Campaigns to shift consumers away from natural gas and toward renewables such as solar and wind are directed at substantial environmental benefits. However, the process could exact a punishing financial toll on poor Americans, a new study found.

Gas Price Outlook

Research co-authored by Catherine Hausman, an associate professor at the University of Michigan, and economist Lucas Davis of the University of California, Berkeley, found a “thorny issue” in what they call a virtuous energy transition effort aimed at minimizing the emissions that cause climate change. As utilities shed natural gas customers, the researchers argued, they would still have to maintain legacy pipeline networks for years and pass along maintenance costs to a smaller pool of customers.

That is because the transition is...