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Water works – marine renewables

Elisabeth Jeffries

New marine renewable spin outs in the UK continue to appear despite tough challenges

No one would doubt the potential for renewable energy – and its accompanying research and development – in the UK, but the UK Government's axe, swung over the higher education sector in autumn 2010, cast an ugly shadow. There was some good news though; the £4.6 billion scientific research budget would be maintained and ring-fenced until 2014.

However, this means a cut in real terms of around 10% if inflation is taken into account. And new tuition fees will be introduced.

If all these decisions usher in a cloudy episode for science laboratories, there is a silver lining. The renewable energy sector will slip past this onslaught relatively unscathed.

In the last few years, boffins working in university laboratories have laboured at an extraordinary array of sophisticated inventions, with differing levels of viability.

They range right across the scientific spectrum – from materials science to physics and plant biology, all of which have an impact on the growth of clean energy, from portable organic solar strips suitable for off grid power consumption in developing countries, to a microbial fuel cell fueled by urine.

To sell their inventions, often funded by Government research grants, universities and individual scientists either license the technology to companies that want to apply it, or form their own spinout company using seed funding either provided by Governments or the private sector.

Tidal power, so abundant in the waters around the British Isles, is the remarkable beneficiary of some of this funding in the UK, hatching a brood of distinctive inventions. Politicians like to claim this as the foundation for a new, local industry, but many examples of wave and tidal technology exist, and only a few appear even close to commercialisation.

A number of device configurations are emerging from several universities, all of which of course claim they harness tidal energy more efficiently than their predecessors. Ideas have surfaced from all corners of the British Isles – from Hayle in Cornwall to the West Coast of Wales; the Pentland Firth in Northern Scotland; the Solent – the strait between the Isle of Wight and Hampshire; and of course Strangford Lough in Northern Ireland.

Oxford University tidal device

Indeed Sean Westrope, a civil engineer and ceo of Kepler Energy, claims that he is already developing a “second generation” tidal device. Kepler Energy was spun out of Oxford University in October 2010: “We're going through a second industrial revolution. Countries that use an energy resource dominated by renewable energy will be in a stronger position economically [as oil prices go up],” he asserts.

Tidal power is the beneficiary of some funding in the UK, hatching a brood of distinctive inventions.

“The first generation was a wind turbine that people replicated and put in the sea,” he continues: “So we said, let's go back to first principles to see how to capture more energy out of the tidal stream. There is limited potential if you use a device that rotates like a propeller, because it can break at a certain level and cannot be made as big as a structure designed as a truss, which can get more loading,” he explains.

Kepler Energy's device, if ever scaled up to full size, is a massive 10 metres in diameter and 60 metres in length. Westrope likens it to a “super-powered lawnmower.” The concept behind it is “to develop a horizontal-axis water turbine intended to intersect the largest possible area of current,” he says. As a consequence, he says the device could produce “twice as much electricity per dollar of investment” as most previous prototypes. Kepler Energy, which received funding from a UK, Oxford University seed fund, also benefited from a Government grant to develop the device.

Having built a prototype 0.5 metres in diameter, the team are developing and improving it before going for a full size turbine they can test at sea.

Nautricity: contra-rotating

Further North, Strathclyde University in Scotland launched a tidal power spinout company during the summer of 2010. Known as Nautricity, it will develop a business based on a device called a contra-rotating turbine, which has been christened CoRMaT.

The inventor of the device, Dr Cameron Johnstone – chief executive and mechanical engineering professor at the university – also argues that the turbine “makes marine renewable energy a much more commercially-attractive option than ever before.”

Executives at Strathclyde University are confident they're off to a good start: “We've been through the proof of concept process and the prototype has been tested at sea with positive results,” states spinout company development manager Stuart Mackenzie of the university's research and knowledge exchange services.

Nautricity's device, which uses patented new rotor technology, differs from many previous tidal innovations in one major respect: it does not require fixed foundations. This is because the turbine's two rotors turn in opposite directions. Nautricity founders say that this makes it more stable under water than many alternative devices and that its design means it can be placed at depths where the current is at its most forceful.

They also claim it to be more efficient; one reason for this, according to the company, is that the design enables more energy to be delivered from the flowing stream while at the same time there is less mechanical complexity. These factors in turn have a knock-on effect on costs; for instance, the improved stability removes the need for the fixed foundations often used by companies developing other devices.

These foundations, often made of concrete and embedded into the sea floor, are a significant additional financial burden to many competing companies. The device could also have a lower environmental impact than others, partly because of the lack of concrete pilings, while it is described as “low maintenance due to simple direct drive and no requirement for a complicated gearbox.”

