■ CASE STUDY Is Capturing and Storing CO2 the Answer? A third output approach is carbon capture and storage (CCS). It involves removing CO2 from the smokestacks of coal-burning power and industrial plants and then storing it somewhere. CO2 gas could be pumped deep underground into coal beds and abandoned oil and gas fields. (See The Habitable Planet, Video 10, at www.learner .org/resources/series209.html for a discussion of how scientists are evaluating this form of CCS.) Or the gas could be liquefied and injected into thick sediments under the sea floor (Figure 19-15). Analysts point to several problems with this approach. One is that power plants using CCS are much more expensive to build and operate than conventional coal-burning plants and thus would sharply raise the price of electricity for consumers. Without strict government regulation of CO2 emissions, carbon taxes to bring coal prices in line with environmental costs, or generous subsidies and tax breaks, coal-burning utilities and industries have no incentive to build such plants. According to the U.S. Department of Energy, the current costs of CCS systems will have to be reduced by a factor of ten before these systems will be widely used. A second problem is that CCS is an unproven technology that