Notes on the Underground
The February issue of Scientific American tells of a new technology that makes me both rejoice and worry. It looks so great, so likely to relieve a massive environmental problem that there’s no way I could oppose it. But on second, third, and fourth thought, I have some doubts.
The technology is called carbon sequestration. It takes carbon dioxide as it is spewed out by a human enterprise (such as a coal-fired power plant) and buries it deep underground or in the ocean. Carbon dioxide accounts for two-thirds of the greenhouse gases our economy emits. If we could put it somewhere other than the atmosphere and keep it there, we could burn fossil fuel without crazing the climate.
We know carbon sequestration can work, because in some places it already does. Natural gas tends to come out of the ground mixed with carbon dioxide, which is usually stripped out at the well and released into the air. But at operations where both gas and oil are produced, the carbon dioxide is often injected back into the well, where it helps push up more oil. This practice pays for itself in enhanced oil recovery. In the United States it sequesters 43 million tons of carbon dioxide a year. That sounds like a lot, but it’s less than 1 percent of global carbon dioxide emissions.
The Sleipner gas field off the shore of Norway is the only one in the world that sends carbon dioxide underground not to bring up more oil, but purely to protect the climate. About one million tons of carbon dioxide per year — three percent of Norway’s total emissions — go into a sandstone bed 3,000 feet below the sea floor. This venture makes economic sense only because Norway imposes an emission tax of $50 per ton of carbon dioxide. It is far cheaper for Sleipner to bury the stuff than to pay that tax.
If we all were as sensible as the Norwegians, there would be a carbon tax everywhere, carbon sequestration would be economic, and the human-induced greenhouse effect would be slowed. I fervently hope that happens. What worries me is the possibility that that will be the end of the story, that we will relax, thinking we’ve found a magic bullet that lets us go on driving gas-guzzling SUVs to our hearts’ delight.
Bullets only work when there’s a single target, one problem, one neat cause, one effect. In this case we have at least two problems, energy and climate, and many causes and effects. Carbon dioxide is the most prevalent climate-changing gas, but not the only one. Climate change is a major side effect of fossil fuel burning, but not the only one. We can’t begin to sequester every carbon dioxide molecule coming from burning coal, oil, and gas, but even if we could, we would still have oil spills, acid rain, urban smog, messed up aquifers, strip mines, Middle East security worries, depletion, and all the other headaches associated with nonrenewable, unevenly located, sloppy fossil fuels.
The good is the enemy of the best. Carbon sequestration is only good. The best energy technologies are those that give us light, heat, or motion using much less energy. High-mileage cars. Insulation. Efficient light bulbs and appliances. These innovations don’t alleviate just one bad effect, they alleviate them all by reducing (potentially by at least 90 percent) fuel use itself.
Next best, especially after we’ve reduced energy use through efficiency, are technologies that tap renewable sources. Solar. Wind. Hydro. Hydrogen. Not completely benign by any means, but much more so than the options farther down the list.
Next would be natural gas, especially if combined with carbon sequestration, which does not need to take place in deep earth or deep water. Reforestation and composting store carbon in trees and soil. These forms of sequestration do more than hide carbon dioxide; they also hold water, moderate climate, provide habitat for living things, fertilize soil, look beautiful, and cost little. And can be done by anyone.
If we work our way down this list of preferences, we need never come to oil, coal, or nuclear power.
If there’s any magic bullet available to us, it’s economic, not technical. It would require us all to be a little smarter than the Norwegians. We’d put a tax not on carbon emission at the end of the pipeline, but on energy production where the pipe begins. The tax would be proportional to the real cost of environmental damage. Zero for energy efficiency. Small for renewables. More for natural gas with biological carbon sequestration (trees and compost); still more for the deep sequestration described in the Scientific American article; and more yet if there is no sequestration. Highest of all for oil, coal, and nuclear.
That may look like a tax, and it could substitute for other taxes, but it really is a fix of a market fault. It takes very real costs, which someone has to pay somewhere sometime — the cost of climate change, air pollution, acid rain — and puts those costs into the price of energy where they belong. Polluters pay. Carbon sequestration becomes economic everywhere, as does solar power, and above all energy efficiency. SUVs get 100 miles a gallon or run on hydrogen or both.
A magic bullet in the economy helps all the technological bullets zero in on all the right targets.