoves, scotch kilns

2,000

20 to 30

7,000 to 10,000

Small-scale production, all manual methods, up draught and down draught kilns

2,000

30 to 40

10,000 to 15,000

Medium-scale production, all manual methods, bull's kilns

20,000

30 to 40

4,000

Medium-scale production, semi-mechanized method, Hoftmann on zig-zag kiln

30,000

30 to 35

3,000 to 3,500

Large-scale production, full mechanized tunnel kiln 1

150,000

10 to 15

3,000 to 4,000

Source: UNCHS (Habitat), Technical Note No. 12.

(b) Innovative technologies to improve fuel consumption in energy-intensive building materials

Some energy-intensive building materials are indispensable to construction so that any improvements in their supply and cost should depend on feasible innovations to optimize the energy consumption patterns in the production process.

Fortunately, recent innovations have proven that energy utilization in the production of materials such as cement, lime, concrete and fired-clay bricks can be optimized with considerable benefits in energy savings. Using Portland cement as an example, table 8 gives an indication of some interesting innovations.

Another innovation regarding energy-savings in cement production is the technology of blended cements. The blending of certain carbonaceous materials such as granulated slag, fly-ash and other pozzolanas with cement makes it possible to produce more cement from the same amount of clinker and thus reduce the final consumption of energy per ton of cement produced. Experience has shown that up to 20 per cent of clinker can be replaced by fly-ash and up to 25 per cent by blast furnace slag without changing the performance of blended cements in comparison to Portland cement for general application in construction. In some countries, this mode of production has led to an estimate of 20 to 40 per cent savings in fuel consumption. Further examples of innovations in production technology related to energy savings for a variety of building materials are given in table 9. Fortunately, most of the materials identified in this table are abundantly available in most developing countries; indeed, they exist as waste products which pose a disposal problem. One way to enhance the wide-scale use of these innovative technologies is to promote effective and economic strategies for collection and distribution of these waste materials.

(c) Innovations related to use of cheap and renewable sources of energy for fuel and electrical power.

Table 8. Selected examples of improvements in energy conservation and in specific energy consumption in cement production

Plant type/location

Energy savings

Measure taken

A. Energy conservation


Wet process

Savings of 150 kcals/kg

Adding a vent air recirculation system toclinker cooler thereby reducing dustwastage and increasing heat recuperation.

Long-dry process

Savings of 512 toe/year, Preheating of fuel oil by using clinker cooler waste heat from heat exchanger inside the cooler.

Preheater-dry

Savings of 625 toe/year, Use of coal mine tailing as substitute processof fuel oil

Semi-dry process

Savings of 625 toe/year

Use of clinker cooler vent air as primary air to hot air furnace.

Dry process

Savings of 14 kcals/kg, Addition of new kiln seal at discharge end to cut out air infiltration.

B. Lowering specific energy consumption

Wet process (Canada)

10 per cent (from 1,416 kcals/kg to 1,280 kcals/kg)

Recirculating clinker cooler air.

Wet process (Canada)

9 percent (from 1,441 kcals/kg to 1,280 kcals/kg)

Slurry thinner to lower slurry moisture to 1,280 kcals/kg) from 35.8 per cent to 31.2 per cent with increase in clinker production by 9 per cent.

Wet process (USA)

17 per cent (from 1,876 kcals/kg to 1.560 kcals/kg)

Reduction in slurry moisture, new seals and closing holes, new cooler grates, and fans, new chain system.

Wet process (Brazil)

11 per cent (from 1,841 kcals/kg to 1,637 kcals/kg)

Changing clay component, modifying chain system.

Wet Process adding (USA)

15 per cent (from 1,617 kcals/kg to 1,381 kcals/kg)

Slurry water reduction, lifters insulating bricks, raw feed chemistry control, chain maintenance, and cooler modification.

Source: Fog, M. H. and Nadkarni, K.L. reference No. 1.

It can be argued that the most important strategy to tackle the energy situation relates to the availability and use of substitutes to coal, oil, gas and firewood. In the search for cheaper alternatives to conventional forms of energy, one should aim first and foremost at those options which are easily achievable within the resource capacities of developing countries -preferably energy options related to waste materials. For choosing the energy sources, the criteria should thus initially ignore disadvantages in rate of energy consumption using "new" forms of energy vis-a-vis conventional forms of energy.

On the basis of the above, one could summarize the innovations worth promoting as follows:

(i) development of energy from bio-mass based on agricultural residues and in a form which could be transported, i.e., by pyrolytic conversion of bio-mass into liquid and gaseous energy or charcoal;

(ii) use of agricultural and industrial wastes such as rick husk, directly as forms of solid fuel;

(iii) recycling and/or incineration of municipal-solid wastes - glass, aluminium, paper, plastics, wood and rubber;

(iv) development of suitable forms of energy from the sun, ocean, wind and geo-thermal power for direct heating or drying processes or for conversion into electrical power.

Table 9. Utilization of industrial and agricultural wastes for production of building materials in energy-saving technologies

Type

Supply of material

Mode of utilization

Energy Saving (percentage)

1. Granulated blast furnace slag

Iron and steel industry

Up to 45 per cent additive to cement to produce blended cement

35 to 40 per cent of energy consumption in manufacturing of ordinary Portland cement

2. Air-cooled and foamed blast

same

Substitute to conventional coarse aggregate.

10 to 15 per cent compared to stone aggregate.

3. Fly-ash

Thermal power plants using coal

Up to 30 per cent additive to cement to produce blended cement

25 to 30 per cent of energy consumption in manufacture of ordinary Portland cement.

4. Fly-ash

same

20 to 40 per cent interground with clay to produce fired-clay bricks

25 to 30 per cent equivalent of energy consumed in firing bricks consumed in firing bricks with coal or wood

5. Colliery waste

Coal washing plants

10 to 25 per cent In interground with clay to produce fired-clay bricks

20 to 25 per cent comparison to normal energy requirements using coal

6. Mineral tailing

Residues of iron, cooper, zinc, tin, lead, gold, silver

Constitutes 20 to 50 per cent of raw materials for production of fired-clay bricks, masonry cement, cellular concrete and sand-lime bricks

15 to 30 per cent Compared to energy consumption in normal production system

7. Calcium carbonate sludge

Fertilizer, tannery, sugar, paper and acetylune industries

As raw material for lime manufacture

10 to 15 per cent Compared production from traditional raw materials

8. Bauxite waste (red mud)

Aluminium or bauxite industry

50 per cent additive inter-ground with clay in production of fired-clay bricks

5 to 10 per cent compared to energy consumption in normal production systems

9. Husks of rice, groundnut, coffee, maize

Various plant sources

10 to 25 per cent additive interground with clay and coconut pithin production of fired-clay bricks. The husks when incinerated into ashes can be mixed with lime to produce low-strength binders of blended with ordinary Portland cement to produce masonry cement.

15 to 25 per cent equivalent of coal consumption in normal production process

Source: UNCHS (Habitat), Technical Note No. 12.

(d) Promotion of small-scale production units

This strategy is the only logical means of ensuring distribution of building materials to the ultimate point of use with minimal demands on fuel for transportation. Fortunately, recent innovations have made it possible for almost every building material to fit into varying scales of production defying the monopoly of large-scale production systems which certain sectors such as the cement, steel and aluminium industries used to enjoy. For instance, in some countries, the introduction of mini steel plants utilizing scrap metal as raw material has led to noticeable savings in energy consumption in the steel industry.

