May 15, 2008

A new wave: Ocean power

By Sonal Patel

Energy islands

Architects Dominic Michaelis and his son Alex recently proposed in an entry to the Virgin Earth Challenge (a competition for solutions to combat global warming) that a series of floating sea-faring platforms could be effectively outfitted to reap many forms of renewable energy. Each “energy island” would be fitted with wave energy devices, wind turbines, and solar panels; each could also harbor a small OTEC plant. With the right conditions, according to the Michaelises, one platform could generate as much as 250 MW of energy.

A decade ago, this idea would have been considered fanciful. Now, considering the advantages such a construct could provide in support of developing renewables, the concept is being taken more seriously.

Last year, Dutch electric company KEMA and civil engineering firm Bureau Lievense announced they have been investigating the technical feasibility and economic viability of an artificial “Energy Island” for storing large-scale energy off the Dutch coast (Figure 11). The 6.2-mile by 3.7-mile island would incorporate a fall lake, or a pumped energy storage (PES) facility.

11. Watery “energy island.” One scheme for “offshoring” energy storage uses an unusual type of pumped energy storage that depends on a dike-enclosed lake—which is filled with water 105 feet to 130 feet below sea level. Courtesy: KEMA

The method reverses the principle on which a conventional PES facility works. When power supply exceeds demand, seawater is pumped out of the dike-enclosed lake—which is filled with water 105 feet to 130 feet below sea level—and back into the surrounding sea; when demand exceeds supply, seawater flows back in, driving a generator. The 24 square-mile island would potentially store a capacity of 20 GWh, enough to supply an average of 1,500 MW to the onshore grid for at least 12 hours. Several construction companies have expressed interest in building or designing the island, a project that would cost about $4.9 billion and take six years to complete.

Development incentives

Given that marine energy resources have the potential to generate 4,000 TW, as estimated by the British government-funded research group Carbon Trust, it is no surprise that venture capitalists and power companies are flooding the sector with ready money. In spite of the fact that marine-generated electricity currently costs 10 times as much as electricity produced by traditional sources, and undeterred by the abundant risks faced by marine energy firms, private investment will continue to increase. According to one projection, marine energy will constitute up to 20% of Europe’s total renewable resources by 2020—compared with the 40% projected for wind power.

Governments, too, are lending their support to this new wave of power generation. The UK government and other public-sector organizations have invested around £15 million ($29 million) in the creation of the European Marine Energy Center, the research facility committed to help emerging technologies evolve from prototype to the commercial marketplace. And the EU is backing the Wave Energy Centre in Portugal, a facility to provide strategic and technical support to companies in this field.

Comparatively, U.S. support is lagging. Despite increased interest in this emerging sector, the Federal Energy Regulatory Commission has only issued one license, awarded to Finerva Renewables’ Makah Bay wave pilot project in Washington State. So far this year, four preliminary licenses have been issued, including two to Pacific Gas & Electric Co. wave projects off the coast of California.

Last year, though approved by the U.S. House Science Committee, a marine renewable energy and development bill (H.R. 2313) that would have appropriated $250 million from 2008 to 2012 was seemingly abandoned before the House vote. And, echoing the fate of marine energy research and development projects born in the Carter and Reagan eras that lost their funding in the 1980s, the DOE’s Energy Efficiency and Renewable Energy 2009 budget for its Water Power Program proposes only $3 million—a 70% decrease from the $9.9 million Congress appropriated for 2008.

Marine energy’s future

If marine energy is to thrive, the monster hurdle that developers must overcome is the cost factor. Following an 18-month initiative, Carbon Trust found in a detailed study of the cost-competitiveness and potential growth of wave and tidal stream energy that marine energy will remain more expensive than other forms of generation until the sector sees the installation of hundreds of megawatts of capacity. Four routes may potentially reduce costs: concept design developments; detailed design optimizations; economies of scale; and lessons learned from production, construction, installation, operation, and maintenance.

Additionally, future growth of wave energy will be affected by a range of factors, among them: strategic and security-of-supply considerations, the availability of financing for technology and project development, technology and risks, electricity networks, and environmental and regulatory factors.