Life cycle assessment of electricity from wind, photovoltaic and biogas from maize in combination with area-specific energy yields - a case study for Germany

Due to the massive expansion of renewable energy-based production capacity, the benefits and drawbacks of wind turbines, ground-mounted photovoltaic (PV) and biogas plants are currently being discussed in Germany and elsewhere. The expansion of renewable energy-based plants is competing with other uses for land area. In addition to area-specific energy yields, the environmental impact of renewables is increasingly gaining awareness. Existing research on the area-specific energy yields and environmental impact for wind, PV and biogas lacks comparability due to factors including time, location, and scale. This study addresses this research gap by combining life cycle assessment (LCA) to compare potential environmental impacts with an area-specific energy yield assessment of wind, ground-mounted PV and biogas from maize in Germany. The LCA includes an assessment of eleven midpoint and three endpoint impact indicators, while the area-specific energy yield is assessed on the basis of both gross and net area-specific energy yield. The LCA results indicate the lowest impact for wind, followed by PV and biogas. This ranking is consistent across all three endpoint and nine out of eleven midpoint categories. The same ranking also applies to the area-specific energy yield, with wind producing the most and biogas the least gross and net energy per area. These results indicate that the current political support in Germany for biogas from maize for electricity generation should be thoroughly re-evaluated in view of the more favourable alternatives, wind and PV. The findings also provide relevant insights for other regions with similar boundary conditions.