The media covers a lot of alternative renewable energy sources such as solar, wind, ocean wave, geothermal and hydropower as methods that do not cause the emissions and resulting climate change of fossil fuels. The main issue with them other than cost as they are being developed is that they are intermittent. Better methods of storing the energy they create are in process.
Renewable energy can be currently commingled with the predictable fossil fuel sources to reduce emissions but energy storage technology must be found for alternatives to fully replace fossil fuels. Hydroelectric dams are one way of
storing energy by using the energy to pump water back into reservoirs during excess energy production and running it through turbines to meet later needs. Some energy is wasted with this method.
One hundred mile square solar arrays installed on each side of the Southwest desert would produce all the energy needed in the United States, but there would still need to be a backup source for cloudy days. Wind power is cheaper to install than solar PV panels, but wind systems are large and more visible and storage is needed for less windy days. Watch the video on using rails for wind storage.
Geothermal is perfect for seismically active and hot spring regions like in the Rockies and Iceland. The steady temperature of 55ºF just below the Earth’s surface can be used to cool warmer or heat cooler air above, but storage is an issue with above ground temperatures fluctuating with seasons. Natural gas turbines can be a backup but the cost does not pay off for utility companies during the times the backup system sits idle.
Different types of batteries and elements are in the experimental stages for storing excess electricity, but advances are slow and funding is difficult. The fact is producing electrical energy removes another type of energy and releases heat. Kinetic energy is removed from the lower atmosphere by wind energy and wind is slowed.
Hydropower plants increase evaporation rates, disturb wildlife, reduce land use for other purposes like agriculture, and prohibit travel by water routes among other issues. Solar roof panels probably affect the environment the least.
Unlike varying winds, tides rise and fall on a schedule and can be as high as 50 feet in deep bays. Barriers have to be built across rivers or beaches to force rising water through turbines. When the tide recedes, the water is pulled through the turbine in the opposite direction creating more electricity. The first tide farm was built near Hammerfest, Norway in 2003 and Scottish Power has installed giant turbines in the sea completely hidden from view.
Studies on wave energy done in Australia, Hawaii, Ireland and Scotland reported wave power is ideal for those countries and nearby Bermuda has similar characteristics. Since oceans cover 70 percent of the earth and contain so much wave and tidal energy, ocean water movement seems like an obvious energy source. Read about German engineer Rainer Schramm’s work with research organization SINTEF on the exciting new method of using seabed water pressure in connection with storing wind energy.