DULUTH – Every other light bulb across a wide swath of northeastern and central Minnesota is now powered exclusively by wind, solar and hydro electricity.

Minnesota Power announced Wednesday it had reached its goal of 50% renewable energy, the first utility in the state to hit the milestone. The Duluth-based utility did so ahead of its 2021 goal.

"We've been really thoughtful and balanced in laying out a vision in advancing a sustainable future for our customers," said Julie Pierce, vice president of strategy and planning. "The transformation is not over — this is not the end milestone."

The activation of the Nobles 2 wind farm in southwestern Minnesota this month pushed the utility over its renewable goal and brought the company's owned and contracted wind power to about 870 megawatts.

About 28% of Minnesota Power's electricity now comes from wind, 21% from hydro — made possible by the Great Northern Transmission Line that was activated this year — and roughly 1% solar.

About 30% of the company's power comes from coal, and the rest is a mix of sources bought from the regional power grid.

"We are proud of how far we have come in this transformation, but we know we have more work to do," Bethany Owen, CEO of parent company Allete, said in a statement.

In part to celebrate the milestone, a wind turbine blade was installed at the plaza outside Allete/Minnesota Power headquarters in downtown Duluth on Wednesday.

Minnesota Power has 145,000 customers in northeastern and central Minnesota. It sells a majority of its power to a handful of taconite mines and paper mills.

The state's largest electric utility, Xcel Energy, gets 30% of its electricity from renewable sources. Xcel is on track to reduce its carbon output 80% by 2030 and intends to be carbon-free by 2050.

Minnesota Power will offer more details on its next steps — including the future of the coal-fired Boswell Energy Center near Grand Rapids — when the company submits its 15-year plan to state regulators in February. Already the company has idled or retired seven out of nine coal-fired generators and said it has cut carbon emissions in half compared with 2005 levels.

"That plan will outline scenarios for the thoughtful transition of our coal units at Boswell 3 and 4, the next steps for the transition to even more renewable energy, and more investments in the grid," Pierce said.

Plans are continuing for a natural gas plant in Superior, Wis., that would produce between 525 and 625 megawatts of electricity. Minnesota Power would split the cost and energy from the $700 million plant with Wisconsin's Dairyland Power Cooperative.

"Natural gas really is a transitional bridge to a cleaner energy future," Pierce said. "It's a much cleaner-burning fuel than coal, and it's also very flexible — natural gas can be converted to much cleaner-burning fuels in the future as they become available."

Environmental activists have argued against the utility pursuing any investment into fossil fuels. The Minnesota Supreme Court is expected to decide in 2021 whether the project needs a lengthy environmental review.

Brooks Johnson • 218-491-6496