Energy Technology Division, Tata Energy Research Institute, Lodhi Road, New Delhi – 110 003,

00-91-11-462 2246, +91-11-462 1770, nanditah@teri.res.in; terine@gw1.dot.net.in

The paper examines the potential of biomass gasification for stand-alone power generation and thermal applications in the state of Arunachal Pradesh in north-eastern India. Two administrative blocks were selected, namely – Yingkiong in Upper Siang district and Hayuliang in Lohit district. Located in remote areas with poor communication links, the villages in Hayuliang block have limited access to grid electricity. Though most of the villages in Yingkiong block are connected to a power grid, fuelwood is used extensively in households and institutional establishments. In view of the abundant availability of woody biomass, gasifiers would be a suitable option for power generation. Biomass gasification for thermal purposes would enhance the efficiency of fuelwood use and decrease the consumers’ drudgery and expenditure on fuelwood. The study highlights the scope of and constraints to wider dissemination of biomass gasification technology and would be useful for planning renewable energy interventions in the state.

The study is based on a decentralized planning approach to identify specific areas where gasifiers could be installed. Secondary data as well as primary data were collected, wherein extensive sampling of the villages was undertaken. For the primary survey, and resource assessment the villages were selected on the basis of the status of electrification and population. The feasibility of installing wood-based gasifiers was assessed in terms of consumer demand for electricity as well as availability of sustainable supply of woody biomass. Power consumers included both domestic and commercial sectors. The domestic sector consumes electricity mostly for lighting, while fuelwood is used cooking and space heating. The commercial sector includes shops, teashops and restaurants. A primary survey was conducted for estimation of average household power consumption and the peak loads for assessing the size of the alternative power generation scenarios.

Upper Siang is expected to become a power surplus district in the next five years with an increase in the installed capacity of hydro power. However, two villages in the Yingkiong block are not electrified. Biomass-gasification-based power generation could be a feasible option for providing these villages with electricity in the present circumstances. The sustainable yield of wood from the block’s forest areas was estimated at 149 361 tonnes/year. The potential generation could be about 25 MW. However, for 1 MW or higher power generation, it was found that there is no single local consumer in the entire block. The biomass available is sufficient to operate 1357 units of 20 kW, or 904 units of 30 kW, or 542 diesel generator sets of 50 kW capacities for 10 hours a day for the whole year.

The current use of biomass for institutional-scale cooking was assessed and the potential of gasifiers for thermal purposes was found to be considerable. This is especially applicable to hotels, bakeries and large kitchens in hostels, hospitals, guesthouses, etc. Such a gasifier for demonstration purposes in the hostels would be useful.

In Hayuliang, only 20 out of the 196 villages are connected to grid electricity. According to the primary survey, the average peak demand in the villages is 3 kW. The availability of woody biomass is expected to be 40 553 tonnes/year from the forests, with which it is possible to generate 32 million kWh power annually. Four gasifiers of 2 MW capacity could be installed, running for 10 hour daily through the year. Alternatively, stand- alone gasifier systems, ranging from 5 kW to 50 kW, may be installed in villages without grid connected electricity. While stand-alone systems were found to be suitable for Hayuliang, their dissemination is subject to limitations. The gasifier technology is relatively new and yet in its nascent stage of development in the north-eastern region. Therefore, it needs to be demonstrated before it can be introduced on a large scale. Adequate training in the operation and maintenance of the gasifier systems is imperative, especially when the units are installed in remote villages. This can be achieved only when there is commitment from the local community to keep the system operational. Further, decentralized power generation units may have to seek permission from government authorities for power generation and public distribution. The formalities involved in seeking permission for power generation may be simplified.

Keywords: Woody biomass, Gasifiers, Power generation, Sustainable yield, Stand-alone systems, Cooking