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August 2011 Issue

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Models for Sound Science and Decision Making in Renewable Energy Projects
By Choong-Ki Kim

With high oil prices, nuclear meltdowns and the impact of climate change, it is becoming ever clearer that the harnessing of energy in a changing world is one of humankind’s greatest immediate challenges. Our economies cannot run without energy, but as we saw with the Deepwater Horizon blowout in the Gulf of Mexico and the Fukushima nuclear power plant meltdown in Japan, our appetite for conventional energy can result in loss of life and deal substantial damage to ecosystems and livelihoods.

Renewable ocean energy captured from waves, tides, offshore winds and currents has great potential to help solve our energy problems. Accordingly, decision makers and the public are increasingly interested in converting ocean energy resources into clean, safe, reliable and affordable energy. As a result, there is a need to understand where to place ocean renewable energy facilities wisely. A variety of key factors should be taken into consideration when siting renewable energy projects: energy resource potential, technology, economic feasibility and potential conflicts with other uses of our coastal and marine ecosystems.

Identifying energy-rich areas is the first step in siting renewable ocean energy facilities. These areas’ potential varies according to conditions of waves, winds, tides and currents. For example, the west coasts of North America (i.e., British Columbia, Oregon and California) and Europe (i.e., Ireland and Scotland) are often considered prime candidates for wave energy projects because of the match between the surrounding ocean’s high potential to generate energy and the high energy demands from coastal populations. Conversely, the U.S. East Coast has poor wave power potential due to its wide, shallow continental shelf, making it a more appropriate candidate for offshore wind energy projects.

The choice of technology is also site-specific and depends on environmental conditions. Many technologies have been developed for wave energy, including attenuators, point absorbers, terminators and overtopping devices. Attenuator-type devices (i.e., The Pelamis, developed by Pelamis Wave Power) work efficiently offshore Ireland and Scotland, where waves are big, while terminator-type devices (i.e., the oscillating water-column device from Oceanlinx) work effectively along the west coast of North America, where swell conditions dominate.

Additionally, it is necessary to weigh the benefits and costs associated with siting facilities in certain locations. The benefits could be the captured ocean energy’s economic value and the potential reduction in pollution. Costs include the facility’s installation, operation and maintenance, as well as the losses from different user groups who can no longer access particular coastal and marine locations due to the facility. Obtaining accurate economic data for a valuation is a significant challenge because we have limited experiences with these projects. As such, results from economic valuations should be interpreted with caution.

While renewable ocean energy is “clean,” facilities may conflict with existing ocean uses or conservation strategies for protecting marine species and habitats. Potential conflicts can stem from direct competition for space with commercial and recreational fisheries, impacts to pelagic and benthic habitat, reduced aesthetic quality for recreational activities, changes to the hydrodynamic environment and hazards to navigation. Because impacts are site-specific and poorly understood, identifying and evaluating such trade-offs is essential.

To help decision makers tackle challenges that arise when siting renewable ocean energy facilities, the Natural Capital Project has developed a GIS-based decision-support tool, the the Wave Energy Model (WEM).

WEM is a component of Integrated Valuation of Ecosystem Services and Trade-offs tools and designed for wave energy, but the framework is applicable to other types of renewable ocean energy resources. In using WEM on the west coast of Vancouver Island (WCVI), Canada, we discovered offshore wave conditions are favorable enough to support a grid-scale power producing system. Harvestable wave energy using currently available technologies gradually increases offshore as wave conditions intensify. However, areas of high economic potential are much closer to shore than the areas with greatest wave power potential and captured energy. Economic hot spots were located as close as a few kilometers from the underwater transmission cable landing points. These hot spots are likely areas of interest to decision makers for siting a facility.

Siting ocean energy facilities offshore the WCVI could influence the existing ocean uses and affect the socioeconomic conditions of coastal communities, which are supported by tourism and fishing. We found that areas with the highest economic potential overlap areas where existing fisheries and recreational activities take place. If we choose areas for siting wave energy facilities that do not have existing uses, there is a significant decrease in the economic potential.

However, decision makers can still get the maximum economic potential if they are willing to accept a trade-off and construct the wave energy conversion facilities in areas with a few fishing or recreation activities. The key motivation behind our approach is to ensure that extracting one benefit from the ocean—wave energy—does not unduly interfere with or harm the many other benefits of the coasts. As the pace of renewable energy projects quickens, approaches like the one outlined here can help decision makers understand the optimal placement of facilities by balancing the desire for the greatest economic potential while avoiding deleterious effects to our coasts and oceans.
Choong-Ki Kim, a Stanford University oceanographer, has worked extensively in numerical modeling studies, focusing on storm surge prediction, hydrodynamics, renewable ocean energy, oyster restoration and larval transport. Kim, a Ph.D. in marine science, is currently developing decision-support tools for the Natural Capital Project to value the services provided by coastal and marine ecosystems.


2012:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC
2011:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC

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