At the Port of Los Angeles on a site that once housed oil tanks, seven steel structures that look like small blue boats are lowered into the ocean, where they gently bob up and down with the waves to generate power. It’s the first onshore wave energy site in the United States. Eco Wave Power installed its technology on an unused wharf where it will generate a small amount of electricity. The goal is to show it works well enough to build it out along 8 miles of breakwater to make enough power for about 60,000 homes. Experts say the technology being officially unveiled this week can be scaled up to tap the immense wave energy off America’s coasts and help meet the country’s growing energy needs.