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BUILDINGMOMENTUMRenewables are making headway on land, at sea and in the air

The renewable energy movement is gathering momentum. Whether on land, at sea or in the air, more renewable solutions are being tried or implemented. In a glimpse that extends from the parochial – a small island off the south coast of England – to the global – as viewed from the edge of space. George Marsh highlights some of the headway being made.

Apicturesque Island off the UK’s cen-tral south coast is developing into a significant centre of renewable

energy-based activities. The Isle of Wight has advantages that include a good skills base, premises with waterside access, good transport links and a desire for sustainable enterprise – plus wind, wave, tidal and bio-mass resources.

Vestas Blades UK, a subsidiary of Vestas Wind Energy Systems, is forging ahead at its Newport, Isle of Wight, facility, with the development of its new 49m blade. This new model, intended for Vestas 3MW V100 generators, is of the resin-infused wood/composite constructional form which is unique to the company, having been developed originally by its UK predecessor AeroLaminates. The wood plus glass and carbon epoxy composite results in a notably light and stiff structure that competes well with the more usual autoclaved prepreg type of structure – though Vestas produces this type of blade also. A spokesman for the company told Refocus that Vestas expects to go into full production with the blade early next year (2007).

Several pre-production prototypes have been produced. First production blades are slated for turbines already being erected in Denmark, Germany and Lithuania.

The 49m blades are being constructed in the same Newport factory as the present 40m model, which equips 1.65MW Vestas V82 machines, popular around the world

especially in low-wind sites. The larger blades can be accommodated on Blade Runner 2, one of two eco-friendly trans-port barges used to transport blades from Newport via the River Medina and Solent to Southampton Docks, whence they are shipped to various countries.

In a related development, a decision is expected in late October on whether a planning application by Your Energy to install a small wind farm on the Island will be allowed by the Isle of Wight Council. Opposition to the planned six-turbine site at Wellow, near Yarmouth, has been orches-trated by ThWART (the Wight Against

Rural Turbines), which submitted an 82-page document to the Council as part of the public consultation process. Objections are mainly on environmental and landscape grounds. However, the pro-Island wind energy group Wind on Wight (WOW) has lobbied in favour of the project, which is also backed by Vestas Blades UK. According to Paddy Weir, Vestas’ general manager,

“Our Newport factory is too small to produce the large blades needed for the off-shore market, so the West Wight project is typical of our future business opportunities, which will largely depend on UK, Irish and French offshore projects.”

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Your Energy has said it will use Vestas blades if its application is given the go-ahead. The Wellow wind farm would pro-vide market, training and R&D benefits, as well as affording a substantial number of Vestas employees their first view of an operational wind farm, says the company.

Approval at Wellow would fit well with the Island’s ambitions to become a signifi-cant renewable energy centre. A Renewable Energy Action Plan drawn up by the Isle of Wight Council recognises the important part onshore wind could play in achieving the UK’s 2010 renewable energy targets, but mainstream wind is not the only possibility.

Of several IoW companies actively engaged in renewable energy programmes, WaB Energy Systems Ltd is working with wind and tidal power; Engenius Ltd is active in micro wind and power systems, and Switch to Switch is working with biomass.

Wight Energy Ltd, a consortium of local businesses involved in renewable energy initiatives, hopes to access some of the £50m the government recently allocated for development of tidal energy. It is work-ing with the Council on its Renewable Energy Action Plan.

Meanwhile, the South East England Development Agency (SEEDA) is fund-ing a study to investigate the feasibility of implementing a renewable energy technol-ogy and test centre, dubbed the Solent Marine and Test Centre (SMART). Cowes-based consultancy Marine and Technical Marketing Consultants (MTMC) is carry-ing out the study.

Radar mitigationAnother company present on the Isle of Wight is involved in finding solutions to the potential problem of radar interference. Aviation interests routinely object to some wind farm development applications on the basis that wind turbines impair the perform-ance of air traffic control (ATC) radar. The UK’s Civil Aviation Authority, for one, wants wind farm planning processes to consider aviation safety along with other issues.

Various attempts made to mitigate dis-ruptive effects have included coating tur-bine blades with ‘stealth’ materials that absorb radar microwave energy rather than reflecting it.

And electronic solutions, in particu-lar from BAE Systems, UK, and Italy’s Selex SI, have shown considerable promise in recent trials. BAES’ Integrated System Technologies (Insyte) operation, based at Cowes, Isle of Wight, has been involved in the programme.

In the so-called Watchman trials, con-ducted by a partnership of the UK Ministry of Defence, Department of Trade and Industry and the British Wind Energy Association, a mobile Watchman military ATC radar was temporarily located to a mid-Wales site chosen for its proximity to four wind farm complexes – Bryn Titli, Llandinam, Cefn Croes and Carno (A and B). Radar operators attempted to track a variety of aircraft flying over the area in diverse directions and at different heights and speeds, on days offering a range of wind conditions and hence turbine operat-ing characteristics.

