Renewable energy isn’t just good for the environment—it’s good for your health too. Fossil fuel–based power plants, especially coal plants, release millions of tons of particulate matter into the air that can find their way into humans’ respiratory systems.
For every megawatt of new renewable energy produced in the United States, pollutants such as sulfur dioxide, nitrogen oxide, and ultrafine particulate matter decrease because fewer fossil fuels are burned. In a recent study published in Nature, researchers at the Lawrence Berkeley National Laboratory put a price tag on the switch from coal- and natural gas-fired plants to wind and solar power, estimating that air-quality improvements have saved nearly $30 billion to $112 billion nationally as mortality rates dropped from those pollutants. The study focused on data from 2007 to 2015.
“As far as public health is concerned, there’s nothing particularly good about [these pollutants],” says Arch Carson, an environmental health researcher at the University of Texas Health School of Public Health in Houston. “We know that all of those things cause injury to the body, especially to the respiratory system. They also have effects on the cardiovascular system.”
While Carson acknowledges that it is difficult to trace causation in complex medical issues, let alone put a price on the health benefits, he says, “We know these are broad estimates, but it’s the best study I’ve seen that estimates these numbers.”
The marginal benefits, or the economic benefits per megawatt of wind or solar power, change over time and vary by region, according to the study. “In the last ten years or so— even longer— the electricity grid in our country has been changing a lot,” says Dev Millstein, the study’s lead author.
About halfway through the time period which the study covered, the effects of the natural gas boom in Texas and other states started to take hold. As the price of natural gas dropped, the fuel composed a larger share of the overall energy mix, as more expensive coal power plants were turned off or phased out. In terms of air quality, coal plants release more hazardous pollutants, although both coal and natural gas power plants produce greenhouse gases that drive climate change.
In 2007, as more wind turbines were installed, they replaced the capacity provided by natural gas plants, which at the time were more expensive but less polluting. The study found that about 80 percent of wind generation in Texas offset natural gas, and the remaining 20 percent offset coal plants. By 2015, closer to 60 percent of the state’s wind power was replacing natural gas, and about 40 percent was offsetting dirtier, more expensive coal.
“The switch from offsetting natural gas to offsetting coal grew quite substantially in Texas over this time period,” Millstein says. “It grew at a stronger rate than the national average.The value of wind power is growing over time.” (The same data isn’t available for the state’s solar power, since it makes up a very small portion of the state’s energy mix.)
Even so, the economic benefit per each new megawatt of wind power is actually smaller than it is in other regions of the United States. “The electricity grid [in Texas] is actually cleaner than the upper Midwest or mid-Atlantic region to start with,” Millstein explains. Coal accounts for roughly 30 percent of Texas’s energy use, for example, but 55 percent of the mid-Atlantic grid’s energy mix, for example.
Replacing that coal capacity with wind or solar has more economic and environmental impact per megawatt than replacing natural gas. But, Millstein says, “One thing we noticed was the total benefits were increasing because more wind and solar kept being installed every year. So the dollars saved every year increased throughout the time period.” In other words, the sheer amount of wind power in Texas that’s coming online still means that there’s a sizeable return on the investment in wind power.
There is a downside to the good news, however. Millstein says that the study didn’t look at life-cycle impacts, or the effects of producing and using technologies for each of the energy sources included.
The toxic effects of mining coal or the methane released from fracking natural gas were beyond the scope of this study—and so were the environmental and health impacts of mining minerals for solar panels.
“With the increase in industrial activity, we’re at the verge of producing an epidemic of occupational disease and environmental pollution from materials that go into the production of [solar panels],” Carson says. That doesn’t negate the positive impacts of replacing coal or even natural gas power plants, however. “I’m an advocate for controlling factors that lead to health effects in pollution,” says Carson. “We have very good scientific evidence on the direct effects of sulfur dioxide, nitrogen oxides, and particulates,” he says, whereas there’s room for much more research on the life-cycle impacts of renewable technologies.
“This is the kind of study that influences politicians and businesses to make changes towards cost savings that are also beneficial to people’s health,” Carson says. “That’s what I hope the outcome of this study will be used for.”