New research from a global group of scientists and engineers, including from the University of Southampton, has been published in a special issue journal of the Royal Society. The work is in support of tidal power, which has the potential to provide more than 20 per cent of the UK’s electricity demand.
In order to develop effective tidal current technology, a special issue of the Philosophical Transactions of the Royal Society A* describes the status of leading research and projects in the field to rapidly advance tidal energy technology.
AbuBakr Bahaj, Professor of Sustainable Energy at the University of Southampton and editor and contributor to the special issue, says: “The energy present in marine currents can be converted using technologies not too dissimilar to those used in wind energy. While technologies harnessing energy from the tides and currents have been discussed for many years, it is evident from recent deployment of single devices at megawatt scale that real progress has been achieved in a very short period of time.
“In essence, experience with single machines at such a power capacity, will make progress to deployment of multiple machines to convert the marine energy resource much faster than that achieved at the start of the wind energy industry.”
Although the potential for marine energy conversion clearly exists, the technology is presently still in a commercial prototype phase and only a handful of devices have so far been tested at full scale in the ocean. Unlike wind energy, there are currently various designs being promoted, with no single device design emerging as a winner so far.
Engineers try to tap tides in two ways: one involves building barrages across tidal estuaries that use tidal differences in sea surface elevation, so that the flowing waters turn turbines in a similar fashion as hydropower installations.
The other method involves placing turbines underwater in areas of the sea where fast flowing tidal streams, such as those found in coastal waters around the Channel Islands and Scotland.
“This is a crucial milestone for technology development and deployment. Currently, it appears this will be the first deployment of an array of tidal stream turbines,” says Professor Bahaj. “Such deployment will give a boost to the industry as it will also provide the needed data of operation in one of the most energetic areas of the sea. Overall, tidal power will also give us another component in the energy mix that’s more energetic and reliable than wind.”
In the past month, the EU has announced funding in the region of £30m for two UK tidal projects. Investors in tidal technology are currently rewarded with a payment of five Renewable Obligation Certificates (ROCs) which are market variable. Each ROC is approximately £40 per megawatt hour of energy generated from such a resource, but this scheme will be reviewed in 2017.
According to Professor Bahaj, this could have serious implications for the emerging industry: “The rollout of the technology in its current state will depend on the subsidies. At this stage, it wouldn’t stack up financially, until wide experience gained from large-scale deployment is achieved.”
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Press release, January 20, 2014; Image: royalsocietypublishing