Anablog

Three interesting “green” articles this week. This one describes how Israel will mandate a large electric car infrastructure. Another article talks about the potential to harvest energy just by drilling deep holes into the earth. The final article talks about the shortages and high prices for food worldwide caused by the government mandates for ethanol and other bio-fuels made from food and feed stocks like corn.

The Israeli program is certainly well meaning. And it is clear they get one thing right. They know that when wild-eyed US futurists talk about charging your car in a few minutes it is just a physical impossibility. I have already detailed how you would need 2000 amps and lethal voltages, as well as an electric utility substation at every “gas” station in order to do this, and that is predicated on a 5 or ten minutes of charge times. So the Israeli plan is to have cars that carry quickly replaceable battery packs that you just swap out at the ”gas” station. Pretty smart. But now do the volume calculation for the number of batteries that would hold the same amount of energy as a 5000-gallon underground gasoline tank. Each gas station needs to have a 10,000 square foot warehouse just to hold the batteries. Don’t believe me? Think I am a shill for the oil industry (I despise those pigs BTW)? OK, one gallon of gasoline has 132 MegaJoules of energy. So 5000 gallons in that underground stage tank at your local gas station has 658,800 MJ. Yes kids, that is 659 Giga-Joules right in your very own neighborhood Shell station. OK the common lithium cell is 25650 so that is 25mm by 65 mm and that is about 2.5 cubic inches. The RC airplane folks seem to have the only honest data, kudos to fellow engineer Sid Kauffman, Ph.D. for posting some very nice work he did regarding li-ion cell performance. So we see from Sid’s chart that the new A123 ferrite based lithium chemistry (E-Moli in Milwaukee tools and M1 in Dewalt) indeed does have smaller capacity that conventional lithium-polymer cells. This may be sobering to all of you that just read press releases about how A123 nano-technology makes the batteries more powerful. It does not. It allows the ferrite anode to have surface area and gives great high-discharge performance, but the big deal is that they are safer; they won’t go into thermal runaway. Anyway Sid shows the A123 cells have between 6500 and 9500 mWH capacity at a 10C discharge, which is great. Hey lets call it 10,000 mWH. So a joule is a watt-second. 10k mWH is 10 WH which is equal to 36,000 Wsec or 36 kiloJoules. 36k goes into 659 Gigs 18.3 million times. That’s a lot of battery cells to equal 5000 gallons of gas. About 318,000 cubic feet of them, or a 32,000 square foot warehouse stacked 10 feet high.

OK, OK, this is a rough calculation for sure. First off internal combustion engines are about 30% efficient. But high-current motor systems are not 100% efficient either. So you get maybe a 10% loss for electric propulsion. But diesel motors are 40% efficient. And I just calculated the size of the cells not the whole pack (yeah, I cubed off the round cells, sorry) but you can bet that when all is said and done the volume is still something like 10,000 square feet stacked 10 feet high. All that to get the same amount of energy storage that every gas station in America has stored safely underground. And you still have to have charging and swap-out stations and the like. No, the Israeli idea is well meaning, but impractical.

These “private-government partnerships” are getting to be more and more popular. Having the government mandate private investment has a name. Actually it has several names. Socialism is one name. Another name for this is fascism. But before these 20^th century flavors came into being, there was mercantilism. That was the medieval system where government was seen as a servant of the rich and oppressor of the poor. It handed out favors to connected groups. The entire system was completely discredited in 1776 by Adam Smith when he published An Inquiry into the Nature and Causes of the Wealth of Nations. So you might think it is great to have the Israeli government tax its citizens and hand the money over to a bunch of politically connected professors and engineers. Heck, if the welfare queens in Chicago can be on the take, why not us technical people? But these government-mandated efforts almost always fail. They fail in Hugo Chavez’s Venezuela, they failed in France when they wanted to have a private internet and it will fail in Israel. If you like a system where the government taxes honest citizens and funnels you the cash, I suggest you move to one of the hundred third-world countries where this is common.

That is not to say that I do not think that government action could not help our infrastructure. If you just can’t help passing laws, then mandate that every US gas station offer both diesel and propane. A twenty word memo, and voila, our mobile energy needs will be solved for about 100 years.

Now, the article on geothermal energy was far more promising. One issue there, familiar to all the power generation engineers, is the problem with low heat differential. If you had to do steam tables in thermodynamics like I had to, you know that the bigger the temperature differential the easier it is to get useful energy. This is why there has been Sterling engines on the cover of Popular Science for 4 decades, and none in use. It is hard to get economically practical energy off a small temperature difference just like it is hard to make electricity from a dam that is 10 inches tall. Nevertheless, it is tantalizing to think we can just bore holes 6 miles down and make a boiler. It remains to be seen if this works out economically. The hardest thing for scientists and media and green-freaks to understand is that engineering is the intersection of science and economics. If it does not cost out, you are wasting capital and should be doing something else. And no, it does not make sense to have the government put in a few billion dollars “just to get things started”. If the technology cannot get started in the private sector it is most likely impractical or an out and out boondoggle.

The bio-fuel article in the third link above is just another tweak to all those people that got upset over my “electric cars kill babies” blog a few months ago. See, when you pass laws that force uneconomical resource allocation, you starve babies. Please let the engineers and businessmen decide how to solve problems, leave it out of the hands of the farm lobby and Archer Daniels Midland, the green equivalent of Halliburton. Once again, I do see a role for the government. We should stop propping up the price of grain, food, textiles and other goods artificially and let the world economy work. By artificiality putting up barriers to cheep cotton and grain the US explicitly and directly starves children. By allowing third-world countries to sell us cheap textiles we allow them a way out of poverty. By not artificially raising grain and food prices, we allow them a way out of starvation. I hope you feel good about pumping that ethanol into your tank today, I don’t.