Feature

Offshore wind potential entices GE back in


David Hopwood

GE's enthusiasm for the offshore wind turbine sector has been rekindled with the acquisition of ScanWind, and a new offshore model is planned. David Hopwood travelled to GE Wind's European wind turbine headquarters in Salzbergen, Germany, and spoke to Stephan Ritter, general manager of Europe & offshore wind for GE Energy's renewable energy business.

GE entered the wind business in 2002 after acquiring Enron Wind, and has since developed a portfolio of wind turbines ranging from 1.5 to 3.6 MW. The company says it has installed 13,500 turbines, which translates into roughly 18 GW in about 20 countries. And since its acquisition of Enron, the company says it has generated annual revenues starting at approximately US$1.3 billion in 2003, to last year's US$6.1 billion.

By far the most well known of GE's turbines is the 1.5 (SLE and XLE), which GE says is the most widely installed machine in the world (around 13,000 installed to date). The 1.5 turbines are one of the mainstays of the US market, which GE Wind has dominated in recent times (according to the American Wind Energy Association the US installed around 10GW of new capacity last year and of that GE's market share was more than 40%). A large proportion of these are the 1.5 turbines of one type or another.

More recently the 2.5xl was launched, manufactured in Salzbergen, Germany mainly for the European region. GE designed the 2.5xl specifically for EU customer needs where the lack of available land can constrain the size of projects. The 2.5xl has also recently been launched into the US market too.

Aside from these two variations on an onshore theme, GE also dipped its toe into the offshore sector fairly early on with a small number (7) of 3.6 MW turbines (adapted from a 3.6 MW onshore design), located in the Irish Sea in Arklow, Ireland. However, rather than becoming a template for a serious entry into offshore, GE classify Arklow as more of an early test bed – a project for understanding how wind turbines work under offshore conditions i.e. operation, service and maintenance. Indeed, following on from this GE originally decided to withdraw from developing offshore turbines completely to focus on those areas which displayed the greatest growth, like the onshore wind sector in the US for example.

“In a quickly growing industry, you've got to focus, so if you look at the growth in offshore over the last five years, and you look at the growth in [the rest of the industry] over the last five years, as a company, what do you focus on?” begins Stephan Ritter, GE Energy's general manager for Renewable Energy Europe: “You've got 2 GW installed in the last 10 years offshore, and you've got much more installed in the US over the last five years alone, and that's what we've focused on.”

It is this focus that has led to GE Wind's continued dominance in the US wind turbine segment, but in other regions it has been a case of smaller strides, though Ritter believes there will be plenty of room in these other regions to develop further, especially if the 2009 capacity increases of 10 GW in Europe and North America, and 13 GW in Asia is anything to go by.

Offshore back on the GE radar

But in the last six months GE Wind has changed its strategy, and expanded its wind turbine portfolio, and as of September 2009 the company re-entered the offshore business segment with the acquisition of ScanWind – a company based in Scandinavia that makes advanced turbine drive train technology (based on a gearless, permanent magnet generator and a full-size inverter system).

ScanWind's team is based in Norway and Sweden (from where the majority of their engineers are based). A relatively small team has already designed and manufactured 15 direct drive wind turbines located just off the coast of Norway.

Of the back of the acquistion of ScanWind, GE's offshore wind plans are moving ahead quickly.

As we go to press, the company has announced that it will invest €110 million to develop offshore wind turbine manufacturing facilities in the UK; GE plans to produce its new offshore wind turbine at this facility – a 4 MW direct drive offshore wind turbine (see GE/ScanWind hybrid – below for details of the turbine planned). In Oslo, GE plans to create an Offshore Technology Development Centre. And GE's current offshore wind facilities are to be expanded by developing a Conceptual and Systems Design Centre in Karlstad. Finally, a technology demonstration unit is planned for Gothenburg harbour, and GE will join the Chalmers Wind Energy Centre in Gothenburg.

One of the interesting issues is the technology that will be employed in the offshore model. The gearbox vs. direct drive debate is one of the hottest topics in wind turbine development currently. Proponents point to reliability as a critical advantage that direct drive turbines have in harsh environments – which means saving money on high maintenance costs necessary in offshore conditions. In a traditional turbine design, a rotor and a gearbox connect to a generator — and it's essential that the gearbox be able to handle high loads. Turbines with bigger outputs of electricity, like offshore turbines, have even bigger loads — which makes reliability of that gearbox even more of a challenge. Direct drive technology, such as that developed by ScanWind, takes the rotor and connects it directly to a generator that is designed to operate at low speeds creating a simple, solid, reliable drive train design.

GE/ScanWind hybrid

Ritter says that GE's plan is to leverage its existing wind turbine expertise, its supply chain and its global research capabilities to “maximise the benefit that ScanWind's technology brings to the table”.

“What we are doing now is taking the ScanWind design (which is a 3.5 MW, 90 metre rotor), adding the technology and scale based on the feedback that we got from our customers”, says Ritter.

He adds that although GE “will change the design as little as possible”, modifications will come in the form of a larger rotor size and generator capacity. In addition, he says that the loads will have to be adapted, using technology that has been “proven” in the GE 1.5 and the 2.5 MW turbine direct loads control. “We will take what the ScanWind team has done and proven, add what GE has done and proven, and combine into a product that we think will be very compelling”, he adds.

