The Home of American Intellectual Conservatism — First Principles

December 15, 2017

FEATURE ARTICLES
Page 7 of 8
The Energy Crisis
P. E. Hodgson - 08/15/08

Tidal

Some river estuaries are so formed that they experience high tides. When there is a high tide, the sea water flows in, sometimes to a surprising distance from the sea. Around low tide this water flows again back to the sea. If a barrier is put across the river the water flows through pipes to the sea. It is then easy to make this flow rotate a turbine and generate electricity. Such a device has operated in the La Rance estuary in France for many years, producing 65MW. It is reliable, although the peak periods vary according to the moon and not the sun, so the electricity is not always available when it is needed.

A similar though much larger scheme has been proposed for the Severn estuary between England and Wales. It would cost about fifteen billion pounds (about twenty-seven billion dollars) spread over about ten years to build and would produce about 7GW. The environmental effects are expected to be severe as the whole ecology of the area would be altered. The cost of the energy produced would be about twice that from a conventional power station. It is a practicable but hardly attractive prospect.

Wave

Once again the energy in the waves is enormous, but it is difficult to concentrate. A number of devices to do this have been built, but the output is not cost-effective. One such device, costing over a million pounds, had a power output of 75 kW, enough for 25 domestic electric heaters. Wave machines are, moreover, always at the mercy of storms, which can destroy them in a few minutes.

Solar

The sun pours energy on to the earth at the average rate of about 200 watts per square meter so that the amount of energy that we obtain is proportional to the area of the collectors. It has been estimated that to supply the energy needs of four houses requires a collector the size of a large radio telescope. The sunlight can be used directly to heat domestic water circulating in pipes on the roof. This process is reasonably economic and is widely used. Nevertheless, there has to be an additional source of energy for times when the sun is not shining. On a larger scale it is possible to focus the sun’s rays on a boiler at the center of an array of hundreds of mirrors. The steam produced can be used to drive a small turbine to produce electricity. The disadvantage is that the mirrors have to be constantly turned by servomechanisms to keep the sun’s rays focused on the boiler so the whole process is uneconomic.

Electricity can also be obtained using photoelectric cells. These are expensive to make and produce electricity with a low voltage. They are not economic for large-scale generation, but are very useful to generate electricity in situations where the other sources are impossible or impracticable, such as in satellites and traffic signals in remote areas.

Thus solar power has useful but small-scale applications that will certainly be developed further when the cost of photoelectric cells is reduced. It is not a practical economic source of energy for the major needs.

Geothermal

The interior of the earth is hot, and in some places hot water gushes out. This can be used as an energy source, but on a small scale in rather few places. Elsewhere it is possible to drill two nearby shafts, pulverize the rock between their ends, and then pump water down one and extract it by the other. Passing through the rock, the water is heated and is an energy source. However if the shafts are close the heat in the vicinity is soon used up, whereas if they are far apart the water has difficulty in passing from one shaft to the other. Trials show that this process is absolutely uneconomical.

Page 7 of 8

Library of Modern Thinkers

Amazon.com Logo

By clicking the logo above to shop Amazon.com, every purchase helps to support ISI.

Intercollegiate Studies Institute • 3901 Centerville Rd. • Wilmington, Delaware 19807-1938 • www.isi.org
Please direct all inquiries regarding First Principles to [email protected].