Trends

Over the past four months, Resource Data International (RDI) has been analyzing Continuous Emission Monitoring System (CEMS) data collected by the Environmental Protection Association (EPA) under Title IV of the Clean Air Act Amendments of 1990 (CAAA). Title IV requires electric utilities to reduce emissions of sulfur dioxide (SO2) and nitrogen oxide (NOx) (em precursors to acid rain. Our analysis indicates that SO2 compliance to date is much cheaper than anticipated in 1990, and that tremendous overcompliance will characterize CAAA performance through 2000.

Title IV has two phases. Phase I specifically affects 256 coal and 5 oil units during the period 1995-1999. These units, the largest producers of SO2 emissions in the United States, will be subject to an annual tonnage cap calculated from the average heat input at each unit during the period 1985-1987 multiplied by 2.5 pounds of SO2 per million British thermal units. Phase II begins January 1, 2000, and affects all utility fossil units with a capacity greater than 75 megawatts. In this phase, the average 1985-1987 heat input is multiplied by 1.2 pounds of SO2 per million Btu to arrive at each unit's cap.