| Coastal A-Z [return to Table of Contents] Alternative Ocean Energy Introduction and Background Numerous studies have established that our reliance on fossil fuels (coal, oil, natural gas, gasoline) is a polluting and non-sustainable practice that has serious long-term repercussions (rising sea levels, acidification of the oceans, stronger and more frequent storms) for the earth (see Surfrider Foundation’s article on global warming1 for more details). These changes are likely to be felt most strongly along our coasts. Breaking our reliance on fossil fuels will require development of a number of alternative sources of energy that are renewable and non-polluting. The term "alternative energy" is typically used to describe sustainable means of generating electrical power that do not involve burning fossil fuels. Some people include nuclear power in the alternative energy category, but for this discussion we have excluded nuclear power due to environmental issues associated with the extraction and processing of uranium for fuel and disposal of spent fuel rods. Alternative energy sources include solar, wind, waves, tides and geothermal energy. There are even proposals to utilize ocean currents such as the Gulf Stream or utilize the temperature differential between warm surface waters and colder waters deeper in the ocean to produce energy. Research into these areas has been going on for decades. For over 30 years, the Natural Energy Laboratory of Hawaii2 has been conducting research on the ocean thermal energy conversion (OTEC) process and its related technologies. For this paper we’ll confine our discussion to offshore utilization of wind, waves and tides to produce energy. These types of technologies are generally supported by environmentalists and environmental groups because they are sustainable (they don’t rely on a finite fuel source) and non-polluting. Because they don’t involve burning fossil fuels, they don’t generate carbon dioxide emissions and therefore don’t contribute to global warming. Many marine-based renewable energy technologies are at relatively early stages of development, so there is little in the way of demonstrated effectiveness, cost, or environmental effects of large-scale ocean-based systems. Despite the seemingly benign nature of wind, wave and tide-powered energy projects, some proposed offshore alternative energy projects have encountered opposition from local environmentalists, or at least concern about potential coastal/environmental impacts. In most cases these potential impacts are site specific, so a thorough understanding of the technologies and how the technologies might be adapted to a particular site is important. Provided below is a brief description of each of these technologies and a summary of environmental considerations (positive and negative) that have been raised regarding their implementation. We hope that this information will aid local environmental activists in their decisions and actions regarding proposed projects. Wind Most modern wind power is generated in the form of electricity by converting the rotation of turbine3 blades into electrical current by means of an electrical generator. A wind turbine can be thought of as an electric fan running in reverse. Wind power is used in large scale wind farms4 for national electrical grids as well as in small individual turbines for providing electricity in isolated locations. Wind energy is abundant, inexhaustible, widely distributed, clean, and mitigates5 the greenhouse effect6. Wind turbines are usually mounted on long vertical support structures extending up to a few hundred feet above sea or ground surface. The wind turbines are usually installed in a line or an array or a "wind farm" situated to catch prevailing strong wings. Offshore wind turbines are considered to be less unsightly than onshore installations since they can be invisible from shore. Because there are fewer obstacles and stronger winds, such turbines don’t need to be built as high into the air. However, offshore conditions are harsh, abrasive, and corrosive, and it is more difficult to maintain a turbine in open marine waters than on land. In areas with extended shallow continental shelves and sand banks (such as Denmark), turbines are reasonably easy to install, and give good service. The largest offshore wind turbines in the world are seven 3.6 MW rated machines off the east coast of Ireland about sixty kilometers south of Dublin. The turbines are located on a sandbank approximately ten kilometers from the coast that has the potential for the installation of 500 MW of generation capacity. As of 2006, the largest offshore wind farm was the Nysted Offshore Wind Farm7 at Rødsand, located about ten kilometers south of Nysted and thirteen kilometers west of Gedser, Denmark. The wind farm consists of seventy-two turbines of 2.3 MW, which produces 165.6 MW of power at rated wind speed. Three offshore wind farms in the United Kingdom8 are currently operating, North Hoyle (30 x 2MW), Scroby Sand (30 x 2MW) and Kentish flat (30 x 3MW). Another offshore wind farm, Barrow (30 x 30MW), is under construction. Under the energy policy of the United Kingdom9 further offshore facilities are feasible and expected by the year 2010.
