IntLibber wrote:Nik wrote:Uh, if they can get controlled fusion working, building even a modest power station --Or replacing / supplementing the fossil-fuel stages-- would pay for their space project...
Getting just one 2 GW fusion power station operating would earn so much profit at todays electic prices that you could fund a whole interplanetary space program with it.
Ideally what you do is build a 2GW power station, then an electromagnetic rail to put a launcher in the air at mach 0.9, then build your fusion launcher to use that rail, and fund the whole thing with power sales.
2 GW at $0.12/kwh means hourly revenues of $240,000.00. Annual revenues of $2,102,400,000 operating at 100%. Given lack of fuel costs and the relative simplicity and safety of a fusion system versus a fission plant, if you can't earn a 50% profit on that annually, you have to be doing something wrong.
Fuel cost may be low, but transport costs will be high, unless you have a highly efficient booster. Then you have to consider the cost of building, operating, decommissioning, and deorbiting the station. Then you need to consider the cost of getting the energy back to the surface- look at some of the criticisms of beaming microwave energy to the Earth. You need huge antennas. Even if there is a workaround, the costs would still be considerable.
Finally, if you have a safe fusion reactor, why spend huge efforts and money for an orbital station when you could much more easily and cheaply build and operate a plant almost anywhere on the surface.
Remember, one of the claimed advantages of Polywell type reactors is that they can be scaled to more convenient sizes and be placed close to the markets. Currently, transmission costs and maintaining the infrastructure accounts for ~ 1/2 of the end cost of electricity.
Unless there are game changing technologies in multiple areas, space generated power may be useful, but only for space based use.
There is one glaring and very bright exception. That is, of course, the Sun. There the power is completely free. All you have to worry about is the capture, conversion, storage and transmission of this energy on the Earth's surface. Some might also worry about the environment effects. Some of the schemes to do this includes solar cells, solar thermal, wind mills, hydroelectric power, and of course fossil fuels. The exceptions include tidal (more Moon, than Solar gravitational energy), and geothermal energy. Fission nuclear plants could be considered an exception, except the heavy elements come from stars also. For that matter, a large part of geothermal energy is provided by radioactive decay of isotopes created in stars. Fusion power (at least D-D fusion) would be an exception to Solar (or stellar) derived power, as the deuterium came from the Big Bang, no stellar intermediaries needed.
Dan Tibbets
To error is human... and I'm very human.