Carbon Capture and Sequstration

Having for years applauded Rudy Baum's expressed concern about global warming, I was shocked and dismayed by his statement, "Meanwhile, most of the boost for coal R&D goes toward technologies to capture and sequester carbon dioxide, which I suspect is a complete boondoggle" (C&EN, Feb. 18, page 3).

At this time, I think it is practically certain that to achieve the 60-80% reduction in greenhouse gases that most experts say is essential to avoiding a catastrophe, we must conserve, use more renewables, and employ carbon capture and sequestration (CCS) in our generation of electricity. An Intergovernmental Panel on Climate Change (IPCC) special report states, "The availability of CCS in the portfolio of options for reducing greenhouse gas emissions could facilitate the achievement of stabilization goals." And "use of CCS in conjunction with other measures could significantly reduce the cost of achieving stabilization."

In his testimony to Congress last year, David Hawkins, director of the Natural Resources Defense Council's Climate Center, said, "We need to be capturing CO₂ from new coal plants without delay in order to keep global warming from becoming a runaway problem."

Investigations of CO₂ storage in underground aquifers has been studied extensively for years in the U.S. and Europe. A 2004 Massachusetts Institute of Technology report claims, "Current evidence indicates that it is technically feasible to store large quantities of CO₂ in saline aquifers." An IPCC report states it is likely that 99% of CO₂ injected in underground aquifers would be retained for 100 years and likely that 99% would be retained for 1,000 years.

CCS could be added to planned pulverized-coal-fired (PV) power plants. And this additional cost is less in the case of plants with the new integrated gasification combined cycle (IGCC) technology. The additional cost for adding CCS varies widely but appears comparable to the cost of reducing CO₂ emissions by other means. The MIT study says that CCS would increase the retail cost of electricity by 20-25% and if CO₂ is taxed at $25-35 per ton, CCS becomes economical.

The Department of Energy's Sequestration News says adding CCS to existing PV plants would increase the cost of electricity 65% and adding it to new IGCC plants would increase the cost 30%. Ethanolamine has been used to absorb the CO₂ in stack gases, but at least two pilot projects are going to use chilled ammonia, so presumably this offers a prospect of lowering CCS expense.

Last month, DOE changed its plans for a FutureGen plant in Illinois (C&EN, Feb. 4, page 20). It now wants utilities to construct several IGCC plants for which DOE will fund the additional cost of CCS. American Electric Power has announced plans to install CCS in two locations, but this is contingent on getting rate increases to cover the added cost. And several demonstration projects are planned by European utilities, but the first one is not expected to be operational until 2011.

John J. Burton
Washington, N.J.