In terms of GE's experience to date, it is clear that the 3.6 has less to add, not because the turbines are running “particularly badly,” Ritter says, “but because they're too heavy, and whoever we talked to before we made the decision of re-entering this market, two things were mentioned – don't take an onshore turbine and put it offshore; and exceed on reliability. The belief is that direct drives are going to exceed on reliability”.

On capacity, it is clear that GE's turbine won't be as big as some of the offshore turbines under development – by some margin. But Ritter doesn't see that as a problem – “if you have a 6 MW machine and it has 80% reliability, that's not where you want to be,” he adds. And even though the further out the projects are, the tendency for more size increases, Ritter is “not so sure it's going to go as quickly as a lot of industry members hope”.

With that in mind, he estimates the final GE offshore turbine model to be somewhere in the region of 4 MW. “More importantly, though, it's going to have a bigger rotor”, he adds.

As far as progress to date goes, the bigger rotor has not been added yet; this will happen later this year. It will first be tested onshore before moving out to sea. From there the next step will be to have a smaller fleet of leader projects and scale development up slowly. According to Ritter, “slowly” means the first projects will be two to four prototypes, moving to a pre-commercial phase with 10 to 15 units. He envisages the first commercial project to be somewhere between 15 and 100 units. Norway is the planned site for testing and demonstration of the 4 MW offshore wind turbine.

The first prototype will be running some time this year, and then building out offshore will begin in 2011/12. Ritter believes the first commercial project could be in the water sometime in 2013.

The wind mix – all in the timing

For GE, the possibility of mass producing ScanWind's technology comes at an exciting time in the development of offshore wind, and many commentators think this deal confirmed a significant commitment into offshore by GE Wind. It is also a further vote of confidence in the fledgling offshore wind industry, which has been plagued by concerns about costs and reliability in the past, but has received major boosts recently with major projects announced in the UK (Round 3) and beyond. According to Ritter – now, in GE's view, is the time to invest in offshore wind, simply because “the growth is yet to come in offshore”.

In fact even though offshore wind is never likely to exceed more than 10% of the total wind industry, for the EU especially a huge expansion of offshore wind will be needed for the region to hit its target of deriving 20 percent of its energy from renewable sources by 2020 (analyst expectations are for a 20-fold increase in offshore wind from a globally installed base of 1.5 GW in 2008 to 30 GW by 2020).

Outside of the EU, Ritter cites other examples of countries and continents that have effectively green-lighted further massive wind power expansion – such as North America and Latin America. There are also aggressive targets in China and India, and even regions like the Middle East and Africa, and Asia Pacific are starting to gain traction. “If you take the targets that we have in 73 countries worldwide, and you look at it from a wind and a solar perspective, to achieve these targets we need an additional 400 GW of wind, which translates into another 800,000 wind turbines,” Ritter says.

R&D priorities

This is clearly a huge challenge and Ritter believes it can only really happen not by just building bigger and bigger turbines, but by increasing efficiency, and making turbines more reliable:

“What is extremely important onshore, and is going to be more important offshore is the reliability of wind turbines,” he reiterates.

With that in mind, how close to some kind of standard turbine technology does Ritter think we are within offshore development? “If you compare onshore and offshore, even though I don't necessarily think it's a particularly good comparison, last year you had 40 GW installed onshore globally, and 500 MW installed offshore, and that kind of shows you where the offshore industry is, in terms of technology, in terms of understanding of the process, how to deal with the soil, how to deal with the different wind conditions, and deciding on what the right technology is. So I think there is a lot to learn in the offshore industry over the next five to 10 years”.

GE is focusing its R&D efforts and budget on certain defined areas: “the blades are obviously important for us,” he says “but also the logistics, because these things are pretty big. On the control side, the load is key to the wind turbine, so you want to make sure that you understand the load management and how they're driven from a drives perspective”.

Another R&D specialist with a view on the developmental horizon at GE is Carlos Härtel, managing director Europe, GE Global Research. He believes that to date wind turbine R&D has brought us up to a point where the technology works, and now the innovation is focusing on improving every individual component significantly: “We see a broad mix of research activities from aerodynamics of the blades; reducing noise emissions from the blades, and experimenting with new blade materials. Now there are more compact drive trains, as well as new monitoring and diagnostics and related concepts such as remote sensing”. He also points to R&D into the power system itself that is needed for further development of wind – such as optimising the power generated from wind farms, as well as grid integration and developing storage solutions.

In addition, Härtel talks about GE Wind's own wind turbine R&D plans encompassing areas like automated manufacturing of carbon composite materials; tower electronics; as well as reducing the weight of components like drive trains and generators.

“I think we have moved to a stage where the fundamental design or layout of a wind turbine is basically known,” he continues, “but nowadays technology-rich companies are going to infuse more and more advanced technologies and innovation into those systems to make them generate power at a lower cost in comparison to other technologies”.

The last word

With this in mind, as we move forward, how much offshore wind could realistically be installed? Stephan Ritter's personal estimate is that there will be an acceleration in growth – “we're going to go from 500 MW last year, to around one or 1.5 GW this year. But it's probably going to find a ceiling somewhere, where we know what's possible from a supply perspective, and what can be put into the water every year”.

And that's a challenge not just for the turbine manufacturer, but the entire wind supply chain.

 

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