CONCLUSIONS

The indispensable role of energy as a factor of production in the building-materials sector is undermined by the crippling trend of its scarcity and high cost in most developing countries. However, as indicated in this article, there is proven know-how to deal with this negative situation. In fact, some of the technological options for energy-efficiency in building materials production are so simple and basic that it may not be too difficult to put them into actual practice. What remains to be done is to find an effective means of promoting the requisite technological innovations at the local level either through transfer of know-how from external sources or even technology transfer within a given country. Normally, information dissemination through written materials such as this article, is not in itself an end to realizing practical achievements in technology transfer or technology innovation. Nevertheless, the existing gap in information flow related to technology innovation in developing countries, makes the information in this article note of relevance to overall development efforts -hopefully it will serve as the framework for designing effective field implementation programme on this subject.

REFERENCES

1. Fog, M. H. and Nadkarni, K. L., Energy efficiency and fuel substitution in the cement industry, World Bank, Washington, 1983.

2. Economic Commission for Europe, Energy savings in the production of building materials and in the construction process, seminar on modern building technologies, Poland, 1985.

3. Ibid, reference No. 1

4. UNIDO, The building materials industry in developing countries, sectoral studies series No. 16, Vol.1 Vienna, 1985.

5. Spence, R. J. S., Small-scale production of cementitious materials, I.T. Publications Ltd., London, 1980.

6. Ibid, reference No. 1.

7. Rai, M., Energy conservation in the development and production of building materials, proceedings of the International Workshop on Energy Conservation in Building, C.B.R.I. Roorkee, India, 1984.

Bibliography

1. Bessey, G. E., "Production and use of lime in developing countries", Overseas Building Note, No. 161, Building Research Establishment, Garston, U.K., 1975

2. Boynton, R. S., "Chemistry and Technology of Lime and Limestone", Interscience, New York, 1966.

3. Bryant, B. S., "Corrugated roofing panels from agricultural residues". Appropriate Technology, 4(4), 26-29, 1978.

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Energy conservation for cost reduction in Indian cement industry - NCB's initiatives*

*By J. P. Saxena, Ashwani Pahuja, Pradeep Kumar, National Council for Cement and building materials, New Delhi. This paper was presented to the third National Council for Cement and Building Materials (NCB) International Seminar on Cement and Building Materials, held in January 1991 in New Delhi, India.

SYNOPSIS

The price of energy is a major component of the cost of cement production, being as high as 60 per cent in some of the cement plants. In today's context of energy shortages and its rising prices, energy conservation has assumed high priority in reducing production costs. The paper discusses the initiatives taken by NCB towards energy conservation and cost reduction in cement plants which include energy audit studies with the help of Mobile Energy Diagnostic Unit (MEDU), encouraging use of incentive schemes, energy monitoring, power system management and motivating competitive improvements. The paper also highlights the salient features of MEDU which has proved to be an effective tool for quick on the spot assessment of energy-use pattern with the help of on-board computer process and electrical parameters and brings out some of the case-studies carried out by NCB which has resulted in saving off energy and reduction in the cost of cement production.

1. INTRODUCTION

During the last few years, there has been an increase in cost of production as the prices of various forms of energy viz. thermal and electrical, which constitute a major component of cost of cement production. This coupled with acute shortage of power and reasonable quality fuels has compelled decision-makers in the industry to examine and find new ways and means for energy conservation by minimizing energy wastage and achieving cost reduction in cement manufacture.

Cement Industry in India has followed the principle of co-existence by old and new cement plants and is in a unique situation wherein more and more large capacity plants, have been installed. These plants use dry process with preheaters and precalcinators, but the old wet and semi-dry process plants as well as small vertical shaft kiln plants are also existing simultaneously playing their complementary roles in meeting the country's demand for cement. The industry has been apt to adopt technological developments and upgradings and most of the new installations are coming up with energy efficient systems and equipment. The problem of high ash and variable quality of coals, inconsistent power supply, low grade raw materials, harder to grind raw materials and coals have become part of normal operations in cement plants and results in high energy consumption. Comprehensive approach is necessary to reduce the energy consumption.

2. NCB'S INITIATIVES FOR ENERGY CONSERVATION AND COST REDUCTION

Keeping in mind the various problems of the cement industry, NCB has taken some initiative to reduce the energy consumption levels (Figure 1). These include both short-term and long-term measures and some of these are discussed below.

2.1 Energy

Energy audit has emerged as an important tool for identification, analysis, implementation of energy conservation measures and energy management. The importance of energy audit studies was realized in early 80's when NCB in collaboration with Bureau of Industrial Costs and Prices (BICP) made a survey of 46 cement plants in the country identifying the status of energy consumption levels, potential areas for energy saving and recommendations for short, medium and long-term measures. Subsequently the Advisory Board on Energy (ABE) commissioned NCB to carry out detailed energy audit of six representative cement plants. NCB has since then completed 22 more energy audit studies in cement plants under its own R&D programme as well as studies sponsored by the industry.

Energy audit studies has shown that 'prevention of false air infiltration' (Figure 2) has the maximum impact on the energy savings by operational control in plants. This factor alone has been identified to have about 64 per cent of the total potential thermal and about 35 per cent of the total potential electrical energy cost savings in the plants studied. Process optimization, reducing the preheater exit gas temperature and waste heat utilization are other important areas of thermal energy savings (Figure 3). Reducing the free running of machines and underloading of motors has emerged as one of the most important factors in saving the electrical energy cost. Other factors of saving electrical energy costs as found out from NCB studies are power factor improvement and retrofitting of energy efficient systems.

2.2 Mobile Energy Diagnostic Unit (MEDU)

NCB has taken initiative in modernizing the techniques for energy audit to serve the needs of the industry. NCB's MEDU, a unique facility not only in the cement industry but in the country, is equipped with latest and sophisticated facilities for faster and accurate energy audit studies with various hardware and software capabilities. The MEDU carries out energy data analysis at site including preparation of action plans, calculation of specific energy consumption in each section, target setting and monitoring, calculation of power factor and load factor of the plant, identification of locations of leakages of compressed air and the heat balance of kiln circuit (figure 4).

The instrument facilities in the MEDU measure parameters such as temperature; radiated heat from surfaces; O2, CO2 and CO quantity in gases; ambient humidity; gas velocity; leaks in high pressure lines; voltage, current, kW, kVA, power factor and luminous intensity etc. Apart from the above instruments for instantaneous value measurement, continuous monitoring and recording facilities are available with the microprocessor-based equipment. The on-board computer is equipped with necessary system and application software for real-time data logging and quick data analysis at site.

2.3 Incentive Schemes

NCB has been a prime actor in motivating the plants to take right steps in energy conservation. Based on the techno-economic feasibility of the energy efficient schemes through energy audits, some of the cement plants have already availed the benefit of the incentive schemes from the financial institutions for energy audit and have secured loans for installation of energy efficient equipment. These initiatives have brought out encouraging results.

2.4 Monitoring Energy Use

Having realized the need for monitoring energy use, NCB has brought out Guide Norms for Cement Plant Operations which provide norms for energy usage in various sections of the plant, besides the operational norms. The norms have been in use in cement plants extensively for evaluating the performance of a given section and identifying the areas of improvement.

NCB jointly with DCCI is monitoring the energy use data and has already analyzed the data of 80 cement plants for the year 1988-89. The analysis made by NCB has brought out the specific energy consumption levels of the industry, process and at the regional level; status of energy consumption levels in each section for dry and wet process plants; comparison of these levels with NCB operational guide norms; effect of coal quality on the specific energy consumption in the plant and energy cost trends, process and at the regional level.

Based on the analysis, NCB has also identified plants pertaining to different processes for detailed energy audit studies where either thermal or electrical energy consumption or both have been found to be on the higher side.

2.5 Energy Information System

NCB studies of various cement plants reveal that systematic recording of the data does not exist and there is a need for developing comprehensive data-base keeping in view the ultimate objectives. The data-base thus created would be helpful for individual units as well as for inter-firm comparison and identifying the real problem areas. Keeping the above in view NCB is currently engaged in developing an appropriate computerized energy information system for the Indian Cement Industry. Such an information system shall greatly help in identifying thrust areas, making right decisions at various levels and formulation of policy guidelines.


