Solar energy. The future of the world, or so we hope. There are loads of problems with modern-day solar panels. Before we can look at them, how exactly do they work? Just like everything else in the world, the explanation for solar panels is material science. Let’s start small, and work our way up.
Solar panels are made of tiny cells, called solar cells or photovoltaic cells. These are what convert light to electricity. They’re made up of two layers — the n-type and p-type.
These layers are comprised mainly of silicon. The p-type silicon has a material like boron or gallium added since these materials have one less electron in their outermost shells than what’s needed to bond to silicon. This gives this p-type layer what’s known as “holes”.
The n-type silicon has a material like phosphorus added to the silicon. This material has one more electron than needed to bond to the silicon, giving it extra electrons.
Now, all the electrons need is enough energy to jump to the other layer. Light gives this energy to the electrons, and they can make the jump. When this jump happens, they go through what’s known as “the depletion zone”. This is where the electrons push ions from one layer to the other, causing polarization, like a battery, where one side is positive and the other is negative. This flow of electrons creates holes when they move from one side to fill holes on the other.
And there you go! Now, you have electricity.
Here’s the simple journey of a solar panel — production, 25+ years of life, and disposal.
This journey in total can be extremely harmful to the environment, negating the usefulness of solar panels. This damage can range from greenhouse gas emissions to habitat destruction and even water pollution. This has various causes. Hydrofluoric acid and sodium hydroxides are released into water during production. Silicon particles can also be released into water. Mining is used to extract raw materials for solar panels — you can check out my article about mining here. All these reasons result in a pretty damaging process for solar panel production.
During the lifespan of a solar panel, there are not really any major issues in terms of environmental sustainability. They last very long, more than 25 years in fact with extremely low maintenance. One notable damaging factor is habitat destruction. Solar farms can be damaging when deforestation is done, etc. To make space for solar panels.
Finally, disposal. This area is ignored compared to other areas when people innovate on solar energy.
Starting in 2006, the American government, among many, started offering subsidies to homeowners to purchase solar panels. This created a major boom in solar adoption, especially in California where more than 1.6 million rooftops have solar panels today.
Many solar panels installed in the mid to late-2000s will be reaching the end of their lifespans in the next decade. This number is in the millions. Check out this quote from Forbes:
“The International Renewable Energy Agency (IRENA) in 2016 estimated there was about 250,000 metric tonnes of solar panel waste in the world at the end of that year. IRENA projected that this amount could reach 78 million metric tonnes by 2050.”
Currently, the process for disposing of solar panels is pretty simple. They get dumped in landfills. This is changing — people have realised that when dumped in landfills, solar panels release toxic materials which leak into soil, groundwater, etc.
There are recycling practices in place — but in the US, only 10% of solar panels are recycled. This is even though up to 90% of the mass in solar panels is recyclable. There still is no mass adoption of recycling practices with solar panels. One major reason for this is the cost. Solar panels cost about $1–2 USD to send to a landfill while recycling them costs more than tenfold that.
Overall, we currently don’t have the infrastructure to deal with the millions, if not billions of solar panels that will be disposed of within the next decade.
This next decade can make or break the value of solar panels to humanity in terms of environmental support.
My mission over the next few months will be to find a way to fix this problem. Follow me here on Medium for updates on my progress!