It looks like the $2.2-billion, 558-megawatt Carlsbad Energy Center power plant will get built.
The 1st District Court of Appeals in San Francisco ruled late Thursday that it would defer to the California Public Utilities Commission, whose members voted 4 to 1 in May 2015 to approve a contract for the power plant.
In a 14-page ruling, the appeals court said that the utilities commission was "just and reasonable" and that its decision on the contract was supported by the evidence.
A number of environmental groups sued to try to stop the construction of the natural-gas-fired Carlsbad Energy Center.
"It's both a tragedy and a travesty," said April Rose Sommer, executive director of the Protect Our Communities Foundation, which took part in a petition to the appeals court asking for a review of the utilities commission's decision. "It's totally in opposition to the state's efforts to reduce greenhouse gases and transition away from a fossil-fuel-based energy system."
The plant is slated to be built by NRG Energy Inc. — whose headquarters are in Princeton, N.J., and in Houston — and will replace the aging Encina Power Station in Carlsbad.
"We appreciate that the Court of Appeal has upheld the CPUC's decision to approve the contract for the Carlsbad Energy Center," NRG spokesman David Knox said in a statement.
San Diego Gas & Electric plans to buy power from the plant.
"The energy produced from the Carlsbad Energy Center is expected to complement the growing amount of renewable energy, private solar, energy storage, electric vehicles and other clean energy innovations being added every day to the modern grid powering our lives," SDG&E spokeswoman Allison Torres said in a statement.
Supporters of the planned Carlsbad plant have called it "a new workhorse for the region" and say it will help California meet its target of 33% clean-energy generation by 2020 and 50% by 2030.
Critics say the plant will harm the environment along the coastline, especially the nearby Agua Hedionda Lagoon, and question whether the plant is needed at all.
"Due in large part to the growth in rooftop solar, the latest demand projections for the San Diego region are far less than expected," Sierra Club attorney Will Rostov said in an email. "This suggests that the plant isn't needed. The California Public Utilities Commission's troubling history of approving costly unneeded gas plants needs to stop."
The commission's vote raised objections from opponents of the plant because the vote was held without holding a public bidding process and after an aide for the commission's president, Michael Picker, met privately with the developer of the project about downsizing an earlier plan for the plant that had been rejected by the commission.
The 62-year-old Encina Power Station is being retired in large part because of its cooling systems that suck in seawater, a process called "once-through cooling" that regulators have opposed in recent years because it harms marine life.
Part of the rationale for building the Carlsbad Energy Center was to make up for the loss of electricity generation from the now-shut San Onofre Nuclear Generating Station.
Natural gas has become a bigger source of power for California in recent years, accounting for 59.9% of in-state generation in 2015. In 2005, natural gas accounted for 42.5% of in-state generation.
On the same day the appeals court green-lighted the Carlsbad plant, the California Supreme Court denied a petition by consumer advocates to reject three other natural gas plants in the Los Angeles basin in Huntington Beach, Long Beach and Stanton. A fifth project is also on the books outside of Oxnard.
"It's been a thoughtful couple of days," said Bill Powers, of San Diego-based Powers Engineering and one of the consumer advocates fighting the plants. "Ultimately, we couldn't get the time of day in the judicial system. There's no other recourse, legislative maybe."
11:55 a.m.: Information about a California Supreme Court action on other power plants was added,