First power is flowing from the 1.2GW Hornsea 1 project off the UK, set to be the world’s biggest offshore wind farm when complete – and to take the sector to a scale matching nuclear and thermal plants.

The wind farm, being developed by Danish utility Orsted and Global Infrastructure Partners (GIP), is being built around 174 Siemens Gamesa 7MW turbines and three giant substations at a vast site some 120km off the coast of Yorkshire, in northeast England.

Hornsea 1 is expected to be fully commissioned by 2020.

“Hornsea 1 is the first of a new generation of offshore power plants that now rival the capacity of traditional fossil fuel power stations. The ability to generate clean electricity offshore at this scale is a globally significant milestone, at a time when urgent action needs to be taken to tackle climate change,” said Orsted managing director Matthew Wright.

“Ten years ago, the thought of a project of this size was just a dream. Our company’s vision is a world that runs entirely on green energy, and this flagship project is a significant step on that journey, proving that large-scale renewable energy is not just an idea of the future, it’s here, right now.”

Project manager Duncan Clark noted that, with another 173 turbines still to be installed, the project “still [had] a long way to go” but was “confident … [the company would] deliver the biggest renewable energy project in the UK” next year.

In November, Orsted divested 50% of its interest in Hornsea 1 to GIP.

Ten years ago, the thought of a project of this size was just a dream.

The monopiles for Hornsea 1 are all in place offshore and the first 86 transition pieces – which connect the foundations to the turbines – have been completed by EEW Offshore Structures.

Hornsea 1 will be double the size of the current title-holder for world’s largest offshore wind farm, the 653MW Walney Extension, also located off the UK.

As well as using what at the time of order were the most powerful offshore wind turbines on the market, Hornsea 1 will also have the world's first offshore reactive compensation station – a key technology for the transmission of high voltage alternating current over long distances, which is increasingly important as offshore wind farms move out further from shore.