Euro astro biz: It's time for solar panels in Spaaace
laser cannons power stations proposed (again)
European space company EADS Astrium has revived an old idea, that of space-based solar power generation. The company says it could have a 10-20kW demonstration spacecraft in orbit "in the next five years".
The BBC reports on speculation by company executives yesterday, but it is acknowledged that without funding, probably from government, nothing much will happen. However, Astrium argues that the European Space Agency or the EU* might invest, or even power companies.
The idea of space-based solar power schemes is to use solar arrays in orbit to generate power and then beam that power wirelessly down to Earth. Photovoltaic panels perform hugely better in space than they do on Earth, freed from the attenuating effects of the atmosphere. It's also easier to keep them facing the sun directly.
The tricky bit is the power-beaming technology. Previously many plans had seen the energy being sent down in the form of microwaves, but results in the event of a beam wandering off the receiving station could be a bit messy - indistinguishable from orbital raygun bombardment.
Astrium believes that the way ahead is the use of infrared lasers, which wouldn't be so prone to fry cities in the event of a mishap.
"Conversion of this infrared energy into electricity - that's something which is progressing very fast and we are working with the University of Surrey to develop converters," company CTO Robert Laine told the Beeb.
"The principle is to get a very high efficiency of conversion... If we achieve 80 per cent then it's a real winner."
Space-based solar power is a potentially unlimited resource, and would avoid most of the downsides of today's power-generation methods. It requires no limited supplies of fossil fuel, isn't erratic or unreliable, and requires no exploitation of other nations' resources.
However, like nuclear power, it does have implicit potential as a weapon. A technofear protest movement might appear if space solar ever became serious. Then there's the matter of expense, orbital lift capability etc. A study for the US military in 2007 concluded that present-day launch technology with throwaway boosters "will not support the business case for space-based solar power".
Space solar power would be a bonanza for companies like EADS Astrium, of course. But just because they'd like to see it happen doesn't mean that it will. ®
*The ESA, despite its name, is not an EU bureau.
I work in the Solar Industry
As the Director of R&D of a solar cell company. And this kind of "solar power in space with energy beamed to Earth" stupidity just drives me crazy. Ground based photovoltaics are marginally economical and, at best, marginally ecological. The whole focus of the entire industry is to drive costs (including BOP) down, and to eliminate/minimize environmental wastes. The only way to make photovoltaics orders of magnitude less economically & ecologically viable so is to rocket them into Space. The higher (and unflitered) solar flux in orbit (as compared to Earth's surface) is just not very large (much less than x1.5 in the wavelengths that matter for solar power generation), and even if positioned to never be in Earth shadow, you only gain another factor which is less than 4 when averaged over a day..
But but ...
It's a series of effects - space W/m2 is only about 150% of terrestrial W/m2. Then, double it because space collectors will work for 24 hours instead of 12. Then, factor in weather on earth which reduces terrestrial collection by a random but large amount. This pushes Space Solar Power (SSP) to much more efficient levels.
Also, SSP can be shifted to different places very easily - just build a new collector elsewhere and aim the beam (and hope you don't miss).
Lots of losses?
But where is the benefit of space PV panels?
PV panels on earth = inefficient. but only one stage of energy conversion
PV panels in space = more efficient, but then have to convert to some other form of radiant energy, squirt to ground, extra losses from inverse square law, passage through atmosphere etc, more losses from converting back to electricity (again) = very, very inefficient