4.1 Description of the wood gas power plant
4.2 Operating experience
4.3 Economic evaluation
As a result of the sharp rise in petroleum prices during the 1970's, large areas of Paraguay, located far from the electric supply network, found themselves at a disadvantage. Transport rates increased considerably, adding further to the high cost of electricity generated by small units fuelled with gasoline or diesel.
The sawmill industry is fortunate in having the option of reducing its costs through increased reliance on wood-based energy and in 1978 the managers of the Sapire sawmill, located in southern Paraguay, decided to install a wood waste gasifier for the production of electric energy. It was necessary to identify a gas producer with flexibility of power output and suitable for operation by mill staff and labour already employed.
The specifications for the purchase of the equipment were the following:
1. A very sturdy low-speed engine with simple mechanics.
2. A gasifier that could use sawmill wastes of variable size and moisture content but at the same time be able to produce good quality gas for the engine.
3. Equipment with excess capacity to allow for flexibility in operation and to provide for the expansion of power production capacity in the future.
4. Provision for regulation of fuel consumption.
5. Design of wood gas generator suitable for operation by local workers and repair by rural mechanics, if necessary.
6. The equipment should meet industrial safety regulations and not cause environmental pollution problems.
7. Easily obtained spare parts, preferably from local suppliers.
In this chapter the experiences of the first four years of operation (up to February 1983) of the plant installed at the Sapire sawmill will be summarized.
The experience has been very favourable. After four years of operation the owner of the Sapire sawmill reported a satisfactory financial return, as the savings in petroleum products enabled him to recover the investment (equivalent to US$ 16900) in a year and a half. He has also reported that other sawmills have imitated him. Equipment handling and maintenance has presented no insuperable problems.