Senator Joe Manchin III on Monday cited a litany of issues that drove him to oppose President Biden’s $2 trillion Build Back Better bill, from Democrats’ refusal to attach work requirements to social benefits to their failure to raise tax rates on the rich. But left almost unsaid was the issue that has always propelled his political career as a Democratic maverick: climate change.

The version of the bill that passed the House last month devoted $555 billion to shifting the nation to renewable sources of energy, such as wind and solar power, and away from fossil fuels like West Virginia coal. Mr. Manchin, who defied gale-force political headwinds in 2010 by running for the Senate on his opposition to President Barack Obama’s climate change legislation, killed a provision in Build Back Better that would have imposed stiff penalties on electric utilities that continued to burn coal and natural gas.

But even with the stick dropped from the House’s bill, West Virginia’s coal interests were working hard to kill off the measure’s carrot, a package of tax credits to make clean energy more financially competitive, and, by extension, struggling coal even less so. Their lobbyists talked frequently to Mr. Manchin.

With every Republican opposing the bill in the evenly divided Senate, Democratic leaders could not afford to lose a single vote, and Mr. Manchin has said he had concerns about energy issues from the start.

“I said, this is absolutely a very, very far-reaching piece of legislation which changes so many categories in American culture and American society, revamping the entire tax code and revamping the entire energy policies for our country — and the social platforms that we use to support people,” he told a West Virginia broadcaster on Monday.

West Virginia coal and gas, and policies designed to stop their burning, have always had a special place in Mr. Manchin’s politics. A Manchin family-owned business has made a small fortune selling waste coal from abandoned mines to a heavily polluting power plant in the state. The blind trust in which Mr. Manchin’s interests lie held between $500,000 and $1 million last year, according to his most recent disclosure form. The company, Enersystems, valued at between $1 million and $5 million, delivered the senator $492,000 in dividends, interest and business income in 2020, the May disclosure states.

He received more campaign donations from the oil, coal and gas industries than any other senator in the current election cycle.

His first run for the Senate featured an advertisement in which he promised, “I’ll take dead aim at the cap and trade bill because it’s bad for West Virginia” as he shoots a copy of Mr. Obama’s climate legislation with a rifle. Six years later, he reprised his performance for his re-election, saying: “Hey, I haven’t changed. I might be a few years older, but I’ll still take on anyone that messes with West Virginia.”

Democrats thought that the substantial weakening of the climate provisions in the House bill had gotten Mr. Manchin within shouting distance of yes.

“We were close,” said Senator Tina Smith, Democrat of Minnesota, of her last conversation with Mr. Manchin, which she said occurred early last week.

Gregory Wetstone, president and chief executive of the American Council on Renewable Energy, a nonprofit group that supports green power, added, “We had good conversations directly with him and with his staff.”

“All of the prior conversations had been along the lines that he did not want to penalize fossil fuel but was fine incentivizing clean power,” Mr. Wetstone said. “We had not seen indications of pushback from Manchin or elsewhere from the clean energy provisions.”

The bill, as passed by the House, includes about $320 billion in tax incentives for producers and buyers of wind, solar and nuclear power. Electric vehicle customers would receive up to $12,500 in tax credits. Also included are $6 billion to make buildings more efficient and burn less fuel, $6 billion to replace gas-powered furnaces and appliances with electric versions, and billions more for research and development of new technologies to capture carbon dioxide from the air. Existing tax credits to lower the costs for homeowners of installing solar panels would be extended, as would credits for geothermal pumps and small wind turbines, covering up to 30 percent of the costs.