Even with the recent development of extracting natural gas from shale, interest about so called “green energy” continues to grow. Although natural gas is a cleaner burning fuel than both oil and coal it is not considered to be “green” because it still produces carbon dioxide.
At this stage of development there are four sources of energy that are considered to be “green”. They are here in no particular order.
Solar is the best known and most fully developed of the green energy sources. Many utility companies are building farms of solar panels in areas of unobstructed sunlight and these are producing power for the nation’s grid.
Solar panels may also be an attractive option for individual home owners as well. The efficiency of panels continues to increase and the price continues to fall. While many homes could potentially benefit from having solar panels installed, many others are not good candidates because of overhead obstructions, poor site location, and limited hours of sunlight per day.
Wind energy is the next most installed form of green energy. There are many wind turbines already installed around the country and the world and, like solar, they are producing electricity successfully. However, there are significant questions regarding the effect of the turbines on bird migration and other factors as well.
Unlike solar panels, few homes are good candidates for the installation of a wind turbine in the back yard. Local permitting and regulation issues frequently have to be overcome and, of course, the home has to be located where the wind blows more often than not. One rule of thumb is that to be successful a home needs to be located where the wind blows consistently at a speed of at least 10 MPH.
Hydraulic (Water) Power
This is the oldest form of green energy and has been used for many years. Harnessing the Colorado River with the Hoover Dam was done specifically to install water powered generation of electricity. Today, many citizens of Nevada and California get their electricity from this installation.
The drawbacks to hydro-electric plants are enormous. Not only are they prohibitively expensive to build, there must be either a waterfall or a rushing river nearby to exploit. It is often said, and I think accurately, that the Hoover Dam would never be built today because of environmental concerns.
Geothermal Energy is produced by the heat from the earth’s core migrating up towards the surface. From hot springs, it has been used as a form of heating since roman times and is both reliable and environmentally friendly. Up to now, however, it has been limited to areas of the earth’s surface above tectonic plate boundaries. But new technology is greatly expanding the size and area of viable resources. Currently, there are more than ten thousand megawatts of electricity generated by geothermal energy around the world.
In home installation of geothermal heat pumps can, at a cost, bring geothermal energy to many homes. Because the upper 10 feet of the earth’s crust maintains a constant temperature of between 50 and 60 degrees (F), a heat exchanger can use this temperature to heat a house in winter and cool it in summer. However, the system requires a series of pipes be buried in the ground around the home which raises the cost of the system dramatically.
Other types of “green” energy include bioenergy (like burning wood) and ocean energy which depends on tides and currents to produce power.
One other potentially green energy source on the horizon is Nuclear Fission. Unlike today’s Fusion reactors, the only waste from a Fission reactor is helium. While the technical challenges are immense, work continues on a demonstration reactor in Europe that scientists hope to have in operation by 2020.
All in all, mankind is at the threshold of an era where cheap and abundant power may finally become a reality.