Renewable energy options, such as solar panels, effectively combat climate change and carbon emissions. Solar energy accounts for about 2% of the world’s total energy budget in 2019, and experts predict solar technology will continue to boom over the next decade.
Nevertheless, some believe that current solar panel manufacturing has a larger carbon footprint than in reality. That belief is especially untrue, considering the many benefits of solar compared to equivalent energy generation methods. So, what is the carbon footprint of solar panel production, and how does it compare to other energy sources? The numbers might shock you.
What is the Carbon Footprint of Solar Manufacturing?
Solar panel manufacturing requires energy to run machinery. Solar cell manufacturing results in carbon emissions, much like any manufacturing process. However, the amount of energy required to create solar panels is harder to measure than some realize. This comes from several details that we need to consider.
The true carbon footprint of solar manufacturing is almost impossible to measure, and for a few reasons. First, we need to consider the types of solar panels used in the process. The two primary types are monocrystalline and polycrystalline, both of which require different manufacturing processes.
When you think of solar energy, you probably picture monocrystalline panels. They are distinguished by their dark color and sleek design. Silicon blocks are molded during the manufacturing process. Small wafers are cut and attached to the solar panel from the block of silicon.
Silicon is also used to make polycrystalline solar cells. However, the manufacturing process differs from that of monocrystalline solar cells. In contrast to the silicon blocks used to make monocrystalline solar cells, polycrystalline cells are formed by melting silicon crystals together. It is a very energy-intensive process. Thus, we must consider panel type when looking at the solar carbon footprint.
Studies show that silicon manufacturing accounts for around 6.0 kg CO2e/kg per silicon metal made. It is estimated that 11 grams of silicon are needed per cell. That means around 660 grams of silicon for one solar panel. The application of silicon goes from solar PV manufacturing to chip manufacturing for every modern technology available.
In addition to silicon, there are other fine metals such as copper, silver, indium, and tellurium that make up the composition of solar panels. Additionally, lithium is also used for solar battery storage. Mining these metals produces carbon emissions. It’s difficult to quantify emissions from mining such metals because of a lack of transparency within the data. The Coalition on Materials Research Transparency is working to set industry standards on carbon emissions of mining metals for solar, but that process is still in an early stage, hence the current lack of transparency with the data.
Another issue is that manufacturing emissions differ from country to country. For example, China is responsible for half of the world’s production of photovoltaic panels and produces double the emissions per panel compared to Western countries.
In general, it is estimated that a solar panel needs around three years to produce the energy required to offset the carbon dioxide emitted in its production. The lifetime of a solar panel system is around 30-40 years, so the amount of energy a solar panel produces in its lifetime will completely outweigh the number of carbon emissions produced to create the panel itself.
So, Are Solar Panels As Bad As Other Energy Sources?
With all that information we have, does it mean that solar panels are as bad as the energy sources it replaces? The answer is definitely no.
Even if only considering carbon footprint, the long-term footprint for solar PV is still better than coal mining, oil drilling, fracking, and other energy options. How? There are two considerations at this point, including Production Process and Life Cycle Greenhouse Gas Emissions (GHG). Here’s a dive into what you should consider.
The first consideration is the production process. As we compared solar panel manufacturing, the comparison with other energy options is not apples to apples. It’s important to make sure you’re comparing emissions during the production of energy sources rather than the operational emissions. The emissions data during both processes are different, so it’s important to make that distinction.
For example, coal mining and abandoned mines account for 8% of total methane emissions in 2019, and that doesn’t even factor in the other greenhouse gases that coal mines emit. The amount of methane produced through coal mining is considered a safety hazard, according to the Environmental Protection Agency. This does not consider other by-products during the mining process, of which many don’t have enough data.
Solar panels emit around 50g of CO2 per kWh produced in its first few years of operation. By the third year of having solar panels, most solar panels become carbon neutral. This is still roughly 20 times less than the carbon output of coal-powered electricity sources. If you take into consideration the number of greenhouse gases coal mining produces versus the amount of the amount for solar panels, it’s clear that solar panels are a much cleaner alternative to coal. Sure, a solar panel produces less energy than a ton of coal, but the devil is in the details, which brings us to the lifecycle GHG.
Here are the most common energy sources and the amount of CO2 that’s emitted in order to produce them:
Life Cycle Greenhouse Gas Emissions
Life cycle greenhouse gas is the carbon emission released through the operation of the energy source. Here is the data for the life cycle of greenhouse gas emissions from the most common energy sources:
Burning coal and petroleum emit a lot of CO2 per kWh. Natural gas burns less than those but it still has a large amount of CO2. Wind power is the most efficient, but it’s extremely hard to do wind power on a consumer scale. That’s why solar is the easiest option because it produces 50g per kWh during production, which is lower than gas, petroleum, and natural gas.
All this considered, the life cycle GHG of solar panels is far lower than other energy sources. Even with solar panel manufacturing accounted for, the entire process puts solar among the cleanest sources of energy available.
The Bottom Line
Now that we have all the information, we can confidently say that solar panel manufacturing has a lower carbon footprint than other energy sources. We can even say that it’s far better than other energy sources, including coal, oil, and even natural gas.
Solar panels produce less carbon dioxide, cost less to produce, and generate power for 20 years. Consider solar energy and how it can positively impact your life. Not only that, but the life expectancy of solar panels is at least 25 years, as Solaris Renewables warranties systems for a full 25 years. Some panels, like SunPower, perform at 70% of their original rated power in their 40th year of use, meaning you could potentially use your solar panels for up to 40 years.
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