California Air Resources Board

Distributed generation (DG) refers to electrical generation sources that are located near the place of electricity consumption.  These generation sources replace or supplement electricity from the grid.  Some examples of distributed electrical generation technologies are engines, turbines, fuel cells, and photovoltaic cells.  Some businesses choose to operate DG technologies with heat recovery systems that capture waste heat produced from the electrical generation process.  This captured heat can then be used to heat water, provide steam or space heating, or power a chiller.  DG can be used at a wide variety of facilities including but not limited to such as hospitals, schools, libraries, breweries, utilities, and laundries.

Senate Bill (SB) 1298 (Bowen, Chapter 741, Statutes of 2000) required the California Air Resources Board (CARB or Board) to establish a DG certification program for electrical generation technologies that are exempt from local air district permits.  SB 1298 mandated that, by the earliest practicable date, the criteria pollutant emission standards be made equivalent to the level determined by CARB to be the best available control technology for permitted central station power plants in California.

Pursuant to SB 1298, the Board adopted the DG Certification Regulation in 2001.  CARB staff proposed interim standards for 2003 and recommended that 2007 be considered the earliest practicable date for DG applications to meet central power plant emission standards.  In addition to establishing emission standards, the DG Certification Regulation included testing protocols, calculation procedures, and other specified requirements that manufacturers must satisfy to certify DG technologies.

Generally, microturbines up to 250 kilowatts, engines less than 50 horsepower, and fuel cells are exempt from district permits.  Although small engines are exempt from district permits, most engines used in DG applications are larger and therefore require district permits.  Consequently, the regulation has so far only affected fuel cells and microturbines.

Microturbines and fuel cells were just entering the California market when the Board adopted DG Certification regulation in 2001.  Because of uncertainties at the time regarding the development and deployment of these DG technologies, CARB staff included in the regulation a requirement to conduct a program review and determine if revisions were warranted.  In 2006, staff conducted this program review and, as a result, proposed to update testing requirements and emission standards to the regulation. The Board adopted these amendments, which became effective in 2007.