Space- and Earth-based solar power for the growing energy needs of future generations

The future global supply with terrestrial regenerative energies (solar, wind, hydro and geothermal) is discussed and compared to energy from space via Solar Power Satellites. It is shown that both have the potential to satisfy global energy needs. Obviously, regenerative solutions must be taken into account and installed with higher priority within the next decades to reduce the deposition of CO2 into the atmosphere. This is absolutely necessary to stabilize the climate. In addition, the threatening depletion of fossil and nuclear fuels in the long run forces research into alternative solutions. Concerning solar power from space, the recently developed concepts for light-weight inflatable and deployable solar arrays/concentrators-like in the NASA 'Sun Tower' and the 'European Sail Tower SPS'-are reviewed and major problems with wireless power transmission are discussed. Compared to earlier concepts the designs have the potential to reduce significantly the masses and, thus, the costs. But the technological demands and operational uncertainties are still immense. Anyhow, major progress with cost reductions of one to two orders of magnitude is required for the space option to become competitive with terrestrial regenerative options. (C) 2004 Elsevier Ltd. All rights reserved.