Assessment of electricity network investment for the integration of high RES shares: a comparative case study

Abstract

In the course of the energy transition, the EU member states' National Energy and Climate Plans seek to install significant amounts of intermittent renewable generation capacity over this decade. Previous studies underline the social, political, and economic benefits of the electricity sector decarbonisation. The economic analysis of renewable energy sources (RES) integration is commonly performed with single-bus generation expansion models that seek the cost-optimal expansion of RES generation ca-pacity to reduce operational expenses. However, electricity grids will require investments to adapt to the integration of high amounts of RES capacity. This paper contrasts the cost-optimal generation capacity mix obtained from a single-bus expansion model with a conservative estimation of electricity network investment requirements for case studies in three different electricity networks. RES network investment costs are put in context with an alternative non-RES generation expansion pathway. Network investment costs considered include expansion costs for both transmission and distribution grids. Electricity network expansion costs represent 3 to 11 of the corresponding generation capacity investment. Despite in-creasing network investment costs, the integration of high RES shares into electricity grids reduces operating costs when compared to non-RES pathways. Fuel and emission savings exceed total invest-ments (generation capacity, network expansion, and connection costs). The additional electricity grid investment costs are numbered at 0.81 to 2.97 EURMWh additional of RES energy injected in the RES scenarios in comparison to the Non-RES scenarios.