Benefits and Barriers
The ocean harbors abundant energy resources, and a variety of ocean energy technologies are nearing commercial application. However, the current state of wave, tidal, and ocean thermal energy is still very much in research and development.
Cost-Competitiveness
Accurate cost-performance data and projections for ocean energy technologies will be possible only after additional field-testing and real-world experience. Based on current knowledge, it appears that tidal current systems and onshore and nearshore wave energy systems may become cost-competitive in niche markets, such as in remote power or dual-use applications, within the next several years.
For broader use, the engineering challenges associated with constructing, operating, and maintaining energy systems in marine environments will need to be addressed. Examples include corrosion and fouling problems, access limitations, and storm potential. For systems installed in deepwater environments, significant technology gaps must be overcome in the areas of siting, underwater cabling, grid connection, and energy storage.
Applicability & Operations
Ocean energy resources are widely available, creating the potential for marine technologies to contribute to the state, national, and global electricity supply portfolios. However, siting constraints exist. Many sites with excellent resources are in locations that are highly visible or widely used for commercial or recreational purposes. High-energy offshore regions and other promising sites are far from load centers.
In serving loads, some ocean energy technologies offer distinct cost and reliability advantages. They supply power continuously, rather than intermittently like solar and wind generation. Examples include nearshore and offshore wave and OTEC systems, as well as tidal current installations in areas where units are always submerged.
Energy Security
Developing ocean energy resources will reduce dependence on fuels-including oil, coal, and natural gas-that must be imported to Massachusetts . It also will decrease U.S. reliance on foreign sources of fuel. Ocean energy is also not subject to fuel cost increases, positioning it as a potential hedge against price volatility.
Air & Water Emissions
Ocean energy technologies produce no emissions of harmful pollutants or greenhouse gases.
Habitat & Wildlife
The experience base with tidal, wave, and ocean thermal energy systems is extremely limited. As a result, overall effects on habitats and wildlife are not well understood. Two things are clear: These technologies will not emit any of the pollutants that can be extremely harmful to wildlife populations, and they will not contribute to climate change, which is already altering habitats worldwide.
Extensive field research and careful siting practices will be required to understand and mitigate any adverse impacts on ecological communities. Given current knowledge, the following generalizations are possible:
• Tidal/ocean current technologies, like in-stream hydro systems, are engineered to generate power without irrevocably altering natural water flows and habitats. Foundations and moorings may have localized effects on habitat-both positive and negative. Wildlife colliding with spinning turbines or other structures may be injured or killed.
• Tidal barrages are analogous to conventional hydro technologies. They can destroy or impair habitats, prevent or restrict the natural movement and migration of aquatic species, and injure or kill wildlife. Ladders, screens, and other fish passage and protection measures can be employed to lessen-but not eliminate-these adverse impacts.
• Wave energy technologies are being developed for shoreline, nearshore, and offshore environments, with systems ranging from the community to the utility scale. As a result, possible effects on habitat and wildlife could vary widely. Shoreline installations, for example, could completely transform habitat in localized areas, while other types of projects might create large-scale, reef-type environments with net benefits for wildlife.
• OTEC systems transport large amounts of deep ocean water to the surface. This raises the potential for wildlife to be drawn into intake pipes. Discharge points could create localized changes in water temperature and chemistry.
Public Perception
Public attitudes toward ocean energy technologies are unknown, but clean energy is generally perceived in a positive light because of its environmental and other benefits. Successful demonstration projects and careful siting practices will help ensure public acceptance of these emerging green energy options.
All new and unfamiliar technologies may initially be viewed with skepticism. In addition, concerns have been expressed over the potential impacts of shoreline and nearshore wave energy devices related to aesthetics as well as sediment transport and other physical processes. These and other technologies may also impact recreational and commercial activities.