Renewable energy from marine sources has a bright future. Potential markets for offshore wind, wave energy conversion, and tidal power show considerable growth over the next decade, especially as technological advances are achieved and as regulatory environments are improved.Offshore wind capacity, for example, has taken off in the European market. Installed capacity has increased more than five-fold within the last year alone. The North American market lags about five years behind the European market, but it is expected to increase capacity and become prominent before the end of the decade. Technological progress is extremely important in this industry, and will drive developments. As better technology is implemented, large strides in capacity will be achieved using proportionally fewer turbines. For example, the average size of a turbine in 2004 is 2 to 3 MW, whereas by 2008, turbines 4 MW and above will be the norm. A potentially large market for offshore wind exists 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. Offshore developers should heed the lessons from the traditional boom and bust cycle of the onshore wind sector in North America. Although the United States has considerable offshore wind potential, regulatory uncertainty is a source of concern, a critical test of the market potential is under way in the form of the Cape Wind project. Cape Wind Associates’ controversial 420-MW, 130- turbine project 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 the wind farm is approved, new and existing players are likely to take advantage of the potential and generate many proposals for new projects. On the other hand, if the project is rejected, and therefore effectively cancelled, it could have dire consequences for the future development of the United States industry. Comprehensive data recently released from the U.S. Army Corps of Engineers, the U.S. government’s regulatory body currently in the position to permit offshore wind farms, is promising. The project is now in an extended public review process — approaching a final ruling fast. Ultimately, the United States government will determine the rate of progress for offshore wind. Mixed signals concerning subsidies and tax incentives have created an uncertain atmosphere for developers. For the offshore wind industry to grow, the U.S. needs to establish a comprehensive offshore management system with clear procedures, because at present, there is no set precedent for applications. As previously mentioned, the success or failure of the early projects, especially Cape Wind, will dictate the terms by which future projects will be judged. Wave energy is moving offshore. Although a number of successful devices have been installed at shoreline locations, the true potential of wave energy will only be realized in the offshore environment where large developments are conceivable. 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 through multiple-unit projects. Offshore locations offer greater power potential than shoreline locations. Improvements in reliability and accessibility will be critical to the commercial success of the many devices currently under development. Most wave energy projects to date have been small, and few are connected to a power grid. However, grid connection will be crucial in the future. For offshore devices, meeting this requirement will be challenging and costly, although not prohibitively so. Limited financial resources, in many cases, hamper launch of technology as the sector is dominated by small and medium enterprises. However, towards the end of the decade, developers will negotiate and plan larger-scale projects based on proven technology, which are unlikely to see installation after 2010. At that time, wave energy farms could begin to emerge. When devices reach this advanced stage, the prospect capacity will begin to rocket. Over time, the initial high costs of development and research will level out, and individual technologies will become more cost effective. Once a device is established, serial production will result in much lower costs. At this stage, there are several devices that have very promising electricity generation costs forecast that would further benefit their commercial success. Historically, tidal projects have been large-scale barrage systems that block estuaries. Yet, within the last few decades, developers have shifted toward technologies that capture the tidally driven coastal currents or tidal stream. At present, smaller units that can be deployed individually or in multiple units characterize tidal current stream technologies. Tidal current turbines are basically underwater windmills. There are a great number of sites suitable for tidal current turbines. As tidal currents are predictable and reliable, tidal turbines have advantages over offshore wind counterparts. The ideal sites are generally within 1 km of the shore in water depths of 20-30 m. It is anticipated that multi-megawatt farms will emerge by the end of the decade. Tidal current turbines represent an extremely important sector for offshore renewables as there are several well-developed devices and such technology, once proven, could be installed in large numbers in the near future. It is conceivable that tidal current turbines such as those of Marine Current Turbines or Hammerfest Strom could eventually be installed in large projects comparable in size to offshore wind farms. 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. The leading devices should be comparable with, and in some cases more competitive than 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. If wave and tidal were compared to offshore wind market data from ten years ago, their market share would be much higher. Offshore wind is booming at present. Around 2010, wave and tidal could begin to see rapid growth. About the author… Dr. Tony Jones is a senior oceanography with oceanUS consulting in San Francisco. He holds a doctorate in oceanography from the University of Hawaii. He has been a consultant to various marine renewable energy developers including SeaVolt Technologies, a winner of the UK Carbon Trust’s Marine Energy Challenge. He is widely published in the field including a seminal paper on economic forecast for ocean energy over the next decade.