Power From the Oceans
Wind energy industries are growing, and as we look for alternative power sources, the growth potential is through the roof. Two industry watchers take a look at generating energy from wind and wave action and the potential to alter the energy landscape.
Underwater turbines generate electrical power from the energy of water flowing by. Turbines like this one can generate 500-1,000 kilowatts of power, depending on water flow patterns and velocity. Several arranged in farms at places with high currents can supply power to thousands of homes.
The prospects for ocean-based renewable energy development look brighter all the time. Current and potential markets for offshore wind, wave energy, and tidal power are all expected to show considerable growth over the next five years.
Offshore wind systems use turbines to generate electricity. Wave systems use floating rafts or devices fixed to the ocean floor and harness the energy generated from bobbing or pitching. Other wave- energy approaches include devices that use the rise and fall of water in a cylindrical shaft to generate electricity and shoreline devices that channel waves into reservoirs to concentrate wave power.
Tidal-energy power traditionally involves erecting a dam across the opening to a tidal basin. The dam includes a sluice that is opened to allow the tide to flow into the basin. The sluice is then closed, and as the sea level drops, traditional hydropower technologies can be used to generate electricity from the elevated water in the basin.
An analysis of the potential market for offshore renewables shows a growing industry promising to supply energy for millions of people. For the entire sector, we project 5,800 megawatts (MW) of installed capacity between 2004 and 2008, of which 99% will be in the form of offshore wind farms. Because the wave and tidal-energy industries are younger and less well developed, it will take until at least 2010 for these industries to take off. During that period, we expect to see the value of the market increase by nearly $3 billion a year. Again, most of that will occur through offshore wind projects.
Currently, Europe is the only region in the world with any operational offshore wind capacity; it is expected to have 88% of the new capacity over the coming five years. European countries increased capacity more than fivefold in 2003 alone, with Germany and the United Kingdom leading the way. These countries will account for 66% of projected capital expenditures between 2004 and 2008, with Germany, buoyed by many large and expensive deepwater projects, dominating the market.
As technology improves, Europe can expect to achieve large strides in capacity using proportionally fewer turbines. Long-term signals are good for the U.K. market. Despite a very promising future forecast, an air of uncertainty hangs over Germany, which is dependent on large, technologically challenging projects. In Denmark, where a lack of government commitment is deterring potential developers and investors, only one project is scheduled for installation by 2008.
The North American market lags approximately five years behind Europe, but it is expected to increase capacity and become prominent in the market after 2007. Offshore wind has a potentially large market in North America, but it could easily fail before it gets a chance to take off. Success of early projects, particularly in the United States, is critically important in the face of uncertain planning regulations for offshore wind. In Canada, there are fewer immediate projects, but the long-term view is more positive. If the flagship Nai Kun project off Prince Rupert in British Columbia is successful, then it could be the first of many such wind farms.
The United States has considerable offshore wind potential, but regulation remains a source of concern. Cape Wind Associates' controversial project off the coast of Massachusetts is considered critical to the future of offshore wind in the United States. Its success or failure is likely to set a precedent for future developments in the country. If regulators approve this wind farm, new and existing players are likely to take advantage of the potential and generate many proposals for new projects. On the other hand, if regulators reject the project, and effectively cancel it, the consequences could be dire for the entire U.S. industry.
The United States has other significant projects in the planning stages, many of which are speculative and not expected to arise until the end of the decade. Ultimately, however, the U.S. government will determine the rate of progress for these projects. Structured and targeted development plans could boost offshore-wind developments, but the current U.S. planning system is too fragmented to support large-scale expansion.
For the offshore wind industry to grow, the United States needs to establish a comprehensive offshore management system with clear procedures, because at present there is no set precedent for applications. The success or failure of projects such as Cape Wind will dictate the terms by which future projects will be judged.
A number of successful wave-energy devices have been installed at shoreline locations, but the true potential of wave energy will only be realized offshore where large developments are conceivable. At present, nearly 300 concepts for wave-energy devices have been proposed, but because of the difficulty of developing an efficient, reliable, and cost-effective wave-energy converter, fewer than 10 are likely to meet commercial demands by the end of the decade.
