Electric cars don't just save the environment, they also save lots of money, according to a new Northwestern University study.

The United States could save up to $70 billion annually if electric cars replaced 75% of current internal-combustion cars, and were paired with increased renewable-energy electricity generation, the study found.

Even if electric cars only replaced 25% of internal-combustion cars, that would still save $17 billion annually by reducing the negative impact of climate change and air pollution, according to the study.

"Vehicle electrification in the United States could prevent hundreds of thousands of premature deaths annually while reducing carbon emissions by hundreds of millions of tons," Daniel Peters, who led the study, said in a statement. "This highlights the potential of co-beneficial solutions to climate change that not only curb greenhouse gas emissions but also reduce the health burden of harmful air pollution."

2020 Chevrolet Bolt EV

Previous studies have noted the public-health benefit of reduced air pollution, with one study published in April specifically linking pollution produced by vehicle exhaust to higher COVID-19 death rates.

The Northwestern study further emphasizes that point with its cost-savings estimates.

The EPA lowered fuel economy and emission standards and rejected higher standards for soot and particulate matter earlier this year.

In contrast, Democrats' climate plan would save 60,000 lives per year by 2050 through reduced air pollution, and save nearly $8 trillion through health and climate benefits over the same period. Democrats will need to win control of the White House and Senate in the November elections to put that plan into action, however.