Michael Bloomberg said Wednesday night that the United States cannot afford to ban fracking because the country is not ready to use exclusively renewable energy, positioning himself with centrists who fear such a policy could cost Democrats the election.

Bloomberg during his first appearance at a Democratic primary debate offered his most expansive views on fracking, a drilling technique for extracting oil and gas deep underground. He joined other centrists, including Amy Klobuchar, in deeming natural gas a “transition fuel” to be used until wind, solar, and other nonemitting energy sources become more widespread. He aligned himself with moderates who fear that curbing fracking could make it harder for Democrats to win the White House, given that they need to win states heavily dependent on the shale boom to beat President Trump.