Monday, December 05, 2005

What we need is a solar powered technofix...


I was sad to read recently that Richard Smalley had passed away. ( news article ). He shared the Nobel Prize for the discovery of Buckminsterfullerene, the atomic geodesic sphere that has led to the creation of carbon nanotubes, the stuff that is poised to revolutionize everything from batteries to solar cells to display technology to nanoelectronics.

I came across Smalley's efforts to champion the development of solar power earlier this year. (paper: "Future Global Energy Prosperity: The Terawatt Challenge", video of speech given at Columbia is available online at http://smalley.rice.edu/). It's a compelling, coherent vision of what we need to do over the next 20 years in order to re-invent the world in a very postive way.

"There is plenty of energy hitting the surface of the earth. Nate Lewis of the California Institute of Technology likes to demonstrate that we could cleanly meet the world’s entire energy needs, two kilowatts per person for 10 billion people by applying the following elegant solution: On a global map, identify six rectangular space located in areas of high solar radiation, create a 10% effiencg [solar collection technology], then collect that power, which would be about 20 terawatts of electrical power. That would totally solve humanity's energy problem."


When I first read this, I immediately thought of another article I'd previously come across that outlines some very promising work being done on Stirling engines ( link to article ).


PORTLAND, Ore. — Electrical Engineers are turning a 19th-century invention into a 21st-century alternative-energy source.

The last leg of a two-decades-long effort by the U.S. Energy Deaprtment to unleash superefficient solar power by 2011 is homing in on the so-called Stirling engine, which is being used to drive solar generators. DOE test site measurements suggest the setup could bring the cost of solar power on a par with traditional fossil fuels and hydroelectric sources — assuming the project engineers can balance the separate power feeds from farms of thousands of simultaneously online 25-kilowatt Stirling solar dishes.

The heart of the design, the engine itself, was invented by the Scottish minister Robert Stirling in 1816.

"The Stirling engine makes solar power so much more efficiently than photovoltaic solar cells can," said Robert Liden, chief administrative officer at Stirling Energy Systems Inc. (Phoenix). "That's because the Stirling solar dish directly converts solar heat into mechanical energy, which turns an ac electrical generator." The bottom line, he said, "is that large farms of Stirling solar dishes — say, 20,000-dish farms — could deliver cheap solar electricity that rivals what we pay for electricity today."

Under a multiyear Energy Department contract that started in 2004, Stirling Energy Systems will supply Sandia National Laboratories with solar dishes for integration into full-fledged power-generation substations capable of direct connections to the existing U.S. power grid. Right now about 20 EEs, including more than a dozen from Stirling Energy Systems, are working full time at Sandia to create the electrical-control systems to manage these sunshine stations.

By the end of 2005, they plan to have six dishes connected into a miniature power station capable of supplying enough 480-volt three-phase electricity to power about 40 homes (150 kW). The next step, in 2006, is a 40-dish power plant that will transform the combined output of the farm from 480 to 13,000 V, for distribution of industrial-level power to an existing substation. From 2007 to 2010, the program proposes mass-producing dishes to create a 20,000-dish farm supplying 230,000 V of long-haul power from its own substation directly connected to the grid.

If the project succeeds, the DOE predicts that by 2011, Stirling solar-dish farms could be delivering electricity to the grid at costs comparable to traditional electricity sources, thereby reducing the U.S. need for foreign sources of fossil fuels.
...
Today Stirling-powered solar dishes at the Sandia test facility operate at 30 percent efficiency while delivering grid-ready alternating current. In contrast, 30-percent-efficient solar cells are direct current and drop to 16 percent efficiency by the time they generate grid-ready ac. And that's on a hot day. Efficiency can drop as low as 10 percent on a cool day.

"Tests have already shown that the Stirling engine can be made into a very efficient power generator," said Chuck Andraka, project leader at Sandia's Solar Technology Department. "Now what we need to show is that many small Stirling engines can be coordinated in farms that together rival traditional power sources."

Eventually, according to DOE estimates, an 11-square-mile farm of Stirling solar dishes could generate as much electricity as the Hoover Dam, and a 100 x 100-mile farm could supply all the daytime needs for electricity in the United States. By storing the energy in hydrogen fuel cells during the day, Stirling solar-dish farms could supply U.S. electrical-energy needs at night too, as well as enough juice for future fuel-cell-powered automobiles, the DOE believes.

(See also the news release from Sandia National Laboratories)

Why is this stuff not a global priority? It offers so much hope for the future, something the world needs badly right now.




http://www.dreamingintechnicolor.com