Figure 1. NCB's initiatives for energy conservation and cost reduction


Figure 2. False air infiltration in kiln section


Figure 3. Impact of areas of energy saving in the potentials of energy savings


Figure 4. Salient features of a mobile energy diagnostic unit

2.6 Power System Management

NCB has developed a comprehensive system for management of power in the cement plants (Figure 5) which includes a software for improvement of load factor through optimized load scheduling thus maximizing the use of available grid power from the electricity board and captive power installed in the plant. Various inputs to the software include grid and captive power availability, power tariff, quality of power, KW load on each equipment in the plant and other operational aspects. The output from the software includes running schedule of each machine at any hour during the day. The software assists in improvement in load factor, reduction in monthly maximum demand, improvement in overall energy efficiency and better production planning.

2.7 Motivation for Competitive Improvement in Energy Performance

NCB realized the need for creating awareness and motivation in cement industry for competitive improvement in energy performance and instituted National Award for Energy Efficiency in Indian Cement Industry in 1986-87 to be given away annually in recognition to the efforts for improving energy performance. The energy award has generated lots of interest and created motivation for energy conservation which is reflected from the analysis of data of the 20 plants which participated for energy award in all the three years from 1987-88 to 1989-90. It is seen that in case of dry process plants in the year 1989-90 as compared to 1987-88, the reduction in specific thermal energy consumption has been 2.4 per cent and in specific electrical energy consumption 7.5 per cent while in case of wet process plants the specific thermal energy consumption has decreased by 3.1 per cent with marginal reduction in specific electrical energy consumption (Figure 6). It is noted that the improvements in the performance of these plants have come as a result of operational control and optimization efforts, retro-fitting of energy efficient equipment, fixation of targets, upgradation of process control instrumentation and manpower training.


Figure 5. Module for power system management

NCB INITIATIVES - IMPACT AND ACHIEVEMENTS

The various steps taken in energy conservation such as energy auditing, monitoring the use of energy, creating an information base through energy information system, a systematic power system management and motivation through National Award for Energy Efficiency in Cement Industry have created a healthy structure for energy conservation efforts in the Indian Cement Industry.

The findings from the studies have been revealing and indicating substantial savings of money through both thermal as well as electrical energy savings. The potential annual savings in the various plants studied ranged from Rs 1 million to Rs 19.2 million in dry process plants and Rs 3.3 million to Rs 6.3 million in wet process plants (table 1).


Figure 6. Reduction in energy consumption


Figure 7. Energy and cost of savings by NCB energy audit studies in a 800,000 ton per year capacity plant

In a specific case of a large capacity of dry process cement plant (800,000 tonne/year), suggestions made by NCB were implemented by the plant which resulted in saving 8.5 kWh/t of cement of electrical energy and 27 Kca/kg clinker of thermal energy during the year 1989-90. The total saving of energy cost amounted to Rs 8.6 million that year (figure 7). These results were achieved through implementation of various suggestions made by NCB in different areas such as:

(i) NCB studies indicated false air infiltration in raw mill circuit up to 22 per cent. Plugging of leakages, maintaining optimum feed size, frequent regradation of grinding media, installation of slip power recovery system for raw mill vent fan resulted in overall reduction of about 2 kWh/t clinker.

(ii) Heat and mass balance of kiln circuit indicated 20 per cent false air in preheater string and 15 per cent false air in PC string. Plugging these leakages to the maximum extent and bringing down PC string exit gas temperature through making changes in raw meal and reducing coal firing in PC string resulted in a reduction of heat consumption by 2.6 per cent.

Plugging of leakages and installation of slip power recovery system for PH fan resulted in a saving of 2.5 kWh/t of clinker.

(iii) A significant reduction of electrical energy was achieved in cement mill and packing section by proper selection and frequent regradation of grinding media, prevention of leakages in compressed air lines. These efforts achieved a saving of 4 kWh/t of cement in this section.

(iv) Improvement of power factor resulted in reduction of electrical losses and maximum demand from 18560 KVA in 1988-89 to 16240 KVA in 1989-90.

CONCLUSION

In view of the complex situation, the Indian Cement Industry is confronted with various shortages and poor quality inputs, it is important to increase awareness for energy conservation. The right steps towards this direction would be effective monitoring, better operational control and introspection of energy saving opportunities through energy audit. This would enable the plant management to prioritize the various opportunities. The experience has shown that substantial cost savings can be achieved if the energy conservation efforts are rightly implemented.

ACKNOWLEDGEMENT

The authors have freely drawn upon completed R & D work/status reports of NCB and some of the unpublished work in NCB. This paper is being published with the permission of Director General, NCB.

Table 1. Expected cost savings due to identified potentials for energy saving



Potential Saving in Energy

Process

Plant Capacity (tpd)

Thermal (Kcal/kg cl.)

Electrical (kWh/t cement)

Potential Annual Savings (Rs. million)

Dry

4800

35.3

4.9

11.3

Dry

3000

5.8*

3.1*

3.894

Dry

2500

62

1.8

11.3

Dry

1800**

62.4

2.3

6.658

Dry

1500**

63.8

7.0

6.94

Dry

1800

211

18

19.25

Dry

1200

126.9

6.3

4.588

Dry

600

113

12

4.26

Dry

600

152

9.0

7.79

Dry

300

97.9

14.8

3.802

Dry

300**

71

0.5

1.078

Wet

1800

38

0.8

3.303

Wet

1200

149.5

1.9

6.27

* kWh/t Clinker
** Energy audit studies by Mobile Energy Diagnostic Unit (MEDU)

Energy efficient method of portland slag cement grinding**

**N. P. Verma, Holtec Engineers Private Limited, New Delhi, India. This paper was presented to the third National Council for Cement and Building Materials (NCB) International Seminar on Cement and Building Materials, held in January 1991 in New Delhi, India

SYNOPSIS

New developments in grinding technology offer possibilities of energy optimization in cement grinding, particularly in case of portland-slag cement-production, by proper system design.

Traditionally in most of the plants, portland-slag cement has been manufactured by the so called "combined grinding process" in which granulated slag and clinker are ground together. However, keeping in view the high quality standard requirements of the consumers and greater emphasis on optimal energy utilization, a system design for the so called "separate grinding process" was developed utilizing high pressure grinding rolls with high efficiency separator for finish grinding of slag and a combination of high pressure for grinding of clinker and mixing of these two powdery material in a continuous mixer to produce desired product quality.

1.0 INTRODUCTION

Recent innovations in grinding technology, particularly, with regard to development of High Pressure Grinding Rolls (HPGR) in close circuit with High Efficiency Separator (HES) offer potential for electrical energy saving in cement grinding. Tests conducted in some of the industrial installations have shown 20 to 50 per cent saving in electrical energy in case of cement grinding using HPGR in close circuit with HES compared to that in a close circuit ball mill system. At the same time, industrial experience has shown that the modern energy efficient method using HPGR and HES influence the characteristics of cement in terms of particle size distribution and water demand of cement which affect the properties of mortar and concrete. Cement properties are also influenced by grinding conditions e.g. materials temperature, specific surface and grain size distribution of the ground material.

These conditions become more complex while designing a system for grinding composite cement e.g. portland slag cement (PSC) where the grinding characteristics e.g. grindability, fragmentation characteristic etc. of the 3 components - clinker, gypsum and slag differ significantly from each other. Further, the product quality assurance has to be ensured also to meet the demands of the consumer and be in conformity with the standards and specifications.

In view of the energy saving potential, application of HPGR and HES for grinding of PSC was made while preparing the system design of a new 280 tonnes/hour PSC production unit under installation.

2.0 LABORATORY-SCALE INVESTIGATION

Laboratory-scale investigations were carried out to study the influence of proportion of slag in PSC, grindability and influence of specific surface on the overall power requirement and influence of specific surface of clinker and slag on the properties of PSC.

