Power on the cards – wave and tidal developments

The Oyster wave energy converter

First power from Oyster

The Oyster wave energy converter from Aquamarine Power has now produced and exported electricity to the grid at the New and Renewable Energy Centre (NaREC) near Newcastle, UK, for the first time.

Oyster has been designed to capture the energy found in amplified surge forces in near-shore waves. The system consists of a simple oscillating wave surge converter, or pump, fitted with double acting water pistons, deployed near-shore in depths of between 8-16m. Each passing wave activates the pump which delivers high pressure water via a sub-sea pipeline to the shore. Onshore, the high-pressure water is converted to electrical power using conventional hydro-electric generators.

By producing electricity onshore on a full scale test rig, Aquamarine has shown that Oyster can deliver electricity on a commercial scale. The output from a single pumping cylinder delivered over 170kW of electricity suggesting that a full scale device, with two pumping cylinders, will deliver well in excess of the modelled output of 350kW.

Oyster is unusual in that it starts generating electricity in almost calm sea conditions and can continue generating even in the worst of storms. The device was put through a rigorous testing process at NaREC to simulate a variety of sea conditions. The tests – conducted during March-April this year – saw Aquamarine optimising the system settings, testing different components in terms of performance and fatigue and obtaining operational experience whilst importantly producing predicted quantities of electricity. The test rig was driven by a hydraulic power pack hired from Pelamis Wave Power. The hydraulic rams drive the Oyster cylinder to produce high pressure water which is fed into a Pelton wheel that is connected to a generator to produce electricity.

Installation of the full-scale machine at the European Marine Energy Centre in Orkney is scheduled for this summer. Aquamarine already has an agreement with Airtricity, the renewable energy division of Scottish and Southern Energy to develop sites capable of hosting 1000MW of marine energy by 2020 suitable for deployment of Oyster.

Optimising site selection

SMRU Ltd, part of the Scottish Oceans Institute based at St Andrews University, and the European Marine Energy Centre (EMEC), Orkney, UK, are working to develop hydroacoustic systems and methodologies for the detection and monitoring of marine mammals and diving birds and potential interactions with Ocean Renewable Energy devices. This project is an important undertaking that will help to prioritize marine areas for use as potential project locations and will help project developers and device manufacturers address permitting issues and concerns over turbines placed in marine habitat areas.

The hydroacoustic, or SONAR, systems used for this project will be provided by Seattle based BioSonics, Inc. After an intensive evaluation process by a panel of UK experts, BioSonics’ DT-X digital echosounder technology was selected based on its unique capabilities and potentially “mammal friendly” characteristics. BioSonics has an established track record in deploying fixed position monitoring systems at ocean energy projects and performing baseline studies for site selection. Its systems are capable of three-dimensional tracking and classification of marine mammals, fish, and diving birds at long ranges and operate at frequencies and energy levels above the hearing ranges of marine life.

The synergies afforded through this alliance between SMRU Ltd, EMEC, and BioSonics are significant. SMRU Ltd staff includes some of the world’s leading authorities on marine mammals and over the next several months these researchers will contribute expertise and collect data on marine mammals and their swimming behaviour. This information will allow BioSonics engineering staff to develop specific classification matrices and optimize their existing hydroacoustic systems for the defined purposes.

Work began in April at EMEC. BioSonics and SMRU technical teams worked in tandem on initial field trials and data collection.

Carnegie Corporation’s CETO system

Subject to agreement

Wave Energy Developer Carnegie Corporation Limited and Investec Bank (Australia) Ltd, the Australian subsidiary of the international specialist banking group, are entering into a Heads of Agreement which sets out their mutual intention to work together to develop Carnegie’s Commercial Demonstration Wave Power Project.

Subject to certain milestones and conditions being met, Investec intends to provide or procure funds of up to $250M for the project. It is intended that the project be developed in a Special Purpose Company jointly owned by Carnegie, Investec and other investors, making the financing non-dilutionary for Carnegie Corporation Limited shareholders.

The Commercial Demonstration Project is the subject of a Federal Government funding application and, as such, details of the project are commercial-in-confidence. The agreement is also conditional upon the successful outcome of this funding application. Carnegie continues to carry out feasibility studies at its portfolio of potential project sites across southern Australia and expects to be able to announce the site of the Commercial Demonstration Project sometime this year.

Upon execution of formal contracts, Investec will secure the first right of refusal for three years to finance Carnegie’s CETO projects that connect into the Australian National Electricity Market and in New Zealand. Carnegie will also immediately issue Investec 1,000,000 unlisted options over Carnegie Corporation shares with an exercise price of $0.31 per share. The agreement will remain “non-binding” until formal agreements are executed.

Carnegie’s CETO has been developed to operate out of sight and is anchored to the ocean floor. An array of submerged buoys is tethered to seabed pump units. The buoys move in harmony with the motion of the passing waves, driving the pumps which in turn pressurise seawater that is delivered ashore via a pipeline. The high-pressure seawater is used to drive hydro turbines, generating baseload, zero-emission electricity. The high-pressure seawater can also be used to supply a reverse osmosis desalination plant, replacing greenhouse as emitting pumps usually required for such plants.

On the RITE track

Initiated in 2002, Verdant Power’s Roosevelt Island Tidal Energy (RITE) Project is being operated in New York City’s East River. In three phases, the RITE Project – the world’s first grid-connected array of tidal turbines – will test, demonstrate and deliver commercial electricity from Verdant Power’s Free Flow Kinetic Hydropower System (tidal).

