When man started to supplement his muscle energy with outside sources, these sources were all renewable and inexhaustible. The muscle power of animals, the burning of wood, the use of hydraulic energy were man's external energy sources for millions of years. Only during the last couple of centuries have we started to use exhaustible energy sources, such as coal, oil, gas, and nuclear. This change in energy sources not only resulted in pollution but has also caused uncertainty about our future because we can not be certain if the transition from an exhausted energy source to the next one can be achieved without major disruptions.
The total energy content of all fossil deposits and uranium 235 (the energy source of "conventional" nuclear plants) on the planet is estimated to be 100 X 1018 BTUs. Our present yearly energy consumption is about 0.25 X 1018 BTUs. This would give us 400 years to convert to an inexhaustible energy source, if our population and energy demand were stable and if some energy sources (oil and gas) were not depleted much sooner than others.
Breeder reactors have not been considered in this evaluation because the plutonium they produce is too dangerous to even contemplate a plutonium-based future. This is not to say that conventional nuclear power is safe. Man has not lived long enough with radiation to know if millions of cubic feet of nuclear wastes can be stored safely.
We receive about 100 Watts of solar energy on each square meter of the Earth's surface, or a yearly total of about 25 X 1018 BTUs. Therefore, 1% of the solar energy received on the surface of the planet could supply our total energy needs. If collected on artificial islands or in desert areas around the Equator, where the solar radiation intensity is much higher than average, a fraction of 1% of the globe's surface could permanently supply our total energy needs. If the collected solar power were used to obtain hydrogen from water and if the compressed hydrogen were used as our electric, heat, and transportation energy source, burning this fuel would result in the emission of only clean, nonpolluting steam. Also, if the combustion took place in fuel cells, we could nearly double the present efficiency of electric power generation (about 33%) or the efficiency of the internal combustion engine
(about 25%) and thereby substantially reduce thermal pollution.
Today, as conventional energy use increases, pollution tends to rise exponentially. As the population of the U.S. has increased 50% and our per capita energy consumption has risen 25%, the emission of pollutants has soared by 2000%. While the population of the world doubles in about 50 years, energy consumption doubles in about 20 and electric energy use even faster. In addition to chemical pollution, thermal pollution also rises with fossil energy consumption, because for each unit of electricity generated, two units of heat energy are discharged into the environment.
It is time to redirect our resources from the military— whose job it is to protect dwindling oil resources—and from deep sea drilling—which might cause irreversible harm to the ocean's environment—and use these resources to develop the new, permanent, and inexhaustible energy supplies of the future.
Was this article helpful?