Environmental Considerations13 Potential environmental concerns include impacts to views/aesthetics, noise, bird kills, interruption of shipping/boating routes, and blocking or diminishing the size of waves eventually reaching the coast. Potential positive or negative impacts on the environment that may occur during operations are highlighted below.
Perceptions that wind turbines are noisy and contribute to "visual pollution" creates resistance to the establishment of land-based wind farms in some places. Moving the turbines offshore mitigates the problem somewhat, but offshore wind farms are more expensive to maintain and there is an increase in transmission loss due to longer distances of power lines. One solution to such objections is the early and close involvement of the local population, as recommended in the sustainability guidelines of the World Wind Energy Association - in the ideal case through community/citizen ownership of wind farms. Regarding impacts to waves, an environmental analysis of the proposed Scarweather Sands Offshore Wind Farm14 project in the UK indicated that there would be minimal (generally 0.1% to about 4%) reduction in wave heights along the area of coast in the "wave shadow" of the wind farm project (Environmental Statement prepared by United Utilities, January 2003). Siting Constraints In selecting OCS wind facility locations, developers will need to consider how candidate areas are already used to avoid potential conflicts. In addition to minimizing the types of potential environmental impacts identified above, potential siting issues that need to be considered include the following:
Waves and Tides In comparison to wind power, wave and tidal power technologies are in their infancy. Wave-power or tidal-power generators are currently being tested near the shores of New Jersey, Hawaii, Scotland, England and Western Australia. A long-awaited tidal turbine project in the East River in New York is scheduled to start in fall 2006. A handful of commercial projects are also in the works, including the world’s first "wave farm," being installed off the north coast of Portugal. A field of tidal turbines is also being built off the shore of Tromso, Norway. In Massachusetts, Representative William D. Delahunt has proposed that the United States follow in Britain’s footsteps to build an ocean energy research center off the Massachusetts coast. TRC Environmental Corporation recently prepared a report Existing and Potential Ocean-Based Energy Facilities and Associated Infrastructure in Massachusetts15. In Oregon, researchers in the College of Engineering at Oregon State University are developing technology that taps the motion of the ocean as a source of clean energy. Annette von Jouanne and Alan Wallace, OSU professors of electrical engineering, are designing, testing, and implementing a buoy prototype energy extraction system that would be anchored offshore in an energy wave park. Research shows that the Oregon coast near Reedsport is one of the best locations in the U.S. for such a park. The wave energy researchers utilize OSU facilities, which include the Motor Systems Resource Facility; the Energy Resources Research Laboratory, where researchers are developing turbine models; and the O. H. Hinsdale Wave Research Laboratory, home to the world's largest tsunami wave. In Florida, Florida Atlantic University (FAU) has been selected by the Florida Technology, Research and Scholarship Board to receive $5 million to establish The Florida Center of Excellence in Ocean Energy Technology. The Center will look at South Florida's ocean currents, specifically the Gulf Stream, as a potentially abundant renewable energy source. Waves The total power of waves breaking on the world's coastlines is estimated at 2 to 3 million megawatts. In favorable locations, wave energy density can average 65 megawatts per mile of coastline. Wave power projects generally utilize the up-and-down motion of a device floating in the ocean encountering ocean swells to generate electricity. Three general approaches to capturing wave energy16 are: Floats or Pitching Devices17 These devices generate electricity from the bobbing or pitching action of a floating object. The object can be mounted to a floating raft or to a device fixed on the ocean floor. Oscillating Water Columns (OWC)18 These devices generate electricity from the wave-driven rise and fall of water in a cylindrical shaft. The rising and falling water column drives air into and out of the top of the shaft, powering an air-driven turbine. Wave Surge or Focusing Devices19 These shoreline devices, also called "tapered channel" or "tapchan" systems, rely on a shore-mounted structure to channel and concentrate the waves, driving them into an elevated reservoir. Water flow out of this reservoir