These trials, along with others con-ducted near a regional airport in England, have resulted in what is said to be the largest set of operational radar/wind farm measurements achieved so far anywhere in the world.

BAES claims that its mitigation device, referred to as an Advanced Digital Tracker (ADT), successfully eliminates false echoes. Essentially a small signal processor that can be added to new and existing radar systems, the device proved effective in tracking ‘difficult’ targets including, for instance, a Royal Air Force Hawk jet flying fast and manoeuvring sharply over the Carno wind farm in Powys.

According to Clive Richardson, man-aging director of BAES Insyte, “Radar interference from wind farms is clearly a hurdle we need to overcome. Wind energy looks set to make a major contribution to the UK government’s aim for 10% of our electricity to come from renewable sources by 2010. Our Tracker technology removes unwanted wind farm returns from radar displays and effectively tracks aircraft over wind farm areas.”

ADT would be a key component of a BAES ‘tool kit’ for removing wind farm interference from radar. At the time of writing, details of how well the Selex device performed were unavailable. Further tri-als of mitigation devices are taking place, and the DTI has commissioned research organisation QinetiQ to produce a com-puter-based model of how proposed wind farms are likely to impact radar perform-ance. QinetiQ is expert in analysing radar scattering from complex targets and has been instrumental in developing ‘stealthy blades’.

Seagoing hazardWind farms offshore have also been in the firing line. As well as the turbines themselves, associated sub-sea power cables could theoretically cause anomalies in navi-gation equipment.

British Maritime Technology (BMT), a leading maritime consultancy, has used an advanced coastal marine traffic simulation tool, Dymitri, to help produce guide-lines for authorities to use in developing

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offshore wind energy safely. Dymitri was used in a Euros 4.5m European safety at sea programme, carried out in recent years, intended to reduce risks posed by wind farm developments. Six countries took part in an offshore wind farm management initiative, one of six pilot projects conducted as part of the programme.

The UK, as a major research contribution, conducted trials around the North Hoyle wind farm off the north Wales coast. A number of vessels took part in the Maritime and Coastguard Agency-sponsored trials, including a P&O ferry. Research partners included BMT, Trinity House and the Northern Lighthouse Board, while Flemish and Danish maritime authorities were also involved.

Based on its experience, BMT has since upgraded Dymitri to more fully represent the behaviour of ships moving in traffic streams and near large fixed objects. This enhanced Dymitri is being used in major marine traffic risk assessments and under-pins the UK DTI offshore wind navigation risk methodology, with scope of application to numerous wind farms around the British Isles. A recent simulation has been that car-ried out for a large seaspace in the Thames Estuary, where major wind farm installa-tions are proposed.

Satellite substitutesSpecialist producers of a new breed of unmanned airship and unmanned heavier-than-air aircraft are racing to produce a cost-saving substitute for communications and surveillance satellites.

High altitude airships (HAA) and high altitude platforms (HAP) would hold sta-tion in the stratosphere for weeks or months at a time, relying on solar or hydrogen power to keep them there. They would satisfy military and security needs for ‘per-sistent’ surveillance, as well as those of communications interests for broadband communications relay.

Florida-based Sanswire Networks has been given permission to flight test its Sanswire 2 high-altitude airship technol-ogy demonstrator, precursor to an intended Stratellite airship which, as the name sug-gests, would provide an alternative to com-munications satellites by operating within the stratosphere.

This would utilise photovoltaically con-verted solar energy to drive steerable pro-pellers via electric propulsion motors. The airship, based on a rigid low-weight carbon composite structure with solar arrays on its upper surface, would operate at around 60,000ft.

Another HAA, from Lockheed Martin will, likewise, be driven by solar-powered electric motors. This enormous 150m long all-electric airship would require some 10-20kW of power, developed by a solar cell array forming part of the airship’s upper surface. Solar power would drive the craft by day, while a battery and/or fuel cell would take over at night. The latter would be charged each day from the solar array.

Under US Defense Advanced Research Projects Agency (DARPA) plans for an ISIS (Integrated Sensor as Structure) airship, the Lockheed Martin HAA power system would be regenerative. The weight of the power system is critical. The ISIS engineering team is aiming for a 400Wh/kg night-time power-to-weight ratio initially, though it would expect this to be doubled eventually as devel-opment proceeds. A series of contracts have been awarded to develop critical technologies and refine the design for a full-scale HAA. A viable airship is not, however, likely to enter service before 2018, though trials could take place several years before this.

