Democrats’ push to eliminate greenhouse gas emissions from the power sector is exposing a fundamental difference in strategy among members of the party and environmentalists: whether to rely solely on renewable energy or support other zero- and low-carbon resources.

Both sides of the debate feel their approach is essential to avoiding climate disaster. Left-wing activists and Democrats say anything less than a singular focus on building massive amounts of renewable energy undermines overall emissions reduction goals and jeopardizes the health of people who live near smokestacks, who tend to be poorer and minorities.