is used to generate electricity, using standard hydropower technologies. Much of the early work on this technology was done by Dr. Stephen Salter, who developed a test device known as "Salter’s Duck."20 Wave power technologies can also be divided into four classes—attenuators, terminators, point absorbers and overtopping devices. Each of these classes of devices are described below, with some specific examples of pilot or commercial application cited. Attenuators Attenuators are long multi-segment floating structures oriented parallel to the direction of the wave travel. The differing heights of waves along the length of the device causes flexing where the segments connect, and this flexing is connected to hydraulic pumps or other converters. The attenuators with the most advanced development are the McCabe wave pump and the Pelamis by Ocean Power Delivery, Ltd.21 (2006). The McCabe wave pump22 has three pontoons linearly hinged together and pointed parallel to the wave direction. The center pontoon is attached to a submerged damper plate, which causes it to remain still relative to fore and aft pontoons. Hydraulic pumps attached between the center and end pontoons are activated as the waves force the end pontoons up and down. The pressurized hydraulic fluid can be used to drive a motor generator. A full-size 40-m prototype was tested off the coast of Ireland in 1996, and commercial devices are being offered by the manufacturer. A similar concept is used by the Pelamis23, which has four 30m-long by 3.5m-diameter floating cylindrical pontoons connected by three hinged joints. Flexing at the hinged joints due to wave action drives hydraulic pumps built into the joints. A full-scale, four-segment production prototype rated at 750 kW was sea tested for 1,000 hours in 2004. This successful demonstration was followed by the first order in 2005 of a commercial Wave Energy Conversion (WEC) system from a consortium led by the Portuguese power company Enersis SA. The first stage, scheduled to be completed in 2006, consists of three Pelamis machines with a combined rating of 2.25 MW to be sited about 5 km off the coast of northern Portugal. An expansion to more than 20-MW capacity is being considered. A Pelamis-powered 22.5-W wave energy facility is also planned for Scotland, with the first phase targeted for 2006.  The EPRI wave energy feasibility demonstration project has selected the Pelamis as one of the technologies for design, performance, cost, and economic assessment (Bedard et al. 2005). Sites for evaluation were selected off the coasts of Hawaii (15.2 kW/m average annual wave energy), Oregon (21.2 kW/m), California (11.2 kW/m), Massachusetts (13.8 kW/m), and Maine (4.9 kW/m). For systems at these sites scaled to a commercial level generating 300,000 MWh/yr, the cost of electricity ranged from about $0.10/kWh for the areas with high wave energy, to about $0.40/kWh for Maine, which has relatively lower levels of wave energy.
Terminators (no, this has nothing to do with the Governor of California) Terminator devices extend perpendicular to the direction of wave travel and capture or reflect the power of the wave. These devices are typically installed onshore or nearshore; however, floating versions have been designed for offshore applications. The oscillating water column (OWC) is a form of terminator in which water enters through a subsurface opening into a chamber with air trapped above it. The wave action causes the captured water column to move up and down like a piston to force the air though an opening connected to a turbine. A full-scale, 500-kW, prototype OWC designed and built by Energetech24 (2006) is undergoing testing offshore at Port Kembla25 in Australia, and a further project is under development for Rhode Island26. The proposed project off Point Judith in Rhode Island ran into an economic glitch in October 2006 when it was learned that the Federal Energy Regulatory Agency (FERC) has a rule to force the company to pay existing power plants to compensate them for the electricity that they didn’t sell because of the free energy the Energetech would provide to customers during their pilot demonstration project.  In an Electric Power Research Institute (EPRI)-cosponsored study (Bedard et al. 2005), a design, performance, and cost assessment was conducted for an Energetech commercial-scale OWC with a 1,000-kW rated capacity, sited 22 km from the California shore. With the wave conditions at this site (20 kW/m average annual), the estimated annual energy produced was 1,973 MWh/yr. For a scaled-up commercial system with multiple units producing 300,000 MWh/yr, the estimated cost of electricity would be on the order of $0.10/kWh.
