How "Green" are Solar Panels?

By Kate Whitney
July 13, 2017
How Green are Solar Panels?

Solar power has long been hailed as a promising form of clean energy, but many consumers are unaware of the pollution and waste created by the process of manufacturing solar panels. While residential solar arrays have minimal land use impact, they do require considerable amounts of energy to produce. Often, this energy comes from nonrenewable sources and results in pollution, though the energy invested in manufacturing the panels is paid back by the panels soon after they begin generating energy themselves. Additionally, the process of manufacturing involves several chemicals and waste products that can cause damage to workers and surrounding communities if not handled properly. The question arises - are solar panels actually “green”?

The Carbon Cost of Solar

Though no carbon emissions are associated with the generation of energy from solar panels themselves, the transportation, installation, and maintenance of the panels do result in carbon emissions. The carbon footprint of solar panel production varies widely by region of production, depending largely on the primary fuel that a region relies on for its energy. In 2014, a study found that the carbon footprint of a solar panel produced in China, where coal is heavily relied upon for electricity, was twice that of a panel produced in Europe.

Despite the energy costs of producing panels, most solar cells pay back the initial energy invested in their manufacturing within just 2 years. Considering a standard solar panel lifespan of 30 years, the clean energy that these panels produce far outweighs the energy required to manufacture them. Estimates of greenhouse gas production per kilowatt-hour of electricity further indicate that solar is a better option than non-renewable alternatives such as coal and natural gas. With all manufacturing emissions considered, estimates for life-cycle emissions from PV solar systems range between 0.07 and 0.18 lbs CO2 equivalent per kWh, while emission rates for natural gas and coal are around 0.6-2.0 lbs CO2e/kWh and 1.4-3.6 lbs CO2e/kWh, respectively.

Solar Manufacturing Pollution

Beyond the Carbon Footprint

Carbon emissions are not the only environmental impact of the solar manufacturing process. In 2008, a Washington Post article exposed the improper waste disposal methods occurring at a polysilicon facility in China. The process of producing polysilicon, a component of solar panels, creates the highly toxic byproduct silicon tetrachloride. Though silicon tetrachloride can be recycled to create more polysilicon, some facilities do not purchase the expensive equipment required to recycle or treat this harmful waste. Instead, it is dumped into the environment. When exposed to water, the silicon tetrachloride releases hydrochloric acid, leading to soil acidification and the release of harmful fumes. Washington Post reporters visited a Chinese town where this dumping was occurring, and residents complained of infertile land and chest tightness due to the pollution. Following the article’s release, public pressure did result in many foreign manufacturers improving their practices. In 2011, China put standards in place that require manufacturers to recycle at least 98.5% of this silicon tetrachloride waste. Still, foreign facilities are often subject to far fewer environmental regulations than those in America, and it is important for consumers to remain informed about the sources of their solar panels to place the necessary pressure on irresponsible manufacturers to improve their practices and reduce pollution to surrounding communities.

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Further, solar panel manufacturing poses occupational risks to the workers involved. Silica for solar cells is often derived from quartz, and the mining of quartz carries the risk of the lung disease silicosis. Additionally, hydrofluoric acid, frequently used to clean silicon wafers and texture their surface to better collect sunlight, is capable of destroying tissue and can significantly harm employees if not handled carefully. It is crucial that manufacturers have worker protection measures in place to mitigate these risks in the production process.

Keeping Score

Despite wide variation in pollution levels by different solar manufacturers, there is no formal environmental rating used to differentiate them. Several organizations, including the Center for International Earth Science Information Network and the Solar Energy Industries Association have proposed guidelines by which to judge manufacturers. The Silicon Valley Toxics Coalition (SVTC), a nonprofit on a mission to track the environmental impact of the high-tech industry, has created annual Solar Scorecards since 2010. They use self-reported data on emissions, chemical toxicity, water use, and recycling to rank solar manufacturers on their environmental and social justice practices. In 2015, the manufacturers SunPower, SolarWorld, and Trina received the highest scores. The SVTC’s mission to develop industry-wide standards is critical in enabling manufacturers to back up their environmental claims, and in generating progress within the industry by allowing companies to compete with each other based on environmental practices. However, the SVTC notes that the market share of manufacturers willing to share their information for the Solar Scorecard is declining, and if consumers do not place pressure on manufacturers to be transparent about their environmental practices, it is possible that the market will be dominated by companies who do not prioritize their environmental impact.


Looking Forward

In environmental friendliness, solar far exceeds traditional forms of energy production from fossil fuels. The clean energy produced by solar panels quickly compensates for the energy required to manufacture them. Combined with other positive environmental impacts such as reductions in water usage, consumers can rest assured that solar panels have a substantial positive effect on the environment.

Still, the industry can continue to improve its practices. As clean energy spreads, more of the energy used for solar panel production will itself be generated from renewable sources, reducing the lifecycle emissions of solar panels even more.

View our 2018 Solar Starter Guide

As an environmentally conscious consumer, you can make a positive impact by requesting information from installers concerning the manufacturers of their products. In turn, installers will be pressured to request this information from their manufacturers and select manufacturers with responsible environmental practices. As a result, manufacturers will have a financial incentive to improve their practices. Environmentally-minded consumers should also choose manufacturers that provide transparent information to organizations such as the SVTC, supporting their mission of holding manufacturers accountable. With consumer choice indicating a preference for environmentally-friendly manufacturers, the industry will continue moving toward an even greener future.


Kate Whitney

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Kate Whitney

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