The predicted energy gains from many tidal power schemes have been overestimated, according to a team of researchers in Liverpool.
The project, in collaboration with the National Oceanography Centre, looked at the process of tidal range power generation. This involves a structure holding back the tidal flow, creating a water level difference across the walls of the structure, which drives turbines.
The amount of energy recovered can be boosted through a process called ‘pumping’, where some electricity is used to pump water to increase the difference between the water levels.
The study, published in the Journal of Renewable Energy, concludes that potential energy gains via pumping reported by some theoretical studies are too optimistic.
Current theoretical studies are a way of calculating the maximum potential energy gains, but the water would have to drop instantaneously to achieve the previously reported figures, and hence are not achievable in practice.
Researcher, Dr Ian Walkington and PhD student, Nick Yates from the School of Engineering, conducted the study. Dr Walkington said: “We have been working with the proposed tidal lagoon in Swansea Bay which will utilise this technology.
“We have the leading energy calculation model in the world at the moment and having these accurate energy use figures makes it easier to plan for major renewable projects like this.”
The research was funded by the Joule Centre and industry partners.
The full paper can be read here.