Another floating OWC is the "Mighty Whale"27 offshore floating prototype, which has been under development at the Japan Marine Science and Technology Center since 1987 (JAMSTC 2006). Point Absorbers Point absorbers have a small horizontal dimension compared with the vertical dimension and utilize the rise and fall of the wave height at a single point for WEC. One such device is the PowerBuoy™28 developed by Ocean Power Technologies (OPT). The construction involves a floating structure with one component relatively immobile, and a second component with movement driven by wave motion (a floating buoy inside a fixed cylinder). The relative motion is used to drive electromechanical or hydraulic energy converters. A PowerBuoy demonstration unit rated at 40 kW was installed in 2005 for testing offshore from Atlantic City, New Jersey29. OPT has also filed (July 2006) an application to the U.S. Federal Energy Regulatory Commission (FERC) for construction permission for a 50-megawatt (MW) wave power generation project in Reedsport, Oregon. This is the first request in the United States for such a power project on a utility-scale level. The company expects to install its ocean-tested PowerBuoy wave energy devices approximately 2.5 miles off the coast at a depth of 50 meters. The buoys proposed for the coast of Oregon would extend about 15 feet above the water - and the wave park eventually would have four rows of 50 buoys for a total of 200. The park would take up 1.5 square miles of ocean - 1/2 mile wide by 3 miles long. The buoys could generate enough electricity to power about 2,000 homes Initially the project is projected to generate a total of 2 MW, but approval for the full-scale project will generate 50 MW from the wave power plant. The company has already consulted key stakeholder groups about its plans and will continue to work closely with these groups over the initial stages of the project. Gov. Ted Kulongoski supports the project. He has organized an Oregon Solutions team to help streamline the process. Port of Umpqua Commissioner Keith Tymchuk and state Sen. Joanne Verger, D-Coos Bay, co-chair the group. According to the company, a key strength of the PowerBuoy system is its compact nature and low visual impact. OPT's wave energy converter consists of a vertically oriented column or cylinder that absorbs the rising and falling motion of ocean waves to cause the buoy mechanics to move freely up and down. This movement in turn drives an electric generator that creates usable on-site power or power that can be cabled away to a nearby mainland location. OPT's PowerBuoy technology was cited in recent U.S. Congressional hearings in support of increasing funding for ocean energy demonstration programs. U.S. Representative Jay Inslee (D-WA) proposed an amendment to the Deep Ocean Energy Resources (DOER) Act, which would increase the funding for ocean energy demonstration programs such as this one from $6 million to $20 million per year. Testing in the Pacific Ocean is also being conducted, with a unit installed in 2004 and 2005 off the coast of the Marine Corps Base in Oahu, Hawaii 30. A commercial-scale PowerBuoy system is planned for the northern coast of Spain, with an initial wave park (multiple units) at a 1.25-MW rating. Initial operation is expected in 2007. The AquaBuOY™ WEC being developed by the AquaEnergy Group, Ltd. 31 (2005) is a point absorber that is the third generation of two Swedish designs that utilize the wave energy to pressurize a fluid that is then used to drive a turbine generator. The vertical movement of the buoy drives a broad, neutrally buoyant disk acting as a water piston contained in a long tube beneath the buoy. The water piston motion in turn elongates and relaxes a hose containing seawater, and the change in hose volume acts as a pump to pressurize the seawater. The AquaBuOY design has been tested using a full-scale prototype, and a 1-MW pilot offshore demonstration power plant is being developed offshore at Makah Bay, Washington32. The Makah Bay demonstration will include four units rated at 250 kW placed 5.9 km (3.2 nautical miles) offshore in water approximately 46 m deep. Other point absorbers that have been tested at prototype scale include the Archimedes Wave Swing33 (2006), which consists of an air-filled cylinder that moves up and down as waves pass over. This motion relative to a second cylinder fixed to the ocean floor is used to drive a linear electrical generator. A 2-MW capacity device has been tested offshore of Portugal. Overtopping Devices Overtopping devices have reservoirs that are filled by impinging waves to levels above the average surrounding ocean. The released reservoir water is used to drive hydro turbines or other conversion devices. Overtopping devices have been designed and tested for both onshore and floating offshore applications. The offshore devices include the Wave Dragon™34 (Wave Dragon 2005), whose design includes wave reflectors that concentrate the waves toward it and thus raises the effective wave height. Wave Dragon development includes a 7-MW demonstration project off the coast of Wales35 and a pre-commercial prototype project performing long-term and real sea tests on hydraulic behavior, turbine strategy, and power production to the grid in Denmark. The Wave Dragon design has been scaled to large sizes, with