Associate professor Johan Hjelm, DTU Energy, at a test setup for flow batteries

New battery systems will provide cheap energy storage for wind and solar

Tuesday 28 Nov 17


Johan Olov Hjelm
Professor, Head of Section
DTU Energy
+45 46 77 58 87


The project ORBATS – Organic Redox Flow Battery Systems – is supported financially by the Danish Innovation Fund. The project parters are DTU Energy, Aarhus University, Harvard University and the Danish companies Vestas, Visblue and Lithium Balance. The project is led by Associate Professor Johan Hjelm, DTU Energy
A new project led by DTU Energy will develop cheap battery systems which by integration with wind turbines and solar cells will increase the stability of the electricity grid and facilitate a higher share of renewables in the energy system. 

Denmark and many other countries around the world aim to increase the share of renewables in their energy system significantly. For this to happen, a significant challenge has to be addressed: Solar and wind are fluctuating sources which cannot be controlled at will as traditional power plants can. This challenge will increase as the share of wind and solar in the energy system increases. But this will also increase the demand for cheap energy storage. The ORBATS project will solve this challenge by developing cheap and scalable storage solutions.

Traditional batteries, as used in cell phones and other electronic devices, consist of relatively expensive solid materials which store the energy. This means that when you need to store twice the amount of electricity, the battery has to be twice as large. To avoid this physical limitation, ORBATS will develop so-called flow batteries where the energy is stored in a liquid outside the battery itself. If you need more capacity, you can simply get a larger storage tank and use more liquid without otherwise increasing the size of the battery. Flow batteries are well suited for energy storage and can be used as back-up in smaller installations instead of Diesel generators.

"Water-based flow batteries have every opportunity to become a key part of a sustainable energy system with a high demand for energy storage."
Associate Professor Johan Hjelm

Flow batteries today use relatively expensive vanadium compounds to store the energy. ORBATS will replace the expensive element vanadium and instead use water-soluble organic compounds. The project will not only develop the new materials but also the control strategies necessary to optimize the performance of the novel batteries. The new battery type will be demonstrated in a 5-25 kW prototype. 

The strong industry participation in the project will ensure a short path from the new solutions the researchers develop to the applications. The participating companies see great promise in the technology. “Vestas is working with a number of partners to develop innovative solutions which will bring down the cost of wind energy. We see a great potential in efficient battery technologies as a step on the road towards a fully sustainable energy supply,” says Anders Vedel, CTO and Executive Vice President, Vestas.

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