04 June 2009

3 Space Solar Posts

From: http://www.ecohearth.com/eco-news/eco-op-ed/593-space-based-solar-power-the-time-has-come.html by Steven Kotler

Dreamy, yes, but not actually science fiction.

In 1968, Peter Glaser—inventor, NASA-advisor and VP for Advanced Technology at Arthur C. Little—figured out in principle how to transmit electric power via microwaves. A study done in 1981 by the EPA, DOE, NASA and the Department of Commerce,researchers found no “insurmountable obstacles” to the whole idea. The hard proof came in 2008, when researchers sent a microwave beam 92 miles between two Hawaiian islands and kept it up for four months straight.

The 92-mile distance was chosen because it’s equivalent to the amount of atmosphere a microwave beamed from space would have to penetrate.

In fact, just about every piece in this puzzle—from inflatable mylar solar panels to the massive antennae needed to catch the signals back here on Earth—has been solved. The real remaining problems are those familiar devils: cost and will.

Skeptics often point out that despite the obvious advantages to space-based solar power, price will always be the determining factor. Currently, using existing technology, everyone’s best guess is that such a system would cost about $10 billion to install and generate electricity at—in a very optimistic scenario—50 cents per kWh.

Certainly that’s not cheap, but skeptics often forget the size of the mess we’re now in.

But shouldn’t we consider a little resource reallocation?

According to Greenpeace, Americans subsidize the fossil-fuel industry in the range of $15-to-$35 billion every year. And this doesn’t include the extra $2 billion we’re ponying up for the Clean Coal Technology Roadmap—a sure way to get lost if there ever was one.

Hmm. What could we spend those billions on…

Well, if you don’t like my low-tech solution, how about the Advanced Research Projects Agency-Energy, ARPA-E—the newly established DOE big-think, no-idea-too-crazy, pie-in-the sky energy research lab.

ARPA-E is one of the Obama administration’s wondrous ideas, touted as our great hope for an environmentally friendly energy future, with a current operating budget of $400 million.

This means we’re willing to spend less than 1/25th (at the least) on serious innovation when compared to what we—meaning the taxpayers—spend subsidizing the extraction industries.

And an interesting architecture discussion
From: http://www.thespacereview.com/article/1383/1 by Trevor Brown
A nation such as the United States would have developed enough clean and renewable solar energy to become one of the world’s foremost energy exporters.

If solar power satellites such as these did come into being, they would very likely necessitate the overhaul of the entire global economy to achieve broad compatibility with the new energy technology. The resultant economic transformation would be incredible, creating many new high technology jobs in industries across the world, but especially in the nation that was at the epicenter of the SSP breakthrough. In fact, of greatest economic impact may not be the new energy technology itself, but rather the wave of innovation arising in complement to the new energy technology.

And yet the tremendous symbolic power that these satellites could possess may have a profound impact far beyond the realm of economics and the environment. Due to their photovoltaic properties, large enough spheres could have a crystalline appearance in space visible from the Earth with the naked eye, giving them the appearance of diamonds in the sky. If this were the case, these satellites would not only drastically reduce carbon emissions and provide a plentiful source of renewable energy, but there physical beauty across the backdrop of both day and night skies could be surreal for onlookers, causing many around the world to become enamored with the entrepreneurial verve of a nation that developed them as well as with the culture that created them. A nation that owned and operated what appeared to be diamonds in the sky producing abundant clean energy would surely be at the forefront of global leadership, attracting the sentiments of much of the world’s population into its socio-political camp.

Of even greater socio-cultural impact could be their effect on the technological aptitude of a nation, as the case may very well be that crystalline discs shining like diamonds in the sky could inspire an entire generation of young Americans to excel in math and science like never before. With the tangible, ever present symbol of mathematical excellence glimmering in the sky by day and by night, kids could very likely develop a whole new appreciation for the “coolness” of science.

http://www.idsa.in/publications/stratcomments/PeterGarretson220509.htm by Peter Garretson
Space as the Source of Our Future Energy
Peter Garretson

May 22, 2009

The idea is to launch giant orbiting solar collectors into space, where there is no night, and beam the power to receivers on the ground, where it is fed as electricity to the grid. Long championed by former President Dr. Abdul Kalam, and the Aerospace Society of India (AeSI), the idea is seen as a long-term solution for energy security and climate change, and the most environmentally benign and scalable renewable energy option, which deserves its own focused development programme.

