Sun Power Called A Ray of Hope

Solar satellites can deliver clean energy, boosters say

Many of us dream of a world where all people enjoy high-tech living without spoiling the beauty of nature. It is all a question of energy, without the mess of burning fossil fuels, without the worries that hang over nuclear plants.

According to Gregg Maryniak, VP of Princeton's Space Studies Institute (SSI) and Managing Director of the International Space University (ISU), the alternative to our dependency on messy fossil fuels and nuclear power is the sun. We see silicon solar cells powering calculators and watches, but few envision solar power providing the thousands of millions of watts of power required by our modern world.

Because the sunshine reaching the earth is not constant, solar cells cannot match the efficiency of traditional energy sources. The advantages solar cells receiving sunlight 24 hours a day are obvious. To do this a solar powered satellite must be placed in geostationary orbit.

What such a satellite would look like shocks some people. Picture an array of solar cells stretched over an aluminum frame about 7 kilometers long and 11 wide, so large it would shine like a star at night. The sun's rays concentrated on the solar cells are converted into electricity with an efficiency of 37%. An antenna complex attached to this solar array converts the electricity to microwaves and beams the energy to an antenna on earth. The energy arrives on earth with an intensity of 20% of that of sunlight.

A rectifying antenna, about 10 km across, is stimulated into producing electricity which is fed into the local power grid. The space below the antenna could be used safely for agriculture since the rectifying antenna blocks the microwaves and is 70% transparent to rain and sunlight. The efficiency of this part of the system is about 85%.

It is because of the ease with which we can convert microwaves to electricity that such a weak beam can be used. The parts which collect sunlight and transmit it to earth are based on technologies found calculators and microwave ovens.

According to Brian Tillotson of Boeing, the typical size of these Solar Power Satellites (SPS) will be about 5000 Megawatts (MW) with the power of 5 nuclear reactors the size of those at Darlington. The cost would be about $100 billion for the first 60 satellites with a power output of around 300 000 MW. Tillotson reminds us that though this sounds like an overly ambitious project, going to the moon was science fiction 30 years ago. There have been a lot of analyses, and SPS is not that tough a thing to do. Once the up front money is in place it is not much more difficult than oil exploration in the high arctic.

A large fossil fuel power plant might run at 35-45% efficiency, versus 30-37% for solar power, but with solar power this type of efficiency, is less important since you are not paying for coal or oil or uranium, and not destroying the environment with mining and pollution. SPS is environmentally friendly, and you get more power out.

Dr. Peter Glaser envisioned a way to make solar power viable on a global scale more than 20 years ago. Glaser's idea is to build SPS in space where we can collect the sun's energy and send it down to earth for our use. The power would be continuous and cheap. For Glaser, SPS is the only way to make our home livable in the future without technologically regressive measures.

"There is a general sort of idea shock when you look at the idea of putting large things in space and sending things to the ground" , says Tillotson. "That's a new idea and people are always a little resistant to them". No one questions that it can be done. The technology is in place as far as the transmission and reception of the energy from the satellites is concerned. "That's been working since the 60s and it has just been getting better all along." Canada, for example, flew a radio controlled airplane in the 80s powered by a microwave beam from the ground, proving that it was possible to keep the beam focused on a single point.

Another pioneer is Gerard O'Neill, a Princeton Physicist who started the SSI. He provided inspiration for a generation when he published The High Frontier: Human Colonies in Space in 1976. Republished in 1982 and 1989, O'Neill's book outlines the environmental, economical, social, and technological advantages and difficulties involved with setting up permanent orbiting colonies around the earth. Their main economic function would be the production of Solar Power Satellites.

In 1985, O'Neill was appointed to The National Commission on Space by then President Regan, and in 1988, O'Neill's Geostar Corporation launched a patented new communications satellite on an Ariane rocket. According to Maryniak, if you look at all the stuff people are doing now, using the moon and talking about using it as the stepping stone for getting to the other planets, it turns out that almost all the current work passes through Gerry [O'Neill]. Peter [Glaser] thought up SPS and Gerry thought of using non-terrestrial materials, and those two ideas coupled together look like they can reduce the cost of SPS by a factor of 20-100, big big numbers.

And here comes the other part of the story. These folks want to build SPS using resources mined on the moon and from asteroids. The International Asteroid Mission project of the ISU is looking at aspects of this type of mining. The $100 billion up front cost is the inhibiting factor. This cost assumes that everything will be done from the earth. According to Tillotson, from the moon the assumption is that it would be cheaper, but the upfront cost would be higher. In the long run it would be a lot cheaper. According to recent studies funded by SSI, building an SPS using lunar materials would be 97% cheaper than on earth, but the infrastructure costs of setting up lunar mining, smelting, and transportation networks would have to be figured into the package.

