t9' on the basis of exprorations carried out so far, indications are that severaldeveloping countries - Brazil, China and zaire - have large oil shale deposits andthat other countries, including Jordan, Morocco, Thailand and Turkey, also possesssignificant exploitable oil shale resources. Developing countries known to havetar sands deposits are Ecuador, ttladagascar, Nigeria, and Trinidad and Tobago. Thephysical characteristics of oil shale and tar sands differ, and thus the extractionteehnologies to exploit them differ also, but both rnaterials can be used to produeelocally significant guantities of liguid fuels. oil shale can also be used forgenerating electricity through direct combustion. An example is the generation bythis method of about 3,000 Mt{ in Estonia, Union of Soviet Socialist Republics. Inthe last few years, projects to develop these resources in the developed eountrieshave been faced with escalating production costs and tbe weakening of'conventi"i.fcrude oil prices, and as a result most of then have been abandoned. An exceptionis the commercial exploitation of tar sands currently under wav in Canada. rf,however, the price of conventional oit should increase signifieantly, then reneweclinterest in both sbale oil and tar sands nay result in their gr."t.r'utilization. (e) Geothernal energy 20. Technically exploitable geothermal resources are located in sone 60 to 70developing countries. More than 50 of these countries have high enthatpy resourceswhich can be used for generating electricity. Eleven developing countries alreadyhave geothermal power plants in operation or under construction, ana in 27 othercountries reconnaissance and pre-feasibility studies have been completed or arebeing carried out. At tbe beginning of 1984, the installed electric capacity ofgeotbermal power plants in deveroping countries was estimated to be appio*tmateiyI'200 [tl'it' or 35 per cent of the world total . 21/ Based on the plans of a nunrber-ofcountries, this capacity has been projected t6-grow to between 51000 and 2,000 M9lby the year 2000 (f) Solar enerqv 2L- Developing countries, most of whieh are located in theabundantry endowed with solar energy resourees. At present,tropical zone, arethe use of solarA/40/srr English Page 9
**Analysis**
The text discusses the availability and potential of various natural resources, including oil shale, tar sands, geothermal energy, and solar energy, in developing countries. The focus is on the technical and economic aspects of exploiting these resources for energy production, rather than on their environmental or social impacts. The text also touches on the challenges faced by projects to develop these resources in developed countries.

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