Dartmouth Wave Energy, Exeter University
Wave power is often talked about as the one truly dependable renewable energy source that the UK has in abundance. Tidal turbines are progressing but are still expensive and potentially difficult to maintain.
The SEARASER is a simple vertical pump that moves up and down with the crest and troughs of waves in open sea, near to the coastline.
It pumps water to a high head-holding tank or purpose-built reservoir on shore (anything up to 100m above sea level), then sends it back down to the sea driving turbines, thus enabling on-demand hydro energy in the form of stored water. The SEARASER was invented in 2006 by Alvin Smith and was subsequently patented. A prototype was demonstrated for one month in the open sea by Dartmouth Wave Energy (DWE) in 2009.
Having proven the concept, DWE needed to expand and execute the SEARASER concept through a recognisable institution – Exeter University.
PRIMaRE is a branch of the UoE with expertise in moorings and has launched a test facility site off the south Devon coast near Falmouth, where DWE will be testing its half-size SEARASER (625mm piston, 12m stroke) next year.
Falmouth Harbour Master is describing the project as a ’clean form of renewable energy’ using no oils at sea. Mojo Marine of Falmouth is projected to be the barge deployment company of the SEARASER pump.
DWE claims that the technology will be cheaper than gas, oil, coal and probably nuclear, once the mass production of the SEARASER is up and running.
Narec, EM Renewables, Meccanotecnica Riesi, Technogama, Subsea Design, Ecotricity Group, Edinburgh University, Ocean Resource
Another project that aims to bypass the high capital costs of current tidal energy solutions is a novel magnet-based power conversion system.
The patented Snapper concept was invented by Prof Ed Spooner of EM Renewables and is being co-ordinated by the National Renewable Energy Centre (Narec), with European Commission funding from the Seventh Framework Programme (FP7).
The device works in a similar way to a typical linear generator in which a set of magnets mounted in a translator is moved up and down inside multiple coils of wire of an armature.
However, the crucial difference is that alongside the armature coils is a second set of magnets of alternating polarity. When the force exceeds a certain threshold, the magnetic coupling can no longer transmit the force and it snaps, allowing the energy stored in the spring to be released quickly and efficiently.
Therefore, the continuous slow movement of the wave power machine is divided into a sequence of rapid bursts. A total of eight organisations are involved in the Snapper project – six industrial partners (EM Renewables, Meccanotecnica Riesi, Technogama, SubseaDesign, Ecotricity and Ocean Resource) and two research organisations (Narec and Edinburgh University).
The overarching objective of the Snapper project – and thus the intended impact – is to develop a prototype wave energy capture and conversion system that is appropriate for deployment in near and offshore environments. Water depths of up to 60m are targeted, along with a lifetime cost of energy of €0.15 (€0.13) per kilowatt-hour.
Based on an analysis of materials required for the Snapper device, the capital costs will be significantly less than that for current offshore wind energy devices at around €2,900 per kilowatt and 4.1 tonnes per megawatt.
Cambridge University, Green-Tide Turbines, TWI, Net Composites, NewPro Foundries, Alpha-Electotech
Green-Tide Turbines (G-TT) is looking to build on its growing experience and knowledge in tidal stream turbine technology with a subtle but important difference. In an effort to reduce costs, the project will make use of novel material combinations and various manufacturing processes that are capable of delivering low-cost and robust turbine blades suitable for mass production.
Particular emphasis is being placed on the use of materials with low embodied carbon emissions and also the potential use of recycled materials such as PET from drinks bottles.
G-TT is the lead partner and is therefore responsible for turbine design, loading characteristics and the initial manufacturing concept. TWI brings technical expertise in materials and material processing technologies while providing overall project management.
Alpha-Electotech is to develop the electrical system and provide consultancy to the project on electrical aspects of materials selection.
NetComposites and NewPro Foundries provide prototyping in cast materials and, finally, Cambridge University brings design, modelling and testing expertise to the project.
The project has received £400,000 of funding from angel investors, £94,800 from the East of England Development Agency and a Technology Strategy Board contribution valued at £500,000.
G-TT has been making progress in the Brazilian market with two major potential customers offering to cover 100 per cent of the research and development costs.