Fact or Fiction: Solar Photovoltaics

When it comes to energy and climate, we’re faced with a wide range of common misconceptions that often lead to conflicting responses. With this FAQ focused on renewable electricity and solar photovoltaics, Carbone 4 aims to shed light on the debate and separate fact from fiction by offering a scientific, data-driven analysis of each common misconception.

To learn everything there is to know about energy and climate, check out the other FAQs available

1. Solar panels manufactured in China do not reduce emissions in France

Today, about 90% of the solar panels we install in Europe are manufactured in China. Although solar power is a renewable energy source, China still relies heavily on coal to generate the electricity needed to manufacture the panels. What’s more, these panels come from far away. So, are they low-carbon or not?

The emission factor for photovoltaic electricity generation that is widely cited is that provided by the French Agency for Ecological Transition (ADEME): 44 gCO2e/kWh. However, this figure dates back to 2014[1]. Since then, Chinese industry has achieved economies of scale, improved its energy efficiency, and benefited from the gradual decarbonization of the electricity mix. According to the grid operator (RTE), The impact would now be 25 gCO2e/kWh, which is half that of France's current electricity mix. This impact will continue to decline: approximately 15 gCO2e/kWh[2] in 2050, according to RTE. Compare this with figures in the range of 5 to 10 gCO2e/kWh for wind or nuclear power and 500 gCO2e/kWh for natural gas[3].

In addition, solar power generation in France reduces the use of fossil fuels (gas, coal, and fuel oil)[4] in thermal power plants among our European neighbors to whom we export this carbon-free electricity. As a reminder, the carbon intensity of their electricity mix is much higher than ours: 180, 240, 330, and 410 gCO2e/kWh[5] for Spain, the United Kingdom, Italy, and Germany, respectively.

Comparison of Emission Factors for PV and the Average French Energy Mix (in gCO2e/kWh)

Notes:
2030 trajectory estimated using the Industry trajectory from the IEA’s STEPS scenario
Futurs Énergétiques 2050 (RTE) 2050 Projection – Trend Projection

2. Solar panels have too short a lifespan to be environmentally friendly

The energy payback time is the amount of time it takes for an energy system to produce as much energy as was required to manufacture it. For solar photovoltaics, the energy payback time ranges from one to two years of production, depending on the technology and the amount of sunlight. This compares to the lifespan of these systems, which ranges from 20 to more than 30 years in many cases. In other words, A panel produces between 13 and 20 times more energy (depending on its lifespan) how much it took to make it[6].

Solar energy—and, more broadly, most renewable energy sources—have the advantage of using a source of energy that is virtually inexhaustible[7] (e.g., wind, water); these are flow-based energy sources. The only energy used to operate them is that required for their manufacture, operation, and maintenance. This is a notable difference from stored energy sources (e.g., fossil fuels, uranium), whose resources are finite.

Illustration of the energy payback time for a 1 kWp crystalline silicon photovoltaic panel (in kWh)

Notes:
Degradation rate of monocrystalline PV panels: -1.55% per year over 20 years. Source: Atia, D.M., Hassan, A.A., El-Madany, H.T., et al., 2023

3. Solar panels are not recyclable

While the first solar panels were difficult to recycle, that has changed significantly. As of 2014, they are classified as Waste Electrical and Electronic Equipment. Since 2018, this European directive has required that 85% of the panels' weight is recyclable. Let's focus on crystalline silicon panels, which account for 90% to 95% of the global market[8].

On the one hand, more than 80% of their weight consists of easily recyclable materials (e.g., glass, aluminum). On the other hand, 15% is not. These include, in particular, the composite materials (various polymers, plastics, and resins)[9]. For lack of a better option, this material is currently recovered for energy through incineration. In France, the recovery rate for crystalline photovoltaic solar panels reaches 94.7% on average[10](recycling + energy recovery).

Nevertheless, This rate varies considerably by region, their level of technological and industrial advancement, as well as their environmental policies. In the United States, for example, less than 10% of end-of-life photovoltaic modules are processed through a recycling program. In Europe, that rate reaches nearly 95%[11].

Breakdown of the mass of a photovoltaic solar panel by material

4. Photovoltaic panels use a lot of critical metals and rare earth elements

Rare earth elements are a group of 17 strategic elements because they are used in high-stakes sectors such as electronics, electric cars, and magnets for offshore wind turbines, among others. Their geopolitical distribution is also quite distinctive: China holds 40% of the reserves and accounts for 70% of global production.[12]. That being said, Rare earth elements are not used in the composition of solar panels currently on the market.

These are 90% based on crystalline technology, which has almost entirely replaced the other major technology (thin-film technology).[13]. Neither of these two technologies contains rare earth elements overall. However, They use other metals classified as critical. : indium and gallium for thin films; silicon, cobalt, and graphite for the crystalline silicon sector[14]. The criticality of these metals depends on their reserves and distribution, which can lead to geopolitical risks in terms of supply. At the other end of the spectrum, construction materials and other so-called intermediate metals (e.g., copper, silver) are used[15].

Nevertheless, this concentration of resources must be viewed in context. Compared to all the materials used in the economy, the energy production sector accounts for only a few percent.

Material intensity by electricity generation method (in g/MWh)

Notes: Based on 2024 technology load factors. Source: RTE - Energy Futures 2050, 2021. Critical metals are those defined by the European Commission.