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Marine Renewable Energy

Devices

To date there are only a few technologies that have progressed as far as the full-scale deployment and testing. However, there are several companies with operations in the UK presently actively involved in the construction of such devices, supported in their endeavours by numerous financial channels including the UK Government and private investors. A number of technologies developed in UK waters have been outlined below.

Follow this link if you would like to see a summary of how each device works.

 

AquaEnergy Group
AquaEnergy Group Ltd. combines technology and project development to produce electricity from ocean energy. AquaEnergy Development UK Ltd. is a subsidiary with a mission to advance AquaEnergy's core technology, the AquaBuOY wave energy conversion device.

AquaBuOY combines elements of two prior, successfully ocean-tested, technologies – the IPS Buoy and the Swedish Hose-pump. It builds upon the proven advantages of both systems, while advancing the state-of-the-art in design efficiency, functionality and reliability.

 

Click here to see an animation showing how the PowerBuOY works (requires Flash plug-in)

For further information please visit the AquaEnergy Website: http://aquaenergygroup.com

or email: aqua@aeg-ltd.com

 

Marine Current Turbines (MCT)
Marine Current Turbines Ltd is an independent company dedicated to developing a revolutionary technology for large-scale generation of clean electricity from the seas. MCT's patented technology is a submarine tidal current turbine based on using pitch regulated axial flow rotors, which has proved to be the successful formula for the vast majority of wind turbines and which seems likely to be the definitive solution for water current kinetic energy conversion too.

An experimental 300kW test system, called "Seaflow" (as shown above) was successfully installed off Lynmouth in Devon in May 2003 and continues to deliver vital data. This is the world's first successful offshore tidal turbine and is the first step in developing this entirely new clean method of power generation. Seaflow is unique among "wet renewable" technologies in having met its design specification in full (it has actually exceeded its rated power of 300kW and consistently exceeded its rotor design efficiency) as well as having remained operable in open sea exposed conditions for almost three years.

The commercial prototype known as "Seagen" is presently under construction (above left) and due for installation in Strangford Narrows, Northern Ireland in the late summer of 2006. The design process has been validated by the leading marine classification agency, DNV (Det Norsk Veritas) with a view to developing and obtaining type approval for the MCT Seagen turbine system.

The Seagen twin rotor turbines, rated at approximately 1MW, incorporate a patented system for raising the rotors and power train above the surface of the sea for ease of maintenance (as illustrated above right). It is hoped that the first commercial demonstration array as illustrated top right will be installed by the end of 2008. MCT is also exploring opportunities for demonstration projects in other parts of the world including North America and S E Asia in parallel with the first UK commercial array. MCT also has plans for more advanced "Second Generation" technology which can be scaled to higher (or lower) power levels than Seagen and applied in a greater range of flow conditions.

MCT is dedicated solely to the development of commercially viable marine current turbines and has a number of commercial strategic partners and shareholders, including EDF Energy, Guernsey Electricity, BankInvest, Seacore and Bendalls Engineering.

The Seaflow project was financially supported by the UK DTI (Department of Trade and Industry) and the European Commission and Seagen is also being supported by the DTI.

For more information go to: www.marineturbines.com

 

Ocean Power Technologies
OPT was formed in 1994 by Dr George Taylor and Dr Joseph Burns in pursuit of their vision of harnessing the boundless energy captured within the waves of the world's oceans. The company has focused on the PowerBuoy technology, capturing the energy using large floating buoys anchored to the sea bed and converting the energy into electricity via innovative power take-off systems.

The primary product of OPT for the utility industry is the PowerBuoy, which is a patented, scaleable energy conversion system engineered to obtain wholesale amounts of electrical power from wave energy. Ocean trials were conducted off the coast of New Jersey from 1997 onwards to demonstrate the concept of a floating buoy capturing energy and then converting it into electricity. The technology is on a growth curve towards full-scale commercial application, the first example of which is the 50kW PowerBuoy recently installed in Hawaii, in a scheme to be scaled up to 1MW.

   

For further information please visit the OPT Website: www.oceanpowertechnologies.com

or email: mrdraper@oceanpowertech.com

 

OpenHydro Group
OpenHydro is a technology business that designs and manufactures the Open-Centre Turbine to generate renewable energy from tidal streams. The Open-Centre Turbine consists of a single piece rotor integrated with a highly efficient permanent magnet generator contained within a duct-shaped housing. The rotor is the only moving component in the turbine unit. Risk to marine life is minimised by its open centre, slow-moving rotor, unexposed blade tips and lubricant-free operation. Open-Centre technology is unique and covered by a suite of worldwide patents.

