Years ago, I told an engineer that I want to cause minimal ecological harm. This man knew that I had my own car, refrigerator, washing machine, phone, Internet access and electricity available 24/7. He took a deep breath and explained to me that every manufactured item requires multiple processes from the extractive, energy-guzzling, water-guzzling, toxic waste-emitting global super-factory. He connected my material goods with ecological degradation--the degradation I want reduced.
I started living with questions: Do I aim to reduce ecological damage worldwide--or just my household's toxic emissions? Do I prefer decreased energy bills--or healthier international ecosystems? Who defines "green," "clean, "carbon-neutral," "zero-emitting" and "sustainable"? Before mandating ways to live within my ecological means, what should I know about manufacturing, infrastructure and waste?
I started applying these questions to computers, Internet access, "renewable" energy systems and electric vehicles. While I've learned plenty, with our society's embrace of all things tech--including, in this case, solar photovoltaics (PVs)--I wonder how we can use this information constructively. May these questions and resources move us all toward minimizing our ecological harm--including individuals and municipalities that have invested in solar PVs.
Manufacturing
Mass-produced goods consume most of their lifetime energy use and generate most of their hazardous waste during manufacturing. For example, a laptop consumes 81% of its lifetime energy before its end-user turns it on for the first time.1 Assessments of any product's ecological impacts should therefore include its manufacturing (design, mining, smelting, chemicals, energy use, water use, GHGs, toxic waste, transport of raw materials, assembly, final shipping)--and its operation and discard or recycling.
You know those white squares under a solar panel's glass? They're made from silicon--unavailable in nature in pure form. Manufacturing solar panels' silicon requires a handful of energy-intensive, toxic waste-emitting processes.2 First, pure quartz gravel, pure carbon (i.e., Tar Sands' petroleum coke) and wood are transported to a smelter kept at 3000 degrees Fahrenheit (1649 degrees Celsius) for years at a time. Since smelters can explode if delivery of electricity to them is interrupted, neither solar nor wind (which provide only intermittent power) can fuel a smelter.3 Typically, smelters and refineries are powered by natural gas, coal and/or nuclear power. To produce 20,000 tons of polysilicon, one smelter (of several refineries) consumes enough power as 300,000 homes.4
To increase solar panels' durability, dirt-repellency and energy production, manufacturers coat panels with per- and polyfluorinated chemicals (PFAs).5-9 Exposure to these "forever" chemicals ("forever" because we don't know how to clear them from our bodies or soil) can harm human health. Do cracked solar panels leak PFAs?10,11 Should people avoid vegetables grown near solar PVs?
Transporting solar PVs' raw materials to smelters and assembly plants--and final products to consumers--requires cargo ships that use highly polluting bunker fuel,12 GHG-emitting planes, trucks and trains. Imagine, also, manufacturing each of these great vehicles.
Operation
In the U.S. on sunny days, solar PVs collect their best sunlight between about 11am and 3pm. On cloudy days, they produce 10-25% of sunny-day energy. Meanwhile, household electricity demands peak a few hours later, at dinnertime. Solar generators wanting electricity 24/7 therefore need backup power.
About 90% of rooftop solar generators rely on their utility's fossil fuels, hydro or nuclear power for backup.13 The batteries that store off-grid solar systems' energy come from mining lithium, cobalt and copper and from chemicals. The manufacturing processes harm nearby ecosystems and violate human rights. Plus, batteries cannot provide the kind of reliable power that coal and natural gas deliver. Outfitting the U.S. with 12 hours of battery storage would cost more than $2.5 trillion.14 Our expectations of electricity do not match up with what solar PVs can deliver.
When rooftop solar generators send power to the grid, they affect the utility's available reserves of power. Utilities must maintain load balancing to keep delivery of electricity safe and reliable. Because of the electricity generated by solar PVs (that stay grid-connected, not off-grid with battery backup), utilities now ask e-vehicle owners to charge during the day--and consume solar-generated power--and keep the utility from power surges. They also may pay other utilities to take their reserves.15 In other words, we've added complexity to our power grid. We may not have added reliability. (Just look at all the blackouts.)
Then, all electrical equipment poses fire hazards. When utility-scale battery energy storage systems catch fire, nearby residents cannot open their windows, leave their homes or run ventilation systems until the EPA determines that toxins have cleared.16 On fields with dry vegetation, rodents chewing soy-based PVC can expose wires and cause arcing. When panels catch fire on a sunny day, firefighters cannot de-energize them.17 On a roof (with possibly flammable materials), solar panels increase electrical connections--and fire hazards.
End-of-life waste
End-of-life solar PV waste does not biodegrade.18 By 2050, we could acquire 78 million metric tons of solar panel waste.19,20 Besides PFAs, solar panels typically contain lead, polyvinyl fluoride, cadmium, cadmium telluride, copper indium gallium diselenide--and more. To prevent toxins from leaching into soil, panels should not be disposed of in regular landfills.21,22
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