The green hydrogen company Nel announced plans Wednesday to build a massive new plant in Michigan as it works with General Motors to drive down the cost of hydrogen.

The Norwegian company makes devices that take water and split it into hydrogen and oxygen, known as electrolyzers, as well as fueling stations. CEO Håkon Volldal said the company will make electrolyzers in the Detroit area to supply up to 4 gigawatts’ worth of hydrogen each year, making it among the largest such factories in the world.

Nel looked at every state, but picked the longtime home of the American automotive industry for its new “gigafactory” to be near General Motors. Michigan also offered attractive financial incentives, partnerships with universities and training programs, and strong support from the governor’s office, Volldal said. Getting the plant up and running will take an estimated $350 million.