Are solar panels toxic or bad for the environment?

For many homeowners, one of the primary motives for going solar is to have a positive impact on the environment. When you use solar energy in your home, you lower your overall greenhouse gas emissions like carbon dioxide, and you reduce your carbon footprint.

While solar panels are considered a form of clean, renewable energy, the manufacturing process does produce greenhouse gas emissions. Additionally, to produce solar panels, manufacturers need to handle toxic chemicals. However, solar panels are not emitting toxins into the atmosphere as they generate electricity.

The primary material used for solar cells today is silicon, which is derived from quartz. In order to become usable forms of silicon, the quartz has to be mined and heated in a furnace (which, in turn, emits sulfur dioxide and carbon dioxide into the atmosphere).

There are some chemicals used in the manufacturing process to prepare silicon and make wafers for monocrystalline and polycrystalline panels. One of the most toxic chemicals created as a byproduct of this process is silicon tetrachloride. This chemical, if not handled and disposed of properly, can lead to burns on your skin, harmful air pollutants that increase lung disease, and, if exposed to water, can release hydrochloric acid, which is a corrosive substance bad for human and environmental health. Fortunately, there is a process that most manufacturers employ to safely recycle silicon tetrachloride back into the manufacturing process for new silicon wafers, helping to eliminate health and environmental risks.

The large majority of panels used in installations are safe, silicon-based panels; however, if you're installing thin-film technology, there are additional toxic materials contained in the thin-film panels itself, such as cadmium telluride and copper indium selenide. These materials are used in the manufacturing process for many other electronics, like your cell phone or laptop. Thin-film panels are not common for residential solar installations and are most often used in large commercial or utility-scaled applications.

While these chemicals can be considered hazardous, they aren't so while the panels are on your roof. The concern for their toxicity comes into play during the manufacturing process, as well as the disposal process from by-products during the manufacturing process and at the end of the panel's lifetime.

Responsible solar panel manufacturers will ensure that the chemicals used in the manufacturing process are handled properly. Unfortunately, there have also been instances in the past of dumping hazardous into nature in various parts of the world (such as China). The resulting public outcry caused stock prices of manufacturers involved in these instances to drop, and solar companies started to implement more stringent rules and regulations in regards to recycling and disposal to protect against this happening in the future.

During the lifecycle of a PV system, the majority of greenhouse gas emissions occur during the manufacturing process. As solar panel manufacturing becomes more efficient, its carbon footprint shrinks significantly: a 2016 study reports that the overall emissions produced in this process decreased by 17 to 24 percent every time install capacity has doubled in the last 40 years.

As your solar panel system produces electricity on your roof, it is 100 percent renewable, free of pollutants and emissions. It is also directly impacting your carbon footprint and the carbon footprint of your community.

If your primary aim in going solar is to benefit the environment, you can rest easy knowing that while the manufacturing of solar panels produces greenhouse gas emissions, your panels are still much better for the environment than other options. The overall greenhouse gas emissions involved in solar energy are still much lower than coal or natural gas. A 2011 report showed that solar's carbon footprint averaged at roughly 85 tonnes of carbon dioxide equivalent (CO2e) per gigawatt-hour (GWh), while natural gas and coal came in at 499 CO2e/GWh and 888 CO2e/GWh, respectively.

While solar panels, like other electronics, contain and are manufactured using toxic materials, measures can be taken to minimize negative effects. Silicon tetrachloride, mentioned above as one of the most toxic chemicals involved in the manufacturing of panels, is usually recycled by manufacturers as a cost-saving measure. They can use this byproduct to create more polysilicon and, therefore, more panels. Many of the other toxic chemicals and products in solar panels can also be recycled.

Recycling of the panels at the end of their life is also a growing trend. Some manufacturers (like SunPower and First Solar) offer global recycling programs for their customers. While not all manufacturers offer recycling programs today for old panels, it hasn't been a huge concern considering the lifespan of these panels. Solar panels didn't start becoming widely popular until the 1990s (and even more so post-2000s). As a result, the majority of panels are still usable and producing electricity. Because of the rising popularity of solar, recycling programs and companies are expected to be even more prominent in the near future than they already are.

Silicon Valley Toxics Coalition

Many panel manufacturers are focusing on sustainability in the manufacturing process to promote the health of the earth, as well as employees and factory workers involved in the production of their panels. A nonprofit organization known as the Silicon Valley Toxics Coalition is leading the pack in advocating for sustainable practices for electronics manufacturers, including solar panel companies. They publish a report known as the Solar Scorecard that evaluates a variety of panel manufacturers on their environmental protection measures, as well as measures for their employees and their communities.

The scorecard uses a few different factors to determine manufacturer ranking on the Solar Scorecard, including emissions tracking, how many toxic materials are included in their modules, water usage in manufacturing, the use of conflict materials (which are those that come from various areas of Africa with unjust mining practices), and worker's rights.

In the most recent Scorecard, SunPower was given the highest ranking of the companies that responded to the survey, followed closely by SolarWorld, Trina, Aleo, and Jinko.

Manufacturers are continuing to improve their sustainability efforts, and if you're looking to install a solar panel system that's as green as possible, the Solar Scorecard can be a good resource to use to find out more general information about various manufacturers.

That doesn't mean that you should automatically rule out companies that aren't included in the list or appear very low on it. While this scorecard is a good resource for homeowners who want the assurance of a sustainable manufacturing process to be as high as possible, it's worth noting that there are many panel manufacturers that don't respond to the survey from this organization, or don't accurately track factors used in the scorecard and therefore cannot report on it.

Keep in mind that your solar panels will keep producing electricity for 30 to 35 years. We're very optimistic that as time goes on, recycling options for solar panels will improve. Every item's manufacturing process has an ecological and social footprint, but the environmental benefit from going solar now and over time outweighs sticking with a utility company and using dirty energy (and saves you money too!).

As you consider your solar options, we recommend signing up on EnergySage to receive multiple quotes from pre-screened installers. These quotes will include information about the type of panel they're recommending and can also be updated according to your preferences (as most installers offer multiple equipment packages!) If you'd prefer to start with an estimate of potential costs and savings of a solar installation, try our Solar Calculator.