The Maryland Senate voted Friday to strip a Baltimore trash incinerator and similar facilities of a state “green energy” label that qualified them for millions of dollars in subsidies paid for by electricity customers over the past seven years.

A day earlier, senators cited a recent Baltimore Sun investigation revealing that a trash-burning facility in Southwest Baltimore has collected roughly $10 million through a state renewable-energy incentive program — despite being the city’s largest single source of air pollution.

“We are keeping these dirty polluters alive, subsidizing them. Trash incineration should not be subsidized,” said Sen. Michael Hough, a Republican from Frederick County who proposed the policy change in an amendment on the Senate floor Thursday.

The legislation now advances to a crowded agenda in the House of Delegates, where it faces a difficult path with three days left in the legislative session.

A slice of Marylanders’ electricity bills has gone to encourage development of renewable energy projects such as windmills and solar farms since 2004. But the program largely benefits trash incinerators and paper mills that burn a byproduct called black liquor, The Sun found in its investigation. In recent years, state lawmakers have repeatedly considered whether they should change that, but the measures have failed in thorny political battles.

“Ratepayers should not subsidize this type of pollution,” Hough said Thursday.

The money is intended to give environmentally friendly power facilities a financial boost as they compete against fossil fuel-fired power plants that generate cheaper electricity but also greenhouse gases and pollution. The costs of the subsidies are baked into the prices Marylanders pay for electricity.

The payouts totaled $135 million in 2016, the most recent year for which data is available. That year, energy generated by the Wheelabrator Baltimore incinerator and a similar facility in Montgomery County made up 15 percent of Maryland’s renewable energy supply.

The proposal to strip incinerators of the subsidies advanced in the final days of the General Assembly’s 2018 session despite the failure week earlier of other, more sweeping proposals to accelerate investment in and development of renewable energy. It only made it to the Senate floor as an amendment to a related bill to extend green energy subsidies for hydroelectric dams, which are set to stop receiving the money after this year.

Hough has put the idea forward repeatedly in recent years, and he said Friday’s 36-8 vote showed that his colleagues finally understand it. A year ago, a similar amendment failed by one vote.

“Everyone knew it was getting close,” he said. “It was going to happen sooner or later.”

There was both bipartisan support and opposition for the measure.

Sen. Thomas “Mac” Middleton, a Charles County Democrat who chairs the Senate’s Finance Committee, was among the opponents even though he had sponsored the bill in its original form. Before casting his vote, he noted to his colleagues that he found himself in the awkward position of opposing his own bill, though he didn’t discourage them from supporting it to protect their voting records with environmental groups.

He later told The Sun he supports subsidizing trash incineration because the Environmental Protection Agency under President Barack Obama endorsed it as a renewable energy source if its emissions are controlled. Incinerators should be used as a complement to recycling and composting efforts, he added.

The Wheelabrator Baltimore trash incinerator, whose smokestack towers over the intersection of Interstate 95 and the Baltimore Washington Parkway, burns most of Baltimore’s household trash, along with refuse from elsewhere across the region.

It also releases thousands of pounds of greenhouse gases and toxic substances into the air every year, including carbon dioxide, hydrochloric acid and formaldehyde. It produced 82 percent of the sulfur dioxide and 64 percent of the nitrogen oxides emitted by industrial facilities within city limits in 2014, according to the EPA. Those levels fall within limits established under federal and state regulations.

A spokeswoman for New Hampshire-based Wheelabrator declined to comment on the Senate vote. The company has said it works “proactively and continuously” to update and upgrade the incinerator.

Environmental groups had all but given up lobbying efforts on legislation to increase the state’s supply of renewable energy and to end ratepayer subsidies for paper mills and trash incinerators. But now they are scrambling to woo delegates, who have not held floor debate about whether trash incineration should be considered green energy since 2011.

Josh Tulkin, director of the Maryland Sierra Club, said it was heartening to see bipartisan support in the Senate on a complicated policy.

“When you talk about the morality of incentivizing an incredibly polluting trash incinerator, people on both sides of the aisle agree it doesn’t make sense,” Tulkin said. “If we are using ratepayer money, at least it should be going to clean renewables.”

To advance in the House of Delegates, it must clear extra procedural hurdles because the Senate approved it so late in the session. Middleton said he doesn’t expect the bill to advance out of the House’s Rules Committee, which must approve it before it can move on to the normal legislative process.

“I doubt this bill goes anywhere now that this amendment is on it,” he said.

Del. Shane Robinson, a Montgomery County Democrat who sponsored a bill this year to revamp how the state subsidizes renewable energy, said he is pessimistic on the bill’s prospects in his chamber. In 2011, the General Assembly — with input from the incineration industry — passed legislation classifying household trash as a green energy source on par with sun and wind, and many lawmakers who voted for it are still in office.

“We would have to change their minds in very short order,” Robinson said. “It’s a long shot because it’s very late in session.”

Even if it doesn’t pass, Middleton pledged to work with environmentalists on a compromise next year.

Hough predicted the policy will pass eventually because of the overwhelming support on the Senate floor.

“The message is clear,” he said. “Whether it’s done this year or next year, it’s going to have to be addressed.”

Baltimore Sun reporter Luke Broadwater contributed to this article.

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