What is the carbon footprint of a solar panel?

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Manufacturing solar panel cells and mining essential minerals both result in some CO2 emissions, which are mostly related to solar energy. However, solar panels leave behind significantly less carbon than fossil fuels.

Making silicon semiconductors used in solar cells, a step in creating solar panels, results in the most CO2 emissions. However, other minerals like rare earth metals and silver also have a larger carbon footprint. In addition, installing battery storage systems results in a larger carbon footprint because lithium is used.

From an environmental standpoint, solar electricity is still a much better option than coal power despite these emissions. However, it is crucial to consider and minimise any potential adverse effects.

Does solar power produce CO2?

While solar panels and manufacturing inverter solutions do not produce CO2 while in operation, some CO2 emissions are associated with solar equipment manufacturing. Although, compared to fossil fuels and other means of energy generation, a solar system throughout its lifetime will have a significantly smaller carbon footprint and overall will be carbon positive.

Carbon positive means the renewable CO2-free energy generated from the PV system over its life will be many more kWh / CO2 than the energy it took to generate the solar system, its components and transport to the installation site in the 1st place.

Where does the CO2 come from?

We must look at a life-cycle assessment of solar gear to determine the total CO2 cost of solar panels and inverters. This calculation must include everything from mining raw materials such as silicon, silver, metals etc., to transporting, manufacturing, installation and end-of-life disposal or recycling of the PV system.

The manufacturing process of solar panel cells and the aluminium frame of the panels and the rails are primarily where CO2 emissions are generated. Solar panels utilise silicon cells to capture and convert the sun’s light energy into usable energy. The manufacturing process of turning silica into solar cells is energy-intensive, requiring significant heat in processing and creating a substantial portion of the panel’s CO2. The transport of the material, often from China or Europe, also adds to the carbon footprint of a solar panel.

What about the components?

The Journal of Sustainable Metallurgy writes in 2021,Aluminum requires 12.5–16 kWh/kg Al in the electrolysis process, while the specific electrical energy consumption for MG-silicon production is in the range of 10.5–13 kWh/kg Si. Therefore, the energy mix for producing the electric power used in these processes is essential for the total carbon footprint of the final product.

Solar cells use other materials, such as silver, as wires/conductors that span the panel, transporting electrons to the panel’s main wires. Additional minerals that work to make up not only a solar cell but also its carbon footprint are phosphate, which is used to coat the panels and earth metals, such as copper, which is also included.

If a solar system has a battery storage system attached, its footprint also increases, as lithium, nickel, cobalt, and magnesium are essential materials for the makeup of the battery. This not only increases the environmental footprint of solar during the manufacturing process but increases the footprint of solar at the end of a system’s working life.

Disposal or recycling?

If disposed of improperly, the toxic lead, copper and nickel-based elements within lithium batteries only harm the environment. However, recycling opportunities for batteries are increasing significantly, and lithium-based batteries are 98% recyclable. High recycling rates will bring down the carbon footprint of the next generation of solar panels.

mining truck driving with a full load in a coal mine increasing CO2
Solar energy is still significantly better for the planet than coal power electricity

How does the CO2 content in concrete equipment compare to fossil fuels?

Let’s look at the life-cycle assessment of solar panels and other system parts. Due to our intense sun irradiation, various industry publications have estimated that Australia’s life-cycle CO2 equivalent for rooftop solar generation is under 40g/CO2 per kWh. This is a complete cradle-to-grave assessment covering mining, manufacturing to usage and end-of-life management.

For comparison, many coal power plants in the world produce over 1kg CO2 eq / kWh, and even the “cleanest” coal power is generally above 700 g CO2 eq / kWh and, on average, globally, is approx. 820g eq/ kWh. Natural gas generation is less polluting, with above 400 g CO2 eq / kWh emissions.

So while solar electricity does have a CO2 content, it is over 20 times less than the CO2 attributed to coal power and 10 times less than gas.

A study published by Nature Energy was more optimistic, with estimated emissions below 21 g CO2 eq / kWh for quality solar. Moreover, quality solar systems have an even better CO2 result because they last longer and generate more clean energy over their lifespan.

Undergound mining railway tunnel lit up

So is solar power bad for the environment?

The bottom line is that solar power is not genuinely CO2-free for now, but it is a positive development in reducing CO2 in electricity generation. However, this is not to say that it can’t be even more CO2-free in future. Despite this assessment, overall, the result is positive. The solar system’s carbon debt is around 20 times less than coal-powered energy sources. This highlights that, overall, solar electricity is still a much better alternative to coal power electricity from an environmental perspective.

Finally, solar energy is becoming more affordable and easier to set up anywhere worldwide. Australia enjoys one of the cheapest solar system prices in the world due to intense competition in the distribution and installation industry.

If companies and nations want to reduce their fossil fuel emissions, they must continue to expand their renewable energy sources and create incentives for developing renewable energy industries. However, it is still essential to consider their side effects and try to reduce them so that solving one problem does not result in another.

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