Introduction

India has about 0.5 million villages of different sizes. In majority of the villages electricity is required mainly for lighting, pumping drinking and irrigation water, flour milling and in some cases agro-processing. Village electricity needs are characterised by low loads. The current programmes of Rural Electrification Corporation and State Electricity Board is to connect all villages to the central grid. Infact many states claim to have achieved full coverage of all revenue villages. Still there are thousands of villages and hamlets to be electrified, many in remote locations.

The current approach of connecting villages to the grid is characterized by the following:

(i) the high cost of transmission lines (Rs. 20,000 to Rs. 40,000/km depending on terrain)
(ii) high transmission and distribution losses (22-24%)
(iii) low voltage
(iv) erratic supply, often due to poor maintenance
(v) power shortages due to failure of the monsoon in the case of hydroelectric plants.

The energy supply options in the past have been confined to centralised electricity generation technologies like (a) the hydroelectric plants which have large reservoir to store rain water throughout the year; which is being built in prime forest areas submerging sizable areas of forests and displacement of local tribal community. (b) coal based thermal (c) nuclear and of recent natural-gas-based power plants. Due to two major difficulties viz (a) shortage of capital (b) growing opposition for ecological reasons, there is an increasing interest in decentralized sources of supply, and energy efficiency improvement to ameliorate the chronic shortage of energy.

In this paper two feasible decentralized energy options based on renewable energy sources are considered namely woodgas based village electrification system in Hosahalli and community biogas system for village electrification at Pura, both in Tumkur district of Karnataka State.