The California Energy Commission (Energy Commission) has the legal authority to license the construction and operation of thermal power plants 50 megawatts or larger and all their related facilities. The Energy Commission completes a thorough CEQA-equivalent site certification process that provides a timely review and analysis of all aspects of a proposed project, including the evaluation of potential impacts on the environment and health and life safety. Aspen Environmental Group is the prime contractor to support the Energy Commission in reviewing the engineering and environmental aspects of all new power plants in California.

A majority of the Air Quality Work Authorizations were developed to support the completion of comprehensive Staff Assessments (SA) for various power plant projects. These Staff Assessments are equivalent to impact assessments under the California Environmental Quality Act (CEQA). These independent analyses determine whether a proposed power plant can be constructed and operated safely in accordance with laws, ordinances, regulations, and standards (LORS). The Staff Assessment evaluates whether the proposed power plant would cause any environmental consequences or create any potential public health and safety impacts.

Aspen has conducted, or is in the process of conducting, 21 air quality impact assessment projects for power plants ranging from 50 MW to 1,120 MW in rural and urban settings. These impact assessments take into account the project's location (ambient air quality), the project's emissions and the proximity of the facility to any sensitive receptors. The analyses also evaluate whether each facility will meet applicable air quality laws, ordinances, regulations, and standards (LORS), and whether it will cause significant adverse environmental impacts. Based on the ambient air quality, and local air quality regulations, Aspen determines if all technologically feasible mitigation measures to reduce air quality emissions below significance levels are being proposed, and if necessary Aspen proposes additional mitigation measures.

During construction of a power plant, emissions are generated from heavy construction equipment during earth moving operations, and equipment assembly. Fugitive dust emission and diesel particulate emissions are of particular concern. The construction emission estimates are reviewed and corrected, if necessary, and the Applicant's air dispersion modeling analyses are reviewed and, if necessary, additional air quality dispersion modeling runs are completed. Aspen recommends appropriate mitigation measures to reduce fugitive dust and construction equipment tail pipe emissions to the greatest feasible extent.

With regard to operations, power plant emissions are required to be controlled with Best Available Control Technology (BACT) and emission increases are required to be offset. Aspen determines whether the proposed emission controls and offset package are sufficient to mitigate all significant impacts due to the project's operation. Aspen evaluates the normal steady state emission impacts as well as the emission impacts during initial commissioning and startup/shutdown; and the cumulative emission impacts from the project along with other new projects located near to the project site. The emission estimates are reviewed and corrected if necessary, and the Applicant's air dispersion modeling analyses are reviewed and if necessary additional air quality dispersion modeling runs are completed.

The power plants (and locations) for which Aspen has conducted, or is in the process of conducting, an air quality impact assessment include:

• Avenal Energy Center (Kings County, CA)
• Blythe Energy Project Phase II (Riverside County, CA)
• Central Valley Energy Center (Fresno County, CA)
• Colusa Power Project (Colusa County, CA)
• Huntington Beach Modernization Project (Orange County, CA)
• Inland Empire Energy Center (Riverside County, CA)
• Ocotillo Energy Project, Phase I (Riverside County, CA)
• Palomar Energy Project (San Diego County, CA)
• Rio Linda / Elverta Power Plant Project (Sacramento County, CA)
• Roseville Energy Facility (Sacramento County, CA)
• San Joaquin Valley Energy Center (Fresno County, CA)
• Tesla Power Plant Project (Alameda County, CA)

• Hanford Energy Park (Kings County, CA)
• Henrietta Peaker Project (Kings County, CA)
• Kings River Conservation District Peaking Power Plant (Fresno County, CA)
• Magnolia Power Project (Los Angeles County, CA)
• Modesto Irrigation Project (Stanislaus County, CA)
• Riverside Energy Resource Center (Riverside County, CA)
• Salton Sea Unit 6 Project (Imperial County, CA)
• Tracy Peaker Power Plant (San Joaquin County, CA)
• United Golden Gate (San Francisco County, CA)
• Walnut Energy Center (Stanislaus County, CA)
• Woodland Generating Station 2 (Stanislaus County, CA)

Prepared project amendment analyses or project compliance assessments, for air quality impacts, for several licensed power plants, including:

• Pastoria Power Plant
• Elk Hills Power Plant
• Henrietta Peaker Project
• Tracy Peaker Project
• Magnolia Power Project
• Delta Energy Center
• San Joaquin Valley Energy Center
• City of Vernon Malburg Generating Station
• Otay Mesa Power Plant
• Riverside Energy Resource Center
• Salton Sea Geothermal Unit #6 Power Plant
• Moss Landing Power Plant

Aspen has conducted several air quality special studies, or special studies that included air quality topics, for the California Energy Commission including the following:

• Preparation of the staff paper "Emission Offsets Availability Issues" and preparation of the Emission Offsets Constraints Workshop Summary paper.
• Assistance in the aircraft safety review of thermal plume turbulence for the Blythe Energy Power Plant Phase I.
• Assistance in the preparation of the Coastal Power Plant Study.