Solar panels are an amazing way to contribute to renewable energy sources, as they produce no emissions and cut down on how much electricity your household uses from the grid.
A solar panel has a power output of 225-350 watts per hour on average. And the more sunlight hours you have, the more electricity that solar panel generates.
It’s reasonable to expect that solar panels are super environmentally friendly, right? But what about when it comes to disposing of old or broken panels?
What are solar panels made of?
There are two types of photovoltaic (PV) solar panels. Silicon-based solar panels are the most common and are divided into monocrystalline and polycrystalline panels, while thin-film-based solar panels are more portable.
Silicon-based solar panels are made from silicon wafers arranged into rows and columns to form rectangles. The wafers are covered with a glass sheet and put in a frame.
Thin-film solar panels, on the other hand, are made of a variety of materials, and some use non-crystalline silicon sprayed on top of glass, plastic, or metal.
The most efficient solar panels are monocrystalline silicon panels, but they are also the most expensive.
Polycrystalline panels are more affordable with lower efficiency, while thin-film solar panels are more lightweight and preferable for curved or smaller surfaces.
Most residential solar panels are silicon-based, while small thin-film-based panels are used for cars or charging devices.
Sadly, all PV solar panels contain toxic substances, as silicon is harmful to the environment.
How are solar panels recycled?
Recycling solar panels happens at processing centers that have facilities capable of recycling panels. Typically these are either part of the PV industry or are electronic waste companies.
While recycling solar panels could be more widespread and efficient, GreenMatch says that if all solar panels went to the landfill, 60 million tons of PV panel waste would be in landfills by 2050.
A review on recycling processes for PV modules in 2016 estimated “that by 2050 [global PV waste] will increase to 5.5–6 million tons”. So, any reduction in this amount of waste is better than nothing.
Silicon-based solar panels are recycled by first disassembling the panel to separate aluminum and glass, with 95% of glass recycled and all external metal remolded into cell frames.
The remaining materials are then sent to a thermal processing unit where extreme heat evaporates plastic and leaves the silicon frames behind, allowing the silicon to be reused.
Even the plastic can be reused for more thermal processing. Overall, 80% of the separated hardware can be reused, with the remainder refined, and this processing allows an 85% recycling rate of silicon.
Thin-film based solar panels have to be shredded before being put through a hammermill to break them up into particles. These particles are no bigger than 5mm in order to break the internal lamination between layers.
Next, a rotating screw is used to rotate the remaining solid materials while liquid materials drip down to go through a precipitation and dewatering process, purifying the liquid before undergoing metal processing to separate semiconductor materials. This allows 95% of semiconductor materials to be reused.
The remaining solid materials are put on a vibrating surface to remove contamination from the liquid interlayer materials and are then rinsed, leaving pure glass to be reused.
Do solar panels have a shelf life?
Suppliers of domestic solar panels include a warranty for some years, guaranteeing at least 80% efficiency for that amount of time. This can vary between 10 years and 25 years. With proper care, a PV solar panel can be expected to provide over 50% efficiency for around 30 years – and some can last much longer!
The average solar panel loses 10% efficiency in the first 10 years and up to 20% after 25 years, according to Forever Green Energy. The more yellowing or peeling lamination, the less efficient the solar panel will be. Taking proper care of your solar panels will help them stay more efficient for longer.
You can extend the life of your solar panels by:
- Avoiding physical damage to the panels.
- Cleaning panels with water twice yearly.
- Scheduling regular maintenance checks.
- Sheltering panels during extreme weather.
Check if your supplier provides free maintenance to save money.
If you’re unable to clean the panels yourself, you should be able to find local cleaning services that offer solar panel cleaning.
Are solar panels worth cleaning?
Cleaning your solar panels will help extend their life expectancy, reduce the need for repairs, and ensure higher efficiency for longer.
A hose pipe or bucket and sponge can work perfectly, and you can also get solar panel cleaning kits. Use mild or plant-based soap as harsh chemicals can cause damage to the surface.
If you find a lot of dirt or grime has built up, use a soft brush or rag with water to brush and wipe away before rinsing.
Whatever you do, don’t use a pressure washer to clean solar panels. You can damage the surface, causing damage to the panels and lowering efficiency. The more scratches on the panels, the more degraded they become.
If you have any trees nearby, don’t let the branches grow too close and sweep away leaves and dirt whenever you can.
The best time to clean your solar panels are in the mornings and evenings, or days when there’s little sun.
Also avoid cleaning when the panels are hot, as this could cause the surface to crack. Rainy and cloudy days are ideal for cleaning.
Some homeowners living near highways, freeways, airports, or industrial buildings will need to do more regular cleaning to remove dust and debris.
Twice yearly is the minimum amount of cleaning needed, though some panels may need monthly cleaning. Ask your supplier what they recommend if you’re not sure.
Are solar panels good for the environment?
Every watt of power solar panels provide a house is another watt that won’t be required from non-renewable energy sources. This has to be balanced against the environmental impact of manufacturing and disposing of solar panels.
The Centre for Alternative Technology outlines three main concerns of environmental impact:
- Energy and fuel required to produce solar panels.
- Toxic or environmentally harmful materials used or created during manufacturing.
- How solar panels are disposed of.
Similar concerns are used with all electronic devices, but you have to remember that solar panels are in use for decades as opposed to years for electronics like phones.
It’s important that the environmental impact is balanced out with the renewable energy created. If the amount of electricity generated by solar panels replaces the same amount used to produce them, this is an important step towards carbon neutrality.
Materials used and created during the manufacturing of solar panels is another struggle. The main component of PV solar panels is silicon, which involves harmful chemicals that require regulation to avoid environmental damage.
Manufacturing solar cells involve multiple toxic, flammable, and explosive chemicals. Components can pose a health risk to workers involved in manufacturing, and disposal of electronic waste is difficult.
Monocrystalline solar panels are generally more wasteful than thin-film-based panels due to being made of slices of silicon. While silicon can be reused to create polycrystalline panels, thin-film panels reduce waste and pollution and more materials can be reused.
In 2013, recycling solar panels was deemed “not currently economically viable” due to the low waste volumes. However, as more solar panels reach their end of life, more waste will be generated.
This paper on the socio-economic and environmental impacts of solar panels suggests that significant volumes of solar panel waste will be reached by 2025 or 2030. It’s down to the PV industry to be prepared for this waste and to have the infrastructure needed to recycle solar panels en masse.
Ultimately, solar panels are good for the environment to a point. As with most electronic industries, we consumers have to rely on and encourage companies to seek out sustainable materials and proper disposal methods.
The Silicon Valley Toxics Coalition addressed what changes can be made to the solar panel industry. In 2009, their report Toward a Just and Sustainable Solar Energy Industry recommended:
- To reduce and move towards eliminating the use of toxic materials.
- Developing more sustainable practices and materials.
- Holding the industry accountable for the lifecycle impacts of their products.
- Properly testing new materials and processes with precautionary measures.
- Expanding recycling technology for solar panels.
- Promoting worker health and safety.
- To protect health and safety throughout recycling operations, supply chains, and the PV industry.
Provided legislators and the solar panel industry carry out these recommendations and stick by them, the environmental impact will remain low and improve in the future.