Dutch small wind turbine trial suffers low wind speeds
Friday 31 October 2008
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| Zeeuwind setting up the Delta wind trial at the site 10km from the coast, where wind speeds have turned out to be half the average predicted |
Manufacturers of small wind turbines taking part in a Dutch trial are to visit the site of the tests, after the first six months brought "disappointing" results, writes James Cartledge.
The trial is one of the first comparative tests of its kind in the
world, looking into how 11 different grid-connected small wind power generators perform in the same conditions on the same site at the same time.
It uses technologies from across Europe, including models from British companies, and seeks to compare the performances of the different systems in relation to the retail price of the products.
Results from the first six months of the trial - from April to September 2008 - have revealed much lower wind speeds than expected at the trial location in Zeeland so far. Some of the manufacturers of the turbines involved have also reported glitches in their turbines that have affected the results.
Visits are being planned to the site at the Techno Park Zeeland in Schoondijke, south-west Holland, for the manufacturers to assess how their equipment is being tested, to ensure it is set up in the best way for the conditions.
And, hopes are that the next six months will see higher wind speeds through the Dutch winter.
Niek Tramper, production manager at community wind farm organisation Zeeuwind, which has been carrying out the trial on behalf of Dutch utility company Delta, said that indications had been that wind speeds would average six metres per second during the trial at that location.
However, the trial itself has seen wind speeds around half that level.
He said yesterday: "Until October the average measured wind speed was 3.5 m/s. However our wind measurement is just an indication, it is low. We expect that the coming months will give a lot more wind speed and so electricity production."
Mr Tramper explained that some of the technology problems on the wind turbines were to be expected, since "most of the manufacturers are still developing", adding that Zeeuwind hoped the manufacturers could optimize their systems.
Ampair
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David Sharman, director at Berkshire firm Ampair, appeared happy with the trial results for his company's wind turbine, the Ampair 600 priced at £7,000.
During the trial, the 600W Ampair machine achieved a net production of 75kWh over the six months, although the first two months of the trial saw the blades, tail, and electronic safety circuits being replaced, which hit the generation figures.
Mr Sharman told New Energy Focus that the Ampair wind turbine was only directly comparable within the trial to the Japanese Zephyr AirDolphin, since they were of a similar size and nature. He said the Ampair machine had compared well to the more expensive rival in the months it was up and running.
The company director, who said the Ampair unit in the trial had been overpriced by its distributor, said that the other turbines in the trial suggested "there is no correlation between money invested in research and development, and product performance."
Mr Sharman was fairly critical of the vertal axis machines being tested in the trial, claiming that the technology was not yet proven with data. He dismissed the view that turbine designs that did not perform well in the Zeeland tests would be more suited to turbulent winds in urban areas.
"Nonsense," he said. "They've got to prove it."
Ropatec
Ropatec supplied two vertical axis machines for the Dutch trial, which produced net generation figures of 213kWh for the WRE060 model and 62kWh from the WRE 030 models. However, these turbines were priced at a much more expensive £31,000 and £25,000 respectively.
Ropatec is to send representatives to the Zeeland trial site next week to look at the equipment being tested.
Stephen Palmer, managing director at Llumarlite, the UK distributor of Ropatec machines, said of the Dutch trials: "It's a little disappointing - they told us it would be five to six metres per second, but it was around 3.7. That's a low wind speed for any kind of wind machine.
"No vertical axis machine is going to produce much power in those conditions - we don't recommend the Ropatec for any site offering less than five metres per second," he explained.
Mr Palmer told New Energy Focus that the Ropatec machine was on the more expensive side of those turbines being trialled in Holland because it was designed to be quiet and very robust in the case of storm wind conditions.
He suggested that comparing the machine to smaller wind turbines would as useful as testing a Smart car against a luxury Mercedes car in motorway travel.
Swift
Designed to be quiet and safe in high winds, the Swift turbine is more suited to urban, building-mounted locations, its makers say
The Swift turbine from Edinburgh company Renewable Energy Devices did not appear to produce much power - just 27kWh net production - and Dr Charlie Silverton, one of the two founders of the company said he was quite keen to visit the trial to look at how the £11,000 turbine was being tested.
Dr Silverton agreed that the low wind speeds hadn't helped, and also pointed out that the Swift turbines were designed to be building-mounted in urban areas, rather than hosted on poles as in the Dutch trial.
The Edinburgh University engineering graduate explained that there is much more energy within a few strong gusts of wind then a steady breeze - "the energy you get from the wind increases with the cube of the wind speed," he said.
"Our turbine has been designed to deal with the pretty aggressive wind conditions you get on buildings," he explained, adding that in America the Swift was being tested against the Southwest Skystream and was "beating it hands down".
He suggested a trip to the Dutch site would allow Renewable Devices to change the power curve on the Swift turbine to operate more effectively in the local conditions. Discussing the higher price tag on some of the wind turbines, Dr Silverton mirrored Mr Palmer in stating that safety was a prime concern, and that making systems much safer than current standards require meant a more expensive unit.
Renewable Devices have orders to sell around 5,000 units in 2009, including 1,500 in America and a similar amount in Australia. But it is still "early days" in the development of small wind technology, Dr Silverton said.
Mr Sharman, who said Ampair was one of the oldest surviving wind turbine manufacturers in Britain, was fairly scathing about the designs of his rivals, but at least praised them for taking part in the trials.
"The UK has got a very competitive small wind industry," he said, suggesting it would be even more competitive with more government support.
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