There’s no doubt that the world needs more renewable energy infrastructure. Clean energy options like solar panels and wind turbines help both the environment, by reducing carbon emissions, and our personal health, by decreasing harmful air pollution. But with limited financial resources to invest into renewables, it pays to be smart about where to put them: Renewables that directly eliminate polluting power plants have more climate and health benefits than ones that simply add to already clean grids.
A new study from the Center for Climate, Health and the Global Environment (C-CHANGE) within the Harvard T.H. Chan School of Public Health, published on October 12 in Palgrave Communications, shows where in the world investors and companies focused on renewables could put their money to make the greatest difference.
A wind turbine or solar panel installed in India, for instance—a country in which air pollution is a serious public health issue—could save 30 times as many lives than if that same turbine or panel was placed in the United States. For climate benefits, that Indian turbine or solar panel would be twice as effective in lowering carbon emissions than if it was located stateside.
“Since renewable energy has benefits for climate and health by displacing fossil fuels, the benefits you get are determined by the fossil fuels you’re displacing,” says Jonathan Buonocore, lead study author and Harvard C-CHANGE research associate. “And not only what you’re displacing, but who lives nearby downwind, the people being exposed, and what the health impacts are.”
The climate benefits from renewable sources are greatest, the study found, in areas where the electricity grid is mostly powered by coal, in countries like Mongolia, Botswana, Estonia, Iraq, and Australia. When it comes to improving health by reducing pollution, densely populated places where people live downwind of high pollution-emitting sources see the greatest impact. That includes Myanmar, Bangladesh, Ethiopia, India, and large parts of Eastern Europe.
“If you’re building renewables in Norway or Iceland or a place that has a lot of renewables already in place, you’re getting much less benefits than if you build in a place like Eastern Europe or India, where you have much more coal being consumed and many more people being exposed [to pollutants],” says Buonocore.
To measure these benefits, researchers combined data on energy use and fossil fuel emissions with a database on air pollution, linking all that information to previous research on the health impacts of air pollution worldwide. (Air pollution has been linked to premature death, respiratory and cardiovascular hospitalizations, lung cancer, stroke, and even neurocognitive diseases like autism and Alzheimer’s, according to Buonocore.) That data went into a model that can be used to estimate the benefits of building renewable energy, and where that energy can have the greatest impact.
To illustrate how the model can be used, researchers compared five anonymous renewable energy companies that share country-level operating data. The climate and health benefits achieved per megawatt of renewable energy changed dramatically based on the country in which that company was operating. One wind company that operates mostly in India saves about 250 lives for every 1,000 additional megawatt of wind energy it installs per year. Another wind company operating mostly in North America and Europe saves just 25 lives with that same amount of annual wind energy installed.
A previous study out of C-CHANGE looked at where renewable energy would be most effective within the United States (spoiler: the Upper Midwest, as opposed to California), and the key factors for why are similar. It comes down to what fuel sources are displaced and how many people live downwind. Buonocore says that it was “nice to apply similar logic worldwide and see similar results,” but there is a difference in these studies. He hopes this latest study could act as a guide to aid policy makers and investors in making the most impactful decisions about where to focus renewable energy efforts, helping to achieve the United Nations’ Sustainable Development Goals.
“A lot of investors out there, sustainability investors, are trying to have a positive social impact with their investments,” says Buonocore. “The idea is that this kind of information would help those types of people better target what they invest in and where.”