Solar Photovoltaics - Cradle-to-Grave Analysis and Environmental Cost 2025

Written-by

Janet Richardson

Reviewed-by

Richard Burdett-Gardiner

Updated on

Dec 31, 2024

Solar Photovoltaics - Cradle-to-Grave Analysis and Environmental Cost 2025

Environmental Cost of Solar Panels (PV)

Unlike fossil fuels, solar panels don’t produce harmful carbon emissions while creating electricity which makes them a wonderful source of clean energy. However, solar panel production is still reliant on fossil fuels though there are ways to reduce the emissions produced during their manufacture. The production of solar panels also involves mining for precious metals which contributes to greenhouse gases and pollution. 

In this section, we discuss the environmental ‘cost’ of solar panels and approach the topic of their carbon payback period. This section can be categorised under many headings: Energy Amortisation, Life Cycle Assessment (LCA), Carbon Cost Payback, and Energy Payback Period. All will be relevant in some form or another but for simplicity, we will use the abbreviation LCA in this document.

There have been many studies in different forms that have been undertaken regarding the analysis of the LCA of solar photovoltaic panels. All conclude that Solar Panels do in fact pay for themselves in a relatively short period of time, both in carbon reductions, embodied energy, and electricity, all redeemed well within their operational life-cycle.

As the volume of PV units manufactured increases, the carbon cost of their production goes down, ever decreasing this carbon and energy 'payback' period. It is very hard to ascertain the exact point at which this ‘payback’ period is reached as there are many varying factors that go into its accurate deliberation. These include manufacturing methods, country and locality of manufacturing, operating conditions, country and locality of installation, and orientation of installation/installation method to name but a few.

An example of how a solar panel would pay back its energy and carbon production cost extremely quickly, would be a French or German-made panel (being manufactured with electricity generated from nuclear power - low carbon) being installed in China, where most of the energy is generated via coal or gas, which is high carbon. This would offset the carbon and energy costs taken to manufacture the panel initially, in a very short period of time. The opposite applies when a China-made unit is installed in France.

Standard Solar Cell CO2 Production Cost Breakdown

A typical solar panel will save over 900kg of CO2 per year resulting in a carbon payback period of 1.6 years. Research has shown that the carbon payback period for solar panels is on average 1-4 years. Even in areas where the sun’s radiation is received at less than 550kWh per m2 such as the northern part of the UK, a typical solar panel will only take around 6 years to pay back its energy cost. As solar panels have an expected life of at least 25 years, they will generate zero-carbon and zero-pollution electricity for decades after any carbon emitted during their production has been paid back.

A study in 2008 by Vasilis M. Fthenakis, Hyung Chul Kim, and Erik Alsema concluded that 1m2 of crystalline silicon took 250kWh of electricity to produce and under the measured conditions, produced in the region of 100kWh of electricity per year. This means that the payback period for the crystalline silicon PV panel tested was roughly 2.5 years.

Authors of a study in the journal Nature Communications in 2016 said “We show strong downward trends of the environmental impact of solar panel production”. They found that for every doubling in solar capacity installed, energy used to produce solar panels decreased by 12-13 percent, and greenhouse gas emissions dropped by 17-24 percent, depending on the material used. 

Below is an infographic displaying co2 emissions worldwide. 

The Carbon Footprint of a Solar Panel 

Although solar panels are an environmentally friendly solution the materials and manufacturing process used to create them do have a significant carbon footprint as mining and industrial processes are used. 

According to the International Plant Protection Convention (IPPC), the carbon footprint of rooftop solar panels is approximately 12 times less than natural gas and 20 times less than coal, in terms of CO2 emissions per kWh of electricity generated. Despite these statistics, rooftop solar has a larger carbon footprint than hydro, nuclear, and onshore wind turbines. 

Most solar panels are created in factories in China or other areas of the world using large quantities of electricity. China produces eight out of every ten solar panels. This means we must also consider the carbon footprint created by solar panels being transported long distances across the world. 
Several factors affect the impact of solar panels on the environment, including: 

• Mining of rare earth materials
• Use of hazardous materials in manufacture
• How far they need to be shipped
• How they are disposed of 
• How they impact land use

Fortunately, there are lots of ways that the carbon footprint of solar panels is already being reduced, and their environmental impact is expected to continue decreasing at a steady rate year on year. 

Environmental Impact of Solar Panel Manufacturing

Solar panel production can be complicated and involve multiple steps, including wafer production, cell fabrication, and module assembly. The manufacturing process creates harmful substances like nitrous oxide gas and perfluorocarbon (PFCs) which contribute to global warming. Each step needs electricity often generated using fossil fuels and emits greenhouse gases. Some processes like wafer production are energy-intensive and contribute more than others to the overall carbon footprint of solar panel production. The environmental impact of manufacturing a solar panel depends on where it is manufactured. The UK for example depends very little on coal to generate electricity whereas in China 63% of its electricity was generated using coal in 2021. While some carbon is emitted in the manufacture of solar panels as with anything manufactured, any claims that solar panels produce more carbon than they save are completely false. 

