AIR QUALITY

(HBRP) would be likely to conform with applicable federal, state and North Coast Unified Air Quality Management District (NCUAQMD) air quality laws, ordinances, regulations and standards (LORS), which precludes staff from making a determination as to whether HBRP would result in significant air quality-related impacts. Staff has identified proposed conditions of certification, but many issues remain either unresolved or lack complete analysis. Staff finds the following: • PG&E has not proposed any annual limit on the number of hours of operation in diesel mode, except for 50 hours/year/engine for maintenance and testing, because PG&E states that a natural gas supply curtailment is an "emergency. " However, Energy Commission staff and the NCUAQMD both seek to limit the hours of operation in diesel mode because the potential emissions of the project need to be clearly defined. The NCUAQMD has determined that the project should be limited to 1,000 engine-hours per year in the diesel mode. • PG&E seeks the flexibility to operate the HBRP during natural gas curtailments, which are determined by gas supply constraints while the transmission gri