AT just 24, Cartmel’s Sam Etherington recently beat the likes of Sir James Dyson to win a prestigious engineering award with a design that’s being tipped to revolutionise the future of energy production. Tom Murphy explores wave power technology
SINCE the turn of the Millennium, as energy prices increased and the threat of climate change loomed, interest in developing wave power has grown massively.
Unlike wind turbines, however, the industry has not yet created one single design, although there are more than 1,000 patented devices.
“There is no clear winner yet in wave power and this means resources have been spread thinly across a large number of designs, hindering progress,” explained Dr George Aggidis, a senior lecturer in Engineering at Lancaster University and director of Lancaster University Renewable Energy Group.
Dr Aggidis has worked for many years with leading experts from across the world to research and develop wave power devices.
In tanks at the university, Sam Etherington, a Brunel University graduate, devised a multi-axis wave energy converter that, unlike existing wave converters, can absorb forces from waves on any axis from any direction.
It means the device, which is in the process of receiving a patent, is both more durable and more effective than current tidal power technologies.
The conditions in the tank were modelled with data taken from buoys off the Orkney Islands.
“George has been really good letting a student he didn’t know use the facilities for free,” said Sam, a former Windermere School pupil. “I think he was interested in the design and he wanted to see what on Earth it was.”
The potential for Sam’s device was recognised recently after he picked up the James Dyson Award. And earlier this year he was entered into engineering body Semta’s Hall of Fame where he sits alongside industrial giants such as Isambard Kingdom Brunel and George Stephenson.
While awards are all well and good, Sam is hoping to attract sponsors so he can take the product forward.
The design is still in its infancy but there are high hopes that it could be developed into a full-scale model. “There has been a tremendous amount of interest from companies and the Government,” said Sam.
“From venture capital investors to angel investors and from Government grant initiatives to individual entrepreneurs.
“As the project is orientated around renewable energy, there is a great deal of interest due to the fact that alternative energy sources have to play a bigger part in the energy production scene.”
Dr Aggidis added: “Many devices struggle to absorb energy efficiently when waves come at it from multiple directions as they are optimised for a single predominant wave direction.
“In this respect, Sam’s multi-axis device is certainly a step in the right direction.
“But at this early stage it remains to be seen if Sam’s particular design in its current format hits the sweet spot between efficiency, survivability and cost.”
Wave power remains around 30 years behind wind power. Dr Aggidis said: “It takes millions of pounds to bring a wave energy device to full scale production. A device should go through several stages of scaled prototype testing to build confidence in the design before committing millions to a full-size prototype.
“It is far cheaper to correct problems on a model design than a full size device. It is too early to tell with this tank tested prototype whether it is suitable for full-scale production in its current format.”
Questioned as to whether the device could be used in Morecambe Bay, Dr Aggidis said it was unlikely.
“Morecambe Bay is a relatively calm wave climate due to its lack of exposure to large fetches of open ocean.
“It is, however, a fair one-fifth scale approximation of the north west Atlantic wave climate and therefore could be used as test site for a one-fifth scale prototype as at this size it would not be worth having an expensive undersea cable to connect it to the grid.”
LANCASTER University’s Dr George Aggidis explains what type of wave energy designs are currently being developed
* Floating body: This involves having one or more floating structures that are moved by the waves and this motion is then converted in to electricity.
* Overtopping: The waves run up a ramp and ‘overtop’ in to a reservoir. Turbines can then be used to extract energy as the water flows back to sea level.
* Submerged pressure differential: As waves pass overhead, the water pressure varies because of the changing water column height. These devices exploit this pressure difference to generate electricity.
* Flap: Fixed either to the sea bed or an external structure, a flap is pushed back and forth as the waves pass. This pitching motion can then be used to generate electricity.
* Fixed oscillating water columns: These may be built on a shore line or mounted on the sea bed in shallow water. Waves passing the device cause the water level inside a chamber within the device to rise and fall. This can push air out or suck air back in to the chamber. By fitting a turbine to the chamber energy can be extracted from the air flow.