Such satellites would be the largest, most ambitious space projects ever contemplated. A single solar power satellite would be several kilometres long, with a transmitting antenna about a kilometre across, and generate between one and ten Gigawatts (as much power as 10 nuclear power plants). It might weigh tens of thousands of metric tons and would require a fleet of reusable space vehicles to construct. Follow-on designs might use materials from the Moon.

Existing communications satellites use a similar process, using the power of the Sun on their solar arrays to power a radio transmitter for sending radio and television signals. But the small antenna on communications satellites prevents them from being able to focus a beam for power-beaming. To beam power, the transmitter must be increased to almost a kilometre long, and a special receiver, a rectifying antenna, or rectenna is required. The rectenna would be several kilometres across, about the size of a municipal airport, made of a thin metal mesh, and would be 80 per cent transparent to sunlight, allowing the land underneath it to be used for pastoral, agricultural use or production of algae biodiesel. Far from some scary space-ray, the large transmitting and receiving antenna, the high conversion efficiency, and the constant availability allow the beam to be very low power—about a sixth the strength of sunlight on a warm sun tan beach day. Except that sunlight contains high frequency ultraviolet rays which can strip off electrons in our cells and cause cancer. The beam from a Solar Power Satellite would be of low frequency, very similar to current wi-fi devices, and is non-ionizing and not dangerous like UV.

Proponents feel it is an attractive option for several reasons. One, by 2025 the world will have added another two billion people, its energy needs will have doubled, the combustion of fossil fuels will continue to alter the composition of the atmosphere with concerns about climate change, and by mid-century we would have exhausted most of our fossil fuels. By mid-century India alone would have added 300,000,000 people, expanded its electrical generating capacity eleven-fold, from 121 GWe to 1350 GWe, moved upwards of 60 per cent of its population to cities, and exhausted all or almost all of its fossil resources. How are we to maintain a sustainable civilization if we remain a closed system and never access the vast wealth of all the rest of the universe?

In space faring advocate Mike Snead’s excellent paper, “The End of Easy Energy and What to Do About It,” he lays out the need and opportunity for Space Solar Power. Today the total world needs about 81 Billion Barrel of Oil Equivalent (BOE) thermal or about 15 TWe. And by 2100, to complete development to the “gold standard” of 30 BOE per capita, will require an expansion to probably 300 billion BOE, or roughly 55 TWe. By 2100 we will probably be about 50 years beyond the age of oil, and will have had to increase our renewable/sustainable energy 26 times. Even with a massive up-scaling of terrestrial renewable energy in the most optimistic estimates, the deficit is still close to 60 per cent. 55TWe is just very hard to come by on Earth. But what if we go to space, where energy is abundant, where the Sun never sets and delivers up to 9 times as much energy per unit area as on Earth, and 24 hours a day? There, in the Geostationary belt alone, is thought to be in excess of 177TWe of exploitable green solar energy—and it will be there for at least a billion years. If we could provide 55 GWe of green energy we fix our climate and energy problems in the long run, and we would grow the Gross World Product (GWP) over ten-fold. Imagine a world greater than an order of magnitude wealthier, a world fully developed with the security that a high standard of living brings. Can we afford to ignore a resource that vast? Does not extraordinary reward justify extraordinary effort? Those in the space movement think it cannot be ignored and that we need not only have to look beneath our feet for our energy, but can look to the stars for renewable, sustainable, scalable energy, and for a cleaner, brighter tomorrow.

1 comment:

Keith Henson said...

To make space solar power come about requires only one thing, getting the cost down to where it undercuts coal.

That's around 2 cents per kWh. If you plug in this number into an economic model (with some modest assumptions about kg/kW) then the cost of lifting parts to GEO has to be $100 per kg or less.

It turns out that a chemical stage to get payload up and high exhaust velocity laser propulsion just might make that possible for a million ton per year model.

Nit picking details if you want to ask for them.

Keith Henson