Space Solar Power
Some time back this month Sam Dinkin made a comment on the Transterrestrial website about how space solar power (SSP) is less cost effective than beaming power to the Moon.
The most depressing figure given is the current $202.5 per watt setup costs (which assumes $10,000 per lb launch costs-reasonable for GTO), however the piece suggests that this estimate could be reduced by up to two orders of magnitude by reduced launch costs and payload weight. In that case I don't think we should need to compare SSP with coal. In a perfect free market energy providers would be free to continue building coal fired power plants until the retail cost of electricity becomes only marginally more than the cost of producing it using coal. In reality NIMBYism and environmental considerations allow less cost effective solutions such as wind powered turbines to exist on the margins as long as the demand exists.
Wind power costs vary but may be estimated at up to about $0.10 per KWh ($0.88 per watt-year) compared with the figure of $0.07 per watt-year for coal, and about $1000 per KW for the turbine compared with $0.75 per watt for a 750MW coal fired plant. (wind power costs based on this source from the UK Oxford Institute for Energy Studies - Disclaimer: quotes^3 ie quotes of quotes of quotes). It still depends on government subsidies and favorable legislation for survival. Perhaps wind power costs would be a better basis for comparison in a real-world scenario.Having said all that, I'm not at this stage an advocate of SSP and I think it's a real stretch to estimate that the costs could be brought down by a factor of 100, but because of its obvious benefits I believe it deserves a second, third, and perhaps a fourth and fifth look to see if it can be made to work. More on this in a later post.