PV system environmental impact: is solar energy sustainable?

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With this article we want to disprove those rumours concerning the negative environmental impact of solar panels. PV panels are highly recyclable products. In order to reduce the carbon footprint produced by each and every one of us, we need to dismiss the non-renewable energy sources and embrace photovoltaic.

Power generation from renewable sources, such as PV panels, has a very positive environmental impact. Although dimensions and proportions are completely different compared to other power generation methods, the carbon footprint of this clean energy cannot be denied.  Which impact does the PV industry have on our planet? Let’s analyse the emissions during the different stages of the product life cycle:

  • Manufacturing
  • Use
  • Disposal

Environmental impact of solar panels manufacturing

Quartz extraction and its transformation in polysilicon require high temperature plants, this means energy-consuming systems. The use of this material – which is a great semiconductor for energy transmission to photovoltaic cells – is not toxic nor dangerous for the public safety, as shown by a study carried out by the North Carolina University.

Silicon is the second most abundant element on the Earth’s crust, the first one is oxygen. It is a very common semi-metal found in nature as a compound: it is contained in sand, granite, clay and precious stones such as quartz, amethyst, agate, opal and it is the major component of glass, ceramic and cement.

Beside being widely used in electronics thanks to its conductive properties, Sillicon is used to produce almost all the PV panels currently on the market and photovoltaic cells are almost entirely made of it. Anyway, these cells weight less than 2% of the whole panel structure. Silicon quantity, in the form of almost impalpable wafers, is a really small one. No doubt that the quantity of glass composing the frontal cover and the aluminium composing the frame (where required) is much bigger. Therefore, we can consider a PV panel just like a window with its frame.

Other types of panels use the cadmium telluride (CdTe) instead of polysilicon. Environmental impact is lower, just like the costs: unfortunately, efficiency is also compromised.

While speaking of environmental impact, our attention focuses on cadmium, known as a toxic heavy metal. In this case too, the study carried out by the University of North Carolina points out that “pure” cadmium is totally different from its compounds, which are more chemically stable, therefore safer. The compound of the heavy metal guarantees a very small quantity of cadmium, with an extremely low degree of toxicity, hundred times lower that the free metal. Cadmium telluride is not volatile, therefore not inhalable and it is not soluble in water. Using this extremely safe compound, this energy conductor is not dangerous for humans, nor for the environment.

We must also highlight that coal and petrol combustions release a 300 times higher quantity of this kind of substances.

Carbon footprint of a functioning PV system

According to a study carried out by the University of Utrecht, a PV system will pay back in 2 years the carbon footprint generated for his realization (energy payback time), corresponding to 20g/kWh of CO2. Considering that a solar panel has an average lifespan longer that 25 years, one-twelfth of its life is dedicated to paying back its environmental carbon footprint. Nothing compared to those 400-500 g/kWh produced by the panels on the market during the ’70s, disposable in 20 years. Most importantly, this is nothing compared to any other energy source, in particular non-renewable energies.

Furthermore, this study has shown that the growing production of solar energy reduces the energy needed to manufacture a solar panel and the connected COemissions (respectively 12% and 17-24% at each doubling of solar power generating capacity).

In recent years, greater energy efficiency and the continuous innovation  towards circular economy suggest an even greener future for photovoltaic.

Disposal and recycle of PV panels

After an average time of 25 years it is more convenient to replace PV panels, even if they are still functioning. This can be defined as the panels “end of life”, although this is not accurate, meaning we have to concern about their disposal.

According to the Italian law, for example, a specific procedure must be followed in order to avoid any dispersion of pollutants in the environment and to optimize the recovery of recyclable materials. In order to ensure a proper disposal of your panel you should rely on a WEEE collection centre, by filling out a specific form.

This way a proper separation of aluminium, plastic, glass, copper, silver and silicon or cadmium telluride – depending on the panel – can be performed. These substances will be recycled to produce new panels: the percentage of recovered materials can reach the 95%.

The positive carbon footprint of photovoltaic in the world

The environmental impact of the photovoltaic must be considered positive and always improving. Globally installed PV capacity exceeds 400GW (gigawatt), with a production of 370 TWh (terawatt-hours) in the last year, corresponding to 1.5% of the global energy supply. This is supposed to reduce the production of greenhouse gases of about 170 Mt (million tons).


Concerns about PV panels disposal is totally unfounded, which result from misleading and rough information.

As a matter of fact, nothing in the world, build by humans, is longer guaranteed than PV panels, not even the rooftop on which they are mounted! When a convenient time to replace them comes, (the panel continue its work and its energy production, even if they are a little less efficient, 15% less after 25 years), their disposal can be discussed.

Since PV panels are mostly composed by glass and aluminium, they are proven to be a very attractive product for waste disposal companies, because these materials are easily recoverable and placeable in the market. It is little wonder that many different supply chains and organizations are ready to collect dismissed PV panels.


This becomes even more reasonable if we consider the environmental impact of other sources such as coal. According to a study carried out by the University of California and published on Nature Sustainability, switching from coal to gas to generate electricity has saved more than 26.000 lives over a decade in the USA. Furthermore, over 300 million tons of carbon dioxide have been spared and the level of nitrogen dioxide and sulphur dioxide have dropped by 60% and 80% respectively. However, this research highlights that natural gas, which is replacing coal, is not harmless in its turn. Just like coal, natural gas is a fossil fuel and its production releases huge quantities of methane, a strong greenhouse gas.

Lots of studies prove that coal and gas must be quickly replaced with other 0 carbon emission solutions, such as solar energy, if we want to avoid exceeding the 2°C threshold in global warming.