Thursday, March 01, 2007

Jump-Starting Solar Energy

The potential of solar energy remains unfulfilled.

By Katherine Bourzac

A design for a satellite solar-power station proposed by the consultancy Arthur D. Little. The satellite would stay in synchronous Earth orbit for a clear view of the Sun; energy from the panels would be beamed to an antenna on Earth via microwaves. Credit: TR

In October 1973, the Organization of the Petroleum Exporting Countries raised oil prices by 70 percent; by December, it had raised prices an additional 130 percent, and its Arab members embargoed oil shipments to the United States.

The U.S. began to look at alternative sources of energy, like solar, wind, and geothermal. Citing the solar energy available at the rate of 1,400 watts per square meter just outside Earth's atmosphere, an article in the December 1973 TR argued in its title, "Solar Energy: Its Time Is Near." The article, by ­Walter E. Morrow Jr., associate director of MIT Lincoln Laboratory, provided an economic analysis of solar's potential to transform the country's energy landscape.

Morrow recommended that the country spend $300 billion over 27 years researching, developing, and implementing solar-energy systems--from solar-panel-equipped satellites that would use microwaves to beam energy back to Earth, to household water heaters, to fields of solar panels like the one featured in this issue's photo essay (see "Good Day Sunshine"). The return on an investment of more than $11 billion a year, he argued, would be huge: by 2000, solar could provide 13 percent of the country's energy, by 2020, 26 percent.

But if these rapid advances are to occur, large capital investments will also be required. ... the cost of the various types of solar energy systems can be projected as follows:

Residential solar heaters: $4,000 each

Total-energy plants: $50/m² of building supplied, or $100/m² of collector area

Electric base-load power plants: $700/kw of electrical output power, or $40/m² of collector

Hydrogen production plants: $40/m² of collector

...

Combining the cost of research and development, production facilities, and the systems themselves gives a total solar-energy investment of about $300 billion in the next 27 years. ...investment at that level would mean that 13 per cent of projected U.S. energy requirements could be filled by solar systems in the year 2000, 26 per cent in 2020.

While substantial collector areas would be required, the total area involved by the year 2020, about 10_­­­⁴ km², would be much less than that used currently for highways. In fact, a substantial fraction of the collector area needed could be accommodated on ... land shared with farming or grazing.

But gas prices fell, and the United States did not spend nearly this much money on solar. In its entire existence, the U.S. Department of Energy has spent $5.8 billion on the technology. In 2004, solar supplied only .0628 percent of the country's energy. And President Bush's 2008 budget calls for only $148 million for solar research.