Jonny Williamson talks intelligent hydraulics with Artemis Intelligent Power’s Professor Win Rampen and Dr Niall Caldwell.
The UK is experiencing a boom in wind energy
Generation from renewable sources grew by 21% during 2014, according to the latest government figures, with wind accounting for 32% of that growth; the 5 GW installed wind capacity milestone has now been surpassed with a further 0.7 GW under construction; and the head of Offshore Wind, Huub den Rooijen has noted that currently, “The UK has more offshore wind turbines than the whole of the rest of Europe put together.”
Reading this, you would expect the future to be pretty bright for wind power generation, but there’s a catch – a problem many are unaware of.
Modern wind turbines typically have an input rotor speed of between 10 and 20 rpm, but their generators want to turn much faster.
The usual solution to this issue is a speed-up gearbox, commonly at a 100:1 ratio; so the input shaft enters at 15 rpm and the output is closer to 1,500 rpm.
According to chairman of Artemis Intelligent Power, Professor Win Rampen, the problem lies in the teeth that the gearbox gears transfer this load across.
“Most of these teeth aren’t in mesh at any one time, so the entire load is being taken by only a handful of teeth at any given time. This can cause teeth, and the whole gearbox, to become deformed and result in mechanical failure,” he explains.
This is a common problem in wind turbines, and one only exacerbated as turbines – and their respective gearboxes – grow in size.
Edinburgh-based Artemis has developed a digital hydraulic power system that it believes unlocks the ability to generate much greater levels of power and solve this issue.
Its advanced Digital Displacement (DD) technology leverages the advantages of hydraulics – providing variable speed gearboxes where are all of the mechanical load components are shared equally – to create a controllable, modular, efficient solution.
In July, HRH the Duke of Edinburgh Prince Phillip presented the UK’s most prestigious prize for engineering innovation – the Royal Academy of Engineering MacRobert Award – to a team from Artemis Intelligent Power.
Renowned for highlighting the “next big thing” in the technology sector, the MacRobert Award identifies outstanding innovation with proven commercial success and tangible social benefit.
According to the Royal Academy of Engineering, the judging panel selected Artemis from the three finalists for its potential to help solve one of the most significant global challenges, while demonstrating technical engineering excellence.
Describing the Artemis story as “truly compelling”, chair of the panel, Dame Sue Ion DBE FREng commented: “The company has achieved a technical advance of global importance, making significant power delivery from offshore wind considerably more credible and realisable, and facilitating the global goal of reducing CO2 emissions.
“As a UK SME, Artemis represents the very best of modern UK engineering with global significance.”
Alongside dramatically improving power capacity, the smart DD system has been designed to overcome the significant reliability issues associated with existing turbines – particularly those located offshore.
“The modular-nature of the design means that should one of the components which transmits the power fail, that break can be remotely identified electronically and taken out of action until the next scheduled maintenance, but crucially the turbine continues operating,” describes Artemis’ managing director, Dr Niall Caldwell.
Caldwell adds that swapping out these components can be carried out by a solitary technician carrying nothing more than a backpack. A far cry from the 100 tonne crane and crew necessary to replace a conventional gearbox, an operation with a reputed price tag of £1m – enough to wipe out a year’s generating revenue.
Producing the DD technology required the fusing of mechanically engineered custom valves – vastly different to standard hydraulic valves – with purpose-built electronics and software.
“The system is similar to a modern rail diesel engine in that you have several hardworking mechanical components and a number of precisely calibrated valves all being controlled with sophisticated software ensuring each valve is fired at exactly the right time,” says Caldwell.
Artemis is already delivering such systems, significantly improving the operational and cost efficiency of turbines, and with it, the prospects for future exploration of wind power.
The business – wholly-owned by Mitsubishi Heavy Industries (MHI) – has seen the first MHI 7 MW wind turbine fitted with a Digital Displacement transmission (DDT) currently on test at the Hunterston facility near Glasgow – a land-based site that has been created to test prototype wind turbines intended to operate offshore.
The second 7 MW MHI DDT turbine – assembled at Onahama port – is destined to operate as a floating wind turbine in deep water 20 km off Fukushima, Japan.
This will be the largest wind turbine of any kind in Japan, and the largest floating wind turbine in the world.
Artemis is also applying the same technology to reduce the fuel consumption of commuter trains and buses.
A regenerative braking energy storage system based on DD can be retrofitted to existing diesel trains, and recent trails with Ricardo and Bombardier have indicated that fuel consumption can be reduced by upwards of 10%.
The system also generates less noise and helps cut exhaust emissions within transit stations.
“Conventional electric hybrid systems for city buses add around 50% additional cost, which means the payback period is longer than the life of the bus. As such, current hybrid buses don’t make a valid business case and have to be supported by subsidies,” Caldwell tells me.
“By contrast, hydraulic systems are far cheaper to manufacture, more compact and because our technology provides such a boost to fuel efficiency, it can pay for itself within two to three years.”
Artemis is also looking to produce a similar hydraulic system for fixed industrial applications such as injection moulding machines, presses and power packs.
The business launched E-dyn 96 – its first commercial product offering – in April with pilot production taking place in Edinburgh.
“It’s an exciting time currently as Artemis transitions from what was, quite recently, an R&D organisation, to a company that designs; develops; tests; manufactures, and distributes.
“One of our objectives over the coming months is to assemble a UK-based supply chain for E-dyn 96, as much as is possible, and make use of the high quality suppliers we have on our doorstep,” Win concludes.