The Antelope Valley Air Quality Management District Board approved on Tuesday the transfer of critical emissions credits for a proposed Palmdale power plant.

The board took a 4-3 vote at the end of a six-hour meeting attended by nearly 500 people at Antelope Valley College, according to media reports.

The transfer was a major hurdle for the project, which Palmdale is selling off to Summit Power Group in Seattle for about $27 million.

The credits would allow the plant to discharge 152 tons of nitrogen oxide a year and 60 tons of volatile organic compounds a year. The credits for the discharge will be acquired from the Mojave Desert Air Quality Management District and the San Joaquin Valley Air Pollution Control District and transferred to the Antelope Valley Air Quality Management District.

Summit will pay for the acquired credits. The deal is expected to close early next year.

The natural gas-fired power plant already has been approved by the California Energy Commission and the U.S. Environmental Protection Agency.

Summit and Palmdale now need to secure a power purchase agreement with Southern California Edison and other power utilities before construction can begin, the Daily News reported.

The seven-member board is made up of two representatives from Palmdale, two from Lancaster, two from Los Angeles County, and one at-large member. The chairman is Marvin Crist, the vice mayor of Lancaster, who opposed the credit transfer.