Wave Energy Tech Is Ready to Plug Into a Real Grid

The OceanEnergy Buoy off Oahu’s coast may prove resilient enough to avoid the fate of earlier efforts

3 min read
Photo of OceanEnergy’s buoy.
Surf’s Up: OceanEnergy’s buoy would be one of many such devices on a utility-scale wave farm.
Photo: Maria Gallucci

Ocean waves are powerful and perpetually replenished. But unlike the wind and sun, waves remain a largely untapped source of renewable energy, despite their enormous potential. A slew of projects is starting to change that, with large prototypes launching near coastlines worldwide.

In Hawaii, the OceanEnergy Buoy is slated to connect to the island of Oahu’s electric grid next month. The 749-metric-ton device was recently towed from Portland, Ore., to the U.S. Navy’s Wave Energy Test Site, where the bright yellow buoy will undergo a year of performance tests. The project builds on a decade of research and several smaller iterations, including a quarter-scale model that was tested for three years in Ireland’s Galway Bay.

“The difficulty has been in developing a technology that actually survives in the marine environment, which can be very harsh,” said John McCarthy, CEO of the Irish buoy maker OceanEnergy.

To limit seawater effects, McCarthy’s team designed a device that puts mechanical parts above the surface. The “oscillating water column” system features a semi-submerged chamber, inside of which an air pocket is trapped above a column of water. When waves crest and water enters the chamber, it forces the air upward, spinning a Siemens subsidiary’s turbine system to generate electricity. As water recedes, it creates a vacuum that sucks in outside air and continues driving the turbine.

The 1.25-megawatt buoy will be moored to a 60-meter-deep berth and should withstand gale-force winds and extreme waves. A subsea cable will link it to Hawaiian Electric’s grid, which still runs primarily on imported oil.

About 100 people built the buoy over 14 months at the Swan Island shipyard in Portland, said Tom Hickman of U.S. shipbuilder Vigor Industrial. Workers cut, formed, and welded steel plates into three massive sections to form the L-shaped hull, then installed mechanical and electrical components. On a crisp October morning, company leaders and dignitaries held a completion ceremony, days before a tugboat dragged the buoy up the Columbia River and across the Pacific Ocean.

Tyler Gaunt, a project manager for Vigor, said he was proud to have successfully finished the project but happy to see the device leave. Constructing a first-of-its-kind prototype at a large scale meant constantly solving problems under a relatively tight deadline. For instance, the supportive steel “stiffeners” that are typically applied inside ship hulls went on the buoy’s exterior, to avoid creating drag within the air chamber.

“It was essentially the opposite of how we would normally construct a ship,” he said from the shipyard.

Globally, about 19 megawatts of “wave energy converters” were deployed from 2010 to 2018, though some devices were decommissioned after pilot tests, according to Ocean Energy Europe [PDF] (an industry organization not connected with OceanEnergy). The bulk of projects have been in the United Kingdom and Western Europe, with other devices deployed in China, Australia, New Zealand, and the United States.

Wave energy is one of several technologies that harness the ocean’s natural features—tides, winds, water temperatures, salinity—and could provide significant amounts of clean electricity. Waves off U.S. shores represent some 2.64 trillion kilowatt-hours in theoretical annual energy potential—equivalent to about two-thirds of the nation’s electricity generation in 2018, according to an estimate by the U.S. Department of Energy. This resource is abundant at higher latitudes, where colder temperatures and weak sunlight make it harder to operate other renewables during certain months.

“Wind and solar are really cheap and ubiquitous on land, but there are challenges with those technologies,” said Bryson Robertson, codirector of the Pacific Marine Energy Center and an Oregon State University associate professor. “In places with very aggressive decarbonization agendas, we’re going to need all renewable resources to really start to mitigate our impact on the climate.”

Marine technologies still face significant hurdles to achieving commercial scale. It’s not yet clear how spinning turbines and rotating blades will affect wildlife. Supporting infrastructure, such as offshore grid connections, isn’t widely available. Licensing and permitting processes must first ensure that devices don’t obstruct commercial fishing, whale watching, or other activities.

Such issues have stifled investment, so public agencies and research institutions are leading the way, with over a dozen testing hubs worldwide. In Scotland’s Orkney Islands, the European Marine Energy Center has 13 grid-connected berths for wave and tidal devices. New sites are under way in Western Australia and Jeju Island, South Korea. At the U.S. Navy hub in Hawaii, three other developers—Columbia Power Technologies, Northwest Energy Innovations, and Oscilla Power—are also expected to test wave energy converters starting in 2021.

Robertson said OceanEnergy’s yellow buoy represents a valuable “data point” in the broader effort to improve performance and drastically reduce electricity costs from marine technologies. “We need to start putting these devices in the water so we can start to learn lessons,” he said.

This article appears in the December 2019 print issue as “ At Last, Wave Energy Tech Plugs Into the Grid.”

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Smokey the AI

Smart image analysis algorithms, fed by cameras carried by drones and ground vehicles, can help power companies prevent forest fires

7 min read
Smokey the AI

The 2021 Dixie Fire in northern California is suspected of being caused by Pacific Gas & Electric's equipment. The fire is the second-largest in California history.

Robyn Beck/AFP/Getty Images

The 2020 fire season in the United States was the worst in at least 70 years, with some 4 million hectares burned on the west coast alone. These West Coast fires killed at least 37 people, destroyed hundreds of structures, caused nearly US $20 billion in damage, and filled the air with smoke that threatened the health of millions of people. And this was on top of a 2018 fire season that burned more than 700,000 hectares of land in California, and a 2019-to-2020 wildfire season in Australia that torched nearly 18 million hectares.

While some of these fires started from human carelessness—or arson—far too many were sparked and spread by the electrical power infrastructure and power lines. The California Department of Forestry and Fire Protection (Cal Fire) calculates that nearly 100,000 burned hectares of those 2018 California fires were the fault of the electric power infrastructure, including the devastating Camp Fire, which wiped out most of the town of Paradise. And in July of this year, Pacific Gas & Electric indicated that blown fuses on one of its utility poles may have sparked the Dixie Fire, which burned nearly 400,000 hectares.

Until these recent disasters, most people, even those living in vulnerable areas, didn't give much thought to the fire risk from the electrical infrastructure. Power companies trim trees and inspect lines on a regular—if not particularly frequent—basis.

However, the frequency of these inspections has changed little over the years, even though climate change is causing drier and hotter weather conditions that lead up to more intense wildfires. In addition, many key electrical components are beyond their shelf lives, including insulators, transformers, arrestors, and splices that are more than 40 years old. Many transmission towers, most built for a 40-year lifespan, are entering their final decade.

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