a span of more than 200 m across the reflector arms and a capacity of approximately 24 MW. The WavePlane™36 (WavePlane Production 2006) overtopping device has a smaller reservoir. The waves are fed directly into a chamber that funnels the water to a turbine or other conversion device. Basic research to develop improved designs of WEC devices is being conducted in regions such as near the Oregon coast, which is a high wave energy resource (Rhinefrank 2005). The Wave Hub37 project (technology not yet specified) is being proposed for the north coast of Cornwall, England. Environmental Considerations38 Conversion of wave energy to electrical or other usable forms of energy is generally anticipated to have limited environmental impacts. However, as with any emerging technology, the nature and extent of environmental considerations remain uncertain. The impacts that would potentially occur are also very site specific, depending on physical and ecological factors that vary considerably for potential ocean sites. As large-scale prototypes and commercial facilities are developed, these factors can be expected to be more precisely defined. Potential environmental impacts include withdrawal of wave energy from the ecological system, interactions with marine life, noise, bottom impacts from anchors, and visual appearances. Environmental impacts from cable landings may be a concern, as are electrical and magnetic energy imparted into seawater. A wave energy facility could also pose a threat to navigation. The following environmental considerations require monitoring: Visual appearance and noise are device-specific, with considerable variability in visible freeboard height and noise generation above and below the water surface. Devices with OWC and overtopping devices typically have the highest freeboard and are most visible. Offshore devices would require navigation hazard warning devices such as lights, sound signals, radar reflectors, and contrasting day marker painting. However, Coast Guard requirements only require that day markers be visible for 1 nautical mile (1.8 km), and thus offshore device markings would only be seen from shore on exceptionally clear days. The air being drawn in and expelled in OWC devices is likely to be the largest source of above-water noise. Some underwater noise would occur from devices with turbines, hydraulic pumps, and other moving parts. The frequency of the noise may also be a consideration in evaluating noise impacts. Reduction in wave height from wave energy converters could be a consideration in some settings; however, the impact on wave characteristics would generally only be observed 1 to 2 km away from the WEC device in the direction of the wave travel. Thus there should not be a significant onshore impact if the devices were much more than this distance from the shore. None of the devices currently being developed would harvest a large portion of the wave energy, which would leave a relatively calm surface behind the devices. It is estimated that with current projections, a large wave energy facility with a maximum density of devices would cause the reduction in waves to be on the order of 10 to 15%, and this impact would rapidly dissipate within a few kilometers, but leave a slight lessening of waves in the overall vicinity. Little information is available on the impact on sediment transport or on biological communities from a reduction in wave height offshore. An isolated impact, such as reduced wave height for recreational surfers, could possibly result. An environmental analysis conducted for the Wave Hub39 project mentioned above indicates a worst case scenario of up to a 13% reduction in wave height along a small section of the north coast, with more likely scenarios showing up to a 5% reduction in wave height. The U.K. organization Surfers Against Sewage40 (SAS) have looked into the Wave Hub project and have issued the following statement: "Since being asked to provide input into the project almost 3 years ago, SAS have pushed heavily to get the impact the Wave Hub will have on the surf investigated. The first of these, an independent peer reviewed study conducted by the University of Exeter is now in the public domain. SAS have been acknowledged by the Authors of this paper for their input. The research concludes that a realistic scenario for the wave hub would produce an average change in significant wave height at the shoreline of 1 cm or less. SAS believes that any slight reduction in wave height will be unnoticeable by surfers. This view is backed by the peer reviewed paper which states:Marine habitat could be impacted positively or negatively depending on the nature of additional submerged surfaces, above-water platforms, and changes in the seafloor. Artificial above-water surfaces could provide habitat for seals and sea lions or nesting areas for birds. Underwater surfaces of WEC devices would provide substrates for various biological systems, which could be a positive or negative complement to existing natural