Instead of using concrete foundations, the device can be connected to the sea bed by a cable that moves with the flow of the tide, rather like a kite flying on a windy day. The contra-rotating turbine also has simple fixed pitch blades, which Nautricity entrepreneurs claim has an optimum sea proven configuration. As a result of this particular design and type of connection, they say that costs may be “60% lower than those of turbines using piled sea bed structures”.

Tests have been taking place at Islay, an island on Scotland's West coast. There, scientists and engineers say they have successfully trialled a scaled prototype system which consisted of a turbine, mooring and electrical generator, for which they have received funding support from Scottish Enterprise's Proof of Concept scheme. The fresh seed funding will be used to scale up the project. For instance, the team wants to develop an 8 metre turbine, nearly four times larger than the original 2.5m diameter rotor prototype.

Pentland Firth, near the Orkney Islands, is generally accepted as the location with the strongest tidal resource, and planning is under way to develop four tidal pilots in this area after the British Crown Estate leased sites there. “The bulk of work is in the Pentland Firth, but there are also opportunities in waters off the Western Isles,” stated a spokesman from the Scottish Government, commenting on suitable test sites. In particular, he cited the isles of Lewis and Barra.

While successful tidal spinout companies from British universities are relatively few in number, there is substantial interest in tidal power development in Scotland, so Nautricity will be facing considerable competition. Government sources say the opening in March 2010 of the Scottish government's £10m Saltire prize for marine power development yielded 120 applicants. Other ideas have emerged from Strathclyde, Glasgow, Edinburgh and other universities.

“No ‘Rolls-Royce’ has been found in the sector…so the search will go on.”
- - Deborah Walter, Kreab Gavin Anderson

Back South again, in Southampton, a new prototype for a tidal device is due to be launched by the end of 2010, with testing planned to begin in January 2011 in test tanks. The Solent presents a wealth of marine power potential, due to the double high water created by the unusual geographical features of the area related to the presence of a large island so near the mainland coast. This, and a well-established maritime culture, mean that Southampton could be ideally placed for the incubation of tidal energy inventions.

Dr Suleiman Sharkh, inventor of the new tidal device, is already responsible for the privately funded development of a smaller tidal turbine generator known as a thruster, which was launched in 2006. If scaled up, this small device, which measures between 50mm-300mm depending on customer requirements, could act as a tidal power generator in rivers – but is generally sold for use on board boats.

It was conceived as an electric motor for rim-driven thrusters, which are used on tethered underwater vehicles. Sharkh and his colleagues realised they could run this backwards, turning it into a generator: instead of using electricity to turn the propellers and drive the vehicle along, the flow of water turns the propellers, generating power.

The design is unique in its simplicity and compact rim-driven design, which does not require a gearbox and is bi-directional, saving the cost of a turning mechanism to change the orientation of the device if the flow of water reverses. However, Sharkh says his new invention, nearly completed, has “a configuration that is quite different.”

NGentech, a company spun out from Edinburgh University in 2009, has not launched a tidal device but has created a component that it says will help wind turbines function more successfully; however, the device will also be applicable to tidal and wave turbines. The company wants to produce a substitute for the sophisticated gearboxes in modern wind turbines – in the form of a lightweight, direct-drive system.

This, its executives argue, is easier to produce, more reliable and more economical. The originality of the idea lies in the arrangement of electro-magnetically active components – namely magnets, steel and copper – in such a way that the structural mass is reduced. It has also been designed so that there are no magnetic forces to be concerned with during assembly.

Far from suffering a cut in funding, the company benefited from a £0.8m grant from the UK's Department of Energy and Climate Change in the summer of 2010. It plans to develop, produce and construct a 1 MW modular unit over the next year, which would be specifically designed to form part of a 6 MW generator planned for 2012.

Tidal power is of course not the only focus of attention; universities from Edinburgh to Manchester and Southampton have created companies to develop a whole gamut of new wave energy generators.

While it is true that sources of public sector funding to the industry are flowing reasonably healthily, the same is not true for the some aspects of private sector finance; venture capital in particular is tighter than a couple of years ago, as was indicated in a 2010 survey by communications consultancy Kreab Gavin Anderson of existing and potential tidal energy investors.

Concerns they raised included the perception that the technologies were high risk and very capital intensive and that the technology was “not scalable,” that it was a “highly fragmented industry” with “too many devices,” that the “market opportunity does not match investment timescales” and that “better returns were available elsewhere.”

Commenting on the introduction of so many new devices, Deborah Walter, deputy managing partner at the firm, said “no Rolls-Royce” has been found in the sector yet, so “the search will go on.”


Elisabeth Jeffries is a multilingual environment and business journalist commissioned by Worldwatch Institute, The Spectator and many other publications. She previously worked for Reed Business Information, Access Intelligence LLC and ENDS Europe.

Renewable Energy Focus, Volume 12, Issue 1, January-February 2011, Pages 66-68

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