How Clean is Clean Energy, Really?

by Andrew Meyer
November 5, 2015

We took a deeper look into the dirtier side of clean energy. Here’s what we found.

We all know that generating electricity through photovoltaics like solar panels is better for the environment than other fuel alternatives, but what about the environmental impact of generating the panels themselves?

Installing solar panels is a key step to getting off the grid. Solar photovoltaics, when used alongside energy storing systems like home batteries, allow households to store energy during the day, and convert it into electricity to use in the evening hours, when the sun goes down and you need electricity the most. Solar panels themselves have been a symbol of environmental friendliness and “green living” since their humble beginnings, but not many know the actual impact this growing industry has on the environment.

We took a deeper look into the dirtier side of clean energy. Here’s what we found.

The Cost of Recycling (Or Not Recycling) Toxic By-Products

There are a number of technologies that can be used to generate solar energy, but most solar cells today start with quartz, a common form of silicon dioxide. It’s refined first into metallurgical-grade silicon, a process that requires a lot of energy (we’ll talk about that later.) Next, the material is further purified into polysilicon. This purification process creates a toxic compound, and if it hits water anytime in the disposal process, it can acidify the soil, and emit harmful fumes.

This, of course, is bad news, but it’s not the end of the story. Many manufacturers recycle this waste to make more polysilicon. Companies can actually save money through recycling. But there’s a catch: the equipment required for this process costs millions of dollars, and many smaller manufacturers can’t cover the up-front costs. The result? Smaller companies struggle to dispose of harmful by-products.

With more and more of the public moving towards solar energy storage through in-home batteries, however, even smaller manufacturers are projected to see huge profits soon. With a little bit of public pressure, a portion of these profits should be committed to investing in recycling equipment. As more and more solar battery companies make battery recycling possible, recyclability will become a valuable asset to even very small companies. When it comes to home batteries, this recycling gap won’t be around for long.

Putting Energy into Clean Energy

The process of refining the silicon used in most solar panels takes heat and energy. A lot of energy. Unfortunately, the source of this energy is often coal. Isn’t this the energy source photovoltaics are trying to eliminate, you may ask? To answer you quite simply, yes. It is.

So, how do we reconcile this? Most of the time, it’s pretty easy. Since the cells being manufactured in this case are actually generating energy after their creation is complete, the initial energy debt can be paid back by the finished solar panels, when they are put into action. Most take about two years to make up for the original energy required to produce them, while some take only six months. (Please note that this is different than the time it takes for the customer to make back the monetary investment they put into their solar panels and home battery. We’ll address that in a later post.)

This get a little complicated when panels are shipped overseas from China. As stated before, the environmental cost of a panel manufactured in China is sometimes double the footprint of a solar panel produced in Europe. If a Chinese-made panel is installed in Europe or the US, it takes a bit longer to pay back the energy debt.

Delayed, clean energy pay back is still clean, however. Don’t forget that the energy produced by solar photovoltaics is completely clean, with no carbon footprint at all. Looking into renewable energy sources like solar panels, and storing energy in home batteries, is one way to invest in a greener planet.

Which Came First? The Recycle Plant or the Recyclables?

At this point, solar panel recycling is having a hard time getting off the ground. There are not yet enough defunct panels that need to be recycled to make recycling economically attractive, so there are not yet enough places the recycle them. Though some companies have made recycling a priority, the volume of recyclable panels and demand for recycling plants simply aren’t there. As both the interest in solar panel recycling and the piles of unusable panels grow, the solar recycling market will inevitably grow as well.

It has to. Many panels contain precious metals like silver, tellurium, or indium, making recycling especially important, as well as lucrative. Though silicon is available in abundance, quantities of precious metals like silver and indium are sure to dwindle, especially taking into account how quickly the solar panel market is growing.

The home energy storage market is growing just as quickly as the solar energy system industry. More and more consumers are looking to home battery storage to control the energy generated by photovoltaics.

What About Water?

Water is used for cooling during the manufacturing process, but the main focus here is on usage during and after installation. Billions of liters are used for dust control during construction, and millions more are used annually for panel washing and upkeep.

Though this may seem like a huge amount (and really, it is), it pales in comparison to the amount of water needed to cool thermoelectric fossil fuel power plants. If you’re wondering how much water power plants in the United States use each minute for cooling, take the average amount of water flowing over Niagara Falls for a minute. Then triple it.

This is a huge argument for the use of the solar home battery. The water it requires to power your home is likely greater in volume to the water you use in your home daily. If you’re looking to reduce your water consumption, look first to your energy source, and consider storing solar energy in a home battery.

The Scores Are In

Since solar panel production is a new and growing market, manufacturing practices are not yet regulated. Because of this, it’s pretty hard to get standardized data about the environmental effects of the industry. Many researchers are seeing that the newer, developing companies (remember the ones who can’t afford recycling equipment?) have little to no accountability, and pretty low environmental standards. Bigger, name-brand manufacturers, by contrast, have a bit more attention, and are more committed to sustainable practices.

This is not the case in China. Because of lower national standards and more coal-burning power plants, the carbon footprint of a panel produced in China could be twice the footprint of one in Europe. The disparity is disappointing, but shows that with public pressure and new policies, solar panel manufacturers could eliminate many of the damaging practices currently set in place. Investors and consumers both could have a lot of influence on photovoltaic practices if they do their research, and give their money to environmentally responsible companies.

Someday, photovoltaic panel manufacturing will be powered by wind, solar, and geothermal energy, ending concerns about the carbon footprint altogether. There is a growing demand for both businesses and homes to get off the grid, using renewable energy sources, and storing them in batteries on-site.

The Future of Clean Energy is Now...

But the future of cleaner energy is still in the future. As the renewable energy industry matures, solar manufacturers will likely adopt stronger sustainability measures. Researchers have reported positive change in this area in the last five years alone.

Many companies have been taking advantage of the unquestioned environmental credibility of the solar business, which has prevented much pressure from consumers and investors for sustainable practices. As the industry grows, public pressure is likely to rise. Solar manufacturers will soon feel the need to be as committed to sustainability as their customers are.

We’re ready to move toward a truly, not just symbolically, green industry.