Hundreds of new jobs could be created after plans were revealed to double the size of a wind turbine factory.
Siemens Gamesa said it was looking at the possible expansion of its site in Hull to allow it to make larger blades to help reduce electricity costs.
Hull City Council said it welcomed the "game-changer" planning application.
About 750 people are currently employed at the factory in the city's Alexandra Dock, which opened in 2016 at a cost of £310m.
Labour councillor Daren Hale said: "This is thrilling news for Hull and if this goes ahead it will help to further cement the city's position at the forefront of the green economy revolution.
"As we've seen in the past, investments like this have transformed the city and this latest plan could be a game-changer. It could be critical in supporting the recovery of Hull in a post-Covid economy at a time when so much is uncertain."
Clark Macfarlane, Siemens Gamesa UK managing director, said no firm decision had been made on whether to invest in the new facility and that the planning application was "part of preparations for our future requirements".
"As part of the continued drive to reduce costs to consumers, future turbines will continue to grow in capacity and this means that changes may be required in our factory operations to create the space and capability to produce blades beyond 100 metres in length," he said.
"We need to look at all options carefully."
If the development goes ahead, the factory would increase in size from 387,500-sq-ft (36,000-sq-m) to 835,270-sq-ft (77,600-sq-m), with a separate office building.
Siemens Gamsea said it was unable to provide details on the potential number of jobs and the cost of the investment.
Blades from the factory are being used in the construction of the world's largest offshore wind farm located 75 miles (120km) off the East Yorkshire coast.