Based on the technological considerations as indicated by the test results, it was decided to grind clinker and slag to specific surfaces 4200 sq. cm/g (Blaine) and 3400 sq. cm/g (Blaine) respectively.

3.0 SELECTION OF GRINDING SYSTEM

Traditionally, production of PSC has been carried out in India by the so called "combined grinding process" in which clinker, granulated blast furnace slag and gypsum are ground together in a close circuit ball mill. Due to difference in grinding characteristics of clinker and slag, this process poses the following problems:

· Optimization of mill grinding media charge is difficult;

· Optimization of grinding fineness of clinker and slag is difficult and often in order to achieve desired particle size of slag, clinker is overground causing sub-optimal utilization of energy.

On the other hand, the so called "separate grinding process" in which clinker mixed with gypsum and slag are ground separately and then mixed together in a pre-determined proportion in a mechanical mixer offers the following advantages:

· Better control of fineness of individual components of PSC;
· Optimum energy utilization for clinker and slag grinding;
· Optimum utilization of slag.

Therefore, in view of the potential of energy saving and flexibility in quality control, a separate grinding process was adopted for clinker - gypsum mixture and slag grinding installations of 140 tonnes per hour capacity each for a cement plant under construction.

4.0 SYSTEM DESCRIPTION

Flow diagrams shown in Figures 1, 2 and 3 depict the basic principle of grinding clinker and slag and mixing ground materials respectively.

4.1 Clinker grinding

Two identical HPGRs are used to pre-grind clinker and gypsum mixture in requisite percentage. The slab produced from HPGR is conveyed to HES equipped with de-agglomerator. Fine product having specific surface around 2500 sq. cm/g (Blaine) is conveyed to an open circuit ball mill for finish grinding to specific surface 4200 sq. cm/g (Blaine); the coarse fraction being fed back to the HPGR. Finish ground clinker is conveyed to silo.

4.2 Slag grinding

Two identical HPGRs are used for finish grinding of slag. HPGRs are operated in close circuit with individual HES. Slab discharged from HPGR is conveyed to HES. Though a de-agglomerator is not provided in the HES at this stage, provision in layout has been kept so that it may be installed in future, if required. Finish ground slag having 3400 sq.cm/g (Blaine) is conveyed to another silo.

4.3 PSC production

A continuous paddle mixer is used to homogeneously mix ground clinker and gypsum mixture and ground slag in predetermined proportion to produce PSC. The homogenizing efficiency in terms of variation of slag/gypsum content in PSC has been guaranteed as ± 2 per cent at a confidence level of 95 per cent in spot samples drawn at mixer outlet.

5.0 ELECTRICAL POWER REQUIREMENT

Based on the above system and for the available clinker and slag, equipment to be supplied have the specific power consumption guarantees as given in Table 1.

Table 1. Specific energy consumption

Material

Equipment

Specific power consumption, KWH/t of ground material

Clinker & Gypsum

HPGR, HES, Ball Mill and Auxiliaries

54.2


HPGR alone

7.1


Ball Mill alone

38.1

Slag

HPGR, HES and Auxiliaries

30.3


HPGR alone

22.2

It is thus seen that power consumption in the system adopted above would be of the order of 43 - 44 kWh/t PSC.

For the conventional combined grinding system, however, based on the laboratory tests, the specific power requirement at ball mill shaft for grinding clinker mixed with slag was estimated at 55-60 kWh/t of material ground to 3500 to 4000 sq. cm/g (Blaine).

Therefore, energy saving to the extent of 12 to 16 kWh/t of PSC is foreseen by adopting the proposed grinding system.

6.0 INVESTMENT

In the above example, a study of relative investment costs of different systems revealed the following:

· Conventional combined grinding 100 per cent
· Using HPGR in Hybrid mode (i.e. HPGR as a pre-crusher grinder) 109 per cent

Using HPGR in finish/semi-finish mode 90 per cent.


Figure


Figure


Figure

Plant audit and energy management***

***By S. K. Gupta, H. K. Dutt, Holtec Engineers Private Limited, New Delhi, India. This paper was presented to the third National Council for Cement and Building Materials (NCB) International Seminar on Cement and Building Materials, held in January 1991 in New Delhi, India.

SYNOPSIS

India is still lagging behind considerably on energy front compared to the world standards. This gap can be narrowed down provided management sincerely initiates energy projects in their plants. It is suggested that an exclusive 'ENERGY MANAGEMENT CELL' (EMC) should be guided by an outside expert agency. This Exclusive Cell (EMC) should be manned by very dedicated, highly motivated and enterprising engineers/staff. The EMC has to work in a well coordinated manner with the production and maintenance group of running plants, to minimize the production losses.

Based on findings of Energy Audit, project should be structured, evaluated and implemented in a well planned and coordinated manner by EMC. The Energy Audit should be repeated periodically for improvements.

This paper emphasises the need of formation of EMC in each and every plant and elaborates its functions and the working style. Benefits from Energy Projects are bound to outweigh the input cost/efforts if the projects are attempted earnestly by EMC, suitably backed-up by Company's management.

1.0 INTRODUCTION

1.1 In recent years, a great deal of emphasis is being laid on analysis of energy consumption, because of the obvious reasons - constant rising energy costs and its share in total production costs (up to 40 to 50 per cent in cement plants). Though considerable progress has been made in developed countries, we, however, in our country are yet to achieve the desired results.

1.2 It will be seen from the following comparison of energy consumption in cement industry that we are still lagging behind considerably:

Comparison/t of cement

World

India

(Dry and Wet Process Combined)

Electrical (Kwh)

110

150

Thermal (G.Cal)

0.77

0.98

Coal consumption (t)

0.17

0.21

(4600 K. cal/kg)



Thus, there is tremendous scope and imperative need for improvement on energy front.

1.3 For energy conservation what is really lacking is -sincerity and application on the part of management. If an exclusive cell is formed for monitoring the energy consumption and implementing the desired modifications with active participation from management, benefits are bound to accrue.

1.4 In this paper, an attempt has been made to elaborate the constitution of this Energy Management Cell, termed as EMC, its role and responsibilities and its working style.

2.0 CONSTITUTION OF ENERGY MANAGEMENT CELL

2.1 EMC should be headed by "ENERGY MANAGER" (EM), a whole time incharge, reporting to management.

It should be borne in mind that energy management is 80 per cent attitude and only 20 per cent technology and also that energy management is in competition with numerous other plant objectives/problems. Therefore, EM has to be a highly dedicated person and with full back-up from Company's top management.

2.2 The EM shall be guided by 'ENERGY ADVISOR' (EA) which shall be an outside expert agency, experienced and qualified in energy management. EA shall take-up plant audit from time to time so that the process/equipment are upgraded, keeping pace with the latest technology/developments.

2.3 The EM shall be assisted by a few enterprising engineers and other staff for working as an independent cell and as a separate profit centre.

The EMC has to work in such a way that production/routine maintenance is least hampered. Simultaneously, results are also obtained, by working in close coordination with production/maintenance staff.

2.4 A typical organizational structure is shown in figure 1.

3.0 ROLE & RESPONSIBILITY OF ENERGY MANAGEMENT CELL

3.1 Broadly, the following activities can be identified in perview of EMC:

- Increasing the efficiency of existing installation.
- Investment in new installations with better efficiency.
- Change over to energy saving technologies/equipment.
- Operation of equipment in an energy saving manner.
- Avoidance of unplanned shut-down costs.
- Optimal sizing of installations.
- Reduction in energy costs by personnel motivation.
- Regulating the running hours of equipment/auxiliaries.

3.2 Tasks of EM could be defined as follows:

- Elaboration of goals of energy management and making them known by giving reasons/justifying them for implementation.

- Appointment of EA in consultation with Company's management and defining his responsibilities.

