Summary: Amid rollbacks of the Clean Power Plan and other environmental regulations at the federal level several U.S. states, cities and towns have resolved to take matters into their own hands and implement policies to promote renewable energy and reduce greenhouse gas emissions.  One popular approach, now in effect in 29 states and the District of Columbia, is to set Renewable Portfolio Standards (RPS), which require electricity suppliers to source a designated percentage of electricity from available renewable power generating technologies.

Boosting levels of renewable electric power not only helps mitigate global climate change but also reduces local air pollution. Quantifying the extent to which this approach improves air quality could help legislators better assess the pros and cons of implementing policies such as RPS. Toward that end, a research team at MIT has developed a new modeling framework that combines economic and air-pollution models to assess the projected sub-national impacts of RPS and carbon pricing on air quality and human health, as well as on the economy and on climate change. In a study focused on the U.S. Rust Belt, their assessment showed that the financial benefits associated with air quality improvements from these policies would more than pay for the cost of implementing them.

Applying their modeling framework, the MIT researchers estimated that existing RPS in the nation’s Rust Belt region generate a health co-benefit of $94 per ton of carbon dioxide (CO₂) reduced in 2030, or 8 cents for each kilowatt hour (kWh) of renewable energy deployed in 2015 dollars. Their central estimate is 34 percent larger than total policy costs. The team also determined that carbon pricing delivers a health co-benefit of $211 per ton of CO₂ reduced in 2030, 63% greater than the health co-benefit of reducing the same amount of CO₂ through an RPS approach.