We can probably guess what you’re thinking – what are carbon footprint and solar panels doing in the same sentence? Solar panels are believed to be carbon neutral. We’ll tell you, but a little preamble first. The carbon footprint of solar panels has multiple angles of approach – the mining of raw materials for the panels, their manufacturing process, the distribution of raw materials, and the recycling of old panels.
Solar energy has risen to the top of the food chain in the renewable energy sector, and installing solar panels on industrial or residential buildings has become commonplace. In fact, the US has made provisions to add about 72 GW of solar electricity in the near future. This figure will put its yearly annual production capacity at twice its initial capacity.
However, this begs the question – what’s the carbon footprint of solar panel manufacturing? How do its carbon emissions compare to other means of generating electricity? Let’s answer all these questions beginning with the solar panel manufacturing process and raw materials acquisition.
Solar Panels Raw Materials Mining and Manufacturing
While it’s an undisputed fact that, unlike fossil fuels, solar panels generate electricity with zero greenhouse gas emissions, mining the raw materials for the solar panels and the manufacturing process has an evident carbon footprint. We’ll explain.
Let’s begin with the composition of the solar panel. This board comprises embedded solar cells that trap, absorb, and convert solar energy into electric energy. These cells consist of a negative and positive layer which creates an electric field that transforms photons from sunlight into electrons. Aside from these photovoltaic cells, the panel has a conductive channel for transporting the electric current it generates, and its surface is coated in a material that makes its surface non-reflective to maximize sunlight absorption.
Solar panels have metals such as tellurium, indium, copper, and silver, while the solar battery bank uses lithium. These are precious metals mined from the earth’s core, and as you know, this process results in greenhouse gas emissions and environmental pollution.
As for the manufacturing process, silicon has to be melted at very high temperatures before it’s attached to the solar panel. In most cases, the furnace heating process uses coal, a fossil fuel that produces a considerable carbon footprint in the environment. When manufacturers construct PV components, that’s another source of emissions as well.
It has been established that producing solar panels increases carbon footprint, but their quantity varies based on the type of panel being manufactured.
Types of Panels and Their Carbon Footprint
There are three major types of solar panels that generate solar power for our energy needs, but the two most common ones are monocrystalline solar panels and polycrystalline solar panels.
Compared to the production process of other panels, this solar panel’s carbon footprint is the highest. Judging from its name, this solar panel is produced from a single piece of crystal silicon which is divided into thin wafers and joined to the panel. This silicon crystal is complex to manufacture, requiring more energy, emitting more carbon dioxide. Interestingly, monocrystalline solar panels are the most efficient panels on the market.
These panels are produced from different silicon crystals, which are melted into a single mold. The production of polycrystalline solar cells involves less energy, making greenhouse gas emissions less than their monocrystalline counterpart. It’s also less efficient in generating electricity but more affordable.
Future solar manufacturing technologies will aim to improve the efficiency of solar panels by using perovskite instead of silicon. Its production will also use less energy.
The Carbon Footprint of Solar Panels From Transportation
As you may have known already, most of the solar panel manufacturing takes place in China. A significant proportion takes place in the US and some parts of Europe. The transportation of raw materials for the solar panel from the mining site to the manufacturing plants involves vehicles that operate on fossil fuels. There’s also the distribution of panels from the manufacturing plants to warehouses.
Now, to the question itself.
What is the Carbon Footprint of Solar Panels?
While there are varying answers, the Intergovernmental Panel on Climate Change stated that the average value among these studies for the carbon footprints of rooftop solar panels throughout their lifespans is 41 grams of carbon dioxide for each kilowatt hour of electricity. That’s the total life-cycle emissions of panels, meaning the entire carbon footprint of a solar panel from mining to manufacturing and distribution.
The total life cycle in this instance is determined to be three decades, and the entire carbon footprint of a solar panel within this period is a measurement that’s equivalent to the weight of a mid-sized chicken egg. When you compare this to other forms of energy, such as natural gas and coal, it’s very insignificant.
How Much Carbon Dioxide is Emitted From Solar Panels as Compared to Fossil Fuels?
These energy generation sources have different carbon footprints. While the emissions footprint of solar panels, as we mentioned earlier, is 41 grams per kWh for each panel, the greenhouse gas emissions of natural gas are 480 grams per kWh, the equivalent of 12 eggs. As significant as this emission is, it pales in comparison to the 820 grams of greenhouse gases emitted from the use of coal as an energy source. This makes solar panel systems the most environmentally friendly energy source by a landslide.
The average daily electricity consumption in the US is roughly 30 kWh. Judging from the above values, renewable energy sources like solar panels have a carbon footprint of 1,230 grams (1.23 KG) daily. On the other hand, non-renewable energy sources such as natural gas will have a carbon footprint of 14,400 grams (14.4 KG), while coal will give a carbon footprint of roughly 24.6 KG, even when carbon capture is implemented.
What can we do about the carbon footprint of solar panels? Well, we can lower it. This begs the question, how do we lower the carbon footprint of solar panels?
How to Reduce the Emissions From Solar Panels?
To reduce the overall carbon footprint of solar panels, we have to tackle all the angles the emissions in the solar industry come from. From the processes described as the “angles of approach,” we can categorize them into three sections, namely:
- Upstream activities
- Midstream activities
- Downstream activities
Let’s look at them individually.
This section is an umbrella term for the following;
- Mining of materials for the solar panels
- Production or processing of these materials
- Production of solar modules
- Construction of the solar power plant or solar farms
- Production of other components of solar systems
How to Reduce Carbon Emissions From Upstream Activities?
Tackling upstream emissions is very important as it’s responsible for most of the carbon emissions from solar energy systems. This is because fossil fuel sources power all these processes. The best way to reduce carbon emissions is to switch from fossil fuels to renewable energy sources to carry out these activities. Solar power is not the only renewable energy option; we can also use wind energy.
Another effective way of reducing emissions from these activities is by upcycling silicon powder waste instead of disposing of it and extracting fresh materials for the solar manufacturing process.
These activities describe emissions from installed and operational panels.
- The operation and maintenance of the solar energy facility
- Power generation
How to Reduce Carbon Emissions From Midstream Activities?
Firstly, manufacturers should produce more efficient panels, for instance, panels that can derive ample amounts of solar energy from UV rays and indirect sunlight. We believe that with the rapid evolution of solar technology, this is just a matter of time.
Secondly, install these panels in areas with adequate peak sun hours or in designated spots where they can get the best exposure to sunlight.
Thirdly, use the same land designated for solar farms for agricultural purposes as well. This will make the panels more carbon neutral because plants absorb the atmospheric carbon, depleting what the panels emit. Lastly, use floating panels and longer-lasting panels.
Although midstream or operational activities bear insignificant emissions, the carbon footprints of these activities are even smaller. The activities here make a very short list:
- Deconstructing solar systems
- Disposal of solar systems
How to Reduce Emissions From Downstream Activities?
Although these processes leave the smallest carbon footprint, there’s a way to make it even lower, and that can be done through recycling. Interestingly, several components that make up the solar PV panel system, including the plastic junction box, silicon wafer, aluminum frame, copper wire, and glass cover, are recyclable. This means that solar power plants will recycle more of these materials, and there will be a need for fewer fresh materials, reducing the carbon output of both upstream and downstream emissions in the process.
The electricity produced from our solar panels leaves no carbon footprint in itself; it’s the associated emissions we’ve been referring to and discussing. Going solar is a highly recommended way of reducing carbon footprint as well because it can offset their life-cycle emissions within a couple of years of generating electricity.