book_cover_big.gifCan we “save” energy? Of course not. We cannot “save” energy as the first law of thermodynamics explains: energy is conserved no matter what we do. The only thing we can do to help solve the planet’s energy problem is to reduce the speed with which we degrade the quality of the energy sources available to us. And indeed the best way to accomplish that is to “use” as less as possible of this high quality energy. Examples of high quality energy are fossil fuels, nuclear fuel, solar or PV energy, wind energy etc. The common factor in all these different sources is that the energy is concentrated in a relatively small volume. A typical example of low quality energy is heat (most of the times at least). Why? Heat is difficult to maintain and tends to leak away and thus disperses over a large volume. One joule of heat remains one joule of energy regardless whether the volume in which it is contained is one cubic cm or the entire galaxy. So where is the problem? Here is where the Second Law of thermodynamics kicks in. High quality energy conditions have a low entropy value whereas low quality energy has a high entropy value. The entropy law teaches us that with each “use” of energy the entropy increases (and thus the quality is decreasing) and that there is no recovery back from that. In other words quite a fundamental limitation and no technology can help you overcome that Second Law!

There are two ways how we can help ourselves to slow down the ever ongoing energy quality degradation.

1) The quickest one is simple: reduce the need for energy as much as you can! Let’s have a look at the energy ‘consumption” breakdown (IEA 2008):

Category Relative energy usage (%)
Industry

32

Road transportation

20

Air/sea transportation

6

Agriculture

3

Services

7.8

Buildings

28

Fertilizers

5

For example, as long as the fuel “consumption” in the USA per km is still about 40% higher than that in Europe it is clear where the focus needs to be. Also, note that about 20% of the total energy needs goes into road transportation. Thus if we would start to drive energy efficient cars, it would cut 10% of the US total national energy bill! No needs for new inventions, just take what exist already today!

 Because of the high fuel prices there have been proposals from politicians and governments to reduce taxes on fuels. This is precisely the wrong measure to implement. What should be done is to lower the tax or subsidize more measures that will result in less energy needs such as home insulation, fuel efficient cars and fuel efficient heating units. The best way to solve the energy problems of the planet in short term is reducing the need for energy in the first place!

 2) The other way to mitigate the energy problems of the planet, but then more long term, is the use of renewable energy sources, basically all based on the solar energy that reaches the earth. The sun is such a rich source. Realize that the energy influx is many times higher than the world energy need. There are massive problems to overcome such as costs price and, more importantly, the capacity of our power grid that can accommodate these variable energy sources. This will ask for clever storage means that must come along with the renewable sources.

© Copyright 2009 John Schmitz

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