habitats. With some WEC devices, it may be necessary to control the growth of marine organisms on some surfaces."There is little cause for concern that effects introduced by the Wave Hub will be felt by shoreline users of the sea."This, along with worst case scenario modeling carried by Halcrow, suggests the impact of the Wave Hub will be minimal. More info41. Toxic releases may be of concern related to leaks or accidental spills of liquids used in systems with working hydraulic fluids. Any impacts could be minimized through the selection of nontoxic fluids and careful monitoring, with adequate spill response plans and secondary containment design features. Use of biocides to control growth of marine organisms may also be a source of toxic releases. Conflict with other sea space users, such as commercial shipping and fishing and recreational boating, can occur without the careful selection of sites for WEC devices. The impact can potentially be positive for recreational and commercial fisheries if the devices provide for additional biological habitats. - - - More information on wave energy can be found at Surfrider Foundation's Wave Energy blog. Tides Tidal power42 is a means of electricity generation achieved by capturing the energy contained in moving water mass due to tides43. Two types of tidal energy can be extracted: kinetic energy of currents between ebbing and surging tides and potential energy from the difference in height (or head) between high and low tides. The former method - generating energy from tidal currents - is considered much more feasible today than building ocean-based dams or "barrages," and many coastal sites worldwide are being examined for their suitability to produce tidal (current) energy. The extraction of potential energy involves building a barrage and creating a tidal lagoon. Barrages are used to close off a basin for trapping a water level inside them. The basic elements of a barrage are caissons, embankments, sluices, turbines and ship locks. Sluices, turbines and ship locks are housed in caisson (very large concrete blocks). Embankments seal a basin where it is not sealed by caissons. The barrage traps a water level inside a basin. Head is created when the water level outside of the basin or lagoon changes relative to the water level inside. The head is used to drive turbines. In any design this leads to a decrease of tidal range inside the basin or lagoon, implying a reduced transfer of water between the basin and the sea. This reduced transfer of water accounts for the energy produced by the scheme. The Federal Energy Regulatory Commission (FERC) has given the go-ahead to a feasibility study for a kinetic energy tidal power project on Little Machias Bay44 in Maine by Tidewater Associates. Other companies interested in exploring tidal energy projects in this area include Verdant Power LLC45 and Maine Tidal Energy Co., based in Washington D.C. Verdant Power has been trying for years to erect a small field of tidal turbines in New York’s East River. The project, with a $1.5 million underwater sonar system to continuously monitor for fish around the turbines, may get started in fall 2006. Maine Tidal Energy is owned by Oceana Energy Corp. Oceana is pursuing potential tidal energy projects at eight sites along the coasts of the United States, including the "The Chops" section Kennebec River46 in Maine, Vineyard Sound47 off Martha’s Vineyard in Massachusetts and in San Francisco Bay, California. The project in the Kennebec River has already brought opposition from several groups, including the Friends of Merrymeeting Bay, who are concerned that rotating blades in the submerged tidal energy system could injure, kill or block passage of species such as the short-nosed sturgeon, seals and eels (see below). Nationwide, at least 22 tidal energy projects are under review by FERC. Over the past two years, the agency has issued preliminary permits for 11 projects in Florida, New York, California, and Washington. This year (2006), it received 11 more applications for projects in the Northeast, Pacific Northwest, and Alaska. Environmental considerations48 Tidal power projects, since they are typically built right on the coast, can potentially have significant impacts on the coast and on coastal resources. The placement of a barrage into an estuary has a considerable effect on the water inside the basin and on the fish. Lagoons, on the other hand, could be used for fish or lobster farming, adding to their economic viability. Turbidity (the amount of matter in suspension in the water or how cloudy the water is) decreases as a result of smaller volume of water being exchanged between the basin and the sea. This lets light from the Sun to penetrate the water further, improving conditions for the phytoplankton. The changes propagate up the food chain, causing a general change in the ecosystem. As a result of less water exchange with the sea, the average salinity inside the basin decreases, also affecting the ecosystem. Again, lagoons do