Don’t Get Burned by Solar Power

Published January 1, 2003

The Rocky Mountain Chapter of the Sierra Club has launched a new campaign to “promote energy generation and efficiency that minimizes harmful impacts on public health and the environment, while improving the state’s economy.”

The group wants to require that 20 percent of all electricity in Colorado be generated by renewable energies by 2020. It also wants renewable energy to become 30 percent more efficient than it is currently. Impressive, but impossible.

According to the Energy Information Agency (EIA)–the nonpartisan data collection branch of the Department of Energy–less than 1 percent of all electricity generation in Colorado currently comes from renewable energy (defined as wind, solar, biomass, and geothermal). The EIA predicts that in the future, on a worldwide basis, renewable energies might increase their market share by a few percent.

Is it realistic to expect that in just 18 years, renewable energy could increase its market share in Colorado by 1,800 percent? In other states where similar policies are in effect, the mandate has never been achieved. For example, Florida requires that 7.5 percent of energy generated in the state be produced by renewables, but the state has reached just 3 percent.

An Inefficient Technology

Whether the share of energy produced by renewables can be increased depends primarily on the efficiency of the technology.

In this case, “efficiency” means how much of the energy source (be it wind or coal or solar) can actually be converted to electricity. For wind power, the theoretical maximum efficiency is 59 percent, but most windmills achieve about 50 percent efficiency with very good land and wind conditions. The efficiency of solar energy–how much heat can be converted to electricity–is approximately 35 percent.

One reason wind and solar energy are so inefficient is because they require vast amounts of land. Wind power requires about 11 square feet of land to generate 4 watts of electricity–the amount needed to turn on a light bulb. To generate that same 4 watts of electricity, a natural gas plant requires 30 to 200 times less space.

Solar energy consumes even more land than wind. Solar panels consist of photovoltaic (PV) cells. A single cell is about 10 centimeters in size and generates about 1 watt of power–enough for a pocket calculator, but not for a radio. A module of 40 PV cells can produce enough electricity to power a small light bulb. The modules can be combined into groups of 10 to form solar arrays. Ten to 20 PV arrays can power a single household, but for larger electrical needs, such as industrial factories, hundreds of arrays must be connected to generate enough power.

The inefficiency of wind and solar power is a major obstacle to increasing the market share achievable by renewable energies. Moreover, the vast amounts of land required by wind and solar farms represent an obvious environmental drawback … and a blight on the visual landscape renewable energy advocates claim they want to protect.

The Sierra Club argues that if the government mandates the use of renewable energy, the efficiency of renewable energy will increase. But corporate welfare–either direct welfare, in the form of subsidies to firms producing renewable energy, or indirect welfare in the form of mandates that protect one form of energy over another–isn’t usually the best way to make a company more efficient. More typically, companies get more efficient because they must compete in the marketplace … not because the government forces consumers to buy their products.

Matthew R. Edgar is a research associate with the Golden, Colorado-based Independence Institute.