Storing the power has been another huge problem, as day shifts to night and cloud cover and storms affect production.

The conversion efficiency is another factor. Traditional solar cells were only 3-7% efficient in converting sunlight to electricity.

Finally, the cost of building arrays of such cells was high. Put these all together and you have an explanation for why solar power hasn’t become widespread even though sunlight is universally available.

Now let’s look at solar power another way.

First, the most intelligent way to generate solar power isn’t on Earth but in space. In space, the sun’s energy is far more intense than when filtered through Earth’s cloud cover, and is available 24 hours a day, 365 days a year, without interruption.

The basic strategy is to create huge flat panels comprised of millions of solar cells (imagine a 10-mile-long gossamer-thin butterfly shape, and you’ve got an approximation). These solar power satellites (SPS) are oriented toward the sun, and the electricity they continuously generate can be beamed to orbital receiving stations via microwave or laser transmission.

The loss of energy in these first stages is negligible. Even after the energy has been subsequently beamed to Earth and converted to electricity, more than 90% of the originally captured power has been preserved.

While this would be a massive engineering project, every element is proven, off-the-shelf technology. Only the scale and configuration of elements are new. Having built an International Space Station, we clearly could build these as well.

A $10 million U.S. Department of Energy (DOE) study determined that each such satellite could replace two conventional fossil fuel plants, and that we could build thousands in this century by tapping just a fraction of a percent of the energy the sun wastes. The study concluded that the technology would be effective, as well as environmentally benign.

SPS have offered us a viable solution to the world’s energy problems since the 1970s. However, SPS have suffered from a perceived barrier to entry that is incorrect.

That same DOE study made the ridiculous assumption that all the SPS components would have to be lifted from Earth to orbit, which is akin to building a city in California out of finished components hauled from the East Coast.

Their estimate of the cost? A $1 trillion. Politically, it was a nonstarter — even though America has subsequently invested money on that scale in its war efforts.

Humanity has never built a frontier this way. Instead, tools for the development of infrastructure would be sent into space. Those tools would be used to mine ores from the moon and construct SPS in orbit, at prices approximating those of ground-based nuclear power plants.

This is a far less daunting prospect than it seems at first blush. Visit  http://ssi.org/?page_id=8 for a detailed explanation of SPS technology. Space Studies Institute, a nonprofit organization, has steadily supported the research necessary to achieve this, and has received support from companies such as Rockwell International.

SPS may not happen. Fortunately, less capital-intensive alternatives are emerging.

I’m aware of a new battery technology coming out of federal labs that offers 10 times the energy density of today’s commercially available batteries. It apparently can discharge and be recharged without the problematic “memory effect.” Assuming unit costs are reasonable in volume production, such technology should help address the storage problem from ground-based solar power cells.

There’s an even more important breakthrough that’s about to enter the market. A new nanotechnology-based plastic has been discovered that can harness the sun’s invisible infrared rays. This enormous source of energy is completely ignored by today’s solar cells, which work only with visible light. This breakthrough should lead to solar cells five times more efficient than current solar cell technology — up to 30% efficient.

It can even be sprayed like paint onto other materials. For example, a fuel cell-powered car could be painted with this material and use the sun to recharge.

I had lunch several months ago in Boston with Josh Wolfe, principal of Lux Capital. Lux is an investor in this exciting new (still private) technology.

This material will be so cheap to manufacture that it can be sprayed onto plastic sheets in a process akin to a web printing press. Those sheets could then be rolled out across deserts or other uninhabited lands to collect sunlight and power the world’s cities. (Here a nod must be given to the prophetic science fiction author Robert A. Heinlein, who foresaw this in his story “The Roads Must Roll,” published over half a century ago.)

Covering one-tenth of 1% of the Earth’s surface with these kinds of sheets would replace all the power consumed today. While this may sound impractical at first glance, consider this: Even in China, 90% of the population lives on 10% of the land. Nearly all the landmass on Earth is basically uninhabited.

On a smaller scale, sheets of this material could cover roofs in residential housing and walls of office buildings, thereby reducing owners’ dependency on grid-based electrical power. That possibility would almost certainly accelerate adoption of this technology, which could eventually lead up to the grand projects described above.

This new solar cell technology doesn’t suffer from the restrictions that plagued solar power satellites.

Another huge competitive advantage of this new technology is its minimal maintenance cost. Once deployed, it should have a life expectancy similar to paint. Every few years, just apply a new coat. Expect this technology to be commercially available within five years.

It will give a whole new meaning to the term “brightening up the house.”

To your profitable future,

Jonathan Kolber
February 22, 2006

P.S. A friend of mine is working with a retired GE physicist who’s developed a new kind of passive solar array that’s reportedly 92% efficient. With only 8% of the sunlight striking this system wasted, the conversion to electricity would be remarkable. They expect to have the first units built and operating later this year. I’ll be keeping a close watch for further developments.

A Renaissance for Solar Power was originally featured in the Penny Sleuth.