Commercial wave energy will grow on the back of modular offshore wave-energy devices that can be deployed quickly and cost- effectively in a wide range of conditions. In the coming decade, we anticipate that wave energy will become commercially successful. Opportunities for expansion of the offshore market are expected to increase in part because the growth of shoreline wave-energy devices will be increasingly limited by the low number of available sites and by high installation costs.
Although offshore locations offer greater power potential than shoreline locations, offshore devices are more difficult to access for maintenance purposes. Improving the reliability and accessibility will be critical to the commercial success of the many devices currently under development. Furthermore, more wave-energy projects will need to be connected to a power grid.
Wave energy will, however, continue to be relevant, accounting for approximately 25% of capacity forecast over the next five years. Indeed, it is the most promising sector into the long-term future.
Although several wave-energy devices are getting closer to full- scale deployments, real-world operation remains limited. Large- scale demonstrations are required in order to test survivability and efficiency issues. Though it is difficult to assess potential of a system until it is tested in its final state, some industry leaders have implemented programs slowly building up to commercial-scale deployments. Realistically, only a tiny proportion of wave-energy concepts will move on to a commercial level. Limited resources, in many cases, hamper the launch of technology, as the sector is dominated by small and medium enterprises unwilling to collaborate because they wish to protect their investments. Needed collaboration and cohesion could be aided if regional and national organizations, such as the British Wind Energy Association, were to take a more active role.
The United Kingdom is expected to be the dominant player over the next five years, with a forecast capacity of about half the market share, thanks in large part to financial support from government grants. The result is a number of advanced wave technologies with good prospects for deployment. Coupled with a worldclass natural resource, the United Kingdom could be the undisputed world leader in wave energy by 2008. The U.S. market shows encouraging levels of interest in wave technology; however, the market will be affected by the lack of positive government involvement.
Overall, wave energy will see a total expenditure of $111 million through 2008, with the total U.K. expenditure ($72 million) expected to be more than all other countries combined.
Capturing the Force of Tides
Historically, tidal projects have used large-scale barrage systems to block estuaries. Within the last few decades, developers have shifted toward technologies that capture tidally driven coastal currents (the tidal stream). Very large amounts of energy are available in coastal waters. The challenge is "to develop technology and innovate in a way that will allow this form of low-density renewable energy to become practical and economic," according to Tony Trapp, managing director of The Engineering Bureau Ltd.
Right: The 750-ton Pelamis Wave Energy Converter is the world's first commercial machine that can harness the energy from ocean waves to produce electricity. Here it is being towed to its launch off the coast of Scotland.
Below: These turbines will be used to produce renewable energy from tides. This unit will rest on the seabed at a depth of some 60 meters, where it will reap the full benefit of tidal flow while avoiding potential damage from storms and violent surface waves.
At present, smaller units that can be deployed individually or in multiple units characterize tidal-current-stream technologies. Two types of technologies are in operation or are planned: tidal- current turbines and tidal-stream generators. Tidalcurrent turbines are basically underwater windmills where currents rotate underwater turbines, ideally within a kilometer offshore in depths of up to 30 meters. First proposed during the 1970s oil crisis, the technology has only recently become a reality. One company, Marine Current Turbine (U.K.), installed the first full-scale prototype turbine off Lynmouth in Devon in 2003. Shortly thereafter, the Norwegian company Hammerfest Str0m installed their first prototype device.
Tidal-stream generators use the tidal stream to generate power from, for example, the raising and lowering of a hydraulic arm. Several very promising devices are at an advanced stage of development. For example, The Engineering Bureau has developed and tested a simple concept of placing hydrofoils in the tidal stream to produce an oscillatory motion in the vertical or horizontal plane. The device, known as the Stingray Tidal Current Generator, "transforms the kinetic energy of the moving water into hydraulic power, which turns a generator by means of a hydraulic motor," Trapp explains.
We anticipate that multi-megawatt farms will emerge by the end of the decade. By 2008, a total of 14.8 MW capacity is expected, with 65% of the capacity in the United Kingdom. Norway, which already has installed capacity, will be the second dominant player, but lacks defined projects over the next five years. Other countries (Canada, France, and the United States) will play only minor roles. We anticipate almost 70% of forecast capacity by 2008 from tidal- current turbines and approximately 30% from tidal-stream generators.
