A clean, green pipe dream

Emissions that aren't clean or green

Courtesy morguefile

 

By Peter Wray

For every ton of coal we burn, 2.89 tons of carbon dioxide (CO2) is released into the atmosphere. Although even the coal and utility industries now acknowledge that these emissions are changing the climate, their primary response to the problem has been to ramp up their public relations. All across Pennsylvania, highways are now dotted with billboards promising that “clean coal” is our energy future. What the billboards fail to explain is that the whole notion of “clean coal” is only theoretical.

To date, no power plants have been built to capture (or “sequester”) the millions of tons of CO2 emissions every year for the simple reason that no one has yet figured out how massive amounts of carbon dioxide could be sequestered.

On a small scale, the technology to capture and store CO2 has been available for years. Carbon dioxide is the “dry ice” used as a cooling agent, and in the form of a compressed gas, it carbonates soft drinks and powers the pneumatic systems in portable pressure tools. Although useful in small quantities, the big question is what to do with the 161 million tons emitted from Pennsylvania’s coal-fired power plants each year. Capturing CO2 on this scale is an altogether different proposition. First, the CO2 has be separated from the rest of the gaseous and particulate mix emitted from a power plant’s smokestack and then compressed into a liquid so it can be piped away from the plant. Because retro-fitting existing coal-fired power plants in this way is considered too expensive, the industry has been developing a new type of power plant—one that would closely resemble complex chemical plants, with their interwoven pipelines that seem to emit nothing into the air. The leading contender for this new generation of coal-fired power plant has been the Integrated Gasification Combined Cycle (IGCC).

In the late 1990s, an IGCC plant in Shady Point, Oklahoma began capturing 200 tons of CO2 a day (or 73,000 a year), a negligible amount when compared to the millions of tons released from a single coal-fired plant each year. A larger scale effort was launched in 2003, when the Department of Energy (DOE) announced FutureGEN, a $1 billion research and development program to demonstrate the feasibility of IGCC. Five year later, on January 30, 2008, the DOE announced that the FutureGEN program would be modified because “the estimated cost of the FutureGen project has risen sharply and could have risen even higher.” The primary casualty is the closing of the $1.8 billion FutureGen plant that promised to be the first to sequester large amounts of CO2. Floundering along with FutureGen is the promise that CO2 can be economically captured on a commercial scale.

So far, the costly pursuit of carbon sequestration has seriously slowed investment in solar and wind energy technologies. Since 2001 the Bush Administration has invested more than $2.5 billion in “clean coal” technology. The DOE budget for fiscal 2009 is expected to contain an additional $241 million for demonstration programs involving carbon capture and storage from coal-burning power plants, including another $156 million for restructuring the FutureGen project.

But why invest anything more in this unlikely technology? Because even if researchers were able to capture a portion of the CO2 produced by our power-plants, how would they store it? And where?

The most popular theory for storing liquid CO2 is geo-sequestration, which would entail pumping the compressed gas underground. This method would most likely be successful in locations with depleted oil and gas fields, such as in Texas, or in areas with deep saline deposits. But Pennsylvania doesn’t have the types of open geological formations that could house the gas, so power-plants in our state would either need to ship the liquefied CO2 via trucks or pump it long distance across high-pressure pipelines—both of which would likely be exorbitant and possibly dangerous.

Given that CO2 is a suffocating gas, how could we ensure that it wouldn’t leak out of the site? Can anyone guarantee that the physical structure of a sequestration site would be stable long enough to render the gas inert? Who would monitor the storage for the next hundred years? And who would be responsible if there was an accident?

Industry optimists like to talk about the possibility of injecting CO2 into deep sea beds. The example they usually cite is the injection of CO2 a kilometer below sea level in the Norwegian North Sea. But pumping carbon dioxide from Pennsylvania to a location far off the New Jersey coast hardly seems viable, even for energy companies like PECO that produce power in the eastern part of our state.

Others, including Pennsylvania’s Department of Conservation and Natural Resources (DCNR), have suggested that because plants naturally absorb CO2, we could offset the emissions with terrestrial sequestration, by planting more croplands and forests, and rehabilitating wetlands. Exactly how the DCNR imagines this could be done is unclear, for there appears to be little room for vast expanses of new vegetation between existing forest lands, farmland, and suburban sprawl.

In 1999, the DOE concluded in its state of the science working paper that “For carbon sequestration to be a viable option, it needs to be safe, predictable, reliable, measurable, and verifiable; and it needs to be competitive with other carbon management options, such as energy-efficient systems and de-carbonized energy technologies.” Nine years and hundreds of millions of dollars later, those words stand true, but the goal remains unfilled. So the next time you see an industry ad for “Clean Coal,” remember that that’s 2.89 tons per ton—and we’ve got no place to put it.

Peter Wray is chair of the Chapter's Huplit's wildlife commitee and is the Allegheny Group's co-conservation chair.

Published April 2008