The Baltic Sea Region: Storage, grid exchange and flexible electricity generation for the transition to a 100% renewable energy system

Abstract

The Baltic Sea Region could become the first area of Europe to reach a 100% renewable energy (RE) power sector. Simulations of the system transition from 2015 to 2050 were performed using an hourly resolved model that defines the roles of storage technologies in a least cost system configuration. Investigated technologies are batteries, pumped hydro storage, adiabatic compressed air energy storage, thermal energy storage, and power-to-gas. Modelling proceeds in five-year time steps, and considers current energy system assets and projected demands to determine the optimal technology mix needed to achieve 100% RE electricity by 2050. This optimization is carried out under the assumed cost and status of all technologies involved. Results indicate the levelised cost of electricity (LCOE) falls from 60 €/MWhe to 45 €/MWhe over time through adoption of low cost RE power generation and from inter-regional grid interconnection. Additionally, power system flexibility and stability are provided by ample resources of storable bioenergy, hydropower, inter-regional power transmission, and increasing shares of energy storage, together with expected price decreases in storage technologies. Total storage requirements include 0-238 GWhe of batteries, 19 GWhe of pumped hydro storage, and 0-16,652 GWhgas of gas storage. The cost share of storage in total LCOE increases from under 1 €/MWh to up to 10 €/MWh over time. Outputs of power-to-gas begin in 2040 when RE generation approaches a share of 100% in the power system, and total no more than 2 GWhgas due to the relatively large roles of bioenergy and hydropower in the system, which preclude the need for high amounts of additional seasonal storage. A 100% RE system can be an economical and efficient solution for the Baltic Sea Region, one that is also compatible with climate change mitigation targets set out at COP21. Concurrently, effective policy and planning is needed to facilitate such a transition.