- Demonstration of latest techniques/developments in the field of energy management at regular intervals.

- Receiving reports from EA, analysis of the same and finalize recommendations.

- Establishment of means of financing of project.

- Removal of all hindrances and difficulties in implementation of energy conservation project.

- Publishing working programme(s) for personnel motivation.

3.3 Tasks of EA could be summarized as follows:

- Check, improve, extend and streamline measuring schemes and activities.

- Develope of a clear, well-defined reporting system and its updating from time to time.

- Energy audit of the complete plant including data collection, evaluation and recommendation on energy conservation programme.

- Elaboration of data and development of project.

- Assist in realization of the energy projects.

- Prescription to operators for correct handling of plant and equipment.

- Evaluation of results of energy conservation measures and to publish them.

3.4 Responsibilities of other members of EMC are:

- To assist/advice/coordinate with EA under supervision of EM.
- To discuss/propagate achievement(s) to their counterparts.
- Motivate plant staff on continuous basis.

4.0 PRE-REQUISITES FOR ENERGY MANAGEMENT

The following list may be considered as the pre-requisites for energy management programmes:

- Flow sheet of production facilities.
- Equipment list.
- Material and gas flows and balance (for normal and maximum throughput).
- Energy flows and balances (for normal and maximum throughput).
- Production log-sheets.
- Laboratory testing results.
- Machine history - damage/shutdown/repair statistics.
- Operation manuals of all equipment.
- Trend curves for heat and electrical power consumption and other statistical data on daily, weekly, monthly and yearly basis.
- Schematic diagram of compressed air and water supply/distribution network and actual operating data.
- Power distribution diagram.
- Energy bills.
- Cost of production statements.
- Latest and well-maintained measuring equipment.
- Highly motivated management and manpower for implementation of energy conservation projects.

5.0 PERSONNEL MOTIVATION

5.1 Psychological aspects of the human being is the reason for most of the troubles, inspite of the fact that he usually blames others. The reason is usually found to be lack of rational attitude of the man towards energy. The following could be attributed for this kind of approach of personnel:

- Lack of technical competence.
- Indecisiveness of energy management.
- Under-estimation of potential advantages.
- Negative attitude towards newer technologies i.e. change.
- Lack of reliable measuring and comparison possibilities.
- Lack of exchange of thoughts and experiences.
- Negative attitude towards consulting.
- Waiting for still better technologies.
- Lack of will for cooperation and acceptance for additional/non-routine work.
- Lack of interest for training.
- Existing overload of work.
- Earlier experience of poor take-off of an energy conservation programme.
- Start of programme with uncertain basis, unclear goals and uncertainty of financial commitment.


Figure 1. A typical organizational structure of EMC

5.2 It is necessary to locate interested, active and qualified personnel for energy management schemes. First of all they should be properly oriented with company's attitudes and goals of energy programmes and then, trained to eliminate ignorance/wrong ideas. A premium or bonus system should be declared which should be commensurate with achieved results. Suggestions and ideas should be invited through suggestion boxes/conferences. This would make the personnel interested and motivated towards energy projects.

6.0 EVALUATION OF PROJECT AND IMPLEMENTATION

6.1 Evaluation of project

Based on the Energy Audit, areas have to be identified for improvements. These shall be analyzed/studied further and shall be categorized as projects. These projects have to be evaluated keeping in view the following:

- Effects on up and down stream part of the process.
- Shut-down costs (stripping, reconstruction, erection etc.).
- Operational reliability.
- Maintenance expenses.
- Evaluation based on rate of return and pay-back period.

Based on the returns and pay-back period, priorities of the projects are assigned.

A typical development of Energy Conservation Project and its evaluation is presented in figure 2.

6.2 Implementation

Once the decision is taken in principle, the project should be expanded to the minute detail and scheduled so that production loss/down time is the least. This is very important since any improvement project directly hits plant operation.

Once the project is in progress, it should be continuously monitored so as to maintain the schedule.

When plant is restarted after implementation of the project, operation is monitored very closely and the results are compared with the initial predictions.

7.0 CONCLUSIONS

- India is still lagging considerably on energy front compared to world standards.

- This gap can be narrowed provided management sincerely initiates energy projects and forms an exclusive EMC which shall work as an independent profit centre.

- EMC should be guided by an expert outside agency (ENERGY ADVISOR).

- This Exclusive Cell should be incumbered by very dedicated, highly motivated and enterprising engineers/staff.

- EMC has to work in a well coordinated manner with the production and maintenance group of running plants.

- Based on findings of energy audit, project(s) should be structured, evaluated and implemented in well planned and coordinated manner.

- Energy Audit should be repeated periodically for improvements.

It can be concluded that if attempted earnestly, benefits of energy projects are bound to outweigh input costs/efforts. It has to be borne in mind that energy projects can never be attempted departmentally with successful results because of conflicting interests/priorities. It has to be done by an exclusive cell assisted by an external specialist agency (ENERGY ADVISOR).


Figure 2. A typical energy conservation project

Events

Meeting of the African Ministers in charge of housing and urban development for the preparation of the second United Nations Conference on Human Settlements (habitat II - City Summit). Dakar, Senegal, 3 October 1994.

The African Ministers in charge of housing and urban development met in Dakar, Senegal, on 3 October 1994 and on the occassion of World Habitat Day adopted the DAKAR DECLARATION. The full text of the Declaration is reproduced here-under.

We, African Ministers in charge of housing and urban development, meeting in Dakar, Senegal, on 3. October 1994 for the celebration of World Habitat Day;

· Taking into account the declaration by African Ministers adopted in Nairobi on 30 March 1994 on the second United Nations Conference on Human Settlements (Habitat II - the City Summit) which will take place in Istanbul in June 1996,

· Taking also into account the decisions of the Preparatory Committee of Habitat II, at its first substantive session held in Geneva from 11 to 22 April 1994,

· Stressing the key role of housing in the development of families, as symbolized by the theme of the present World Habitat Day: "Home and the family",

· Having reviewed settlements conditions in Africa, in particular:

- The rapid growth of urban population and the need to manage this urban growth better;

- The deterioration of the living environment and the need to provide appropriate infrastructure for water supply, solid-waste management, sanitation and public transport;

- The lack of adequate and affordable shelter and the need to be resolute in adopting facilitating policies involving all stake-holders from the public and private, formal and informal, governmental and non-governmental sectors;

- The growth of urban poverty and the need to generate more productive employment as well as basic services in low-income areas;

- The impacts of political and social crises and natural disasters on human settlements and the need to launch actions for disaster mitigation, reconstruction and development for the benefit of affected communities;

· Conscious of the leading role of cities in economic, political, social and cultural development and aware of the complementary relationship which can and must be established between cities and rural areas,

We re-emphasize that human settlements should constitute a priority sector for African Governments.

In that perspective, we solemnly commit ourselves to:

1. Adopt and implement enabling, participatory and innovative housing and urban development policies so as to reach the objectives of Habitat II, namely:

(i) Adequate shelter for all;
(ii) Sustainable human settlements development in an urbanizing world.

2. Define and implement programmes aimed at preserving the living environment, upgrading infrastructure and basic services, as well as reducing urban poverty;

3. Collaborate closely with municipalities and encourage decentralization processes with a view to improving technical and financial management of cities and their efficiency in promoting economic and social development;

4. Support non-governmental and community-based organizations in their initiatives geared towards improving low-income settlements and alleviating urban poverty;

5. Review, whenever needed, the legal and regulatory framework for human settlements development with a view to promoting the activities of the public and private sectors and taking appropriate measures towards the urban informal sector,

6. Promote mutually supportive linkages between urban and rural development, particularly through adequate investments in secondary cities and communication infrastructure;

7. Strengthen the role of women and youth in human settlements development by ensuring their access to education, resources and decision-making processes;

8. Formulate mitigation strategies for natural and human-made disasters and promote harmonious and equitable relations among social groups so as to reduce the impact of such disasters;

9. Participate actively in the preparations for Habitat II by creating National Bodies involving all public and private actors in human settlements;

10. Favour the establishment by these National Bodies of National Plans of Action including:

- An assessment of shelter and urbanization trends and issues, based on UNCHS (Habitat) housing and urban indicators;

- A review of the effectiveness of existing policies;

- A five-year first-step action programme for the period 1996 to 2000.