Capital expenditures for tidal energy will reach $35 million by 2008, with the United Kingdom as the biggest market ($23 million) and Norway second ($10 million).
The Future of Ocean-Based Power
While success in 2003-2004 has been high, much of the promised capacity has failed to materialize because of problems across the board. However, a number of countries have made significant progress in the sector, most visibly the United Kingdom, which now has more approved offshore wind capacity than any other country and leads the world in planned wave and tidal-current-stream capacity.
Wave and tidal energy will grow in importance during the next five years, but they are overshadowed by the massive offshore wind sector. Progress in wave and tidal energy has been extremely encouraging over the last year, and in the near future a number of further key developments are set to take place. Within the five- year period ahead, we will see a number of technologies reach commercial application and be installed in multiple-unit configurations. In this respect, these developing industries can be seen as being at a stage similar to offshore wind a little more than a decade ago. With time and sufficient encouragement, sizable wave and tidal farms could be in place by the next decade.
It is becoming clear which countries are paving the way for an increased offshore renewables energy share, by creating the necessary market conditions and supporting projects from their outset through to realization. Commitment to renewables, especially offshore, must be sustained over the long term or the market will founder. Although the level of installed capacity is growing quickly and the proposed number of projects is ever growing, the fragility of the entire industry is evident through project failings and aboutturns by countries that have lost the will to foster the industry.
The world's first commercial wave machine-the oscillating water column-on the Isle of Islay, Scotland. This system supplies power to the island grid, playing a crucial part in enabling lslay to displace fossil fuels and become self-sufficient using renewable energy.
The United Kingdom is a particularly important market for the three offshore renewables sectors. Driven by a world-class natural resource, this country has experienced notable successes in wind, wave, and tidal energies. Offshore wind, in particular, has generated much attention, as the United Kingdom's first major offshore wind farm has been installed and the second is nearing completion. With more approved offshore wind capacity in the planning stage than any other country, the United Kingdom has bright prospects. The system of offshore leases has shown a structuring that is lacking in other countries. Recent decisions to extend renewable energy portfolio targets to 15.4% by 2015 have provided a signal of long-term commitment. This sustained outlook is crucial to offshore renewables-not just offshore wind, but the growing wave and tidal sectors as well.
In the United Kingdom, the domestic offshore renewables industry is set to develop on the back of the high level of prospects, but challenges from other European countries where renewables, particularly wind, are more established should not be discounted. The United Kingdom has a large manufacturing sector and a highly skilled oil and gas workforce that will be able to diversify into offshore renewables as the industry grows.
Worldwide, the value of the market over the next five years is projected at $9.6 billion, growing from $276 million a year in 2004 to nearly $3 billion a year by the end of the period. Growth between 2004 and 2008 is forecast at more than tenfold. By the end of the period, costs per megawatt will have fallen noticeably, making offshore renewables increasingly viable.
At $150 million, wave and tidal power will only be a small percentage of the total expenditure in offshore renewables. However, wave and tidal power currently attract higher expenditures per megawatt. This indicates higher costs of these developing industries. These costs will fall as time goes by and the industries progress. The leading devices should be comparable to offshore wind by the end of the decade.
The dominance of offshore wind does not mean wave and tidal energy are not important; they are just less well developed, and the industry is much younger. From around 2010, wave and tidal could begin to experience equally rapid growth.
We have based our analysis of marine renewable energy on identified projects. The forecasts are conservative-the prospective markets could be far larger as technology advances and as regulatory environments improve.
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About the Authors
Anthony T. Jones is an oceanographic consultant with oceanUS consulting in San Francisco, offering forecasts in ocean energy systems development. His address is 22 Battery Street, Suite 401, San Francisco, California 94111. E-mail firstname.lastname@example.org.
Adam Westwood is an analyst with Douglas-Westwood Ltd., Canterbury, United Kingdom, providing business intelligence for the renewable sector, including an offshore wind database. His address is St. Andrew's House, 2nd Floor, Station Road East, Canterbury CT1 2WD, United Kingdom. E-mail email@example.com.
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