Dong Energy launches a new battery system

Much of the talk at the Offshore Wind Energy 2017 conference in London this week has been about Danish utility’s Dong Energy ‘zero-subsidy’ offshore projects, and how the market should adapt to those.

But the company also got people talking yesterday as it launched a battery system, which it is set to integrate into its 90MW Burbo Bank project in Liverpool Bay. It presented this at its ‘Offshore Wind Power Research and Innovation’ side event.

Specifically, Dong will link Burbo Bank, which has been operating since 2007, to a 2MW battery system on land near Liverpool, supplied by Swiss technology firm ABB. This will be the first time that an offshore wind farm is integrated with a battery system designed to maintain a stable output frequency at 50Hz on the grid.

Frequency response is a mechanism used by National Grid to help manage grid stability. It is required because the frequency of the grid changes continuously, but it must remain close to 50Hz to ensure a stable output. If the frequency deviates from these limits, it would disrupt businesses and consumers connected to the grid.

James Sun, senior asset manager at Dong Energy, presented the project, called Project X, and explained how offshore wind farms could help to support the grid. He said that there are three main reasons.

The first one is that offshore wind schemes are usually large-scale projects. This means that a battery system linked to a large project can provide fast and less expensive frequency support than alternative systems. Burbo Bank may be a relatively small offshore wind project, but it is bigger than most onshore in the UK.

Second, as this battery system could be linked to offshore projects that are already connected to the grid, it would avoid the hassle of having a battery system that has to be connected to the grid itself.

And finally, as the energy mix worldwide increasingly relies on renewables, including offshore wind farms, investing in this new kind of technologies could ensure that renewables can help the grid to deliver a stable output.

That is the theory. The technology must now be installed and tested – but, if Dong can prove that offshore wind can help to stabilise grid output, that will be another argument in favour of more support for the sector. We await the results with interest.