Monday, January 25, 2010


Some Thoughts about Energy

We Americans use a lot of energy. Most of our energy comes from burning carbon. That is, we find or grow various forms of carbon: coal, petroleum, natural gas, alcohol; then we chemically combine it with the oxygen in the air. The heat produced operates an engine with an efficiency not greater than the ideal efficiency, attributed to Carnot, the French engineer who studied heat engines. Other sources of energy include water power, wind, geothermal power, power from fissioning uranium, and solar power.

It would be ideal if we could replace all the carbon power stations with power plants that use these other sources. Aside from the engineering work needed to design and build efficient and safe power plants, some of the non-carbon power sources have characteristic problems.

First, we are used to having power available at all times of the day or night. We want light, we flick a switch. If we're cold, automatic equipment in the house starts using more carbon (methane or ethane gas) and more electrical energy, also powered by burning carbon. Solar power requires only a simple, automatic plant. However, the plant doesn't produce any power at night. If we were to depend on solar power for all or nearly all our requirements we would have to develop and build eqipment for storing energy so that we could have television, warmth, and other comforts at night as well as in the daytime. Wind power poses a similar problem. A natural location for windmills is a place with wind nearly all the time. The catch is "nearly." There are few places that boast perpetual wind. Again we would need a means of storing energy for use during calm air. Geothermal power is constant. Potassium and other radioactive elements in the earth's core maintain a steady source of heat, waiting for our exploitation.

Water power seems like a nice alternative to the uncertainties of sunlight and wind and the extreme engineering difficulties of exploiting the heat of the earth's core. However, we have already put in use nearly all the water power available. We are also learning that water power is reduced during times of drought and water power plants (i.e., dams) interfere with the migration of important food fish, such as salmon.

We are left with two options. First, we can develop an efficient and cost-effective way of storing the excess energy of a solar or wind plant. Second, we can use existing technology to build and use nuclear fission plants. I have some thoughts on both subjects.

I know of two means of storing electrical energy: batteries and electrolysis. The size of the battery needed to store the energy of a large solar plant or a large windmill plant is great enough that there may not be enough batteries in the world to satisfy the need. In such a case, some of the power of the plant could be used to electroyze water into its constituent gases, hydrogen and oxygen. These gases would be stored in high-pressure tanks. They could be used to fill containers for transportation to other plants. They could also be used at the site of the windmills or solar panels to power an auxiliary power system that would operate when the wind had died down or the sun was not available to operate the solar cells.

I also know of some improvements in the design of nuclear reactors to make them safer to operate or more efficient in their use of available fissile metals. One improvement was suggested more than 60 years ago by Edward Teller. What is needed is a kind of fuse for a power reactor that will operate automatically and completely reliably to shut it down in case of an uncontrolled power excursion. When I worked at Atomics International an engineer and I worked on the design of a fuse for a power reactor. We never got as far as testing and demonstrating the concept in an actual reactor. We did conduct some experiments with a prototype to verify the mechanical features of the design. We obtained a joint patent on the device. About that time I left Atomics International and my partner in the enterprise (I can't remember his name) was assigned to another program. Atomics International was getting out of the reactor business and had no interest in pursuing additional work on the fuse.

I do not claim any originality for these ideas. I think they are good ideas and it would be a good thing to start some young, energetic engineers working on them


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