In a new study published in Renewable & Sustainable Energy Reviews, a team from Michigan Technological University calculated that 51,999 American lives per year could be saved by transitioning from coal to photovoltaic-powered electrical generation in the U.S. By transitioning to solar photovoltaics (PV) in the US, up to 51,999 American lives would be saved at $1.1 million invested per life. Courtesy of Sarah Bird/Michigan Tech. The study, focused on the cost of combusting coal in human lives along with the potential benefits of switching to solar, aimed to inform public health policy. First, the geospatial correlation with coal-fired power plants and mortality was determined for the U.S. at the state level. Then, current life cycle mortality rates due to coal combustion were calculated, and current energy generation data was collated. "Unlike other public health investments, you get more than lives saved," said Joshua Pearce, a professor of materials science and electrical engineering at Michigan Tech. "In addition to saving lives, solar is producing electricity, which has economic value." To accomplish such life-saving numbers, the researchers calculated that 755 GW of U.S. photovoltaic installations are needed. Over the span of 25 years, the first cost per life saved is approximately $1.1 million, which is comparable to the value of a human life used in other studies. However, as the solar electricity has value, the cost per life is determined while including the revenue of the solar electric generation using a sensitivity analysis on the value of the electricity. These results found that for most estimations of the value, saving a life by offsetting coal with photovoltaics actually saved money. Certain geographic regions are harder hit by coal-related deaths from air pollution, shown by calculating US deaths per kilowatt hour per year. Courtesy of Emily Prehoda/Michigan Tech. "Everybody wants to avoid wasting money,” Pearce said. “Just based off the pure value of electricity of the sensitivities we looked at, it's profitable to save American lives by eliminating coal with solar.” The researchers concluded that it is profitable to save lives in the U.S. with the substitution of coal-fired electricity with solar power and that the conversion is a substantial health and environmental benefit. "My overall takeaway from this study is that if we're rational and we care about American lives – or even just money – then it's time to end coal in the U.S.,” Pearce said.