The Netherlands, famous for its iconic windmills, is planning to build the largest offshore wind farm on Earth by 2027.

The vision is so massive that the developers will have to construct a 2.3-square-mile artificial island in the North Sea to support the 10,000-turbine complex.

The proposed wind farm, spearheaded by Dutch electric grid operator, TenneT, could produce 30 gigawatts of power—or enough electricity to power a city of 20 million people. That's more than twice the amount of offshore wind power installed across Europe today.

To compare, the London Array, currently the largest offshore wind farm in the world, has a 630-megawatt capacity, or enough to power about half a million homes.

Once built, TenneT's giant wind farm will eventually send power over a long-distance cable to the UK and Netherlands, and possibly later to Belgium, Germany, and Denmark, the Guardian reported. The facility will be located in Dogger Bank, a windy and shallow site about 80 miles off the East Yorkshire coast, which is also within ideal reach to the five countries.

So why build a wind farm offshore? Well, space is major problem for many onshore wind projects.

"The big challenge we are facing towards 2030 and 2050 is onshore wind is hampered by local opposition and nearshore is nearly full," Rob van der Hage, TenneT's program manager, told the Guardian. "It's logical we are looking at areas further offshore."

While the $1.8 billion project seems expensive, the developers tout that their project is actually cost-effective compared to traditional wind farms.

Business Insider explained:

"Offshore wind farms typically use expensive underwater cables that convert the turbines' electric current into a type that electricity grids can use. TenneT's island, however, would house equipment that would perform this conversion on-site, thereby allowing the farm to send electricity directly to the UK and Netherlands via less pricey cables.

"…Putting additional equipment on the island would also allow the team to operate more turbines at a lower cost—and thus generate more power—than a traditional offshore wind farm."