In celebration of the 30th Anniversary of NASA Tech Briefs, our features in 2006 highlight a different technology category each month, tracing the past 30 years of the technology, and continuing with a glimpse into the future of where the technology is headed. Along the way, we include insights from industry leaders on the past, present, and future of each technology. This month, we take a look at the past 30 years of Power & Energy Technology.

One of the most debated issues today is power and energy, and the available resources for both. According to the U.S. Department of Energy (DOE), U.S. energy consumption is projected to increase by about 32 percent by 2020, and our nation’s dependence on foreign sources of oil is at an all-time high — and is expected to grow.

This wind turbine electrical power generation facility on San Clemente Island, CA, features turbines that begin producing power at 9 miles per hour (mph), and continue producing power up to 56 mph. (Warren Gretz, DOE/NREL)

The Energy Information Administration (EIA), which provides official energy statistics from the U.S. Government, predicts that carbon dioxide emissions from energy use will increase from 5.9 million metric tons (in 2004) to 7.6 million metric tons in 2025, an average annual increase of 1.2% per year. Renewable energy sources that provide alternatives to oil, coal, and other fossil fuels can significantly reduce or eliminate carbon dioxide emissions into the environment. These renewable sources include solar, wind, geothermal, and hydropower energy.

Over the past 30 years, the U.S. has significantly improved its energy efficiency through the use of renewable energy sources, but according to the DOE, even with considerable conservation, the U.S. will need more energy supplies of all types.

Solar Energy

Technologies to capture, store, and deploy solar energy have been around for decades, and although the use of these technologies continues to increase, widespread implementation has not happened, despite the proven advantages of energy efficiency, lower cost, and environmental friendliness associated with solar energy. Today, solar cells of various sizes are used to power everything from handheld calculators and watches, to road signs, homes, and commercial buildings. Harnessing the power of the sun is accomplished by technologies such as photovoltaic cells, concentrating solar power, and active and passive solar collection.

Photovoltaic (PV) cells — or solar cells — are electricity-producing devices made of semiconductor materials such as silicon, and convert sunlight directly into electricity. The PV cells are connected together to form modules that, in turn, are connected to form solar arrays. The size of an array depends on how much sunlight is available in a location and the amount of electricity demand.