German Roofs Solar Potential 3 Times National Consumption
…says the German Fraunhofer Institute, whom we trust blindly in these matters.
Total potential yield German roofs: 1,710 TWh/year
[efahrer.chip.de] – Jedem Dach eine Solaranlage: Wäre Deutschland unabhängig?
[ise.fraunhofer.de] – Aktuelle Fakten zur Photovoltaik in Deutschland
Im Jahr 2020 deckte die PV mit einer Stromerzeugung von 50,6 TWh [UBA1] 9,2% des Brutto-Stromverbrauchs in Deutschland
In other words, in 2020, German electricity consumption was 550 TWh. So, indeed a factor of 3.
This is an interesting Q&A-document, btw. A little quote-mining from it:
p39 – a solar roof over all parking-lots would bring 59 GWp.
There are still morons who claim that it costs more energy to build a solar panel as that it will ever give back. Rubbish:
p36 – Energy payback time slightly over a year in NW-Europe. In Sicily, it could be 6 months and in the Chilean Andes 4 months. This corresponds to an EROI of more than 20 in Germany or 60 in Chile.. Note, this is related to a life-time of merely 25 years. If you keep them for a century, you’ll have an EROI of 80.
p43 – Eine Studie des Fraunhofer ISE an 44 größeren, qualitätsgeprüften Aufdach-Anlagen in Deutschland hat eine durchschnittliche jährliche Degradation der Nennleistung von ca. 0,15% ergeben [ISE2]. Die häufig getroffene Annahme von 0,5% Leistungsverlust pro Jahr erscheint in diesem Kontext sehr konservativ.
Average degradation solar panels over a century: 15%. Interesting consequence: like with cars, second hand modules could have a new life span in poorer countries.
[deepresource] – Solar Panel Still Working After 40 Years
(Example of 35-year-old AEG-Telefunken panels that degraded with 4% or 12% in a century)
p38 – 14% of German agricultural land is used for biomass production for energy purposes. If the same land would be covered by both solar panels and crops (“Agri-PV”), the energy yield would be a factor of 32 higher!
p39 – Lignite mining led to 1773 km2 destroyed country-side. In many cases these grounds were flooded, 3 times the Bodensee area. Potential floating solar: 44 GWp.
p42 – the efficiency of newly installed panels in Germany is ca. 20%.
p42 – average domestic electricity consumption is 1600 kWh/capita.