Mr Obama said offshore energy could create as many as 250,000 jobs
US President Barack Obama has marked Earth Day by announcing a plan to allow offshore electricity generation from wind, waves and ocean currents.
Mr Obama says the move will help to reduce carbon emissions and combat global warming, while creating jobs.
Wind could generate as much as 20% of US electricity demand by 2030, he said.
Coastal US states such as New Jersey and Delaware have already developed plans to build offshore renewable energy projects.
"The choice we face is not between saving our environment and saving our economy, it's a choice between prosperity and decline," said Mr Obama, as he announced the move, in a speech at a wind tower factory in Iowa.
And he insisted that his plan for offshore energy would not damage the economy.
"As with so many clean energy investments, it's win-win," he said, predicting that offshore energy would create as many as 250,000 jobs.
"Good for environment and great for our economy."
Mr Obama has indicated that combating climate change is one of his administration's top priorities.
He has pledged to pass legislation establishing a "cap and trade" system to reduce greenhouse gas emissions, although members of Congress from both parties may attempt to block the changes, or water them down.
Mr Obama delivered his speech at the Trinity Structural Towers plant, which employs 90 people manufacturing the towers that support wind turbines.
The site was formerly home to Maytag, an appliances firm that closed down in 2007, costing hundreds of jobs.