OLYMPIA, Wash. Washington's largest utility is asking state regulators to approve $1.5 billion in rate increases over the next three years, KUOW reported, a proposal that would cost a typical Puget Sound Energy electricity customer an additional $612 a year by 2029 and a typical gas customer $276 more.

The for-profit utility says the revenue is needed to build more power plants as demand increases and as the state cleans up its power supply. In a press release, CEO Mary Kipp said the rate plan reflects the balance the company must strike between keeping the gas and electric system strong and dependable and investing in cleaner resources as responsibly and thoughtfully as possible.

Environmentalists and low-income advocates are opposing the rate hike and PSE's plan to build more gas power plants, including converting a shuttered coal-burning plant in Centralia to run on gas until 2045, when fossil-fuel power plants are banned in Washington. Earthjustice attorney Victor Zertuche said there are cheaper and cleaner alternatives available to the company.

State law requires the power supply to be carbon neutral by 2030, with at least 80% coming from non-polluting sources, while utilities can get 20% from fossil fuel sources if they pay to offset that pollution. Environmental advocates say PSE plans to get just 66% of its power from clean sources in 2030.

The utility is also seeking approval to boost its profit margin to 10.8%, up from the current 9.9%. The Washington Attorney General's Office, which is opposing the proposed rate hike, is urging the Washington Utilities and Transportation Commission to allow PSE only an 8.2% profit margin.

The commission took public comment on the rate request at a hearing in Lacey on Sept. 29 and an online hearing on Oct. 7, and advised in-person commenters to dress for the weather in case the meeting room reached capacity. The commission is expected to decide the case in January, with new rates going into effect that month through 2029. Puget Sound Energy serves 1.2 million electric customers and 900,000 natural gas customers in Washington.