US energy secretary Steven Chu said the finance would come in the form of 41 projects focused on research, wind-turbine design and manufacture and infrastructure development.
Department of Energy said the investment would aim to improve technological and infrastructure development, increase competitiveness in the turbine market and improve information for potential investors.
But according to the AWEA, although the US is yet to install an offshore turbine, the country has more than 4GW of offshore-wind potential.
Chu said: "The US has an abundant offshore wind resource that remains untapped," he said. "The Department of Energy is developing the critical technology and knowledge base necessary to responsibly develop this resource, enhance our energy security and create new clean energy jobs."
Cape Wind, a planned 420MW offshore wind project — and the closest to being built with a power-purchase agreement in place — is currently facing stiff opposition in the Massachusetts Supreme Court from a group of four organisations opposed to its construction.