On May 22, 2012, U.S. EPA issued a proposed rule, that among other things, would allow backup stationary electricity-generating engines to operate for up to 100 hours during demand response emergency and peak-use periods without having to comply with emissions limitations applicable to non-emergency engines. The provision governing operating hours is part of a series of amendments to the NESHAP ZZZZ standards governing reciprocating internal combustion engines. Under the proposed rule, backup generators would be able to be operated for up to 100 hours per year for the following purposes: (1) monitoring and testing; (2) demand response for Energy Emergency Alert Level 2 situations; or (3) when there is at least a five percent or more change in voltage. Through 2017, for engines located at sites that are sources for hazardous air pollutants, 50 of the 100 allowable hours could be used for non-emergency purposes and to meet peak power demand. U.S. EPA will accept comments on the proposed rule for the next 45 days. Please click here to go the Federal Register notice.