Ocean energy technologies, including ocean wave, tidal current, ocean thermal energy conversion (OTEC) and salinity gradient, are at the early stages of development compared with other, more well-established renewable and conventional generation technologies.
The International Energy Agency’s Implementing Agreement on Ocean Energy Systems commenced in October 2001. The Agreement’s mission is to enhance international collaboration to make ocean energy technologies a significant energy option in the medium term future.
In 2003, under Annex 1 of the Agreement, a report was published which presented the status and priorities for wave and tidal current energy research, development and demonstration (RD&D). This report reassesses the status of ocean energy RD&D in 2006 and examines policies that impact on development, as well as services and facilities which support RD&D, and the barriers to progress.
This study has identified 81 individual ocean energy concepts which are currently being developed. These include 53 ocean wave technologies, 25 tidal current devices, one OTEC system and two salinity gradient concepts.
There has been a significant growth in the number of devices being pursued since 2003. Many more countries are now active in ocean energy RD&D. Activity is concentrated in Europe and North America. Some research projects have been discontinued as initial results showed that certain technologies would not be commercially viable in future market conditions.
The current development status of ocean energy technologies is varied. There are a relatively high number of emerging designs at the conceptual stage, several of which have advanced to detailed designs. Many device developers have constructed more advanced part-scale models and are undertaking simulated ocean testing. Several prototypes are now undergoing sea trials at full-scale or near full-scale. Only one device developer is involved in the demonstration of several devices in a pre-commercial farm, although other such projects have been proposed.
There is a wide range of ocean wave and tidal stream devices being researched, showing that RD&D is far from producing optimum design solutions. As yet, the level of understanding gained through demonstration is not sufficiently developed to identify which schemes will perform in the harsh marine environment as predicted and prove the most cost-effective.
Growth is further restricted by uncertainties surrounding the grid connection of demonstration projects, insufficient understanding of the environmental impacts, and a lack of collaboration and sharing of intellectual property between developers. Progress is also limited by the absence of guidelines and standards that enhance project development, evaluation, testing and comparability. This will better enable stakeholders, such as policy-makers, electricity network companies and investors, to select the technologies which meet their needs.
Generally, government funding for ocean energy RD&D is growing. Several RD&D programmes supported by governments and organisations are currently funding the development of ocean energy technologies. The increasing trend in the number of projects and the recent launch of dedicated RD&D schemes indicate that government expenditure will continue to increase provided RD&D objectives are met.
Importantly, as several technologies are nearing the market deployment and pre-commercial stage, some governments are reacting by proposing market support mechanisms to cover the current cost gap, and consenting arrangements to accelerate the rate of deployment while advancing industry learning and improving cost competitiveness.
To date there has not been sufficient demonstration of full-scale prototypes to prove that the technologies work. This is fundamental and the key barrier preventing deployment of ocean energy technologies. Developers must demonstrate their devices by establishing actual technical performance and the cost of generation, as well as proving availability, reliability and the survivability of concepts, and demonstrate these by publishing results. This obstacle must be tackled to ensure that RD&D progresses to the pre-commercial stage of demonstrating multiple devices in farms.