Energy Dreamin'

Donald Sensing over at One Hand Clapping posted today about how we're really stuck with internal combustion engines, as the alternatives under development today (hybrids and hydrogen-fueled cars) don't really solve the problems. An excerpt:

But what about hydrogen cars? They would burn hydrogen and oxygen and emit water. How cool would that be, eh? But writer Patrick Bedard says that if by a trick of science autos had been invented using hydrogen-oxygen motors, so that everyone was driving them now,

... President’s FreedomCAR initiative would be anteing up its $1.8 billion to invent the gasoline engine. Freeing us from hydrogen would be “the moral equivalent of war,” to use the words of a long-past energy-crisis president. Gasoline would be the miracle fuel. It would save money by the Fort Knoxful. It would save energy by the Saudi Arabiaful.

The reason is that the amount of energy required to produce a kilogram of hydrogen is simply enormous, many multiples more than the energy recovered by using the hydrogen as a fuel. Where would all that energy come from?

Virtually all the hydrogen produced today, about 50 million tons worldwide, comes from natural gas. The process, called “steam reforming,” is only about 30 percent efficient, much less, he [Donald Anthrop, Ph.D., professor emeritus of environmental studies at San Jose State University] says, “than if the natural gas were simply burned” in the generating plant.

Producing enough hydrogen to replace gasoline by reforming natural gas would increase our [natural] gas consumption by 66 percent over 2002’s usage. And don’t forget the carbon emissions.

Mr. Sensing is talking about one of my pet peeves with the alternative energy promoters: in general, they seem to have neglected the most fundamental problems with whatever energy source they're promoting — and I can't think of a better example of this than the promoters of hydrogen vehicles. The hydrogen-powered cars are a great example, as Mr. Sensing points out. Where's all that hydrogen going to come from? While it's true that today most hydrogen is produced from natural gas, what most promoters of a hydrogen-based energy economy assume is that hydrogen will be produced by "cracking" water into its constituents (hydrogen and oxygen). Cracking water requires as much energy as was produced when the hydrogen originally "burned" to produce the water in the first place, plus whatever inefficiencies are inherent in the process. Because cracking water is best done through electrolysis, this means lots of new generating capacity — 241 gigawatts just to run the cars in the U.S. — is needed. From Leon Walters at the Argonne National Laboratory:

"Renewable energy technologies - wind, solar and geothermal - can make an important contribution," he said. "These technologies tend to be too intermittent to provide reliable base-load electricity, but they can generate hydrogen and store it when the wind is blowing or the sun is out. On the other hand, they are too diffuse to generate 241 gigawatts of new capacity. You'd need 640,000 windmills, for example, which would occupy a total land area of 71,000 square miles - nearly the size of Ohio and Indiana combined.

Mr. Walters goes on to say that (basically) the only technology available to us to produce this kind of power without polluting the air is ... nuclear. Reactors could be built to produce that extra 241 gigawatts of electricity, or could be used in other processes (such as thermochemical) to produce the hydrogen needed.

Can't you just hear the environmentalist wackos reacting to the idea of (say) another 50 or 100 nuclear power plants scattered around the country? And while the reactors may not pollute the air, what the heck would we do with all the nuclear waste they generate? We can't even get rid of the waste from the few reactors we have today.

Sigh.

Further information about hydrogen cars can be found here, here, and here.

Hybrid cars provide another interesting example of this neglect of fundamentals. For people who drive mostly in the city, with little highway driving, it is possible to make a hybrid vehicle that will get much better gas mileage, and will save enough money on fuel to pay for the extra cost of the vehicle over its lifetime. But that's the exceptional case, unfortunately.

Drivers who spend a lot of time on the highway will see no gain in their fuel efficiency for those miles. In fact, it may actually be worse — as all the extra weight of the batteries and extra mechanical components has to be lugged around. These drivers will not win on either fuel efficiency or overall cost.

As hybrids enter the market, manufacturers are learning what consumers like and dislike about them. One early lesson: consumers want power and responsiveness. The result is that more recent hybrids have compromised fuel efficiency to deliver what consumers want — and actual fuel efficiencies achieved (as opposed to the highly unrealistic EPA tests) are often little better than can be had for much less money with conventionally powered cars. Once again, a double "no win".

So what's the lesson in all this? Just this: be skeptical about the "save the earth" claims of the alternative energy promoters. Nobody has yet come up with an alternative energy source (to hydrocarbon) that is (a) practicable to implement, (b) delivers increased efficiency and reduced pollution, and (c) is usable for all those things we use energy for, most especially vehicular systems. Energy generation and distribution is a very challenging problem that hydrocarbon fuels happen to address very, very well. It's going to be quite a while before something better can displace it...