As the growth of renewables mirrors the decline of fossil fuels, some of the biggest backers of dirty energy are changing sides. Bank of America (BAC), the top U.S. coal financier as recently as 2012, poured $14.5 billion last year into projects that promote renewable energy, energy efficiency and sustainability through its environmental business initiative. That brought the bank’s total green investment to $31.8 billion since it launched that initiative in 2013.

Bank of America has also underwritten two major “green bonds,” which fund low-carbon or sustainable business projects, for a combined $1.1 billion. It was the main underwriter for a $1 billion bond for Southern Power, a subsidiary of coal-dependent utility Southern Company (SO), to fund its clean energy projects; it also backed a 400-million-pound bond to aid the London transport network’s sustainability upgrades. Bank of America also took a big step forward last year with its Catalytic Finance Initiative (CFI), which it expanded through eight new partnerships with financial institutions that have pledged a combined $8 billion toward a variety of sustainable investments aimed at lower-income communities. The CFI has already underwritten a $204 million green bond for wind developer ContourGlobal through its subsidiary in Peru.

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A version of this article appears in Fortune’s September 1 issue as part of the Fortune Change the World list, our annual ranking of major companies whose business activities are having a positive social impact. Click here to see the entire package.