01-05-2012, 05:25 PM
Solar High:
16KwordBrief.pdf (Size: 340.83 KB / Downloads: 44)
The Solar Problem
The DOE Energy Information Administration (EIA) forecasts a 50% increase in worldwide electric generating capacity by 2035, from ~ 4,650 gigawatts (GW) to just over 7,000 GW. This does not include the additional plant that may be required to enable
replacement of obsolete or environmentally unacceptable facilities;
widespread adoption of plug-in hybrid or fully electric vehicles;
desalination of seawater on a large scale; and
substantial economic growth in poor nations.
The Solar Solution
If we want to make solar energy affordable, we must put the collectors in space, where the sun shines 24/7 and the intensity of sunlight is 1,360 W/sq.m., 40% greater than on Earth. The best location is geostationary orbit (GSO, 35,800 km above the equator), where a satellite remains fixed relative to terrestrial sites.
Objections to Space-Based Solar Power
1. Space hardware is expensive. Satellite equipment is expensive because it is constructed in small quantities, by hand, in clean rooms. The mass production needed for power satellites will reduce these prices to terrestrial levels. In fact, the fabrication cost for a power satellite will be much less than for a comparable terrestrial solar power plant, because the solar array is much smaller.
The current study by the Solar High Study Group indicates that technology available now permits a Block I power satellite to be built at a hardware cost of ~$8,500 per kilowatt. Foreseeable near-term advances are expected to reduce the cost of a Block II satellite to ~$4,000/kW. Building the rectenna would add ~$1000/kW to these figures.
Conclusion
The expected cost of deploying SBSP is ~$7,400/kW, including the rectenna as well as construction and launch of Block II satellites. Amortized over an expected life of 30 years at a discount rate of 5%, the contribution of this capital cost to the delivered cost of electric energy would be 5.6 cents/kWh. SBSP is thus much more promising than terrestrial solar as a replacement for fossil fuels or nuclear power.