The Open-Centre Turbine is designed to be deployed directly on the seabed, located at sufficient depth to present no hazard to navigation. Installations are silent and invisible from the surface. Farms of Open-Centre Turbines will provide a significant supply of clean, predictable, renewable energy.

During 2006, OpenHydro became the first company to install a tidal turbine at the EMEC facility in Orkney, Scotland, UK. The turbine in Orkney is installed within a dedicated, twin-piled test structure enabling the unit to be raised and lowered. In 2007 agreements with Alderney Renewable Energy Ltd and Nova Scotia Power Inc for tidal farm deployments were announced. In May 2008 the Open-Centre Turbine became the first tidal device to export power onto the UK grid.

www.openhydro.com

 

Pelamis, Ocean Power Delivery (OPD)
OPD was established at the beginning of 1998 by Dr Richard Yemm to develop the Pelamis Wave Energy Converter. This device is known as a 'point absorber' and can effectively focus energy from a wide area by interacting with an area of waves much larger than its physical size. As it is flexibly moored it swings head-on to the incoming waves and can therefore span successive wave crests.

The Pelamis is a semi-submerged, articulated structure composed of cylindrical sections linked by hinged joints. The wave-induced motion of these joints is resisted by hydraulic rams, which pump high-pressure oil through hydraulic motors via smoothing accumulators. The hydraulic motors drive electrical generators to produce electricity. Power from all the joints is fed down a single umbilical cable to a junction on the sea bed. Several devices can be connected together and linked to shore through a single seabed cable.

  

Following six years of detailed design and development, OPD has completed the build of the first full-scale Pelamis Wave Energy Converter. The 750kW machine measures 120m long by 3.5m wide (about the size of four train carriages) and weighs 750 tonnes fully ballasted. In August 2004 Pelamis was connected to the UK gird at the European Marine Energy Centre (EMEC) in Orkney to be tested. This is the first offshore wave energy to be exported into the UK electricity system.

Video footage of Pelamis in action (2.7 MB © OPD)

For more information go to: www.oceanpd.com

 

Sperboy™
SPERBOY™, developed and patented by Embley Energy, is a floating wave energy converter based on the 'oscillating water column' principle. Air displaced by the oscillating water column is passed through rectifying turbine-generators. Designed to be deployed in large arrays 8 to 12 miles off shore providing large-scale energy generation at a competitive cost.

With a minimum number of moving parts, which are above the surface of the sea, maintenance requirements are minimised and energy is produced at a very competitive rate. Current research is looking to extend the life of the vessel to some 50 years and includes several initiatives to deliver higher levels of power. Consequently the device has considerable potential for further reducing the cost of delivered power.

The absence of large quantities of invasive products such as oils and lubricants coupled with minimal impact on seabed ecosystems makes the device environmentally friendly.

SPERBOY™ has completed the Marine Energy Challenge, where independent consultants investigated its performance in terms of power capture as well as carrying out a detailed study of both capital and maintenance costings in arriving at their prediction for the cost of delivered power. The device is now ready to exploit the very successful and encouraging results of this 'Challenge' and will now proceed to the deployment of full-scale prototypes.

For further information see www.sperboy.com

 

Stingray and the EB Frond, The Engineering Business (EB)
The Engineering Business started investigating renewables as a potential third market, behind submarine telecom and offshore oil and gas, in 1997 and comments that it soon became clear that Renewable Offshore Power Generation would be the most attractive technology area given the experience and expertise of EB staff. The devices currently being developed include both tidal and wave energy technologies, dominated by the 'Stingray' tidal generator and the 'EB Frond' wave energy converter.

Stingray uses the flow of the tidal stream over a hydroplane to create an oscillating motion that operates hydraulic cylinders to drive a motor that, in turn, drives an electrical generator. This device is a seabed mounted machine, to be situated typically in any water depth up to 100m.

The Stingray Device EB Frond

The EB Frond, on the other hand, is a seabed mounted nearshore wave energy device designed for installation in 20-35 metres of water. A paddle-like collector on the end of a long lever is placed close to the sea surface and driven by the waves to produce hydraulic power similar to that of the Stingray.

In September 2002 EB tested the Stingray generator offshore in the Yell Sound off the Shetland Islands in the Highlands. The 180 tonne, 150 kW machine was installed and removed safely and data collected for analysis to aid the further development of both the demonstrator and commercial units. The 3rd phase of the development programme, a reinstallation of the demonstrator in the Yell Sound, has also been completed in 2003 and included a more flexible control system to allow the performance of the generator to be accurately controlled and recorded over a longer period.

