Compressing, Storing Co₂ Could Minimize Climate Change

GLOBAL WARMING

Capturing and storing the carbon dioxide generated by power plants and factories could help mitigate climate change, says a United Nations report approved on Sept. 25. The CO₂ would be separated from exhaust gas, compressed, and stored in geological formations, the oceans, or minerals.

The report prepared by the Intergovernmental Panel on Climate Change (IPCC) was written by about 100 experts and widely reviewed by still more climate-change experts and governments. No single option, the report concludes, will provide all the emission reductions needed for stabilizing greenhouse gas concentrations. In addition to CO₂ storage, energy efficiency improvements, switching to less-carbon-intensive fuels, nuclear power, and renewable energy will be required, the report says.

Storage of CO₂ in geological formations, such as depleted oil wells, is the best understood technology for capturing carbon, the report says. It is likely to be safe because it uses many of the processes now being employed by the oil and gas industry.

But the system is expensive. If CO₂ were separated from power-plant emissions and stored in geological formations, the cost of electricity would increase from 1 to 5 cents per kWh over its current cost of 4–6 cents per kWh, says Bert Metz, cochair of the IPCC panel. So geologic storage is not likely to be used by power companies unless governments prompt them to do so by placing strict caps on CO₂ emissions.