The two leading candidates for becoming major alternative energy sources are wind and solar. Both are subject to outages. The sun goes down at night and the wind sometimes fails to blow. So what do we do during the interruptions?

Let’s start with the obvious answer: We will keep the power grid and generators we now use. When an alternative energy source is available we will use it, otherwise we will use the traditional sources. The logic is that we use free fuel when it is available, but otherwise we keep on as always, for a net saving of whatever fuel was saved. The fault in that logic is that fuel costs are not the dominant costs in energy. Capital costs dominate.

Wind and solar have no fuel costs, the only costs are in construction and maintenance. those costs can be averaged over the life of the system and appear as a component of the cost of electricity. A few years ago, the cost of fuel for a coal burning electric plant was roughly a third of the total cost of a delivered Kilowatt-hour of electricity. Coal has not gone up like oil, so that’s probably still close. Some of costs beyond fuel are in the paperwork of billing and such, but most is the capital cost of building and maintaining the coal plant and the power grid that delivers the electricity.

cost of coal power = coal capital costs + coal fuel costs

We will set the total cost to 1 for comparison purposes.

cost of coal power = .7 + .3 = 1

It is difficult to put a figure on the capital costs of wind power. It is heavily subsidized, and claims of its competitiveness seem to ignore the subsidy. The best I can come up with is that the true costs per kilowatt are about 1.5 that of coal. To those costs we must add the cost of a backup system to be used when the wind stops.

How often the wind system fails to produce energy depends upon the wind, of course, but also the design of the system and the political climate. If the wind is too light there is negligible output, and if the wind is too strong the props musts be feathered to prevent damage. In California, the giant wind farm in Altamonte Pass is shut down all winter to prevent bird strikes, the consequence of a lawsuit by the Sierra Club.

My best estimate is that at a good wind site, the facility operates at a total of about 30% of the time. With better technology and better lawyers that might increase, to say 80%. Capital costs are due whether or not the system produces, for the same reason that parking a car does not reduce the car payments.

The total cost of wind power is then:

total cost of wind power = wind cost + backup cost

= wind capital cost + wind fuel + backup capital + backup fuel

= 1.5 + 0 + 0.7 + 0.3*0.2 = 2.26

I used 80% efficiency for the wind farm, so that the coal plant uses only 0.2 of the normal fuel consumption. If the wind farm were 30% efficiency, the total cost would be 2.41, not much different. With present technology, wind power is about two and a quarter times the cost of coal. Whatever your current electric bill is, multiply by two and a quarter to figure the switch to wind.

What about new technology? Tokyo Electric Power has a pilot project using sodium batteries. They use it for “peaking,” to even out the load on their generators. The total cost is a little more than a generator, but the economics of the peaking application make it appealing. There are other technologies that have potential, one experiment involves storing energy as compressed air stored in the ground.

Wind power offers the advantage of not polluting, but so does nuclear. At 2.25 the cost of conventional power, saving the pollution through wind would be achieved at extreme cost. There is no saving of foreign dependence on oil in the U.S., because the energy to make electricity comes mainly from domestic coal and natural gas.

T. Boone Pickens wants to use wind power to free up natural gas for use by trucks powered by compressed natural gas. The questions there are whether there are cheaper ways to get more natural gas and cheaper ways to get electricity. In both cases there are. On the other hand, the guy gets credit for proposing something concrete.

What is needed for both wind and solar is a practical way to convert the electricity to liquid fuel that can be burned in cars and trucks. That not only stores the energy, it is easily shipped, and it displaces foreign oil. Maybe we could use the best wind site in the United States, Alaska’s Aleutian Islands. The most promising avenue for that is probably fuel cell technology. The time horizon is perhaps 20 years.