technologies achieving 50 to 60 percent efficiency offer the potential to reduce CO₂ emissions up to a third relative to current new plants.

The potential for CO₂ capture and disposal also has received preliminary study (Ormerod et al., 1993; MIT, 1993; EPRI, 1991a). The consensus is that the technological means of scrubbing CO₂ from flue gases already exists today but that the feasibility of CO₂ disposal in deep wells, oceans, or other final storage sites remains a critical issue to be resolved. From a cost viewpoint, CO₂ removal today is very expensive. Estimates for a 90 percent CO₂ reduction suggest roughly a doubling of electricity generation costs and about a 35 percent energy penalty for removing and transporting CO₂ to a hypothetical disposal site (NRC, 1992). Somewhat lower energy penalties are estimated for advanced combustion and gasification cycles. The development of viable CO₂ removal and disposal processes remains a long-term challenge to control technology development.

The Control Technology program in the Office of Fossil Energy is divided into four program components: Flue Gas Cleanup, Gas Stream Cleanup, Waste Management, and Advanced Research. As noted in Chapter 2, DOE has established incremental emission control goals for its Advanced Power Systems program (Table 2-3) that must be supported by the Control Technology program. The FY 1994 authorized budget for this activity was $13.25 million for flue gas cleanup, $19.29 million for gas stream cleanup, $2.41 million for waste management, and $1.16 million for advanced research.

As noted previously, commercial technology developed by the private sector with DOE participation already can achieve the DOE emission goals for 2000 and 2005 for conventional coal combustion systems. With the anticipated increase in demand for baseload generating capacity beyond 2005 and the expected tightening of future emission control requirements, the DOE program emphasis on developing improved control technologies for highly efficient, "superclean" power systems appears to be well placed.

The Flue Gas Cleanup program has a goal of reducing SO₂, NO_x, and particulate emissions to one-tenth current NSPS levels without high-volume waste generation (DOE, 1993a). Further goals are to control air toxics and CO₂ emissions and to develop salable by-products from the control systems. Development of advanced FGD systems and combined SO₂/NO_x removal systems is also part of this program area. The other major component is the Gas Stream Cleanup program. It has a similar focus of removing contaminants from gasifier or combustor streams prior to their entry into advanced power systems such as the PFBC, IGCC, and IGFC systems. Activities focus on the development of high-temperature, pressurized contaminant control systems.

DOE also has a Waste Management program focused on waste products formed by advanced power generation technologies. The goal of that program is