Managing Grid Capacity with Storage

This project aims to assess methods to increase the capacity of the Swedish power system using energy storage as well as enhanced control of generation and consumption. These Non-Wire Alternatives provide a potentially faster and more flexible approach than conventional network upgrades, which take 3-15 years to complete.  

Electrification of the Swedish industry and transportation sectors leads to significant increase in electric power consumption over the next 20-30 years. The number of V-RES (variable renewable energy resources) in the system is expected to increase further to meet the demand. The developments in generation and consumption lead to insufficient capacity in power lines and transformers (shown red in the illustration). More grid capacity for power transfer is thus needed, but construction of new lines to reinforce the grid is not keeping up with the need. Distribution line projects typically take 3-5 years to complete, and transmission line projects have lead times of 10-15 years. Alternative methods for network capacity enhancement are needed to maintain the pace of the energy transition.

To capture the future Swedish power system, the project develops system models with associated V-RES scenarios. It then proposes methods to manage the capacity challenges: On one hand coordinated battery energy storages at transmission level are controlled to act as Virtual Power Lines. On the other hand, V-RES and consumption at transmission and distribution levels are controlled in a coordinated manner.

Grid capacity needs of the future Swedish power system

Aiming at studies relevant for 2045 and 2050, a simulation model of the Swedish power system with explicit representation of the transmission network is developed. The model is combined with scenarios for V-RES in 2045-2050 to quantify the needs for grid capacity. Each scenario is one year with hourly resolution and the scenarios represent different weather years such as dry, wet, windy or calm.

Virtual transmission lines

In operation, a power line is characterized by a certain power entering one end of the line and the same power (less losses) simultaneously leaving the other end. If battery energy storages are installed at each end of the line (see illustration), they can act as a Virtual Power Line: When power enters one end of the line, additional power can enter that battery storage. Simultaneously, the same power is drawn from the other battery storage. Controlled in this way, the two battery storages increase the transfer capacity between the two ends of the line. The project develops real-time control strategies for the battery storages forming the virtual power line.

Coordinated capacity management in transmission and distribution networks

Both TSOs (Transmission System Operators) and DSOs (Distribution System Operators) need to manage the capacity of their grids to permit electrification and expansion of V-RES. TSOs and DSOs are separate organizations, but their electricity networks are closely coupled, and it is important the capacity management of one network is not detrimental to the other. The project develops methods for coordinated capacity management of TSO and DSO networks.

Involved in the project

Martin Lundberg, Olof Samuelsson, Emil Hillberg, Industrial Electrical Engineering and Automation, Lund University

Partners

Lund University, DNV, Göteborg Energi, Hitachi Energy, Svenska Kraftnät, Vattenfall, Volvo Cars, Volvo Energy, Chalmers University of Technology

Funders

DNV, Göteborg Energi, Hitachi Energy, Svenska Kraftnät, Vattenfall, Volvo Energy