Published: January 15, 2009 11:35 pm      

Wind can help fill our energy demands

The United States in 2007 (last year for which figures available) used 102 quadrillion British Thermal Units of energy (source: World Almanac 2009). A quadrillion is 1 followed by 15 zeroes.

If we divide this energy by the 2007 U.S. population (301.6 millon), this works out to be 11,240 watts per U.S. person continously. Now at current electric rates, of about 10 cents per kilowatt hour, this would be an annual bill of $9,853 per person!

This is far from our actual electricity bills, because it includes energy being used by our various kinds of transportation, armed forces, industries, stores, schools, hospitals and houses of worship. Our energy consumption per person is about twice as high as other modern countries with comparable conditions and living standards.

Our high rate of national energy usage is supplied by fossil fuels (petroleum, coal and natural gas) 85 percent, nuclear 8.2 percent, and renewable sources, 6.8 percent. The petroleum we used in 2007 was 65 percent imported and subject to big swings in prices. The long-term prospects for continued large flow of imported petroleum are unsure, as global oil production will likely decline in coming decades and demand will surge from Asian countries (where many more cars will be on the roads).

Coal is America’s fossil fuel of biggest reserves, but coal mining relies heavily on petroleum to power its huge devices. So when the petroleum wanes, how will we get our coal mined (presently, U.S. mines a billion tons of coal a year!)?

Natural gas has the benefit of new domestic discoveries every year to keep pace with domestic consumption but only by drilling thousands of new wells each year. Will the discovery rate continue decade after decade? (Natural gas can’t be easily transported over large distances as petroleum. So pipelines are essential.)

Our present nuclear plants are doing well, but new nuclear plants will be far more expensive than any other kind of energy generating plants. The only place in the world that can forge the massive steel cores for nuclear plants is in Japan and they have a three year backlog presently (ref. Jan 12th issue of Time).

In the same way as recoverable world petroleum is limited, the total amount of economically recoverable uranium is also limited. At current rates of consumption, neither petroleum or uranium will last to the end of this century.

We are left with renewable energy as the only sources for the long term. Presently most U.S. renewable energy is either from hydroelectric facilities or wood burning. The U.S. has tapped all of its prime hydroelectric sites.

But small hydro or microhydro will grow in importance for small communities or small factories that are nearby a creek. These facilities may generate a few hundred kilowatts. Wood burning can not only heat homes but also power electric generators as in paper mills. Tree plantations relying on fast growing trees can supply wood to wood burners (outside houses) that can produce heat at a cost comparable to natural gas costs. (Ordinary wood burning in fireplaces is much less efficient as most of heat goes out of the chimney.)

What remains are solar energy (two forms, passive and active) and wind turbines (two forms, residential and large units). Hopefully, there will be much work in the future for contractors who will modify existing homes so they can capture free solar energy for space (air) heating and hot water.

More new buildings will feature solar energy features such as solar interior lighting, rooftop gardens (to grow vegetables and insulate roofs) or roof solar panels (for interior power), most large windows facing south and interior heat storage (behind these large south facing windows).

Large solar panel installations using curved mirrors that follow the sun could generate much thermal energy in liquids that would be stored in insulated tanks. These hot fluids could be used to drive electric generators for several days following one sunny day (this kind of solar facility would provide power at night and on overcast days). But if overcast for a number of days in a row, then alternatives needed.

Wind turbines are only cost effective for windy areas. In Maryland, this means the ridges of our Appalachian mountains and off shore (in the Atlantic Ocean). Just like offshore oil rigs, wind turbines off shore are more expensive than land based wind turbines. Local wind turbines I have visited are rather quiet (compared to sounds of birds, crickets or wind blowing through trees) and could power a home when wind blows. Over long time periods, amount of power generated averages about one-quarter of full rated power.

The large wind turbine farm proposed for the Dan’s Rock area would provide about 20 megawatts of power. In terms of cost per kilowatt, large wind turbines on their high towers are cheaper than small home units. The charge that these power sources are intermittent is correct, but if there were enough wind farms widely distributed over a large enough area, there would be a near continual flow of wind electricity across that area.

Looking forward to the time when petroleum wanes, these wind farms could provide power for local coal mining operations to continue. My feeling is that every sizable community and county would be wise to encourage installation of renewable energy facilities to contribute to a regional power grid that might be more dependable than a national grid that may break down when there is unusual demand (during extremely cold or hot weather).

Venus and Uranus line up on Thursday

This Thursday early in the evening, the brilliant planet Venus and the dim planet Uranus will appear only 1.2 degrees (a little more than two moon widths) apart.

Since Venus is several thousand times brighter than Uranus, you will likely need binoculars to see dim Uranus to the left of Venus. Venus will then be 58 million miles away while Uranus will be more than 32 times farther at 1,869 million miles from Earth.

Bob Doyle invites comments and questions from readers, either by email at rdoyle@frostburg.edu or by phone (leave message) at (301) 687-7799.