On the road to climate neutrality by 2050, the expansion of renewable energies must be accelerated. The Space efficiency play an important role in the generation of renewable energy. The Thünen Institute has published an interesting Comparison between PV systems, wind energy and biomass and the respective energy yield per hectare is calculated.
A comparison of the space efficiency of renewable energies
On one hectare of agricultural land Maize or rapeseed cultivation and the subsequent generation of electricity 23,000 kWh per year. This includes storage losses and could seven households with electricity for a year. Converted to the production of biodiesel and the entire use of the by-products as animal feed, a car could drive up to 66,000 km with this.
On an area of 100 x 100 meters there is also an approximately 800-900 kWp PV system place. It delivers at least 700,000 kWh annually and can 230 households with electricity. An electric vehicle could travel around 4 million kilometers with this amount of energy.
For solar energy and biomass, the calculations in the study refer to the complete use of a contiguous hectare. When calculating wind energy efficiency, the necessary soil sealing was estimated for a wind turbine and extrapolated to 100 x 100 meters, so that the calculated values represent a entire wind farm represent: This therefore generates 18,000,000 kWh annually, thus providing 6,000 households and an electric vehicle could drive 100,000,000 km with it.
The area efficiency of PV systems is 30 times higher than that of biomass
Farmers currently use around 14 % of the total area of Germany for the cultivation of energy crops. This corresponds to around one million hectares of agricultural land on which they grow maize or rapeseed to produce biogas, biodiesel, vegetable oil and bioethanol. Experts at Fraunhofer ISE estimate that switching to more effective PV systems than Solar parks or agri-PV approx. 600 GWp nominal output could be realized. That would be twice as much electricity as Germany needs to achieve its climate target. The high area efficiency of PV systems compared to biomass clearly speaks in favor of accelerating the expansion of photovoltaics on open spaces as well. The target set by the EU and Germany for 2030 PV capacity of 215 gigawatts could also be realized in other ways: So far, we only use 10 % of all roof surfaces in Germany to generate electricity through photovoltaic systems, and the same study by the Fraunhofer Institute estimates that the untapped potential of roofs is around 1,000 GWp.