that by the year 2000, assuning increasing oit prices, oil is still expected to meet slightly more than one half of the total commercial energy needs. 25. The exploration, development and production of a particular enerqy source depends in the first instance on the relative costs of alternative sources. As the price of oil, the dominant energy souree, increased substantially during the I970s, the other sources became increasingly more attractive. An indication of the relative costs of the alternative sources can be obtained by comparing' for example, the cost of electric pohrer generation using different types of fueL. 2V A cornparison of diesel and steam generators powered by different types of fuel and nuclear generators of different sizes yields the conclusion that, at 1980 prices, other conventional energy sources becane competitive with oi1, nith the exception of diesel and stean generators located inland. 26/ On the other hand, the investnent costs (which include transnission and distribution costs) of oil- and gas-porrered generators were still the Iowest.27.t/ It seems, therefore, that the advantages that the alternative conventional sources had over oil with regard to cost per unit of energy generated hrere outtreighed by their higher investrnent costs. 25. 9{ith the exception of biomass energy and possibly wind sources, the costs of generating power using new and renewable sources seem to be substantially higher than the costs of using conventional sources, W especially following the recent decline in oil prices. Furthermore, the investment costs of these new and renewable sources have been estimated to be substantially hiqher tban those of the conventional sources. Even though tbe figures used bave been considered as rough estimates only, they provide an indication of the comparative costs of the different energy sources. Frorn this picture it seems clear that an increase in
**Analysis**
The text discusses the relative costs of different energy sources, including conventional sources such as oil, gas, and nuclear power, as well as new and renewable sources like biomass and wind power. The text also mentions the investment costs of these sources and how they compare to each other. This suggests that the category related to energy and natural resources is the most fitting.

**Category**
Natural resources and environment, Science and technology