- By Lisa Busch   

The experts say that existing technology can reduce the carbon dioxide emissions that may cause global warming, but it's very expensive, and the United States isn't investing enough to make a difference.

President George W. Bush caught plenty of flak from environmentalists when he refused to sign the Kyoto Protocol to reduce carbon dioxide (CO2) emissions. Bush called the plan unworkable and unfair and claimed it would devastate the U.S. economy without significantly cleaning up the Earth's atmosphere. The president has acknowledged that CO2 may be contributing to global warming. But he promises there will be solutions emanating from U.S. laboratories. "America is a leader in technology and innovation," he says. "We all believe technology offers great promise to significantly reduce emissions." It's certainly true that engineers and scientists at universities across the country are conducting research into technologies aimed at capturing CO2 and rendering it harmless. The question is whether these technologies can make good on Bush's claim. The answer appears to be a qualified yes. "I think that without technology we will not solve the problem, but technology alone will not solve the problem," says Howard Herzog, principal research engineer at MIT's Laboratory of Energy and Environment. "The technologies exist, but do we have the political will to pay for them?" Herzog says that currently the necessary technologies are very expensive, while the market price for CO2 shifts between $1 to $10 a ton. To make it more viable for companies to invest in corrective technologies, that price needs to rise to around $100 a ton. Ultimately, however, as with most technology, the cost of these solutions should fall once they're in widespread use. Herzog cites technology used by power plants to control sulphur emissions. It, too, was initially costly, but as the industry became more efficient, productivity gains more than offset the costs of the sulphur controls. "The same thing could happen with carbon dioxide."

Across the country at the Renewable and Appropriate Energy Lab at the University of California-Berkeley, program director Daniel Kammen thinks fears about the cost of clean-up technologies are overstated and agrees with Herzog that prices will tumble rapidly once they're employed. Kammen says President Bush is right about the technologies, but that his remarks ring hollow because the United States is not investing in them. The energy sector invests less than 0.4 percent of revenues into research and development, he says. That competes poorly against, say, the pharmaceutical sector, where 15 percent of revenues are shoveled into R&D. "The costs (of technologies) aren't too high. What is expensive to do is not to invest."

There's not universal agreement that anthropogenic CO2 contributes to global warming, but many researchers think the gas acts like an atmospheric glass ceiling, trapping heat that is bringing about huge changes in climate that may trigger droughts and floods. Greenhouse gasses like CO2 result when fossil fuels, particularly oil and coal, are burned, and about a fourth of these gasses vented into the atmosphere come from the United States. Research sponsored by the United Nations estimates that the world's climate has already risen 0.6 degrees Celsius since the start of the Industrial Revolution and predicts the Earth's climate could skyrocket another 1.4 to 5.8 degrees Celsius this century.

Ultimately, the best solution will be a reliance on alternative, renewable energy sources that don't emit harmful pollutants, like hydrogen, wind, and solar energy. But Herzog says the replacement of fossil fuels with clean alternatives is 50 to 100 years away. And, given that 85 percent of commercial energy is fossil-fuel based, an awful lot of carbon dioxide could be spewed into the air during that period unless something is done. That's why the immediate emphasis is on so-called sequestration technologies that either remove CO2 from the atmosphere or capture it before it's released. The culled CO2 would then be safely stored away.

Earth or Sea?

Herzog's group studies these technologies and assesses their social and economic effects. Currently, he says, only two technologies are economically viable. The first takes carbon dioxide and injects it into the ground to make oil flow out more easily. The price of the oil offsets the cost of the CO2. In the United States, oil companies inject 32 million tons of carbon into the earth. The second is capturing the CO2 that is a byproduct of the process used to cleanse natural gas. Historically, the CO2 is released into the atmosphere, but it can be captured and stored, perhaps underground, as well. It's a bit more costly than venting the carbon, but the value of the natural gas still makes it economically feasible. Where to store CO2 poses another quandary. Two prime possibilities are pumping it underground or sinking it into the oceans, but scientists still aren't sure that these are safe options. So there is research underway to determine if they are environmentally benign solutions.

Beverly Saylor, assistant professor of geology at Case Western Reserve, is working with the Ohio Coal Research Consortium to study the engineering and science of geological sequestration. She analyzes the reaction rates of carbon dioxide with minerals it may come in contact with underground. Saylor also simulates deep Earth conditions in her lab to study how CO2 behaves 800 meters below the Earth's crust. "We could start earthquakes and cause a different kind of carbon dioxide problem," she notes. Scientists are convinced that CO2 will remain safely stored in old oil and gas reservoirs, but they don't know for how long. That's a key question. Saylor estimates it could work for 1,000 to 10,000 years. That's encouraging, but it's still far from being a precise estimate.