• Phase 1 (2002 – 2006): Prototype Testing

• Phase 2 (2006 – 2008): Demonstration

• Phase 3 (2009 – 2012): MW-Scale Build-Out

In November 2008, Verdant Power achieved a major milestone by successfully completing the Phase 2 Demonstration, which began in 2006 with the installation of the company’s first full-scale (5m diameter rotor) Free Flow System turbine into the East River.

Over this two-year period, Verdant Power operated six full-scale turbines in array at the RITE Project, demonstrating the Free Flow System as an efficient source of renewable energy with the following outcomes: excellent hydrodynamic, mechanical and electrical performance; grid-connected power with no power quality problems; fully bidirectional operation – passive yawing with high efficiency on both ebb and flood tides; automatic control and continuous, unattended operation; no fouling or damage from debris; 80MWh of energy delivered to two end users; 9000 turbine-hours of operation.

Preparations for the RITE Phase 3 Build-out are now underway, beginning with Verdant Power’s application for a pilot license to the Federal Energy Regulatory Commission (FERC) in November last year. In early May, FERC issued a public notice stating that it has concluded the pre-filing process related to Verdant Power’s application for a commercial license and that the requisite regulations have been waived in order to allow for an expedited review of the application under the Hydrokinetic Pilot Project Licensing Process.

The next step in the application process is for Verdant Power to submit its Final License Application. If granted, this license would allow Verdant Power to build out the RITE Project in the east channel of the East River to a 30-turbine 1MW pilot project and to commercially deliver the energy generated by the field. Plans are also underway to expand development into the west channel of the East River for an additional 2-4MW of capacity.

A key aspect of the RITE Project’s Phase 2 Demonstration was to identify any impacts of the six-turbine array on the local environment. Toward this end, Verdant Power conducted unprecedented monitoring activities during the two-year demonstration period.

These efforts included the operation of an array of fixed underwater hydroacoustic sensors that monitored the turbine field for any underwater activity. In addition to this fixed monitoring, Verdant Power also conducted on-vessel mobile fish monitoring in the project area. A characterization and analysis of the river’s benthic habitat was also conducted.

The results of these activities to date show no observed evidence of increased fish mortality or injury, nor any irregular bird activity in the project area. The data demonstrate that fish avoid zones of impact with Verdant Power’s system and populate inshore areas.

Verdant Power will continue monitoring activities during the Phase 3 build-out of the RITE Project in order to analyze any impacts from a larger array.

Out to sea

A new wave energy converter called Anaconda has been developed that mimics the action of a sea snake. Now in final proof of concept testing, Anaconda is producing energy data at low estimated costs. The Anacondas – up to 200m long and made almost entirely of rubber – could each be capable of generating 1MW of power; and typical farms could consist of 50 units.

Anaconda is being developed by the Checkmate Group, and chairman Paul Auston said: “We’ve seen excellent results in scale model testing, and now we are now gearing up to attract the necessary investment to develop Anaconda and begin producing the first full sized units for ocean testing within the next three years.”

The first field of Anacondas could be in commercial production and start deployment off the UK coastline by 2014. Anchored to the seabed and floating just beneath the surface, each Anaconda is continually squeezed by passing ocean waves. These waves form bulges in the water-filled tube and travel down its length developing the power to drive a turbine in the tail. The electricity created would be captured and cabled ashore.

The original idea came from Professor Rod Rainey, a chief engineer with engineering design consultants Atkins. He said: “The beauty of wave energy is its consistency. However, the problem holding back wave energy machines is they tend to deteriorate over time in the harsh marine environment. Anaconda is non mechanical: it is mainly rubber, a natural material with a natural resilience and so it has very few moving parts to maintain.”

Early stage research & development was supported by the Carbon Trust’s Marine Energy Accelerator (MEA) which helped identify and tackle key development challenges. They said Anaconda ‘has the potential to deliver breakthrough reductions in the cost of energy’ and that ‘it could represent the next generation of marine renewable energy’. Based on their MEA study they said the projected costs of Anaconda could represent a significant improvement over the best current renewable energy devices.

Anaconda is now in the final stage of exhaustive proof of concept testing at a 270m wave test tank run by QinetiQ in Gosport, Hampshire. The QinetiQ ship tank is the UK’s largest and was used to simulate the strength and frequency of ocean waves the device may encounter.

Taking on the tide

Irish tidal energy company OpenHydro has secured a major contract to develop a tidal energy pilot project for a public utility provider in Washington State in the US.

The contract with Snohomish County Public Utility District (SnoPUD), the United States’ twelfth largest publicly owned power utility, is to develop a tidal energy project in the Admiralty Inlet region of the Puget Sound, the second largest estuary in the United States with a shoreline of 3790km.

The pilot project, which has received a grant from the US Department of Energy Advanced Water Power Projects, involves the installation of up to three tidal turbines in the Puget Sound, which will be connected to the electricity grid via subsea cables. OpenHydro will install the turbines using its purpose-built installation barge, the OpenHydro Installer, the world’s first specialist barge for installing seabed mounted tidal turbines. Installation is expected to begin as early as 2011.

‘OpenHydro’s vision is to develop arrays of tidal turbines, silently and invisibly generating renewable energy under the world’s oceans. This is a significant contract for our business and it marks a further step toward achieving that goal. We truly believe that tidal energy will make a considerable contribution towards meeting SnoPUD’s renewable energy targets and we are extremely excited to be working with such a visionary partner,” said James Ives, Chief Executive, OpenHydro.

“We’re thrilled to partner with OpenHydro to develop a clean, emission-free energy source that has the potential to make a significant contribution to meeting our region’s growing energy needs,” said PUD General Manager Steve Klein. “Tidal energy can be sited right here in Western Washington and easily integrated into our existing electrical system without requiring hundreds of miles of new transmission lines.”