The artificial island, which will be roughly the size of 20 football fields, will be surrounded by 200 to 600 massive wind turbines—each potentially taller than Seattle’s Space Needle. Because the hub will be around 50 miles off the Danish coast, the turbines can be larger than ones on land, and they can also access higher wind speeds. In its first phase, the hub will send electricity to 3 million households; eventually the size will more than triple. As massive batteries are added the hub will be able to store energy and send it on demand. While offshore wind power already exists, this island will be the world’s first clean energy hub, gathering and distributing power from multiple wind farms simultaneously. The hub will also be able to produce fuel.

If wind power can be produced cheaply, “you can make very competitive green hydrogen, and it has zero carbon footprint,” says Patrick Molloy, a senior associate at RMI, a nonprofit that focuses on clean energy. (Hydrogen is made by splitting up water molecules with an electric current, and when the electricity is renewable, the hydrogen is considered green.) The hydrogen can be used to make ammonia, which cargo ships can use instead of fossil fuels; ships running on ammonia are in development now and will likely be in use within the next few years.

Airplanes could also run on green hydrogen or on synthetic fuels that combine the hydrogen with CO2 captured from the atmosphere. The hydrogen can also be used in fuel cells in vehicles, or in industrial plants that can’t easily run on renewables. It could even be piped into homes to replace natural gas. “It offers a pathway for us to step away from fossil fuels and to move to a zero-carbon solution in sectors that a very short time ago looked very difficult to reach,” Molloy says. The hub will send liquid fuel back to Denmark and surrounding countries through undersea cables.

The project, which will be funded both by the Danish government and by companies that will partner with it, will cost around $34 billion and will be the largest construction project in the country’s history. A second energy hub will be added later. It’s one piece of Denmark’s larger plan to rapidly cut emissions—by 2030, emissions legally have to be 70% lower than they were in the 1990s—and to become carbon neutral by 2050. Says Molloy, “I think this just speaks to the commitment of Denmark to reach its climate goals.”