sunny regions (for example Egypt, Lybia, Middle East, Australia, California and so on). We assume that the space system will remain at least 4 to 10 times more expensive than the terrestrial system. In these regions where SPS land productivity is never more than 2 to 3 times the one of solar power plants, there is no chance for it to become competitive with earth based plants while the price of photovoltaic cells decreases. However SPS might be competitive in crowded areas where sunny sites and other fossil or renewable energies arc not available, for example in equatorial West Africa or South East Asia cloudy regions with very high population densities (> 1000 inhabitants/km^) predicted. Under these assumptions, table V shows a possible regional distribution for GSPP and SPS by 2100. Standard units of 10 km^ sized ground power plants have been selected, since they are supposed to have a 5 GW peak output, like an SPS, and about one fourth of SPS annual energy production (10 TWh versus 40 TWh). Conclusion Beginning with a long-term evaluation of energy needs which takes into account a sustained effort toward energy efficiency and conservation, the NOE scenario points out the importance of renewable energies for a sustainable world energy supply. Among those renewables, solar energy can contribute significantly through use of decentralized systems, grid connected solar plants and solar power satellites. The map of ground solar power plants and reception antenna for solar power satellites (figure 3), although indicative, gives rise to some comments. Ground solar power plants produce two times more electricity in the world than solar power satellites in 2100. They never require more than 1% of the desert areas of the concerned regions. Even in North Africa and Middle East where we propose a very great number of GSPP. the land requirement remains less than 10"^ of the desert areas. It appears clearly that SOLAR SPS and TERRESTRIAL POWER PLANTS 2100, Scenario NOE TWh total TWh Ground TWh Number of sites 10 km x 10 km 5 GW (10 TWh) km^ Spatial TWh Number of satellites 5 GW (40 TWh) km^ North America 220 220 22 2200 0 0 0 Europe 70 30 3 300 40 1 150 Japan, Australia, New Zealand 180 140 14 1400 40 1 150 USSR Central Europe 320 80 8 800 240 6 900 I zatin America 750 270 27 2700 480 12 1800 N Africa Middle East 2670 2670 267 26700 0 0 0 Africa 1680 1680 140 140000 280 7 1050 India 150 70 7 700 80 2 300 China 430 30 3 300 400 10 1500 Asia Oceania 730 130 13 1300 600 15 2250 World total 7200 5320 504 50400 2160 54 8100
RkJQdWJsaXNoZXIy MTU5NjU0Mg==