Meanwhile, manufacturers of heavier-than-air alternatives say that unmanned air vehicles (UAVs) are a better answer. US pio-neer of solar and human-powered aircraft, AeroVironment Inc, is due to fly, about now, its Global Observer hydrogen-powered high-altitude UAV to test communications equipment developed jointly by European and Japanese interests.

The flight test is being organised by Japan Stratospheric Communications, which is

participating in a HAP project supported by the Japanese government and under the European Union Sixth Framework research programme Capanina. Global Observer made the first ever liquid hydrogen-powered UAV flights in May 2005.

AeroVironment has wide experience of solar/fuel cell/battery powered aircraft, hav-ing built and flown the Pathfinder and Helios series, as well as their 1970s and 1980s predecessors, Gossamer Penguin and Solar Challenger.

These aircraft were essentially light, flex-ible ‘solar wings’ that had their upper surfac-es dedicated to solar arrays and flew at about 25 mph. Helios, for example, succeeded in flying to 97,000ft using power from bifacial silicon solar cells that converted solar to electrical power with 22% efficiency on the front side and 11% on the reverse side. This was sufficient to drive 14 two-blade propel-lers via 1.5kW DC electric motors. Global Observer, however, has a more conventional aircraft form and uses fuel cell-powered electric motors to drive eight propellers. One thousand pounds of liquid hydrogen, which can be generated by renewable means or from conventional fuels, is stored in a central ‘fuselage’ pod in a 300lb insulated storage tank.

This aircraft is expected to be able to fly for at least a week at a time, at altitudes in excess of 60,000ft. Aerospace giant Boeing has tested a hydrogen-fuelled propulsion system for a UAV that would stay aloft for up to 10 days. The UAV, based on Boeing’s Condor design which flew in the late 1980s, would operate at 65,000ft.

The UK, too, is building up to long-endurance UAV flights. QinetiQ intends during 2007 to prepare its Zephyr high-altitude solar-electric UAV for an endurance flight proposed for the following year. This

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would, the project team hopes, last up to three months and set a world record.

The programme may be opened up to other nations and commercial interests so that present funding sources are augment-ed and development can be accelerated. Currently, the UK Ministry of Defence is the main sponsor, but QinetiQ says that such a vehicle could be useful for disaster relief and environmental monitoring as well as for defence and security purposes.

At a more normal flight level, the US Air Force has flown a B52 bomber with two of its engines powered by a 50/50 mix of conventional jet fuel and synthetic fuel produced by the Fischer-Tropsch (F-T) method. Franz Fischer and Hans Tropsch were German scientists who, seeking alter-natives to scarce conventional fuels during World War 2, developed a system for syn-thesising hydrocarbon fuel from natural gas, coal or biomass sources. F-T fuel burns cleanly with negligible pollution and can be used by standard, unmodified jet engines.

The USAF hopes that F-T fuel will help reduce its dependence on expen-sive and polluting fossil fuel, much of it imported. Trials are continuing and, given maintained positive results, the Air Force intends to work up to flying the B52 with all eight of its engines running on the synthetic fuel. The USAF already has a considerable commitment to renewables - so much so that Air Force Under Secretary Dr Ron Sega claims that it is number one in the country and number three on the planet in purchases of renewable energy.

Solar boats Solar power is propelling boats as well as high-flying aircraft. A new solar-powered ferry, named Bata Greine – meaning ‘boat of the sun‘ – launched onto Scotland’s Loch Lomond in July, is one such. The catama-ran, which can accommodate 12 passengers including wheelchair users, will ferry day trippers to the island of Inchcailloch in the Loch Lomond National Nature Reserve. It was built by Kopf Solar Design GmBH & Co for the Loch Lomond and Trossachs National Park Authority, which wanted an eco-friendly craft to reduce noise and pol-lution caused by diesel-powered boats on the Loch.

The boat is part of a European-funded project, MoPark, to try out sustainable ways of getting about in National Parks. Park officials were inspired to consider solar power after witnessing the operation of a 50-passenger solar-powered ferry on Lake Constance in Switzerland. The latest ves-sel’s solar system maintains a useful power output even in the cloudy conditions for which Scotland is well known, since it is most sensitive to the ultra-violet end of the spectrum.

The Loch Lomond launching fol-lowed the earlier debut, also in July, of the £230,000 Serpentine Solarshuttle in Hyde

Park, London. This 14.5m long 42-pas-senger craft has 27 curved glass solar panels that provide power for two electric motors. It crosses the Serpentine at 5mph. When it is docked, surplus power developed by the solar panels are fed into the National Grid. Solarshuttle’s designer, Chrisoph Behling, is already working on designs for a solar-pow-ered ferry intended for 300 passengers.

Another solar photovoltaic vessel is the 14m long 50-seat catamaran Solar Heritage, which has been operating in Chichester Harbour for three years. Other examples are at work in the Lake District and on the Norfolk Broads.

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