Clean energy — such as solar, wind and batteries — is often considered a zero-emission technology that doesn’t generate any climate-change-inducing carbon dioxide when it produces electricity.
But manufacturing the solar panels, wind turbines and battery cells for those energy sources is anything but clean.
Most production facilities require large amounts of electricity from emission-spewing coal and gas plants to make them, explained Sergey Paltsev, deputy director of the Massachusetts Institute of Technology’s Center for Sustainability Science and Strategy.
Mining the minerals needed for solar panels and batteries also requires huge amounts of mostly dirty energy and can also pollute the environment and endanger the health of local residents.
“Low-carbon sources are lower, but they’re not zero,” Paltsev said. “We definitely need to educate both decision-makers and the general public on making sure that we are not making claims which are not realistic.”
It all begs the question: How clean really is green energy, and do the potential benefits offset the negative impacts?
‘There’s a big difference’
Manufacturing wind, solar and batteries can come with a significant upfront carbon footprint. But nearly all research agrees that those energy sources produce far fewer greenhouse gas emissions than coal or gas over their entire lifecycle.
Coal plants, on average, generate 1,000 grams of CO2 for every kilowatt hour of energy produced, according to an analysis by the U.S. Department of Energy’s National Renewable Energy Laboratory.
Wind generates 13 grams per kilowatt hour; solar produces 28 grams; and lithium-ion batteries generate 33 grams, according to the analysis.
“When you are comparing around 10 grams versus 1,000, that’s a big difference,” Paltsev said. “We need to keep that scale in perspective.”
To put those numbers in perspective, solar panels need to operate for 4 to 8 months to offset their manufacturing emissions; wind turbines need about three months to two years; and lithium batteries take 1 to 3 years.
That’s a short stretch in the lifespan of a solar array.
“When we do a solar system, it’s there for 30 years if you want it to be,” said Allan O’Shea, president of Contractors Building Supply in Copemish. “You will continue to make your return on investment on the minerals and silver and steel, the aluminum you’ve put into it and the glass.”
Fossil fuels also generate huge amounts of toxic air pollution that killed more than 8 million people worldwide in 2018, according to a Harvard University study released in 2021.
While manufacturing solar, wind and other clean energy sources produce some air pollution, the technology is completely clean once it’s operational.
Reducing air pollution through clean energy sources could help save 400,000 American lives by 2050, according to Princeton University’s 2021 Net Zero America study.
“Coal is really out there in terms of the bad impacts,” Paltsev said. “So, at this point, even though wind and solar isn’t at zero emissions, it’s still better.”
Getting green clean
But even with clean energy’s clear track record of producing less pollution and earth-warming gases, its downside shouldn’t be ignored, argued Dustin Mulvaney, an environmental studies professor at San Jose State University.
Today, many solar panels and batteries contain toxic chemicals that could be hazardous to human health, but still slip under the regulatory radar.
A case in point: The U.S. Environmental Protection Agency in December banned the use of trichloroethylene, which increases risks of certain cancers, in nearly every industry. Battery manufacturers, however, don’t have to phase out their use for 20 years.
“Here’s a hazardous chemical that’s in the battery supply chain that is not necessarily being adequately addressed,” said Mulvaney. “The EPA is putting this green halo on batteries, saying we forgive all of the bad sides to this.”
Mining lithium for electric-vehicle batteries is notoriously bad for the environment, using vast amounts of water in sometimes arid locations while employing heavy machinery that generates tons of emissions.
Silicon mining for solar panels also poses major health risks to workers, who face permanent and sometimes fatal lung diseases by inhaling toxic silica dust.
Mining can also pollute groundwater and degrade soil.
Most solar panels, wind turbines and some batteries also end up in landfills at the end of their lifecycle, which negatively impacts the environment.
Although the research is clear that clean energy produces fewer carbon emissions than fossil fuels, there currently is no metric measuring the overall, life-to-death environmental impact of green technologies, noted Paltsev with MIT.
Mulvaney argued that although it’s imperative to reduce the impacts of climate change through green energy, the people who do deal with its negative side effects, like polluted groundwater or increased health risks, shouldn’t be ignored.
“I think it’s dangerous to dismiss these impacts,” he said. “Even if 7 billion people benefit and only 20 people suffer on the planet, I think those 20 people deserve attention.”
Approaching zero
But new technology and improved manufacturing processes for clean energy sources are quickly diminishing those adverse impacts.
Companies like Arizona-based First Solar have developed a panel that doesn’t use silicon, greatly reducing its carbon footprint and water usage, compared to traditional arrays.
The publicly traded company with facilities in four countries also started the first global solar recycling program, and today recovers 90% of the materials in each module it produces.
The American Battery Technology Company is innovating ways to recycle lithium batteries and extract the rare metals inside to sell back into the battery-supply chain. The system reduces the need for mining and produces American-sourced metals with less environmental impact, according to the company.
Even China, where about 80% of all solar panels are manufactured, has since 2011 halved the CO2 produced through its manufacturing processes, according to the International Energy Agency. Still, total emissions from solar manufacturing there have almost quadrupled in the same time as production skyrockets.
Solar panels can be recycled, O’Shea said. His solar array company has replaced a few dozen out of the thousands it’s installed since transitioning to installing the arrays in the mid-90s. Those were broken by hail, the occasional golf ball or vandalism.
While those panels went back to the manufacturer to be recycled, others that still function could get a second life, O’Shea said.
Advances in photovoltaics have improved a panel’s efficiency from converting 17% of solar energy to electricity up to 23%.
That’s led some utility-scale array operators to upgrade their panels, as even a small increase in efficiency adds up over time and across thousands of panels, O’Shea said. If the old ones still function, they can be refurbished and resold.
“So if it tests properly … it can still be very viable for 15 years or more,” he said.
Paltsev said how quickly green energy can move toward net-zero emissions in the U.S. really depends on policymakers and the economic incentives that they can provide.
That matters, he argued, because reduced emissions from clean energy won’t be enough to curb climate change in the long run. Greenhouse gases are also coming from non-energy sources like agriculture and deforestation, Paltsev noted.
Until zero emissions are reached across the globe, temperatures will continue to rise and contribute to a surge in catastrophic weather events around world.
“At some point, I think there will be a huge demand for much more aggressive actions, because when you see things which are destroying your way of life, you will start asking more and more loudly that policymakers do something,” he said.