What Is the Carbon Footprint of Solar Panels?
Solar panels emit zero Co2 while they they sit on a rooftop generating electricity for the home, but they do have a carbon footprint. But how?
Solar panels generating are carbon footprint in the manufacturing and transport process which studies show is 50g per kWh manufactured. This includes the mining of raw materials such as silicon, aluminim, copper, plastic and rubber, we well as their refinement, transport and construction into a working panel.
Although it doesnt sound like it’s a huge deal, and it is 20 x less than CO2 produced by burning coal, it is still notable and has an impact.
There are several steps in manufacturing a solar panel. Also, there are several parts of a single solar panel. Getting the raw materials for the product and the entire manufacturing process contributes to a solar panel’s carbon footprint. The same applies to when the solar panel reaches the end of its lifespan and has to be discarded and needs to be recycled.
So, while using this renewable energy source is cleaner and better, you must consider the following factors to calculate the amount of carbon solar panels emit in their lifecycle.
What Are Solar Panels?
Solar panels convert sunlight it to usable electricity. They are usually mounted on the rooftop where they receive maximum sunlight. They are also ground-mounted if the have the space. There are various manufacturing methods for solar panels. But the most popular is polycrystaline which has a max efficiency of about 22%.
Sourcing Raw Materials
A solar panel is made of mostly silicon; Silicon semiconductors are excellent trappers of sunlight to convert to energy. These semiconductors comprise negative and positive silicon layers, which absorb enough sunlight to produce electric currents. They do this when they move electrons between the negative and positive layers within the solar cell.
One solar panel comprises multiple solar cells, each with a coating that reduces reflection. That way, they can maximally absorb sunlight without losing some of it. Also, manufacturers use other minerals and rare earth in producing solar panels, such as tellurium, indium, glass, plastic, rubber and copper.
They have to mine these substances, and the mining process produces carbon emissions. There is currently no standard way to measure the carbon footprint from mining the materials, although there are steps to check mining-induced carbon emissions in the solar power industry.
Producing Solar Panels
There are a few types of solar panels, two of which are at the forefront. One is the monocrystalline panel, and the second is the polycrystalline panel. Each of them has a separate production process, but they all contribute to carbon emissions.
Monocrystalline solar panels have the highest efficiency level, between 15% and 20%. They are made from thin layers of a single piece of silicon, hence the name. They are the commonest type of solar panels because of their high-efficiency rate. But the manufacturing process for single silicon crystals is complex. Therefore, the process of making them leads to a high carbon emission rate.
Polycrystalline solar panels are not as efficient as their monocrystalline counterparts, but they still have a considerable efficiency rate. The manufacturing process involves melting and fusing silicon crystals, and it does not require as much energy as the single-crystal process. That also means it does not cause high emissions.
There are other types of panels, such as the thin-film panels, but they are not as efficient as the crystalline panels. Consequently, they are not yet as popular as the rest. Also, new solar technologies look to improve efficiency while reducing production energy. The goal is to reduce the carbon footprint of solar panels during production.
The process of manufacturing silicon solar panels is complex. Since they are the commonest types, they are in high demand, pushing the need to produce more of them year after year. However, they cause significant emissions; mining silicon is not the only issue because it is abundant in nature.
But melting it needs high temperatures, which means burning fossil fuels that release greenhouse gases. The increasing demand for panels has increased production rates, especially in places like China. This increase also means burning more fossil fuels, hiking the amount of carbon emitted into the atmosphere.
Getting the raw materials for solar panels usually takes place far away from the manufacturing and installation areas. In most cases, the mining is one continent, and the production is another.
If a solar panel is manufactured and installed in one continent, the process emits less carbon than one manufactured in one continent and shipped to another. Suppose some solar panels are manufactured in China, which is one of the top manufacturers? The process of melting and fusing the silicon to the panels already needs a significant rate of fossil fuel burning. Then, add to that the transportation from China to the installation place, and you have high emissions.
However, if there are regulations to curb the emissions during manufacturing, it will go a long way in reducing the carbon footprint of solar panels in this regard. Also, if other countries can adopt solar panel production, it may lessen the burden on China to be a primary manufacturer, lowering the emissions from that area.
