A demolition contractor on Thursday imploded the towering smokestack and 19-story boiler building at Portland General Electric’s shuttered coal-fired power plant near Boardman, bringing a symbolic close to the era of coal-fired power generation in Oregon.

Imported electricity generated from coal still flows through transmission wires across the Pacific Northwest, but that looks to be winding down soon, too.

Strategically placed explosives toppled the 656-foot tall stack like a logger might fell a tree and collapsed the adjacent boiler building into a heap of concrete chunks and twisted steel.

In seconds, a huge cloud of dust enveloped the partially disassembled coal plant. A small crowd of onlookers invited by Portland General Electric, including former plant workers, oohed and aahed, but mostly refrained from clapping or cheering as the moment was tinged with sadness or melancholy for many.

“Very emotional for me and very emotional for a lot of the people that I worked with for a number of years,” said Brad Jenkins, Portland General Electric’s vice president of utility operations and a former plant manager at Boardman.

“The coal plant has been just a workhorse of the fleet for 40 years,” Jenkins said. “But if you look around the landscape here, we’ve got lots of clean, renewable resources coming in. We’re transitioning and this is just part of that transition.”

Portland General Electric livestreamed the controlled demolition on social media but did not enable comments. Before the explosion, a smattering of people on the utility’s Facebook page bemoaned the demise of the coal plant. A recurrent theme among those commentators was that the Northwest needs reliable, baseload power such as what Boardman provided to balance intermittent renewable energy sources.

Jenkins said the fleet of natural gas power plants in the region would provide grid stability for the coming years until those are phased out and replaced with developing, zero emissions technologies.

The Boardman coal plant operated from 1980 until its early retirement in 2020. It is located in Morrow County about 11 miles southwest of Boardman. The plant’s 585-megawatt generating capacity was for a long time the single biggest electricity source for Oregon’s largest utility. It was also the state’s single largest source of climate-warming pollution.

There are now no coal-fired power plants operating within Oregon.

“It’s sort of bittersweet,” said Morrow County Commissioner Don Russell, who befriended many of the coal plant workers and had a view from his house of the landmark stack, which was taller than Seattle’s Space Needle. “The roughly 125 permanent jobs that they had out there were really coveted jobs.”

“For Morrow County, at one time this plant was our largest taxpayer by a really large margin,” Russell added before watching the demolition from the viewing area.

He said the plant closure had limited economic effects, though, because the rural county has lately diversified its economy with Amazon data centers and a number of renewable energy projects.

Portland General Electric executives decided more than a decade ago to shut the Boardman plant down by 2020 when the economic and environmental outlook for coal power darkened. The announcement helped settle a Clean Air Act lawsuit brought by green groups, plus the utility avoided having to make costly emissions control upgrades down the road.

The closure eliminated about 2 million tons of greenhouse gas emissions that were coming from the plant every year. That amount of carbon dioxide equals the annual pollution from about 431,000 passenger cars in average use, according to the U.S. Environmental Protection Agency’s greenhouse gas calculator.

The closure also ended mercury and sulfur dioxide emissions that were blamed for haze and air pollution in the surrounding area and the Columbia River Gorge scenic area.

In the short term, Portland General Electric replaced the electricity from Boardman with a wide mix of other resources, partly purchased on contract from other generators.

Jenkins said renewables will play a prominent role going forward, potentially including a company-owned 50 megawatt solar farm proposed for the coal plant site that could repurpose the existing transmission connections. He also praised the reliability and flexibility of the utility’s large natural gas-fired power plant at Boardman, the Carty Generating Station, which opened in 2016 across the street from the former coal plant.

The transition from old to new is also reflected in the immediate area at Portland General Electric‘s Wheatridge wind, solar and storage battery complex, which went fully online in central Morrow County earlier this year.

Portland General Electric spokespeople said some of the Boardman coal plant workers retired when the plant was decommissioned, many transferred to other roles in the company and some are working on the demolition, leaving very few who were laid off.