For the love of FSM, please, go, build a successful and highly profitable SBSB company and prove us all wrong. Just stop wanking about it on a rocketry mailing list. On Tue, May 6, 2014 at 1:53 PM, Rüdiger Klaehn <rklaehn@xxxxxxxxx> wrote: > On Tue, May 6, 2014 at 12:03 PM, Uwe Klein <uwe@xxxxxxxxxxxxxxxxxxx> wrote: >> >> Am 06.05.2014 02:32, schrieb James Bowery: >>> >>> About 5 years ago I did a blog post titled "Arrival of the Solar Power >>> Satellite >>> >>> <http://jimbowery.blogspot.com/2009/07/ive-been-following-space-solar-power.html>" >>> >>> and did a rough calculation that, based on the Powersat patents, it >>> would take 20,000 Falcon9 launches to loft 250GW capacity and the total >>> installed capacity would be under $3/W. If you do that over the course >> >> Medium scale Photovoltaics are now @ ~1€/Wp here ( Germany ) >> >> > > 3 USD per watt of _continuous_ power from a solar power satellite is much > more economical than 1 EUR per watt for seasonal, intermittent power with a > capacity factor of less than 0.1 (in Germany). You would need 10W of > terrestrial solar for the same _average_ power production. But producing > power when power is cheap is not economical without subsidies. So you would > need 13W of terrestrial solar power (because of storage inefficiencies) and > maybe a month of storage to have roughly the same capability for base load > production. I guess space solar power will have a hard time being > competitive with ground solar power in places like California and the > American south west where there is plenty of sun and cheap property. But in > places like Germany where there is very little sun and property is very > expensive, it will be much easier to be competitive. > > Good luck finding a place for the huge pumped storage plants that would be > necessary for storing energy on a large scale. Every time somebody proposes > to build pumped storage in Germany, the environmentalists are up in arms > about it. See the proposed Schluchseewerk or Jochberg pumped storage > facilities. > > > In fact I think providing peak power could be a niche for space solar power > to grow in until it is cheap enough for base power. You are already > transmitting energy over 36000km. You can easily redirect the power to the > other side of the world in seconds by just moving the beam. So you might as > well take advantage of this to provide power to wherever in the world it is > most valuable at the moment. > > If you imagine a world mostly powered by intermittent power sources like > solar and wind, there will always be places where there demand exceeds > supply and energy costs are therefore very high (*). For solar power, there > is a mismatch between demand and supply in the morning and especially the > evening. And of course there are large fluctuations due to cloud cover and > seasons. For wind there are also large fluctuations that can last several > weeks to months. > > If you had receivers near most large consumers around the world, you could > follow the seasonal, daily and even hourly demand/supply mismatch. The > economical advantage is huge: while bulk base/off-peak energy costs less > than 5 cents per kWh in most countries, peak energy costs up to 10 times > more. Of course, to take advantage of this you would need a design where the > receiver is relatively cheap (maybe infrared laser power transmission to > tethered stratospheric platforms). But that is exactly what is required for > a small prototype power plant anyway. > > (*) Providing full backup using gas power plants is becoming uneconomical > for the few days per year that backup is needed. In Germany, extremely > efficient gas power plants are being shut down because they are > uneconomical, while lignite coal power plants thrive. > >> >>> of 5 years that's an average of about of one Falcon9 launch every 2 >>> hours. >>> >>> The calculations I went through are pretty simple so any bad assumptions >>> or calculation errors should stand out. >>> >> Ever looked at the carbon footprint for those PowerSats ;-? >> > If it is cheap enough to be economical without subsidies, it will > automatically have an EROI (energy return on investment) of much more than > 1. It is just in heavily subsidized markets like corn ethanol that something > can be economical without having a positive EROI. > >> >> Uwe >> >> >