The EB Frond is not at such an advanced stage of development but the phase 1 physical testing has been undertaken at scales of 1/33rd and 1/25th in the Lancaster University test tank, the academic partners in the project. Phase 2 is proposed for development in which a larger model will be deployed in more varied and extreme wave conditions. EB state that if this is successful it should lead to the design, build and installation of a full-scale demonstrator in a real near-shore wave environment, possibly as early as this year.

Future plans for the Stingray include a 5MW pre-commercial Stingray farm to be connected to a local power distribution system in order to test an innovative system for smoothing the flow of electricity from the oscillating devices. For more information go to: www.engb.com

 

TidEL, SMD Hydrovision
SMD Hydrovision has developed a device for the extraction of energy from tidal flows. The TidEL concept consists of a pair of contra-rotating 500kW turbines, mounted together on a single crossbeam. The complete assembly is buoyant and tethered to the seabed by a series of mooring chains. The mooring system allows the turbines to align themselves down stream of the prevailing tidal flow without requiring any external intervention, providing a reliable and economical way of tracking the alternating tidal flow-cycle. As the system requires no support structure, it can be fitted in any reasonable coastal water depth.

  

At present SMD Hydrovision is in the process of testing a 10th scale device in a specially developed tidal facility at NaREC. The results of this testing will feed into the development of a full-scale prototype with 15 meter diameter fixed pitched blades driving the turbine powertrains that are housed within a pod. For more information go to: www.smdhydrovision.com/products

 

Wave Dragon
Wave Dragon marks a significant breakthrough towards commercial exploitation of the abundant energy concentrated in ocean waves, where seagoing trial of the Wave Dragon 20 kW prototype has proven its offshore survivability since March 2003 and verified the potential for commercial feasibility with large scale power generation below the costs of offshore wind power.

Wave Dragon consists of three main elements:

  • Two patented wave reflectors channelling waves towards the ramp, linked to the main structure. These increase energy capture by 70% in 3m waves.
  • The main structure consisting of a patented double curved ramp and a water storage reservoir.
  • A set of low head propeller turbines for converting the hydraulic head in the reservoir into electricity.

When waves have been channelled by the reflectors, they overtop the ramp and fill the reservoir, which is situated at a higher level than the surrounding sea. This hydraulic head is used for power production through the hydro turbines. Wave Dragon is unique among wave energy converters as it harnesses the energy in the water directly via water turbines in a one-step conversion system. A very simple construction in which, importantly, the turbines are the only moving parts.

Click here to see a video of Wave Dragon in operation (.mpg file, 7.3MB)

 

For further information please visit the Wave Dragon website: www.wavedragon.net

or email: info@wavedragon.net

 

The Wave Rotor, EcoFys, Holland
The Wave Rotor, a concept designed by EcoFys of Holland, is part of the Carbon Trust Marine Energy Challenge. At present a scale device has been tested but there is potential for this to develop further during the MEC process

www.ecofys.nl/nl/expertisegebieden/product_systeemontwikkeling/waverotor.htm

 

Wavegen
Wavegen was established in 1992 by Professor Alan Wells and has developed into one of the key leaders in the manufacture of wave power systems. Together with Queens University, Belfast (QUB), Wavegen has built the world's first commercial scale wave energy converter, LIMPET, on the coast of Islay in the Highlands of Scotland. They also develop the OSPREY, a near shore Oscillating Water Column (OWC) and are working on a number of similar concept designs.

The LIMPET (Land Installed Marine Powered Energy Transformer) is the smallest of Wavegen's shoreline energy modules, generating 0.5MW of power for local communities. At the end of 2000 it successfully fed electricity into the local Islay electricity network having secured a 15-year Power Purchase Agreement with the major public electricity suppliers in Scotland.

LIMPET, Islay

More recently Wavegen has collaborated with SEV, a Faroese energy company, with the intention of bringing wave energy to the Faroe Islands. The boards of both companies have agreed to form a joint venture company to oversee the initial design and engineering phase of the project with a value of £600,000. Phase two will see the construction of the wave power station in a cliff wall using a series of Wavegen's air turbine power generation modules. This project is reported to be worth up to £7m and could provide a maximum capacity of up to 100MW. Wavegen state that this will form the blueprint for wave power stations in similar locations both in the Faroes and other parts of the world.

For more information go to: www.wavegen.com

Wavegen also have a test facility.