Ten states across the Midwest and Great Lakes region of the US could see $4.7 billion in health benefits in 2030 if they stick with current renewable energy standards, according to a new study from MIT. That’s about a 34 percent return on the $3.5 billion price tag associated with actually building out that infrastructure of renewable energy sources such as wind or solar farms.

“This research shows that renewables pay for themselves”

“This research shows that renewables pay for themselves through health benefits alone,” Emil Dimanchev, lead author and senior research associate at the MIT Center for Energy and Environmental Policy Research told The Verge.

There’s no shortage of studies into the potential costs associated with climate change — from insuring vulnerable coastal properties to rebuilding after more frequent and intense storms. And then there are the health risks, ranging from more annoying allergy seasons to a jump in heat-related illnesses and deaths. But this study, published August 12th in Environmental Research Letters examined the health benefits and financial incentives that come along with states using more renewable energy.

Why are there such big returns? On top of limiting greenhouse gases that warm the planet, moving away from dirtier sources of energy also affects air quality. The health benefits scientists quantified are a result of limiting exposure to fine particulate matter coming from power plants. And there’s a vast body of evidence that shows how particulate matter, or soot, can adversely affect respiratory and cardiovascular health. One of the reasons researchers focused their study on Pennsylvania, Ohio, Wisconsin, Michigan, Illinois, Indiana, West Virginia, New Jersey, Maryland, and Delaware is because the region tends to have poorer air quality, a characteristic linked to its greater reliance on coal. In 2016, the Rust Belt generated 42 percent of its power from coal, compared to 30 percent for the US as a whole. And that was before the Trump administration’s push to revive the struggling industry.

But if those states switch to more renewable energy, air quality will improve. As the pollution rates diminish, so should lung cancer, heart attacks, and strokes among people living there. That, the researchers say, could also reduce the medical bills and lost wages associated with those health effects, which leads to their estimated benefits of $4.7 billion in 2030 if current standards are adopted. This is something that medical researchers call a co-benefit of taking action against climate change.

To get to that $4.7 billion number, researchers focused specifically on states’ current renewable portfolio standards, policies requiring utilities to generate a certain percentage of their electricity from renewable sources. The average goal for those states is now set at 13 percent. But if states in that region up the percentage of renewable energy in their mix to 19.5 percent instead, it would result in $13.5 billion in health benefits in 2030 compared to $5.8 billion in costs. Doubling their renewable usage to about to about 26 percent of their total energy mix would lead to $20 billion in health benefits versus $9 billion in costs to implement. The team used a framework combining economic and air pollution models to arrive at their conclusions.

The research team predicted even bigger health benefits if states enact carbon pricing — a market-based climate strategy that in this case would entail capping the amount of companies industry can put out, and allowing them to trade carbon credits with each other. The caveat is that carbon pricing is more politically volatile compared to renewable portfolio standards. California boasts the cap-and-trade system policymakers have looked to as a model elsewhere, but critics have found evidence that it could concentrate emissions in lower-income neighborhoods and communities of color closest to polluters that buy up the most carbon credits. Renewable portfolio standards in comparison are already widely implemented across 29 states, the District of Columbia, as well as in the European Union, China, and India.

States are leading the way

The MIT team strategically honed in on local measures that can be taken even as Trump rolls back federal action on air quality and climate change. His administration is facing a massive lawsuit filed by 22 states and seven local governments challenging his Affordable Clean Energy Act, which would weaken emissions standards for coal plants. “States are leading the way right now,” Dimanchev said. “That’s where climate policy is taking place and renewable energy policy is largely taking place.”

But there are still state battles, too, especially in the Rust Belt. Dimanchev presented his research on Ohio’s senate floor in June as it deliberated on whether to roll back its renewable portfolio standards to subsidize nuclear energy and coal. Throwing out the standards completely would lead to an average of 50 premature deaths per year starting in 2030. Ohio Governor Mike DeWine eventually signed a bill that didn’t gut the standards completely, but significantly walks them back. “The negative impacts on health will be significant and will not be very far off from the numbers we estimated for a full repeal,” Dimanchev says.