On August 15, the U.S. Environmental Protection Agency ("EPA") issued a notice denying petitions for rehearing of its new rules governing air emissions from stationary Reciprocating Internal Combustion Engines ("RICE"). RICE, especially diesel engines, are widely used for emergency backup generation for hospitals, factories, and other facilities requiring an uninterrupted supply of power. They are also an important source of power to stabilize the electric grid in certain types of emergencies. Developments concerning the RICE emissions rule are therefore of great concern to electric utilities and a multitude of end-use electric consumers who rely on diesel back-up generators.
The rehearing petitions stem from EPA's 2010 proposal to extend its regulation of hazardous air pollutants emitted by stationary RICE from the previous 500 horsepower limit down to engines as small as 100 HP. As we reported early last year, in response to concerns related to the mismatch between the proposed RICE rule and NERC reliability standards, EPA modified the proposed rules to allow generators that have not been retrofitted with expensive pollution control equipment to operate for up to 100 hours per year during declared electrical emergencies, and for such generators to operate for up to 50 hours per year to prevent voltage collapse or overloads in local transmission or distribution systems.