PORTLAND, Ore. (AP) — Tuesday marks the first-ever U.S. auction of leases to develop commercial-scale floating wind farms, in the deep waters off the West Coast.

The live, online auction for the five leases — three off California's central coast and two off its northern coast — has attracted strong interest and 43 companies from around the world are approved to bid. The wind turbines will float roughly 25 miles offshore.

The growth of offshore wind comes as climate change intensifies and need for clean energy grows. It also is getting cheaper. The cost of developing offshore wind has dropped 6...