11. Call on multilateral and bilateral organizations to support the Habitat II conference and its preparation in African countries.

We thank UNCHS (Habitat) for having held for the first time, and actively supported, the global celebration of World Habitat Day on the African continent;

We congratulate the President of the Republic of Senegal, the Government and the Senegalese people for their welcome within the traditional Senegalese Teranga.

Meeting of the Ministers in charge of human settlements in Eastern and Southern Africa sub region, preparatory process to the second United Nations Conference on Human Settlements (Habitat II), Kampala, Uganda, 26-28 February 1995.

The Ministers in charge of human settlements of Eastern and Southern Africa met in Kampala and adopted, on 28 February 1995, the Kampala Declaration which is reproduced here-under:

We, the Ministers in charge of human settlements in the countries of Eastern and Southern Africa, assembled in Kampala, Uganda from 26 - 28 February 1995 to review the in-country preparatory processes for the second United Nations Conference on Human Settlements (Habitat 11).

Recalling United Nations General Assembly Resolution 47/180 of 22nd December 1992, convening the United Nations Conference on Human Settlements (Habitat 11) with a view to among other things, arresting in the long-term, the deterioration of global human settlements conditions and ultimately creating the conditions for achieving improvements in the living environment of all people on a sustainable basis, with special attention to the needs and contributions of women and vulnerable groups.

Recognizing and appreciating the policies and programmes aimed at improving human settlements conditions world-wide including those of the International Year of Shelter for the Homeless (IYSH) 1982-1987; the Global Strategy for Shelter to the year 2000 and the programme of the United Nations Conference on Environment and Development, Agenda 21, particularly its Chapter 7 on Human Settlements.

Recalling also the decisions of the special meeting of Ministers in charge of human settlements in the Africa Region on the preparatory process of the Habitat 11 Conference held in Nairobi in March 1994 which reiterated resolution CM/Res 1469 of the OAU Council of Ministers and inter alia, urged proper consultation and coordination at all levels to enhance the preparatory process.

Cognisant of the decisions of the first preparatory session of the United Nations Conference on Human Settlements (Habitat II) in Geneva in April 1994 to encourage broad participation in the preparatory process and in the formulation of national plans of action.

Further recognizing the Dakar Declaration by African Ministers in charge of housing and urban development at their meeting in Dakar, Senegal, 3 October 1994 on the occasion of the first global celebration of World Habitat Day in the Africa continent, calling upon all African countries to participate actively in the preparatory processes of the Habitat II Conference.

Conscious of the importance of cities as centres for economic, social, political and cultural activities and the complementary relationship between cities and rural areas.

Taking into account the "guidelines for National Preparations" prepared by the Secretariat of the Habitat 11 Conference.

Noting the progress made by some countries, and the difficulties faced by others in preparing their national plans of action towards Habitat II.

Taking into account the human settlements conditions in the Africa Region in general and in the Eastern and Southern Africa subregion in particular, namely:

(a) the high population growth rates in African countries, rapid urbanization, the increasing deficiency of services and lack of employment opportunities in the rural areas;

(b) the growing inadequacy of shelter in the urban centres, the deterioration of the living environment and the pressing need to provide appropriate services and infrastructure;

(c) the vicious cycle of urban poverty and the urgent need to generate gainful employment, so as to enable all sections of society to improve their living conditions, in view of the important link between poverty and the urban environment;

(d) the impact on human settlement conditions of political/social crises and the armed conflicts in the subregion, as well as natural disasters, resulting in massive loss of human lives, destruction of housing and living environment, displacement of populations within national boundaries and massive movement of refugees;

(e) the need to fully involve local governments and communities in the decision-making for the planning, development and management of all aspects of human settlements;

Concerned that there are still approximately one billion people many of whom are in Africa, who are homeless or lack adequate shelter.

We, the Ministers in charge of human settlements in the Eastern and Southern Africa Subregion;

1. Re-affirm the decisions and declaration by African Ministers in charge of human settlements on the preparatory process to the second United Nations Conference on Human Settlements (Habitat 11) adopted in Nairobi, Kenya on 30th March 1994.

2. Endorse the decisions contained in the DAKAR DECLARATION on the Habitat II Conference adopted by African Ministers in charge of housing and urban development, in Dakar, Senegal 3 October 1994 on the occasion of the celebration of World Habitat Day.

3. Commit ourselves to design, adopt and implement enabling, participatory and innovative human settlements development strategies towards realizing (he twin objectives of Habitat 11 viz:

(i) Adequate shelter for all;
(ii) Sustainable human settlements development in an urbanizing world.

4. Recognize that adequate shelter is a basic prerequisite for the full development of the human being and that the basic unit for human and material development, the family, can only flourish in a healthy, secure, just and sustainable environment.

5. Recognize also that housing is a powerful stimulus of economic development and an integral part of human resources development and not simply a product of economic development.

6. Emphasize that while accepting that human settlement issues must be perceived in terms of sustainable development world-wide, special emphasis should be placed on an African perspective that focuses on key priority areas of critical relevance to the subregion's developmental needs namely: urban poverty; the deteriorating urban environment; energy in rural and urban areas; and the rural-urban balance.

7. Re-affirm the enabling role of central governments in establishing positive relationships with local governments and translating such measures into effective decentralization of responsibilities and resources.

8. Underscore the critical need for central governments to create an enabling environment and promote strategies, especially through legislative reform and institution-building in the land and housing finance sector, so as to expand the participation of the private sector, the CBOs and NGOs in the development of human settlements, particularly in the provision of affordable shelter, and necessary infrastructure facilities.

9. Stress that human settlement policies in Africa should simultaneously address (he needs of both urban and rural areas; in particular, appropriate linkages should be created with rural areas so as to enhance their attractiveness by providing infrastructure, employment and services in the rural areas to enable them retain their populations and minimize the current trend of rapid out-migration to urban centres where existing services are already strained.

10. Emphasize the urgency in addressing the root causes of poverty and developing poverty alleviation measures especially for female-headed households and other disadvantaged sections of the population both in the urban and rural areas so as to minimize, inter alia, the negative impact of structural adjustment measures in these areas: such measures should form an integral part of the emerging global consensus for achieving political and economic stability, good governance, popular participation, taking into account gender balance, investing in people, concern for the environment and vigorous private sector.

11. Commit ourselves to strengthen good governance, and sound administrative and revenue collection capacity in both central and local government systems, especially in urban centres, with a view to create an atmosphere of popular participation, transparency and greater financial accountability in municipal affairs which will in turn allow these local governments to provide increasing and better services for their constituent populations.

12. Resolve to redouble our collective efforts in finding a more permanent solution to the causes of the persistent massive refugee problem in the subregion including conflict -induced refugee and environmentally-displaced persons by evolving more stable political solutions in their respective countries.

13. Commit ourselves to cooperating and sharing innovative experiences including appropriate technologies, and institutions for the mobilization of financial and other resources for human settlement development and management.

14. Undertake to give priority consideration to (he issue of land-tenure reform, to ensure equitable access to land by all segments of the population especially the poor and the disadvantaged, drawing inspiration from significant reforms and good practices in countries of the subregion, particularly in the development of human settlements finance systems and in the improvement of informal settlements.

15. Call for the urgent designing and implementation of innovative and appropriate financial mechanisms as well as strengthening (he existing ones for the mobilization of both short-term and long-term finance for shelter development, including pension funds, insurance funds and municipal bonds. Such mechanisms should enhance accessibility to housing finance by low-income sections of the population, taking into consideration the many existing informal economies in the urban and rural areas.

