Source: Adapted from Tröndle, Marelli, Lilliestam and Pfenninger (2020).
Renewable electricity supply in Europe would be cheapest with a continent-wide optimised system where wind and solar power are deployed at the best locations. However, it is also possible to build nationally or subnationally balanced supply systems with cost penalties of 20% or less. Such a low-cost but regionally balanced electricity supply requires continental-scale balancing of renewable fluctuations and an expansion of cross-border transmission capacities, but not necessarily an overall large transmission grid. → Tröndle, Marelli, Lilliestam and Pfenninger (2020), Joule.