Transporting an offshore wind array from the factory floor to the ocean floor is no easy feat. Giant, specialized marine vessels must carry the blades and turbines—which sit atop rigs hundreds of feet tall—out miles from shore. Steel or concrete foundations are built to hold them in place, and underwater cables are laid on the seabed to transfer the power to land. One other industry has spent decades constructing and maintaining such massive energy infrastructure that can survive the storms of the open ocean: oil and gas. Now, with global demand for wind power growing, major oil and gas companies like Shell and Statoil are diversifying their portfolios by developing offshore wind, and the companies that provide services to offshore fossil fuel platforms are seeing a new market rising in their wake.