With U.S. electricity demand starting to rise quickly and expected to continue rising, largely because of the power needed for data centers that process artificial intelligence, people are looking for almost any potential solution.

And people are warning that the full projected demand may not actually develop, which could make massive investments in power plants unnecessary, raising Americans’ electricity rates even more.

U.S. Secretary of Energy Chris Wright is among those who have been promoting what might seem to be an attractive idea: “We have 35 gigawatts of backup generators that are sitting there,” he told an audience of natural gas industry leaders in December 2025. He was referring to diesel-fired engines at hospitals, office complexes, corporate campuses and even data centers to provide electricity if the grid goes down.

That amount of power would be a significant step toward meeting the nation’s expected energy needs, without needing new long-term investments in power plants or transmission lines. But it’s also vital to know, as Wright went on to note, that “emissions rules or whatever” mean those generators can’t just be turned on and left running when there’s not a power outage or other emergency.

As an environmental engineer who studies air pollution from the energy system, I believe this proposal is concerning. Those emissions rules are in place because diesel-powered generators are among the dirtiest sources of energy, emitting fine particulate matter and related chemicals. That is a pollutant whose total emissions from all sources are estimated to cause about 100,000 premature deaths every year in the U.S. And in fact, emissions regulations on backup generators........

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