not suffer from this problem. Estuaries often have high volume of sediments moving through them, from the rivers to the sea. The introduction of a barrage into an estuary may result in sediment accumulation within the barrage, affecting the ecosystem and also the operation of the barrage. Once again, as a result of reduced volume, the pollutants accumulating in the basin will be less efficiently dispersed. Their concentrations will increase. For biodegradable49 pollutants, such as sewage, an increase in concentration is likely to lead to increased bacteria growth in the basin, having impacts on the health of the human community and the ecosystem. The concentrations of conservative pollutants will also increase. Fish may move through sluices safely, but when these are closed, fish will seek out turbines and attempt to swim through them. Also, some fish will be unable to escape the water speed near a turbine and will be sucked through. Even with the most fish-friendly turbine design, fish mortality per pass is approximately 15% (from pressure drop, contact with blades, cavitation, etc.). This can be acceptable for a spawning run, but is devastating for local fish passing in and out of the basin on a daily basis. Alternative passage technologies (fish ladders, fish lifts, etc.) have so far failed to solve this problem for tidal barrages, either offering extremely expensive solutions, or ones which are used by a small fraction of fish only. Research in sonic guidance of fish is ongoing. There have been proposals to combine tidal and wind power and install tidal stream turbines on the bases of offshore wind turbines. The hybridization of wind and wave energy could enhance cost competitiveness with onshore wind facilities because of synergies that include single permitting; shared foundation/mooring infrastructure; shared deployment and operation maintenance with common facilities, equipment, and personnel; and higher capacity. However, marine-based renewable energy technologies are all at relatively earlier stages of development than offshore wind, so such amalgamated facilities are not imminent. Conclusions There appear to be several potentially viable ocean-based alternative energy technologies that do not rely on petroleum products and directly produce no air, water or solid waste emissions. In spite of these positive environmental considerations, each of the aforementioned technologies (wind, waves, tides) may have site-specific environmental considerations that should be thoroughly evaluated before a full-scale system is constructed. Most of these technologies, particularly those based on generating electric power from waves or tides, are in the early stages of commercial development and will likely go through the small demonstration project phase before any large-scale facilities are constructed. Additional References: Surfrider Foundation Wave Energy Blog NY Times, "Energy From the Restless Sea; A Renewable Source, and Clean, But Not Without Its Critics", August 3, 2006 OCS Renewable Energy Programmatic EIS Oregon Renewable Energy Oregon State University wave energy research Oregon Sea Grant wave power videos Wikipedia information on Alternative Energy FOOTNOTES 1 Surfrider Foundation Global Warming article 2 Natural Energy Laboratory of Hawaii Authority 3 Wikipedia information on wind turbines 4 Wikipedia information on wind farms 5 Wikipedia information on mitigation of global warming 6 Wikipedia information on the greenhouse effect 7 Nysted Wind Farm 8 Wikipedia information on Wind power in the United Kingdom 9 Wikipedia information on energy policy of the United Kingdom 10 Cape Wind Associates LLC 11 Long Island Power Authority 12 Renewable Energy Access 13 Minerals Management Service, Renewable Energy and Alternate Use Program, U.S. Department of the Interior. Technology White Paper on Wind Energy Potential on the U.S. Outer Continental Shelf 14 Friends of the Earth 15 TRC Environmental Corporation report for Massachusetts Office of Coastal Zone Management 16 Wave energy info from U.S. Department of Energy 17 Ibid 18 Ibid 19 Ibid 20 AAAS Atlas of Population and Environment 21 Ocean Power Delivery Ltd. 22 Pulse of the Planet 23 The Coordinated Action on Ocean Energy Project 24 Energetech 25 Ibid. 26 Ibid. 27 Japan Agency for Marine-Earth Science and Technology 28 Ocean Power Technologies 29 Ibid 30 Ibid 31 Aqua Energy Group Ltd. 32 Ibid. 33 AWS Ocean Energy 34 Wave Dragon 35 Ibid. 36 Wave Plane Production 37 South West of England Regional Development Authority 38 Minerals Management Service, Renewable Energy and Alternate Use Program, U.S. Department of the Interior. Technology White Paper on Wave Energy Potential on the U.S. Outer Continental Shelf 39 Ibid. 40 Surfers Against Sewage 41 Ibid. 42 Tidal Power News 43 Wikipedia information on Tides 44 Federal Register 45 Verdant Power LLC 46 MaineToday.com 47 Capecodonline.com 48 Minerals Management Service, OCS Alternative Energy Programmatic EIS Documents. 49 Wikipedia information on biodegradation |
