An educated guess is made of the energy demand in developing countries well into the next century in order to estimate the possible role of new and renewable sources in meeting this demand. The world is roughly divided into industrialized (IND) and developing (LDC) countries. A plot of energy demand in both parts shows a possible structure of mixed energy to meet LDC demand, but there is a gap between demand and supply from conventional sources in LDCs that has to be met by new and renewable sources. When the demand for specific energy forms is projected, as much as two thirds of the final energy needed from new sources should be based on centralized-electricity and liquid-fuels technologies. Solar and geothermal energy must compete with nuclear and thermonuclear breeders, while solar prospects for chemical fuel supply in LDCs lacking adequate coal reserves seems promising. There is a large gap in research and development (R and D) spending on new energy between the two parts, which means that LDCs will have inappropriate technology at a high price. An increase in R and D spending on a regional basis should target funds to appropriate options. 6 references, 7 figures.