Deregulation across the country has resulted in the proposal of hundreds of new power plants within the last several years. Each power plant, individually, is required to demonstrate conformance with state and federal air quality regulations. However, there is still a great deal of public concern over the combined or cumulative impact that all of these proposed plants may have on future air quality. Although there is regulatory guidance for assessing the combined impacts of 'existing' sources under the federal Prevention of Significant Deterioration (PSD) review program, there are no formal requirements for addressing impacts from other 'proposed' sources under review. Furthermore, the requirements for assessing combined impacts under the PSD review program are limited in scope and applicability.
This paper contains a brief overview of the air quality impact analyses performed as part of the PSD review process, the impetus for impact analyses above and beyond that required under PSD, as well as the concept of a cumulative air quality impact assessment. To illustrate the concept of a cumulative air quality impact assessment, recent studies completed by power plant developers in Virginia are reviewed. In particular, the approach taken by one developer, Tenaska Virginia Partners, L.P. (Tenaska), is presented with a case study and a discussion of the results. The approach taken by Tenaska provides insight into developing a strategy to address environmental requirements outside the bounds of well-defined regulations. The results of Tenaska's cumulative air quality impact assessment validated the current technical analyses required by the Environmental Protection Agency under the PSD review program as adequate to protect the health and welfare of the citizens of Virginia.
Cumulative Air Quality Impact Assessments - A Case Study