Feb 15, 2009

Here Comes the Sun Shower

Published: February 9, 2009
NYTimes.com

Amherst, Mass.

THE Obama administration is poised to start a huge program to develop renewable energy sources — and at the same time, it hopes, create jobs, limit pollution and narrow our trade imbalance. The program is likely to include incentives for conservation — to encourage people to insulate houses and buildings properly, drive cars that need less gas and use low-flow shower heads and high-efficiency lighting. Reducing energy use, after all, is the cheapest way to reduce our carbon footprint.

But after conservation, one of the most effective and efficient steps the government can take is to encourage the use of solar hot-water systems — a well-developed and relatively low-tech method for using the sun’s energy.

Solar hot water systems are not as well known as the electricity-generating solar panels that use photovoltaic cells to gather energy. But hot water systems are more efficient than photovoltaic systems and can create the same amount of useful energy with fewer panels. Water heating accounts for a large share of a home’s energy use — typically the largest share after heating and cooling.

Three 4-foot-by-8-foot panels (covering a total area of 96 square feet) can, in full sunlight, deliver about 4.5 kilowatts of heat — enough to heat about 50 percent to 80 percent of the water used by a family of four. The cost to install such a system, including the panels, a water storage tank, piping, a pump and control electronics is usually less than $10,000.

In comparison, a photovoltaic system that can produce 4.5 kilowatts in full sun requires 11 like-sized panels and costs about $40,000. Here in New England, where our annual average illumination is equivalent to only about three hours of direct sunlight per day and relatively high electricity rates (about 16 cents per kilowatt hour), either system can replace about 5,000 kilowatt hours of energy a year. A conventional coal-fired power plant delivering the same amount of energy would emit about five tons of carbon dioxide. But the hot water system pays for itself in 13 years, while the photovoltaic system takes about 50. In places with more sunlight like the Southwest, much more energy can be produced.

Solar hot water systems also work better than many photovoltaic systems in partial shade. And they are simpler and easier for most contractors to install.

Ramped-up production of solar hot water systems would create jobs. Construction workers, many of whom are out of work, possess skills needed to install the systems. Several manufacturers of solar hot water panels and storage tanks are based in the United States. Increased production would also shore up demand for aluminum, which has declined as the American auto industry has shrunk.

Homeowners are eligible for a federal tax credit on solar heaters of up to 30 percent of the installed system's cost, with a cap of $2,000. If Congress and the Obama administration were to raise the credit to 40 percent or 50 percent, and the cap to $5,000, it would reduce the payback time to only six to eight years. At the same time, we would be taking a step toward a sustainable energy future.

Larry Hunter is a professor of physics at Amherst College.

Correction: February 13, 2009
An Op-Ed article on Tuesday, about tax incentives for solar water heaters, incorrectly described the federal tax credit for installing photovoltaic solar panels. There is no longer a cap on the credit. The previous cap, which was $2,000, not $5,000, ended on Jan. 1.

3 comments:

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  2. There could be no better investment in America than to invest in America becoming energy independent! We need to utilize everything in out power to reduce our dependence on foreign oil including using our own natural resources. Create cheap clean energy, new badly needed green jobs, and reduce our dependence on foreign oil. The high cost of fuel this past year seriously damaged our economy and society. The cost of fuel effects every facet of consumer goods from production to shipping costs. After a brief reprieve gas is inching back up. OPEC will continue to cut production until they achieve their desired 80-100. per barrel. If all gasoline cars, trucks, and SUV's instead had plug-in electric drive trains, the amount of electricity needed to replace gasoline is about equal to the estimated wind energy potential of the state of North Dakota. There is a really good new book out by Jeff Wilson called The Manhattan Project of 2009 Energy Independence Now. http://www.themanhattanprojectof2009.com

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  3. Suggest you to provide link to

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    and encourage your readers to use the Energy Environment Forum and get a link back !
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    ReplyDelete