Monday, June 18, 2007

Ethanol numbers

I've been hearing a lot of advertising for GM "flex-fuel" vehicles, and supported ads for ethanol producers telling us to "go green!" It's a hot topic, and it seems that the verdict really isn't in on whether moving to ethanol as an alternative fuel (E85- - 85% ethanol, 15% gasoline) is a good idea.

It sounds good on the surface, of course -- fewer emissions, using a "renewable" resource vs reliance on fossil fuels (and the necessary reliance on foreign supplies of oil). I'm all for changing what we do if it's really better; I'm not a tree-hugger by any means, but I think we all have a responsibility to use resources better and try to keep our impact on the rest of the world as small as possible. We Americans love our cars, and I think we need to be more careful how we use them and fuel them.

But the ads that I've been hearing have some disturbingly vague information. Most notably, the "Live Green, Go Yellow!" campaign touts that "Ethanol can cost up to a dollar less per gallon and save x dollars a year in fuel!".

Well, not quite. First, in many states, E85 is actually more expensive than gasoline, and it is available in only a few places. In March, the adjusted average for gasoline was 2.30 a gallon, for ethanol, 2.96. The difference was a bit smaller recently, but only because gas is climbing near the 3.50 mark, at least around here.

Second--and more importantly--Ethanol has fewer BTUs than gasoline (about 80K/gallon, vs 109-125K), that is. it has less energy in it. So, your car gets fewer miles per gallon of ethanol than it does for gasoline, despite the higher octane. Estimates range from 25-25% decrease in fuel efficiency. The latest studies from the Energy Dept suggest that the drop could be as high as 40%. (Their tools are here)So that mythical dollar you save on buying ethanol is easily outweighed by the additional gallons you have to buy. It's hard to get actual numbers, since Ethanol is not yet widely used and most cars mix a tank of gasoline in once in a while, but at least one example noted a 17% difference in fuel efficiency running "mostly E85" and 24% using solely E85.

[Businessweek] From General Motors, an ad campaign called "Live Green, Go Yellow" gave America the impression that by purchasing GM vehicles capable of using E85 ethanol, we could help reduce our dependence on foreign oil.

What GM left out of its ads was that the use of this fuel would likely increase the amount of smog during the summer months (as the EPA's own attorneys had admitted in 1995) -- and that using E85 in GM products would lower their fuel efficiency by as much as 25%. (USA Today recently reported that the Energy Dept. estimated the drop in mileage at 40%.)

Newer cars, with computer-managed fuel-injection systems are likely to do better, but even cars designed as flex-fuel vehicles show a definite drop in fuel efficiency. Ok, so it doesn't cost less -- that has never really been a goal of using alternate fuels (although it sure seems to be touted as a benefit in advertising). Does it at least cost less to produce? Early data suggested that it actually was a zero-sum game: it took as much energy to produce a gallon of ethanol as it contained. Newer methods of generating ethanol are not as bad, and there is a net energy gain from ethanol. I was also surprised to learn that ethanol cannot be transported in pipelines like gasoline (it picks up impurities and excess water too easily) and thus must be trucked to processing plants and distribution centers. If you balance the cost of having to drive trucks to haul the stuff, the balance sheet doesn't look as good, either. [Ethanol's Net Energy Balance]

But cost of fuel is not really the driving issue here. Even if it costs you the same to drive with E85, the benefits of cleaner air, etc, would be enough to get people to swap, right? Well, even that is up in the air. E85 use can actually cause more smog during some periods even if it doesn't belch out hydrocarbons and other greenhouse gasses.

But it's the invisible cost that strikes me as more dangerous. If we pursue creating ethanol from food crops (corn, beets, etc) as a primary use, we're going to drive up the cost of food. No one is really sure just how far the ripple effect will go -- but the demands of producing corn, for example, as a source of ethanol have already impacted corn prices and land use. Recently, the UK reported that:

the final figure is equivalent to 1.2 billion litres of bioethanol and 1.35 billion litres of biodiesel. If this were to be produced in the UK, 1.2 million hectares would be required, about 20% of the UK's arable land.

Now, the US has a lot more land under cultivation, as does the rest of the world, so the assumption is that most ethanol/biodesiel will be shipped around the world from producers to users.

So if I sound skeptical about the lovely claims that ethanol is "the perfect plan", I am. Perhaps in the balance, it is a better choice, but the campaign to get it accepted seems to be relying on some pretty shady marketing tactics. Appealing to my pocketbook might get me to look at other options, but when in the end, it might cost more to use it, I'm definitely going to be doing a lot more research first. If a large chunk of the things I buy get more expensive because we shifted land-use, transportation methods, and other costs from oil to cover crops...the benefit of fewer emissions may not be enough to sway most people away from common, (relatively) cheap and familiar gas.

1 comment:

The Tiger said...

Ethanol is definitely NOT the perfect plan. Cellulosic ethanol is a good intermediate plan, as long as the cellulose can be efficiently (and "greenly") gathered.

One good possibility for a phase III biofuel is a higher alcohol -- butanol. Butanol has virtually the same energy content as gasoline, but still burns cleanly like any pure alcohol. However, at present, butanol is very hard to make.