Uncertainty about CO(2) emissions legislation is prompting power plant owners to consider the possibility of accommodating "add-on" CO(2) capture and sequestration solutions for coal-fired plants in the future. Those same plant owners may be overlooking the possibility that future natural gasfired combined cycles will also be subject to CO(2) capture requirements. This month we examine the. capture options. In a future issue, Part II will present the installation and operating costs of different carbon capture technologies.