Photograph by Ruslan Dashinsky/Shutterstock
While many people consider the benefits to outweigh the costs, there are still some downsides to solar energy. Purifying the silicon for crystalline solar cells requires heat, which typically comes from burning fossil fuels. Toxic metals like lead, cadmium, and arsenic are used in solar cells and wiring.
Sulfur hexafluoride is used to clean reactors where the silicon is made. It is an extremely potent greenhouse gas (one ton is equivalent to 25,000 tons of carbon dioxide), and it can break down into sulfur dioxide, which can cause acid rain. Silane gas, used to grow silicon crystals, is extremely explosive. Silicon tetrachloride, produced as a waste of the same process, reacts violently with water, can contaminate soil, and causes skin burns and eye and lung irritation.
Recycling and control systems exist for most of these problems in countries with strong environmental and worker protection laws. These gases can be a problem in countries, like China, that have less protective policies.
Rechargeable batteries can contain toxic cadmium, lead, and lithium. However, battery recycling programs are widespread, helping to keep toxic chemicals out of landfills.
Plastics used in casings can contain the same toxins as other electronics, including the use of flame retardants that contain endocrine disruptors. For more information, see our e-waste article.
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