16. Emphasize the urgent need to develop and promote the use of a wide range of local building materials, as well as to review building and land development codes and regulations with a view to create an enabling environment and thus increasing the affordability of housing to a larger proportion of people than would otherwise be the case, recognizing that devising schemes (ha(increase the stock of affordable houses is a prerequisite to achieving the goal of shelter for all.

17. Commit ourselves to continue to give priority to policies which encourage and support popular participation in this process, using the combined capacity of central and local governments, the private sector, community-based organizations, youth organizations, women associations, and non-governmental organizations and acknowledge the fact that internal mobilization and initiative through empowerment of the people must provide the principal driving force in the realization of declared human settlements objectives.

18. Further commit and dedicate our countries to the preparatory process for Habitat II, by developing national participatory processes through national committees, involving public, private, non-governmental and community-based organizations as well as women groups and the youth, preparation of National reports and formulation of National Plans of Action for Habitat 11, as well as to using relevant and acceptable indicators to measure progress in these and other areas of human settlements development and management in the post Habitat 11 period.

19. Resolve to give full practical recognition to and further strengthen the role of women in human settlements development and management by ensuring their unencumbered access to credit and ownership of land as well as by ensuring adequate gender balance in all aspects and levels of policy and programme decision-making.

20. Further Resolve to more actively explore and utilize the framework and resources of such sub-regional institutions as the Preferential Trade Area (PTA) of Eastern and Southern Africa, Southern African Development Community, the Inter-Governmental Authority on Drought and Development (IGADD), the Eastern and Southern African Management Institute (ESAMI), the PTA Bank, the budding Common Market for Eastern and Southern Africa (COMESA) etc. towards improving the conditions of human settlements and environment in the sub-region.

21. Request the donor community and the international institutions to complement our own initiatives by providing both financial resources and technical assistance resources to enable implementation of human settlements development policies and programmes, as well as to facilitate the preparatory process for Habitat II.

22. Commend the Secretary-General of the Habitat II Conference and Assistant Secretary General of UNCHS (Habitat) and his staff for facilitating and supporting this sub-regional meeting;

23. Express appreciation to the other organizations that have supported the meeting namely: UNDP, Shelter-Afrique, United Slates Agency for International Development (US AID) and the Uganda National Housing and Construction Corporation.

24. Call on African Regional institutions/organizations to give stronger support to the Habitat II Conference preparatory processes in African countries in general and in the countries of the Eastern and Southern Africa sub Region in particular.

25. Request the Heads of State and Heads of Governments to endeavour to attend the Habitat II Summit Conference in Istanbul. Turkey in June 1996 and help make the Conference a resounding success.

26. Express profound gratitude to President Yoweri Kaguta Museveni and the Government of Uganda for hosting the meeting and to Her Excellency, the Vice President Dr. Specioza Wandira Kazibwe for graciously opening the meeting and for the copious hospitality extended to all the participants.

African Regional Ministerial Meeting in preparation for the second United Nations Conference on Human Settlements (Habitat II), Johannesburg, South Africa, 16-18 October 1995.

The meeting was attended by African Ministers which ended on 18 October 1995 on an exhilarating note with President Nelson Mandela congratulating the African Ministers on reaching an African consensus for Habitat II on key issues of interest to the continent.

In a hard-hitting but optimistic speech, the President of the Republic of South Africa said that the specific challenge Africa faces is that of poverty, and that most African people were too poor for a pure market solution to the housing problem. "Our approach to housing in South Africa, as in other parts of Africa, embodies the principle that the government has an important role to play. But it recognizes that government alone cannot solve the problem. We totally endorse the need for an urgent and meaningful partnership of government, the private sector and homeless communities."

President Mandela emphasized the role of women in human settlements development by saying that the success of any housing programme is very much a function of the extent to which women are directly involved. "When we talk about people-centred development," he added, "we should understand that the involvement of women is often the difference between success and failure." President Mandela used the occasion to present a scholarship to David Dladla, a South African pupil from KwaZulu-Natal for the best essay in a competition organized by the South African Department of Housing for World Habitat Day. At the same event, a 1995 Habitat Scroll of Honour was presented posthumously to the late Joe Slovo, first Minister of Housing in the Government of National Unity. The Scroll of Honour is one of eight bestowed by the United Nations Centre for Human Settlements (Habitat) on the occasion of World Habitat Day. Dr. Wally N'Dow, Secretary-General of Habitat II, paid tribute to the late Mr. Slovo for spearheading the search for housing solutions and inspiring commitments by all actors to the development of housing for the disadvantaged majority in South Africa.

At a press conference preceding the closing ceremony, the Secretary-General of Habitat II summed up the African common position for Habitat II - now adopted as the "Johannesburg Declaration" - as one that reflects the rural-urban balance in human settlements. "Despite the appellation 'City Summit' for Habitat II, Africa feels the necessity to light on two fronts: rural and urban. Although Africa is urbanizing rapidly, the majority of its people are still in rural areas. The African Ministers present here want human settlements policies in Africa to simultaneously address the needs of both rural and urban areas and want to stem the flow of rural-urban migration by enhancing the attractiveness of rural areas through the provision of infrastructure, employment and services to rural areas."

The Johannesburg Declaration is the consolidated position of Africa on the Habitat II Conference. It encapsulates the continent's total political commitment to the Habitat II Conference and to UNCHS (Habitat), which was reconfirmed as the focal point for follow-up find monitoring of progress in the post-Istanbul era. The Declaration will ensure that Africa's concerns are fully reflected in Habitat II's Global Plan of Action - the blueprint for sustainable human settlements development in the 21st century that will emerge from the Habitat II Conference in Istanbul, Turkey next June.

The Secretary-General of Habitat II congratulated the African Ministers for comprehensively addressing problems related to housing finance and the need to help the poor members of society to gain access to credit. He noted with appreciation that African Ministers have welcomed the African private sector and recognized that the sector had an important role to play in housing delivery. He reiterated Habitat's recognition of the need for strong partnerships among the various actors, including local authorities, the private sector, non-governmental organizations and community-based organizations in addressing human settlements issues.

The South African Housing Minister Sankie Mthembo-Nkondo, reiterated Africa's concerns about housing finance and urged the international community to help Africa address its housing backlog. Speaking on behalf of the delegates, the Nigerian Minister for Housing, Alhaj Abdullahi Adamu, paid glowing tribute to the Government of South Africa for successfully hosting the meeting.

The full text of the Johannesburg Declaration will be printed in the next issue of the Journal

Publications review

Published by UNCHS (Habitat)

Application of Biomass -Energy Technology


Figure

The availability of energy and the security of its supply are of paramount importance to all human communities. Unfortunately, in most countries - both developed and developing - current energy markets ignore the social and environmental costs and risks associated with fossil-fuel use. If externalities such as employment, import-substitution, energy security and environment are considered, then biomass systems compare very favourably with fossil-fuel systems.

Biomass currently accounts for about 14 per cent of the world's energy supply and is the most important source of energy for three quarters of the world's population living in developing countries. With increases in population and per capita demand, and depletion of fossil-fuel energy resources, the demand for biomass energy is expected to increase rapidly in developing countries. Even in developed countries, biomass is being increasingly used. For example, the United States of America now has 9000 MW of biomass power plants and Sweden, which derives 14 per cent of its energy from biomass has plans to increase it further as it phases down nuclear and fossil-fuel plants into the next century. With technologies available today, biomass can provide modern fuels such as electricity and liquid fuels, in addition to more traditional cooking fuels, and this energy can be produced and used in and environmentally-sustainable manner.

