truck" and it is hoped that costs for transportation of material into orbit would be about $10—20 per pound, considerably lower than what is expected for the shuttle. About half of SPS RDDT&E costs are for space transportation, requiring perhaps four different vehicles: the HLLV for transporting construction material from Earth to low Earth orbit (LEO), a Cargo Orbital Transfer Vehicle (COTV) for taking that material from LEO to geosynchronous orbit (GEO), a personnel launch vehicle (PLV), for example the shuttle, for carrying people from Earth to LEO, and finally a personnel orbital transfer vehicle (POTV) for transporting crews from LEO to GEO. The NASA/DOE reference design estimated that for building two 5,000 megawatt SPSs per year, a silicon cell design would require 375 HLLV flights, 30 PLV flights, 30 COTV flights and 212 POTV flights; while a gallium system would require 225 HLLV flights, 38 PLV flights, 22 COTV flights, and 17 POTV flights. Peter Glaser has estimated the cost for an individual 5,000 megawatt commercial SSPS at approximately $7.5 billion including launch costs, or $1500 per Kilowatt. This would result m a cost before transmission (busbar cost), according to Glaser, of 27 mills per kilowatt hour. Less optimistic estimates suggest the cost to be about 55 mills per Kilowatt hour, and all these estimates are contingent upon the HLLV actually reducing space transportation costs to $10-20 per pound as well as a significant reduction in the cost of photovoltaic cells. During the time it was proposing a Brayton cycle SPS, the Boeing Company estimated the cost of an individual Powersat at $13 billion. Advocates claim that SPS could be commercially available in the 1995-2000 time period. The number of SPSs required to meet U.S. electrical needs would depend on the rate of growth in demand over the next decades, although for April 1979, total U.S. electrical capacity was approximately 586,000 megawatts, meaning that fifty-nine 10,000 megawatt SSPSs would be needed to equal that capacity. Capacity is different from use, however. The use factor for present U.S. electrical power plants is only about 43%, since the plants need to be shut down for repairs for varying lengths of time. The SPS use factor is expected to be about 80-92%, so fewer SPSs could provide an equivalent amount of electricity. Considering the high RDDT&E costs of SPS, it seems unlikely that private industry would be able to completely fund such a program, although several industries (such as Boeing, Arthur D. Little, Grumman, and Rockwell International) are expending some of their own money for feasibility studies. In addition, the Sunsat Energy Council was established in April 1978 representing 25 U.S. scientific and industrial organizations. Formation of the Council was announced by former Senator Frank Moss at a Senate press conference on Apr. 6, 1978; Senator Moss is now legal counsel for Sunsat. Council President Peter Glaser reported that the group will study the technical, environmental, socio-economic, and institutional issues involved in the development of SPSs, as well as trying to increase public awareness of SPS as an energy option. The Council's activities will be funded by contributions from member organizations and individual members, although this money will not be used for research and development of an SPS. Nevertheless, initial investment would almost certainly have to come from the Federal Government. SPS advocates argue that the government would spend equivalent or greater sums on energy research and development in the next fifteen years anyway, and that it could just as well be spent on SPS as on other energy sources. Conversely, the present Administration's emphasis is on short-term energy solutions, such as coal and conservation, and it appears unlikely that a concept such as SPS would receive sufficient support to
RkJQdWJsaXNoZXIy MTU5NjU0Mg==