Тандем - 2, шлакоблочные станки, бетоносмесители

Производство оборудования и технологии

Economy of a producer gas tractor

The annual difference in cost between a diesel tractor and a wood gas tractor will be evaluated for three economic situations, namely:

European conditions (Sweden)


1b Us$/n

rWood fuel

3.5 US$/GJ

Diesel fuel

8.5 US$/GJ

Intermediate conditions


2 US$/h

Wood fuel

2 US$/GJ

Diesel fuel

8,5 US$/GJ

Favourable conditions for producer gas


0,5 US$/h

|Wood fuel

0,5 US$/GJ

Diesel fuel

16 US$/GJ

The annual utilization will be assumed at 500, 1000 and 2000 hours. This range is believed to cover what is encountered in practice. To simplify the comparison, it will be assumed that the power loss of 20 percent can be accounted for by adding an investment to the producer gas alternative equivalent to the difference in cost for new tractors with that power difference. The cost difference can be estimated to be about US$ 2500 and it will be assumed that it must be depreciated on 10000 operating hours. The comparison is made in Table 3.20 where the indifference costs for wood fuel and diesel fuel are also shown for each case.

It is quite understandable that wood gasifier tractors are not in regular use in Sweden. The operation implies a loss even if the wood fuel is free of charge. It is not until the price of diesel fuel increases by 100 to 200 percent that a wood gas tractor would be economic.

Table 3.20 Economic Comparison between a Wood Gas Tractor and a Diesel Tractor (1984 US$)

Table 3.21 Economic comparison between a wood gas truck and a diesel truck

The situation is quite different if the wages and the cost of fuel wood are lower. For the intermediate case analyzed the producer gas tractor will be economic if the annual operating hours exceed about 700. At the very lowest wages and wood fuel cost, and the high cost for diesel fuel, the producer gas tractor appears very attractive. The payback time for the gasifier system is of the order of 13 to 36 months under the conditions analyzed for this situation. It is an interesting observation that use of expensive systems built in Europe would not entirely eliminate the-economic possibilities for gasifiers in the Third World. The producer gas tractor would still be economic in the case of very low wages and wood costs and with a high price for diesel fuel. In the intermediate case it would still be economic for long annual operating times. It is also true that even a very cheep gasifier system would not be economic in Europe. Even if the gasifier did not cost anything, the additional labour costs exceed the savings on fuel and this eliminates any possibility of economic operation with producer gas, except perhaps in cases where the tax system works in such a way that a person’s own labour effectively costs much less than that of hired hands. 1/

1/ The situation could be applicable under some circumstances in Sweden.

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