Comment: Integrating battery storage into Hornsea 3

Battery storage can help mitigate the intermittency of renewables, but long term storage is also vital, writes Luke Bridgman, Managing Director of Hornsea 3 Offshore Wind Farm.

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On any given day, up to 50 per cent of the UK’s energy can be renewable, with a substantial proportion of that renewable energy being supplied by the offshore wind industry. Offshore wind is a UK success story, being one of the most mature markets globally, generating enough electricity in 2023 to supply 14.2m of UK homes.

However, to tackle the growing impacts of climate change, more needs to be done. The ramp up of renewable energy is critical for the UK to meet its legally binding Net Zero target, and the UK government is committed to supporting the build out of 40GW by 2030 and 50GW by 2050.

Huge infrastructure projects like the one I manage, Ørsted’s Hornsea 3 - the world’s single largest offshore wind farm - are key in delivering these targets. Hornsea 3 has a capacity of 2.9GW alone - enough to power more than 3 million UK homes.

Intermittency: Renewables Biggest Challenge

To meet Net Zero by 2050, the UK really needs to step up a gear to expand its offshore wind capacity. Yet, due to mismatches in how we use electricity compared to when it’s produced, we are already facing challenges to how it is transported via the national grid as well as how and when it is consumed.

Renewable energy is clean and unlimited but its issue is intermittency. The UK grid was designed to accommodate controllable (or dispatchable) centralised fossil-based generation that could respond in real time to changes in demand for electricity. The increase of variable renewable generation on the system needed to achieve Net Zero targets is displacing these carbon intensive, but dispatchable, conventional generators. This means that operating the grid or ‘system’, will have to be done more flexibly and tap into new sources of dispatchable technologies.

In other words, what happens when the sun isn’t shining for the solar panels, or the wind isn’t blowing to power the turbines? It’s also a problem in reverse – when there’s too much wind (often when we’re asleep) or too much sun (at midday when we don’t need to turn on the lights). That is why battery and other storage technologies are game changers for the renewables industry.

Bolstering Energy Security

Introducing battery energy storage solutions is therefore key to overcoming variable renewable energy supply.

At Ørsted we’ve just announced our investment in a battery energy storage system for just this reason. It will be co-located with the Hornsea 3 Onshore Converter Station – where power is converted from HVDC (High Voltage Direct Current) to HVAC and enters into the grid. It makes use of our existing grid connection and will help reduce volatility in the UK energy supply. It’ll take power not just from our own wind farm, but from others being developed off the coast of East Anglia. This should also result in energy systems being easier to manage by helping smooth out the variations between supply and demand.

The Battery Energy Storage System has other benefits including supporting the regulation of the frequency and the voltage of electricity in the grid, through the ancillary services market, as well as services to support rebuilding the grid in the event of a major power outage. These are all necessary when operating a Net Zero grid.

Unlocking the Power of Renewable Energy

Delivering a range of projects within a project of this magnitude is an engineering challenge on a huge scale. What I find most interesting about it is overcoming the complexity. But it is the challenge of taming that technical complexity which gets engineers like me out of bed. Technology in the electrical system is changing at an amazing pace – the innovation is immense, and the solutions to problems which seemed beyond us not long ago are now within our grasp.

Hornsea 3 benefits from experts across the whole sweep of engineering disciplines as well as within the sphere of new technologies and storage systems. We are also working collaboratively with government, regulators and industry on how to integrate the increasing levels of renewable energy into our national grid system to drive the transition from fossil fuel to clean energy.

At Ørsted, we want to see storage technologies mature and scale up, including long duration energy storage that can hold energy reserves for days, weeks, or even months. We believe that a diverse range of energy storage projects need to be pursued to test and innovate new technologies and bring about growth in energy storage at the lowest cost.

Luke Bridgman is Managing Director of Hornsea 3 Offshore Wind Farm