About 40 power plant workers who help keep the lights on across Oahu received thanks from local government leaders and their company Thursday, two weeks before the facility’s long-planned shutdown.

Gov. David Ige, several state lawmakers and city representatives participated in a retirement ceremony outside the AES Corp. coal-fired plant, which has been Oahu’s largest single generator of electricity for 30 years.

The 180-megawatt plant at Campbell Industrial Park in Kapolei is slated to cease operations and electricity sales to utility company Hawaiian Electric on Sept. 1 as part of an effort to achieve a state goal to produce 100% of Hawaii’s energy from renewable sources by 2045.

“AES has been such a vital partner to Hawaii for so many years,” Ige said. “Thank you to the employees of AES Hawaii for 30 years of outstanding service.”

Thursday’s ceremony included music, food, proclamation presentations and a video in which many employees explained their roles at the plant with pride. The event was held in a landscaped area fronting the sprawling complex emitting a fanlike drone and mild industrial smell as 1,800 to 2,000 tons of coal gets burned daily to power a giant steam-driven turbine that generates electricity.

Pat Murphy, who was a newly hired maintenance technician in 1991 when the plant was under construction and helped commission operations in 1992, will soon help decommission the facility where he is now vice president of plant operations.

“I’ve come emotionally to accept what’s going on,” he said. “I’ve come to that realization that we’re done. I’ve been able to be involved in a great commercial run.”

Bernerd Da Santos, chief operating officer of Virginia-based AES, praised workers for their dedication and commitment to safety. “You have done an amazing job,” he said.

Of the facility’s 41 employees, about six will do decommissioning work, and a dozen are to dismantle the plant over three years. Another dozen are retiring or have found new jobs outside AES, while about eight have secured jobs at other AES facilities in Hawaii or on the mainland.

Several state lawmakers led by Sen. Maile Shimabu­kuro (D, Kalaeloa-Waianae- Makaha) presented AES representatives with a certificate recognizing the plant for its operations and saving ratepayers $2 billion to $4 billion over three decades compared with the cost of power produced from oil.

City Managing Director Mike Formby presented AES representatives with a proclamation from Mayor Rick Blangiardi that included a similar recognition of cost savings.

Per kilowatt-hour, electricity from the AES plant costs 6 cents, compared with about 30 cents for power from oil. The AES plant had supplied around 16% of Oahu’s electricity in recent decades, though more recently it had been 10%.

Though a growing amount of power on Oahu is from solar farms where costs range from 9 to 13 cents per kilowatt-hour, Hawaiian Electric initially will have to burn more oil to offset the loss of production from the coal plant, and therefore recently estimated that a typical residential customer using 500 kilowatt-hours of electricity a month will see their bill rise by $15, or 7%.

The coal-powered plant is Oahu’s cheapest source of electricity but also is one of the state’s largest emitters of greenhouse gases, putting the equivalent of 1.5 million metric tons of carbon dioxide into the atmosphere annually.

Ige, in his remarks at the ceremony, alluded to mixed public views about the plant’s existence and impending closure, the latter of which is cheered by environmental organizations but will result in job losses and higher electricity bills.

“Our state’s energy needs and concerns were very different (30 years ago) than they are today,” Ige said.

When AES was building the $383 million plant in 1991 to address growing electricity needs on Oahu, it announced an effort to offset plant greenhouse gas emissions by contributing up to $2 million to help The Nature Conservancy buy 143,000 acres of forest in Paraguay to save the land from being cleared for logging and farming.

Now, AES is among energy firms shifting away from producing electricity from fossil fuels in favor of generation using renewable sources.

In Hawaii the company operates solar farms on Kauai, Maui and Oahu totaling about 35 megawatts, as well as a 24-megawatt wind farm in Kahuku. AES also has six solar farm projects in design or construction on Kauai, Maui, Oahu and Hawaii island to produce about 110 megawatts of electricity plus battery storage. The six solar farms are projected to start running in 2023 and 2024.

“Our team looks forward to continue to serve the people of Hawaii over the next 30 years and beyond, with smarter and greener sources of energy,” Da Santos said.