It all started a few years ago with a dream of developing a battery to store electricity. Today, the research has become a business, and production of the first batches of flow batteries is in full swing in a small Danish company with a very promising global market potential.

Enabling residential properties and companies to store energy from the sun in our homes cheaply and safely could be nothing less than a game-changer in our energy system. In both the US and China, private individuals are beginning to erect entire parks of flow batteries, and the first batteries for storing solar energy have now also been put into production in Denmark.

According to the researchers behind the battery, even under Scandinavian weather conditions, costs will be recouped in the course of just ten years.

“We’ve matured the technology very quickly, and we’re now preparing the first large Danish installations for sale. Development work is still a core activity in the company, and our clear expectation is that we can improve the technology so that the return on investment for the consumer is even better in the future,” says Associate Professor Anders Bentien, one of the driving forces behind the development of the flow battery and co-owner of the Visblue company.

New collaboration with Harvard University
Basically, the battery is based on vanadium technology, which gives a very long service life and makes it possible to scale power and energy capacity independently of each other. This makes the battery cheap in the long run and at the same time very flexible for the individual customer to use.

In 2018, the researchers and the Visblue spin-out company started a new project in collaboration with, among others, Danish wind turbine producer Vestas and Harvard University. The aim is to develop an improved generation of batteries based on new fluid compositions with organic electrolytes. This will make it environmentally friendly and at the same time reduce the cost per kilowatt hour.

One of the cornerstones of the future energy mix
Initially, the company is primarily producing batteries for the Danish market. This is being done while they are upgrading production facilities for the growing global demand for new technologies that can store green energy.

“If we’re to have a 100 per cent green energy supply, one of the most important issues is storage. What are we to do with solar and wind production that fluctuates from day to day and from season to season? How do we secure stable supplies without backup from power stations? Flow batteries could play a crucial role here,” says Associate Professor Bentien.

According to the associate professor, batteries for storing energy could also turn our distribution system on its head.

“Who says that, in future, it’ll be a good idea to transport electricity between countries. In principle it’s unnecessary, as individual householders can store their own electricity for their own needs,” he continues.

In many cases, private storage of surplus energy from solar cells is already much more profitable than selling electricity back to the grid.

Important relief for the supply grid
The new flow battery solves another important problem in the way the modern world has organised its energy systems. In many countries, underground cables are getting old and they come from a time when no account was taken of the amounts of electricity from solar energy we transport today.

“This is most evident in Danish residential areas from the 60s. They’re connected to a substation through a supply grid that has difficulties coping with the solar energy from the large number of solar cells on house roofs. In the middle of the day, when production is typically greater than consumption, large amounts of electricity flow in the opposite direction, and the system isn’t dimensioned to deal with this,” says Associate Professor Bentien.

Over the coming year, the researchers want to test the possibilities of using the battery technology to relieve the supply grid in full scale in a Danish residential area.