IEA (2021), Operational cost savings from a flexible fuel supply contract in 2030 based on 15% VRE penetration, IEA, Paris https://www.iea.org/data-and-statistics/charts/operational-cost-savings-from-a-flexible-fuel-supply-contract-in-2030-based-on-15-vre-penetration, Licence: CC BY 4.0