Saturday, April 12, 2008

More about alternative energy

About a month ago, I wrote about the shortcomings of various alternative energy sources. That was mainly about a variety of problems with nuclear energy, solar energy (photovoltaics), and hydrogen.

I didn't even get into the subject of biofuels, but I should have, because the problems in that area are becoming painfully obvious.

Ordinarily I would not expect to find much significant reporting on a scientific/technical subject in Time magazine, especially something that challenges "conventional wisdom". But via DarkSyde at Kos I see there's an interesting article on the problems of "biofuel": The Clean Energy Scam
Several new studies show the biofuel boom is doing exactly the opposite of what its proponents intended: it's dramatically accelerating global warming, imperiling the planet in the name of saving it. Corn ethanol, always environmentally suspect, turns out to be environmentally disastrous. Even cellulosic ethanol made from switchgrass, which has been promoted by eco-activists and eco-investors as well as by President Bush as the fuel of the future, looks less green than oil-derived gasoline.

Meanwhile, by diverting grain and oilseed crops from dinner plates to fuel tanks, biofuels are jacking up world food prices and endangering the hungry.

The Time article focuses on the loss of rainforest, and consequently the loss of its ability to soak up and sequester CO2. When the forest is gone, CO2 will still be incorporated in biomass (crops of some sort). But then that is converted to biofuel, and released back into the atmosphere when it's burned. (To say nothing of the energy that's just wasted along with release of CO2 when the forest biomass is burned to clear it away.) Given all the energy that has to be expended to grow and harvest biofuel crops, with resulting additional release of CO2, we are worse off in terms of greenhouse gas emissions than if we just burned oil (or even coal).

But that's not the only serious problem. Crops that are grown to make fuel (from sugar cane, corn, switchgrass, or whatever) use land where food crops (for people and animals) could be grown instead. Driving up the cost of food for everyone on the planet. (Have you checked the price of bread or eggs at the market recently?)

Economists have spoken out about this problem for several years, when the hype for biofuels and ethanol was just beginning to build. For instance, we have from Howard Simons in early 2006: Making Our Food Fuel Isn't the Answer
If high prices strengthen energy's claim on food supplies, governments everywhere will intervene on behalf of their hungry citizens. If low prices torpedo biofuels' economics, governments everywhere will respond with subsidies for these industries. Only an elimination of current mandates and subsidies today will avoid these problems tomorrow, but the likelihood of this happening is near zero. Somehow I believe we will rue the day when we decided to make food and fuel substitutes at the margin.

In early 2007 Paul Krugman picked up the story: The Sum of All Ears
There is a place for ethanol in the world’s energy future — but that place is in the tropics. Brazil has managed to replace a lot of its gasoline consumption with ethanol. But Brazil’s ethanol comes from sugar cane.

In the United States, ethanol comes overwhelmingly from corn, a much less suitable raw material. In fact, corn is such a poor source of ethanol that researchers at the University of Minnesota estimate that converting the entire U.S. corn crop — the sum of all our ears — into ethanol would replace only 12 percent of our gasoline consumption.

So ethanol doesn't even help the U. S. all that much in terms of dependence on foreign oil. And this February Krugman returned to the subject here, linking to this: Ethanol Demand in U.S. Adds to Food, Fertilizer Costs
About 33 percent of U.S. corn will be used for fuel during the next decade, up from 11 percent in 2002, the Agriculture Department estimates. Corn rose 20 percent to a record on the Chicago Board of Trade since Dec. 19, the day President George W. Bush signed a law requiring a fivefold jump in renewable fuels by 2022.

Increased demand for the grain helped boost food prices by 4.9 percent last year, the most since 1990, and will reduce global inventories of corn to the lowest in 24 years, government data show. While advocates say ethanol is cleaner than gasoline, a Princeton University study this month said it causes more environmental harm than fossil fuels.

And then last week Krugman had even more: Grains Gone Wild
The subsidized conversion of crops into fuel was supposed to promote energy independence and help limit global warming. But this promise was, as Time magazine bluntly put it, a “scam.”

This is especially true of corn ethanol: even on optimistic estimates, producing a gallon of ethanol from corn uses most of the energy the gallon contains. But it turns out that even seemingly “good” biofuel policies, like Brazil’s use of ethanol from sugar cane, accelerate the pace of climate change by promoting deforestation.

And meanwhile, land used to grow biofuel feedstock is land not available to grow food, so subsidies to biofuels are a major factor in the food crisis. You might put it this way: people are starving in Africa so that American politicians can court votes in farm states.

Here's a report of a scientific study on the issue: Some Biofuels Risk Biodiversity And Could End Up Harming Environment
Corn-based ethanol is currently the most widely used biofuel in the United States, but it is also the most environmentally damaging among crop-based energy sources.

Finally, to bring this back to a solid scientific foundation, Sean at Cosmic Variance reminds us that Energy Doesn’t Grow on Trees
In particular, biofuels (such as ethanol) and hydrogen are not actually sources of energy — given the vagaries of thermodynamics, it costs more energy to create them than we can get by actually using them, as there will inevitably be some waste heat and entropy produced

Although all this bad news about just about every prospective near-term form of alternative energy is discouraging, there are a few other options that may become available in the slightly more distant future. There's the old perennial, controlled nuclear fusion. Even though work on that is even more active than ever, it's still at least several decades away.

But there's another significant option that's often overlooked: solar power satellites. This technology uses very large arrays of photovoltaic panels high in orbit around the earth. The energy is beamed back to the ground in the form of microwaves. (So this should not be confused with simply using mirrors to redirect additional sunlight, which presents serious problems of its own.)

Solar power satellites also have many uncertainties and potential problems, but the largest is simply boosting enough of them into orbit, and maintaining them. A possible approach to those problems involves space elevators. But those, again, present a whole additional set of challenges.

For now, here are a couple of articles from last fall with more details:

Pentagon backs plan to beam solar power from space

New Space Solar Power Report from DoD NSSO

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