Ocean sequestration also offers some hope. It's theorized that CO2 dumped into the ocean, two miles below the surface, will sink to the bottom and stay there for a very long time. Again, the question is for how long. Also unknown is how carbon dioxide will react under such great pressure and whether it will harm deep-sea organisms. The Moss Landing Laboratory at California State University is investigating another means of using the seven seas to rid the world of unwanted CO2: ocean fertilization. Here's how it could work: Small plant matter, phytoplankton, consume CO2 and are in turn eaten by zooplankton (small animals), which are then gobbled up by bigger fish, and the process continues on up the food chain. The carbon, now part of dead organisms or fecal material, sinks to the ocean floor and is remineralized to CO2 by bacteria through the decomposition process. Scientists at Moss are considering the effects of supercharging the cycle by adding fertilizers to promote phytoplankton growth so that even more CO2 can be absorbed.

They are seeding small amounts of iron sulpha—tea fertilizer—into an area of ocean 800 miles south of New Zealand and watching to see how it affects the carbon cycle. The results are then compared with ice cores from the last glacial period when atmospheric CO2 was low. "Our research could form the foundation for figuring how much carbon could be put into the ocean," explains Kenneth Cole, Moss director. The fertilization process is controversial, but it gets attention because it's an inexpensive way to sequester huge quantities of carbon. Cole doesn't dispute it may cause other environmental problems, "but if we start having serious warming problems we may be forced to consider this."

At the Goldwater Materials Science Laboratories at Arizona State University, researchers are studying techniques to turn gaseous CO2 into an environmentally-friendly rock. The resulting carbonate could be used to refill mine pits in land reclamation efforts. The idea is to take carbon dioxide from the atmosphere and mix it with certain minerals, like olivine or serpentine. "We are studying the atomic level and trying to understand what governs the reaction rates of carbon dioxide and rocks," says Michael McKelvy, director. But MIT's Herzog is pessimistic, saying the economics of turning carbon to rock appear "intractable." We can accelerate what takes nature 100,000 to a million years to do, Herzog admits, "but the cost may be too exorbitant."

Dirt is another possible option for storing CO2. Agricultural schools are looking at changes in farming practices to sequester carbon dioxide terrestrially. The U.S. Environmental Protection Agency estimates that of the 1,500 metric tons of carbon the United States puts into the atmosphere each year, 30 million come from agricultural practices. Undoubtedly, the manufacturing of herbicides and fertilizers generates pollution, but just plowing the fields creates masses of CO2. Planting fields without plowing can cut CO2 emissions significantly, and reforestation programs can help suck carbon from the atmosphere and siphon it into the soil. Keith Paustian, professor of soil ecology at Colorado State University, uses computers and soil analysis to study the impact of land management practices on carbon emissions. He argues that improvements in agricultural methods can have the most immediate effect in reducing emissions. "We don't have a lot of hydrogen cars running right now, but changes in agricultural practices can have an effect in the next three to five years," Paustian claims.

Of course, before carbon dioxide can be stored, it first must be captured and isolated. One futuristic idea comes from Klaus Lackner, a physicist at Columbia University. He suggests erecting giant adhesive strips down wind from cities and factories. They would be treated with a chemical that reacts with CO2, so as carbon dioxide drifts past, it sticks to the strips and is removed from the air. Separating CO2 from the waste stream of a power plant or factory constitutes about 75 percent of the cost of sequestration, researchers say. It's costly because it requires either building new plants with carbon-emission-reduction technologies or refitting existing ones. So engineers are looking into chemical and physical absorption methods, as well as new membranes to filter out CO2. Universities also give researchers opportunities to seek multidisciplinary approaches to the problem. Berkeley's Kammen, for instance, employs teams of engineering and
public-policy graduate students to investigate potential solutions. "Sometimes it's just small policy changes that can help make it easier to adopt certain technologies," he says. For example, in Kenya, kerosene fuels most households. Not only is kerosene incredibly polluting, it's costly and the price is unstable.

While Kenyans were interested in solar energy, they didn't know much about it. So one of Kammen's teams organized a conference in east Africa, bringing together consumers, manufacturers, and budding entrepreneurs. One student who attended now writes a column for east Africans who want to learn how to sell solar panels and windmills. Back at MIT, Stephen Connors is coordinator for multi-disciplinary research at the Laboratory for Energy and the Environment. Connors—whose teams can include such disciplines as engineering, architecture, and computer science—argues that breaking down the walls between academic departments should help speed the development of technologies. "The interesting and challenging topics are at the interfaces between disciplines, particularly if they have a societal dimension," he says.

Clearly the effort to remove carbon dioxide from the atmosphere will require a variety of solutions. A paper published in Science last year, in which 18 engineers and scientists analyzed existing technologies for carbon reduction, concluded, "It is unlikely that a single silver bullet will solve this problem." But for any of those technologies to become fully effective it requires strong political will. MIT's Herzog says what is needed is a federal program that's as intense, focused, and as well funded as the 1960s moon-landing program. If it becomes clear that this is one of the government's top priorities, the necessary R&D, innovation, and investment will follow, he says. But that remains a big "if." The Bush White House has backed off from its original stance, calling the link between global warming and greenhouse gasses "bad science." It now says the scientific evidence "justifies a serious and measured response." The technological silver bullets in which President Bush has placed his faith do exist. It remains an open question, however, whether the United States is ready to bite down on them.

 

Lisa Busch is a freelance writer living in Alaska.
She can be reached at lbusch@asee.org.