The UK’s first transmission-connected solar farm which went live in 2023 is expected to generate enough electricity to power the equivalent of over 17,300 homes annually and displace 20,500 tons of CO2 each year compared to traditional energy production. The carbon payback period is likely to decrease further as manufacturing processes advance.

There are three different types of solar panels, monocrystalline, polycrystalline, and thin film which are each manufactured differently which means they each leave a different-sized carbon footprint. 

Monocrystalline solar panels are the most commonly used panels as they have the highest energy conversion efficiency ranging between 19% and 22%. Monocrystalline solar panels are made of pure, single-cell silicon crystals wedged between thin glass. To make a monocrystalline solar panel, a large piece of silicon is moulded into a block, then cut into small wafers to be affixed onto a solar panel. It’s a complex process which means it produces the highest emissions compared to any other solar panel manufacturing method.

Although polycrystalline solar panels are also made from silicon the process does not require as much electricity. Instead of coming from a block, the silicon crystals are melted together and then placed onto the panel. The melting process does require a bit of electricity but much less than is needed to create a monocrystalline solar panel. 

Lastly, there are thin-film solar panels that can be made from a number of different types of material such as amorphous silicon, cadmium telluride (a type of silicon), or copper indium selenide. Usually, thin-film solar panels leave a smaller carbon footprint compared to the other more popular types of solar panels. Unfortunately, they're created from extremely toxic materials which can be harmful to humans and the environment if not properly handled. 

Environmental Impact of Mining for Solar Panel Materials

Most solar panel cells are composed of silicon semiconductors and glass as well as metals like silver, copper, indium, and tellurium. If solar batteries are included in the solar panel system for storage you will also be adding lithium to the list. 

The mining and processing of the materials required for the manufacture of solar panels such as silicon, silver, and aluminium can have significant environmental consequences. The process of mining for these metals can lead to habitat destruction, water pollution, soil erosion, and greenhouse gas emissions. 

Each type of solar panel emits different amounts of CO2 although each uses silicon cells. These rare materials can be found across the world, but the biggest deposits are located in Australia, Brazil, China, and the US.

According to a report from Engineerinc, these minerals can have a substantial environmental cost. Not only can they release harmful toxins into the air and water but processing them can require large amounts of energy. 

Companies are working on ways to diminish these effects by using recycled materials and more efficient production processes. Although there is still some way to go progress is being made with positive initiatives towards reducing the energy emitted during the production stage. 

Environmental Impact of Transporting Solar Panels 

Another challenge that has to be faced is the amount of carbon emissions created by solar panel transportation. Although solar panels are produced all over the world, they are primarily produced in China followed by the U.S. and Europe. Not only are solar panels shipped to other parts of the world for the retail market, but solar panel manufacturers may require shipments of parts from different countries.

The carbon emissions from transporting solar panels come from trucks, ships, or planes that take them from the manufacturing location to their final destination. These emissions include the CO2 generated by the vehicles burning fuel. 
However, it has been reported that transporting solar panels, accounts for just 3% of the manufacturing emissions involved in producing solar panels, a lot less than you might expect. 

There isn’t currently a lot of data available on the environmental impact of solar panel production but the Coalition on Materials Research Transparency is working on measuring and reporting on the carbon impacts linked to mining, producing, and transporting solar panels.

Environmental Impact of Recycling Solar Panels

Some estimates say that the world could see as much as seventy-eight million tons of solar panel waste by 2050. This poses an enormous challenge for recycling operations that are not yet set up with proper disposal systems.

Fortunately, the problem was recognised early on, and many companies and scientists are working on this and producing solutions both technological and economical. However, there is still a long way to go. At the same time, the number of solar panel installations continues to increase. The U.S. alone could have 1 billion solar panels collecting solar energy over the next decade if they reach the target set by the Solar Energy Industries Association (SEIA) for solar energy to account for 30% of energy generation by 2030. This is of course great news for reducing carbon emissions but does expedite the problem of how to safely dispose of old solar panels. 

When solar panels reach the end of their lifespan, proper waste management becomes vital. If they are not disposed of carefully it can lead to environmental contamination and potential health risks. Solar panels contain hazardous materials such as cadmium which can be toxic to humans and the environment if released into the air or water. Luckily, these materials are tightly bound in glass and plastic so they’re not likely to be a problem unless the panel is broken or burned in a fire. This is where recycling and resource recovery come into play.