Solar Panel Lifespan
A solar panel can last between 25 years and 30 years, and it takes only about ten percent of that time to pay its carbon debt back. The rate of energy output that a typical solar panel delivers drops by only 0.5% yearly. In other words, a solar panel remains highly efficient for decades without contributing to carbon emissions.
But the older a panel gets, the more likely it is to create emissions. While it does not emit carbon during its usage, it must be disposed of when it reaches the end of its life. How it is disposed of may cause emissions. Furthermore, there is the issue of prematurely discarding panels in a bid to upgrade.
Solar rebates in Australia are pushing many people to discard panels before they are due for disposal. As everyone rushes to be a part of the incentives, you will find a lot of usable panels.
Installers tend to replace damaged panels with an entirely new solar power system instead of simply replacing only the damaged ones. Additionally, some people want more efficient systems after only a few years, so they discard all the panels while they are still usable. As a result, Australia is currently dealing with a considerable amount of e-waste.
Recycling is one way to end the problem of growing e-waste, not only in Australia but worldwide. However, it is only a partial solution because not every country has recycling plants for solar panels.
Those that do regulate the process can be expensive. There is also the problem of moving the solar panels to the recycling plants, which has the potential to add to the carbon footprint. Extending the lifespan of a solar panel may be the only solution without cons at this stage.
Solar Panels and the Environment: The Impact
Several other areas of solar panel usage, apart from carbon emissions, affect the environment. When considering how solar panels impact the environment, you must also consider production affects biodiversity and natural habitats, among other things.
Solar energy is renewable, but the materials that make up solar panels are not renewable. Recycling is not a fully-viable solution yet, so there have to be other ways of disposing of the materials.
Mining operations and how they affect those living in the area, both humans and animals. Roads have to be constructed for transporting the raw materials, which may upset some creatures’ natural habitat. For areas where the panels are processed, gas emissions exist; regularly burning fossil fuels in large amounts impacts human health.
Comparing Solar Panels and Conventional Electricity
From everything discussed so far, it is evident that solar panels have some carbon footprint, although it is not extensive, and you cannot easily calculate it. But when you consider the advantages of using these panels, they overshadow the negative environmental impact.
However, comparing the use of solar panels to conventional electricity is crucial. It helps you understand the difference in the impact between both sources. There is no comparison between the emissions from solar panels and those from fossil fuels in any form.
The emissions from the panels are primarily from mining, manufacturing, and production. They do not produce any carbon or other greenhouse gases while they generate energy. The same is true for other sources of renewable energy, such as wind and nuclear.
|Energy type||Carbon footprint
|Solar Energy||41 g|
How to reduce the carbon footprint of solar panels
The carbon footprint for solar panels comes during minding and transport of raw materials as well as the manufacturing process. At the end of the day we are talking about the digging machines running on diesel fuel as well as the lorries and trucks transporting the materies. Then the factories using “dirty electricity” generated by burning coal as well as the power supplied to the factories building the panels.
The biggest problem in all this is that panels are built in china. They have very low standards and open up a new coal power plant each week as there population emerges from 3rd world to first world and they need to catch up with the demand on power.
1. Electric excavation equipment
After electric cars there will be electric trucks and lastly electric mining machines. Once that switch is made, the carbon footprint will come right down.
2. Local sourcing of materials
When you look at the amount of times raw materials, then base materials, then parts then finally panels are transported from one factory to another on the opposite side of the world, it is easy to see how the carbon footprint can grow so quickly. China buying coal from Australia to burn to make power to run factories is just one example.
If the materials are source, refined and turned into parts and panels locally with minimal transport the CO2 footprint of panels would be cut by 80%.
Vertical integration is something that Tesla motors is looking to master but sourcing raw materials for batteries close to the point of refinement and manufacturing. A perfect example of this would be having everything under the one roof. Raw materials enter though the back door and a fully build EV rolls out the front door.
Author: Ben McInerney is a renewable energy enthusiast with the goal of helping more Australians understand solar systems to make the best choice before they purchase. Having an accredited solar installer in the family helps give Ben access to the correct information, which allows him to break it down and make it easily understandable to the average homeowner.