Yet, biomass energy continues to receive the lowest priority in energy planning in developing countries. Many factors contribute to this: the unreliability of production and consumption statistics; the uncertainty of production costs which are quite site-specific; its diverse sources and end-uses; and its interaction with land uses.

Integrating biomass energy in national energy planning and policy-making on an equal footing with other energy sources will not be easy and will require concerted action at national and sub national levels. A reliable information base will have to be developed on the supply and utilization of biomass energy in the country; the policy environment must be made responsive to the need of the biomass-energy sector, research, development and engineering efforts will have to be stepped up in required areas; and the commercialization of biomass technologies will have to be promoted through selective and well-targeted subsidies and fiscal and other forms of incentives.

This publication forms a part of the Centre's continuing efforts to promote wide dissemination and commercialization of renewable energy technologies - an area of expressed concern in Chapter 7 of Agenda 21 on sustainable human settlements development.

158pp., HS/287/93E, ISBN 91-1-131210-8

Booklet on small-scale technologies for construction


Figure

One of the main reasons for inadequate national capacities to respond to the construction requirements of the low-income populations is that there is as yet no comprehensive technological policy to overcome the limitations of the small-scale construction sector. The vast majority of enterprises operating in the small-scale sector, and particularly those in the informal sector, continue to rely on traditional technologies with very little ability or opportunity to upgrade and improve their production process or to diversify into new product lines.

Appropriate and innovative technologies differ from country to country depending on their local conditions, natural resource endowment, available skills and socio-cultural traditions. However, most of these technologies are modifiable and adaptable to different localities if other prerequisites such as information flow, absorption capacity, adequate policy environment, and favourable financial conditions are set to encourage new small enterprises to apply such technologies.

The choice of the right technology in a given context, taking into account the natural resource endowment is crucial. Choice of technology relates to a variety of issues none of which can be taken for granted. A selected technology must follow a number of parameters, the most significant of which, are: adaptation capability to suit the specific local condition; effective marketability; determination to make it succeed; and the efforts to enhance competitiveness by reducing costs of application.

UNCHS (Habitat), in line with its mandate and in an attempt to disseminate technological information in the construction sector, has compiled a number of appropriate technologies (in the form of technology profiles) which are presented in this publication.

The compiled technologies in this publication are intended to be of use by individuals, small construction enterprises, and also decision-makers who wish to acquire and make use of suitable technologies for the construction of low-cost housing in both urban and rural areas.

114 pp., HS/302/93E, ISBN 92-1-131224-8

People, settlements, environment and development


Figure

Sustainable development means improving the quality of life of all. It cannot be achieved in a world where more than 1 billion people live in absolute poverty. It is unacceptable, and even inhuman, to talk about long-term environmental sustainability without considering the short-term problems of mere survival for such a large portion of humanity.

Global urbanization will continue. While almost half of the world's population is already urban, by the first quarter of the next century the majority of the world's inhabitants - over 5 billion people - will live in urban settlements. A growing share of the world's poor will live in rapidly-growing urban agglomerations.

The intolerable and worsening living and working environments of the poor in urban slums and rural areas, with their implications in terms of human suffering, deteriorating health and reduced life expectancy, are a major determinant of poverty. Therefore, the improvement of the living and working environment of the poor is a priority concern.

The industrialized countries bear the main responsibility of leading the way in changing consumption and production patterns through energy efficiency, efficient use of other resources, replacement of non-renewable resources by renewable ones, and minimization of waste production and pollution.

Human settlements, and particularly large urban agglomerations, are major contributors to environmental degradation and resource depletion. At the same time, human settlements, large and small, are also areas of unused opportunities, creativity, economic growth, communication; accessibility for transfer of knowledge; and an efficient and effective attack-on waste and pollution.

The undesirable environmental implications of settlements growth can be addressed and reversed. Human settlements can be managed in an orderly and equitable manner through participatory and resource-conscious planning and management. This enabling approach applies to all urban functions, such as land use, construction, water supply, sanitation, waste disposal, transport and recreation.

Better planning and management of human settlements, including access to and use of environmentally-sound technologies, and reduced demand for mobility and transport can produce significant energy savings and therefore help prevent global warming and climate change.

International cooperation must be intensified to encourage and support national and local efforts in all countries to achieve the dual objective of sustainable development: meeting the development aspirations of people today and safeguarding the right of tomorrow's generations to do the same in healthy and humane environments.

This publication address issues such as:

- Human settlements and sustainable development
- Human settlement management and sustainable development
- Sustainable land-resources management
- Water-supply policies reflecting sustainable-development principles
- Sanitation and wastewater-management policies reflecting sustainable-development principles
- Solid-waste management policies reflecting sustainable-development principles
- Sustainable energy systems for human settlements
- Transport policies reflecting sustainable-development policies
- Construction-sector policies for sustainable human settlements development pp 55,

Supporting the informal sector in low - income settlements


Figure

The United Nations Centre for Human Settlements (Habitat) has. for many years. been emphasizing the importance of low-income housing development in national programmes of economic growth and employment generation. The potential of the housing sector and of the construction industry in general to create large numbers of jobs for unskilled and semi-skilled workers, to build industrial strength on the basis of indigenous inputs of human, natural and financial resources, and to establish the human settlements foundation for the functioning of all sectors of the national economy gives construction investment a first priority in practically all developing countries. With a well-established construction industry, other industrial sectors can be promoted on a self-sustaining basis instead of remaining within the constraints of import-dependent activities.

Spin-off effects from the construction of human settlements will vary from country to country, so that there can be no universal blueprint for linking human settlements development to other employment-generating and income-generating activities. However, it can generally be expected that the bulk of human settlements development will rely on the capacities of the small-scale, low-technology sector (usually referred to as the informal sector). Therefore, it is reasonable to assume that the primary spread-effects of human settlements development will be found in the same sector. By integrating informal-sector support programmes in human settlements and related fields, governments can strengthen human settlements elements, particularly those focused on low-income housing, and at the same time, quickly multiply the impacts of investments in infrastructure and other facilities.

This document suggests some of the principles which apply to the promotion of informal-sector activities in connection with low-income housing programmes. Three case studies are presented to illustrate ways in which employment and housing programmes have been linked in particular instances in India.

44 pp.. HS/142/88E, ISBN 92-1-131070-4

Improving income and housing: employment generation in low-income settlements


Figure

It has been widely recognized that employment, incomes and access to housing and associated services are highly interrelated. The biggest constraint to developing improved housing for the lowest-income groups is their poverty. Their incomes are too meagre or too unstable to permit the commitment of scarce resources to shelter. Poor people first and foremost need to generate income or increase their earning to improve their living conditions in general and their housing in particular.

The majority of the populations of cities in developing countries are employed in or derive income through small-scale enterprises and are housed in self-help settlements. These settlements not only provide a place in which to live, they offer income-generating opportunities and an entry point to the urban economy.

Although poverty is not only a condition of insufficient income hut a function of lack of access to land or security of tenure, to information and to active participation in the decision-making processes affecting the lives of low-income people, the main focus here is on income generation and employment creation.

This publication examines the relationship between income generation and human settlements by focusing on areas where intervention might benefit the development of both improved shelter and income-generating activities. The topic is covered in five main chapters. Chapter I provides a general background to the subject; Chapter II deals with the potential for income generation and employment generation in the construction and building-materials sector: Chapter III examines the possibilities for promoting income-generating activities in human settlements; Chapter IV discusses the opportunities for employment generation in the provision and maintenance of basic-urban services; and Chapter V concentrates on an examination of the institutional-support mechanisms required to implement the proposed strategic responses.

72 pp., HS/189/89/E. ISBN 92-1-131110-0


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UNITED NATIONS CENTRE FOR HUMAN SETTLEMENTS (Habitat)
PO Box 30030 Nairobi, KENYA. Telephone 621234; Fax: (254)-2-624266/624267
e-mail: habitat@unchs.org URL:http://www.undp.org/un/habitat/