The number of materials that can be recycled depends on the type of solar panel being recycled. A typical crystalline silicon PV panel is composed of materials that can all be recycled. These include glass, polymer, aluminum, silicon, and copper. If these elements are reused to create new products, solar panel greenhouse gas emissions can be reduced by 42%. 

Solar panels are made up of a lot of precious metals and the carbon footprint of producing solar panels could be greatly reduced if all these materials could be recycled and repurposed rather than having to mine for more. If recycling systems are not improved, it could lead to there being a shortage of solar panel materials.

Although solar panel recycling schemes are becoming more popular worldwide there is still room for a lot of improvement. The global solar panel recycling market size was recorded at $238.7m (£187.4 m) in 2022 and is projected to grow to $1.7bn (£1.3bn) by 2028. 

Ways to Reduce the Environmental Impact of Solar Energy

Habitat loss
Solar farms require land for the installation of solar panels. Any area that has been cleared and developed for this purpose is considered lost habitat. One way to minimise habitat loss is to use existing infrastructure whenever possible, such as parking lots and brownfields, and to develop new solar installations on land that has already been cleared for other reasons. 

Ecosystem Disruption
Clearing an area of trees or other vegetation to install solar panels can lead to serious consequences for local ecosystems. Additionally, constructing roads and transmission lines that are needed to support large-scale solar energy development can fragment habitats, disturb wildlife, and introduce non-native species. One way of minimising ecosystem disruption can be to ensure that local materials are used and to follow construction best practices to create as little disturbance as possible. 

Water Use
Significant amounts of water are required for solar energy systems for cleaning and cooling. The exact amount of water used depends on the type of solar technology but can be as much as twenty gallons per megawatt hour. Efficient water management systems should be used to help reduce the water consumption of solar panels. 

Exposure to hazardous materials: 
Recycling old solar panels instead of disposing of them in landfills can help diminish the potential harm caused by these materials.

Solar Panel Waste: 
Developing more efficient recycling technologies for solar panels can help reduce the potential harm caused by these materials.

Harmful Emissions: 
Emissions from solar panel manufacturing can be reduced by including the use of biomass instead of fossil fuels in production processes and installing pollution-control equipment on smokestacks at factories.

Environmental Benefits of Solar Panels

As mentioned earlier solar panels have been proven to pay for themselves in regards to the carbon and energy used and released during their creation. What is often overlooked is the other positive effects that their existence and continued usage have on the world around us. The primary benefit to our planet is that they steadily reduce our reliance on mainstream Industrial power generation. When fossil fuels are burned both particulate matter, and carbon dioxide (and if the combustion process is inefficient, carbon monoxide) are released into the atmosphere.

Many fossil fuel power stations have methods to try and curtail these by-products, but these systems only reduce the resultant emissions marginally. Although nuclear power generation is often seen as a ‘Green Energy’ many would argue otherwise. Nuclear power generation creates large amounts of highly toxic waste during its operation, which takes an enormous amount of time to degrade to acceptable levels, so as a result the large volumes of radioactive waste have to be stored somewhere safely.

Other than the disposal and recycling of the materials contained in solar panels there is no harmful waste produced during their operation.

Carol Olson is a researcher at the Energy Research Centre in the Netherlands who specialises in solar energy. Her work focuses on the technical, social, and economic aspects of renewable energy versus fossil fuels. 

“PV electricity contributes 96% to 98% less greenhouse gases than electricity generated from 100% coal and 92% to 96% less greenhouse gases than the European electricity mix.”  “Compared with electricity from coal, PV electricity over its lifetime uses 86 to 89% less water, occupies or transforms over 80% less land, presents approximately 95% lower toxicity to humans, contributes 92 to 97% less to acid rain, and 97 to 98% less to marine eutrophication.” 

By the end of 2023, the global solar capacity was just over 1.5 terawatt (TW) which is up by 30% from the previous year. It is expected that this growth pattern will continue. The International Energy Agency (IEA) has gone as far as to say that global solar capacity will double by the end of 2028, making it one of the largest power sources in the world.

Earlier this year enough capacity was generated by solar photovoltaic panels across the globe to power over thirty million households. That’s a saving of more than fifty-three million tons of carbon dioxide annually, proof that the expanding industry is helping combat global warming and helping to reduce our negative effects on our environment. 

Although solar panels do have hidden emissions as you have seen in this article, they still have a significantly lower carbon footprint than many other types of energy. Research and development continue to come up with ways to further reduce these emissions while experts continue their search for more sustainable materials. On top of that more countries are putting laws in place to make solar panel recycling mandatory, and more farmers are looking into ways to host their solar farms amid working farms. The future of solar is bright!