4. Photovoltaics (Schönau's revolutionists)
Is solar power carbon neutral?
This question is not so easy to answer: In the future, solar power will probably be produced largely carbon (that is CO2) neutral, but nowadays (in 2018) this definitely not the case.
The reason: a lot of electricity is required for the production of solar panels. Although no greenhouse gas is released during the actual operation of a solar system, the large energy requirement during production must be taken into account in the overall life cycle assessment. A modern solar system takes about one to three years to produce more electricity than was consumed for its production.
Power mix at the production site
With respect to the climate, the crucial question is how the electricity is generated that is used in the production of the solar panels. If 100% of this electricity came from coal-fired power plants, 220g of CO2 per kWh (calculated for total lifetime of the solar panels) would be released by photovoltaics that are installed on roofs in Germany (in southern Spain, for example, the total electricity yield would be considerably higher and the respective CO2 output per kWh would be lower).
However, as soon as electricity or fuel from renewable sources is used for production and transport, solar energy will be virtually carbon neutral.
According to calculations of the Federal Environmental Agency (Umweltbundesamt, UBA 2018, p. 33), renewable energies currently release climate gases in the following quantities in Germany:
- Solar power: 67g CO2 / kWh
- Wind power (in land): 11g CO2 / kWh
- Offshore wind power: 5g CO2 / kWh
- Biogas from energy crops (corn): 404g CO2 / kWh
Comparative values for electricity from fossil-fuel sources (UBA 2019, p. 16):
- from lignite: 1142g CO2 / kWh
- from hard coal: 815g CO2 / kWh
- from natural gas: 374g CO2 / kWh
Note: This information refers to:
- so-called CO2 equivalents,
i.e. on total greenhouse-gas emissions, including methane and others, converted to the greenhouse effect of CO2
- the overall life cycle of energy production plants,
i.e. the CO2 emissions in the course of extraction of raw materials, transport, production of the components, ongoing operation (possibly including the extraction of fuels such as oil or corn) as well as dismantling and disposal or recycling of the plant components.
Literature and Links:
- Frauenhofer ISE (2017): Aktuelle Fakten zur Photovoltaik in Deutschland. Fassung vom 21.10.2017. S. 6. www.pv-fakten.de.
- Janzing, Bernward (2008): Ich bin ein Störfall. doldverlag, Vöhrenbach. S. 76ff.
- EnergieAgentur.NRW (2018a): Klimabilanz Photovoltaik. Wie groß ist der CO2-Fußabdruck von Solarstrom? pptx zum Download unter https://www.energieagentur.nrw/mediathek/Praesentation/klimabilanz_photovoltaik_wie_gross_ist_der_co2-fussabdruck_von_solarstrom
- UBA (2018b): Emissionsbilanz erneuerbarer Energieträger. Climate Change 23/2018, Online: https://www.umweltbundesamt.de/sites/default/files/medien/1410/publikationen/2017-10-26_climate-change_23-2017_emissionsbilanz-ee-2016.pdf
- UBA (2019): Entwicklung der spezifischen Kohlendioxid-Emissionen des deutschen Strommix in den Jahren 1990 – 2018. Climate Change 10/2019, Online: https://www.umweltbundesamt.de/publikationen/entwicklung-der-spezifischen-kohlendioxid-5
The panel for download as pdf (425.2 KB)