According to Gregg Maryniak, "it is possible that Canadian people will be operating mining equipment on the moon from Canada" using tele-robotics due to our experience with the Canada-arm "coupled with Canadian companies" experience with mining. Canada has this really interesting idea in discovering where the pivotal technologies are... doing the Arm was a brilliant move and doing the space-station arm is another.

Studies have been done on the lunar construction by General Dynamics and MIT, but Maryniak claims they were largely ignored by the National Academy of Sciences which shut off most SPS research funding in the 1980s. This occurred in deference to the fusion research community. According to Tillotson, fusion people believe now as they did 30 years ago, that they are 10 years away from commercial fusion. Fission (nuclear energy derived from splitting the of Uranium isotopes) which is used to produce energy at Darlington, Pickering, Chernobyl, Three-mile Island, and Seabrook is both messy and dangerous.

Fusion (the joining of light elements like the nucleus of Hydrogen atoms) is less messy, but after the spending of billions on research, scientists have only recently made the breakeven point. But for SPS, "the technical stuff is really well understood. We could do it. In many ways it is easier than a lot of things we are doing now, only bigger" concludes Tillotson. It will take about 5-15 years to get online.

The easy access of large coal deposits and the relatively low price of oil kept governments from being really interested in solar power. "Now people are aware of the greenhouse effect again," says Tillotson,"people are aware of the vulnerability of the oil supply again and so... the climate is getting much more positive for solar power satellites."

Perhaps the most striking realization is that everyone involved with the SPS concept cites the environment as a central reason for continuing their struggle to popularized the SPS concept. As O"Neill wrote, the benefits of their vision of expanding human experience is ultimately "the preservation of the Earth, and its fragile biosphere, as a place of great beauty, deserving our care and our nurturing, as it has nurtured us through our evolution."

Tillotson encapsulates the regrets voiced by many environmentally aware members of the scientific community, "an awful lot of people interested in the environment have an automatic negative response to technology. Here we have a technology which can help the environment, but there are very few environmentalists who think that you can use technology to help you improve it."

There is some environmental concern with the transmission of microwaves. The effect of long term exposure of people to microwaves is similar to our concerns about living too close to electrical transmission corridors, says Tillotson, "studies are confused and need to be clarified a little."

Carbon Dioxide absorption of the sun's rays (the greenhouse effect) far exceeds any other forms of waste heat, "if you can get the same energy as burning a ton of coal without the greenhouse gasses, basically the earth's temperature rise will be a lot smaller." With SPS, about 90% of the energy reaching the ground will come out as electricity, so the waste heat produced on the ground is much less.

"There are people on the US congressional staff who are aware of the idea and think that it is a good idea. But, I would say that the climate is much better for it now than at any time in the last decade. Especially now that people are taking the greenhouse effect seriously." Even thought there is no government funding for SPS in North America, the commitment of privately funded agencies like SSI and individuals like Gerry O'Neill keep coming up with more hard data to show how it will work.

Of the 5 billion or so inhabitants of our planet, 40 percent (2 billion) are without electricity, and they are not going to be content to remain that way. In North America, we use over 10 500 kwh per person annually (1 kwh (one kilowatt hour) is the equivalent of a one hundred watt lightbulb burning for 10 hours). Our yearly use of electricity is that of burning 12 such lightbulbs 24 hours a day for a full year, and demand is growing by over 2.6 percent per year.

On the other hand, the developing world uses 300 kwh per person per year, but the demand is growing a 7 percent every year. With 25% of the population using 80% of the available power either we must drastically curtail our energy use or build the equivalent of 5000 new nuclear power stations by the year 2030.

The world is in the midst of a crisis, and the crisis is centered on energy. This problem is nothing new. The oil crisis in the mid-seventies increased the world's awareness of the fragility of the energy source which powers our economies and makes our modern culture possible. It looks as if we learned little from the experience. History has repeated itself and with oil prices still rising, we are back to where we started.

Record Acid Rain levels were recorded in Algonquin Park in 1991. While our knowledge of the damage caused by greenhouse gasses grows daily, new coal-fired generators are still being built. We are avoiding alternatives.

D. Jason Nolan Condensed version originally published in the Toronto Star, September 9, 1990.