The cost of grid stability with 100 % clean, renewable energy for all purposes when countries are isolated versus interconnected

This study examines the impacts on energy costs and requirements of interconnecting versus isolating the electric grids of countries in Western Europe when each country's all-purpose energy is provided by 100 % wind, water, and sunlight (WWS). A weather model is used to predict wind and solar fields and building heat and cold loads. A grid model is used to match electricity, heat, cold, and hydrogen demand with WWS supply; electricity, heat, cold, and hydrogen storage; and demand response. Stable solutions are found for all countries, including the smallest (Luxembourg and Gibraltar) and largest (France, Germany, Spain, Italy, and the United Kingdom), and for all combinations of countries. Results indicate that interconnecting countries reduces aggregate annual energy costs, overbuilding of generators and storage, energy shedding, and land/water area requirements in most, but not all, situations. Interconnecting Western Europe may decrease aggregate annual energy costs similar to 13 % relative to isolating each country. The best reductions are found by interconnecting hydropower-rich Norway with Denmark (20.6 %) and Northwestern Europe (13.7 %). Interconnecting the smallest countries, Luxembourg and Gibraltar, with larger countries benefits all countries. Whether isolated or interconnected, all countries examined, including France and Germany, can maintain a stable grid at low cost with 100 % WWS. (C) 2021 Elsevier Ltd. All rights reserved.