Photovoltaics generate cheap and emission-free solar power. Although the production of PV components causes carbon dioxide emissions, the overall CO₂ balance of photovoltaics is extremely positive. In this guide, you will learn more about the CO₂ balance of photovoltaics.
How much CO₂ does a photovoltaic system produce?
During its lifetime, a photovoltaic system emits approximately 40 g CO₂/kWh These emissions are the result of the combustion of fossil fuels, which are primarily generated during the manufacture and transport of solar systems.
For the production of solar cells, high-purity silicon which is produced at high temperatures and with high energy consumption. The production steps are similar to those of typical semiconductor production and include chemical and energy-intensive processes that generate by-products. For every kilogram of ultrapure silicon, up to 19 kilograms of by-products are generated. Selecting suppliers who take environmental aspects into account is crucial for the environmental compatibility of a PV module.
CO₂ balance during operation
The operation of PV systems is emission-freeUnlike conventional power generators based on fossil fuels, PV systems generate electricity without combustion.
This helps reduce the costs of avoiding CO₂ emissions that result from environmental, climate and health damage. These additional costs are around 1 cent/kWh. In comparison, the costs for nuclear power and lignite are 24 to 28 and 22 to 24 cents/kWh, respectively.
How much CO₂ does photovoltaics save in comparison?
Compared to conventional energy sources using fossil fuels, photovoltaics saves over 500 g CO₂/kWh. A coal-fired power plant emits 750 - 1,200 g CO₂/kWh, a gas-fired power plant 400 - 550. A PV system, on the other hand, only emits around 30 g CO₂/kWh.
| energy sources | CO₂ emissions |
| coal-fired power plants | 750 - 1,200 g CO₂/kWh |
| gas-fired power plants | 400 - 550 g CO₂/kWh |
| nuclear energy (without final storage) | 10 - 30 g CO₂/kWh |
| wind energy | 10 - 40 g CO₂/kWh |
| hydropower | 10 - 40 g CO₂/kWh |
| photovoltaics | 20 - 40 g CO₂/kWh |
According to the Federal Environment Agency, the energy industry had the highest share of carbon dioxide emissions in 2022 at 37.0%. Around 247 million tons of carbon dioxide were released by this sector. Photovoltaics is an important component in reducing CO₂ emissions.
How long is the energetic payback period of a PV system?
The term "energy payback" describes the period of time in which a PV system must be operated in order to amortise the energy and environmental impacts of its production. PV roof systems The estimates for the energy payback are between 1 and 4 years:
- 4 years for current multicrystalline silicon PV modules
- 3 years for current thin-film modules
- 2 years for future tandem modules
- 1 year for future thin-film modules
Assuming a life expectancy of 30 years, 87 to 97% of the energy generated by PV systems does not contribute to pollution, greenhouse gases or resource depletion.
What is CO₂?
Carbon dioxide (CO₂) is a colorless gas. It dissolves easily in water and is non-flammable, odorless and non-toxic. Together with nitrogen, oxygen and noble gases, it is a natural component of the air. It makes up only 0.038 percent of air. However, CO₂ is a greenhouse gas and contributes to the greenhouse effect. This prevents heat from escaping into space.
Can photovoltaics be recycled?
EU laws require the testing, reuse or recycling of old solar panels. Currently, over 80% of PV modules are recycled, with aluminium and glass being the main reused materials.
