Democrat Tom Steyer has been playing up his track record of climate advocacy in his bid for California governor — but a flip-flop on his position regarding AI data centers may infuriate some environmentalists backing the billionaire’s campaign.

Greenpeace released its grades of the the crowded field of gubernatorial candidates and gave Steyer an “A” grade, one of only two candidates to receive that mark.

One of the platforms on which candidates were graded was the promise to enact a moratorium on new data centers, which AI companies and other businesses store servers in to help make the internet and other digital services work more effectively.

Those data centers have seen unprecedented investment thanks to the AI boom, but they also have become more politically contentious as neighbors living next to them contend with their heavy water and electricity usage. Environmentalists hate the centers for such impacts on the environment.

On the Greenpeace survey, Steyer’s campaign marked “Yes” when asked about supporting a moratorium on data center “until regulations can be put in place that will protect ratepayers and require new renewable energy capacity and sustainable water procurement.”

Steyer elaborated further in the survey that “no new data centers should be built in our state unless they pay their own way so they don’t cost ratepayers a dime.” Companies should pay for all energy usage, he argued, as well as expenses to maintain and update the energy grid.

But the billionaire had previously told Politico he didn’t think a moratorium was needed, instead stressing a focus on ensuring electricity rates don’t increase at data centers and communities’ water won’t be “stolen.”

A Steyer spokesperson clarified to Politico on Monday that he is not calling for a moratorium on data centers.

“As governor, Tom will enforce these standards on any proposed data centers in the state,” the spokesperson said. “If the wealthiest companies in the world are raising electricity demand in California, they should pay the bill and be required to lower electricity costs for everyone else.”

Greenpeace USA Climate Director Amy Moas issued a stern warning to Steyer on not backing a moratorium.

“If he’s changing his position, we will be changing his grade,” she told Politico.

This is not the first time Steyer has faced questions about his pro-environment track record.

Rivals in the race have repeatedly hammered him for making his wealth off of a hedge fund that invested in fossil fuel companies. Steyer has long maintained that he left the investment world to focus on climate change, telling voters he “walked away” from his hedge fund to fight global warming.