The new 3.0 MW direct drive permanent magnet generator wind turbine from Siemens (image courtesy of Siemens Energy)

There has been much interest in the development of direct drive systems in recent years, since the elimination of the gear box theoretically the turbine system more reliable.  What Siemens appears to have done is to take that a step further – by eliminating half of the components at the top of the tower, there is less maintenance for the service technicians to have to worry about.  This is good for onshore systems, but even more valuable for wind turbines that are to be located offshore, far from land. It also means, in theory, more uptime for each turbine, thus allowing them to produce electricity over wider intervals.

Siemens installed the first prototype of the SWT-3.0-101 at the beginning of December 2009 close to the town of Brande in Denmark. Siemens entered the wind energy business through the acquisition of the Danish company Bonus Energy A/S approximately five years ago, a company that had been in business since 1980, as Danregn Vindkraft. This company was a pioneer in the early days of recent interest in wind power, and was a logical acquisition for Siemens as it looked to enter the market. The Siemens Wind Power business unit is still headquartered in Brande. The permanent magnet generator is being produced by the Large Drives business unit within the Siemens Industry Sector.

The compact nature of the nacelle for the new wind turbine from Siemens means that it is easier to transport than other systems (image courtesy of Siemens Energy)

Siemens first tested direct drive systems in the form of two 3.6 MW concept turbines in July 2008, leading to the 3.0 MW prototype installed late last year. While Siemens acknowledges that they were not the first to market with a direct drive permanent magnet generator system, the company appears to have deliberately taken its time with the development of its own systems. In a news release from late last year, Mr. Stiesdal indicated that rushing to the market with immature technology was not an option for Siemens. While the nacelle contains new technology, the blades, rotor hub, tower and controller were developed from existing products. Full commercial launch of the new turbine through serial production, is expected to commence next year, with a number of systems being installed around the world in the meantime.

One comment from Siemens is worthy of note for the permanent magnet industry and its supply chain. In a promotional video that was released to coincide with the launch of the new turbine, Ernst Frendesen, Director of Global Sales and Proposals for Siemens said that the

“market demand that we expect on this machine will be extremely big and therefore for a period, we think that the magnet demand will outweigh the production capacity.”

This is a very significant comment. Attempts to ascertain the specific amount of permanent magnet materials used in SWT-3.0-101 turbine design were declined by the company for reasons of confidentiality, and so at the moment it is difficult to determine just what this statement means, and on what basis it was made. It is clear, however, that Siemens is putting the permanent magnet industry [and indirectly, the rare earths supply chain] on notice.

Schematic of the new 3.0 MW direct drive permanent magnet generator wind turbine from Siemens (image courtesy of Siemens Energy)

Mr. Stiesdal has kindly agreed to do an interview with me on the SWT-3.0-101 wind turbine and its direct drive, permanent magnet-based drive system, which I will post to Terra Magnetica once completed, along with any other developments in the area of DD PMG turbines as they happen.

In the meantime, however, I wanted to mention that I have now uploaded a PDF file that contains the slides from my talk, titled “Recent Developments in Permanent Magnet Gear Systems & Machines” – click the aforementioned link to download it.

The primary purpose of any gearing system is to convert between speed and torque. Typically using a rotating input power source, we want to either increase or decrease the speed in the output shaft, via a converse decrease or increase in torque – and vice versa. Typical examples of such systems are automobiles [where we want to convert the high speed of the rotary crank shaft in the internal combustion engine to a relatively high torque at the wheels] and wind turbines [where we want to convert the high torque but relatively slow movement of the turbine blades, into the high speed required by typical generators]. This conversion between speed and torque is actually a form of power conversion from one part of the system to another.

A key drawback of using mechanical systems for such conversion is that there is friction, wear and tear. Only a few gear teeth mesh at any one time, the rated torque values are by necessity lower than peak torque because of fatigure issues, and there is a lot of lubrication and maintenance required. In addition, failures of such devices tend to be catastrophic – when a mechanical gearbox fails – it fails!

Enter the magnetic gearing system. With no contact between elements, there is no friction to cause wear and tear. Multiple magnetic poles are engaged and thus the systems are highly efficient at converting power. Input and output shafts can be isolated too, which presents additional options for the mechanical designer.

Going a step further – fully integrating magnetic gears with electrical machines such as motors and generators, results in superior, best-in-class torque densities for any electromechanical / electromagnetic power conversion system. This result makes magnetic gearing a very promising technology for a variety of devices, including the possibility of highly compact, high powered traction motors for in-wheel drives for vehicles. Torque densities of up to 140 kNm / m^3 have been achieved, with the ability to produce up to 35 kW of power in a single in-wheel traction motor.

My presentation in Florida covered the recent developments in this area, including low gear ration and high gear ration systems, the history of research into magnetic gears, as well as some potential applications. These are early days for such systems, but I think it’s only a matter of time before they are widely deployed.

You can download a copy of the paper from here.

It could have gone either way; but what did happen next, is in my mind a fascinating case study on the value of scientific collaboration in the absence of a profit motive, combined with a remarkable leap of faith, to successfully overcome political, geographic, cultural and scientific challenges.

Late in 1984, the Concerted European Action on Magnets [CEAM] was born at a meeting in Brussels, the result of a unique coming together of the leaders of five European academic laboratories. This was a time before the fall of the Berlin Wall, before the Single European Act and before the European Union. It was a time when the bureaucrats of Europe were trying to find ways to help member countries work more closely together, as part of efforts to reduce mistrust and to achieve the objective of a more integrated pan-European economic system. This is a system that today most Europeans simply take for granted, but at the time, it was far from clear as to whether or not it would, or could, be achieved.

By the end of its remarkable eight year run, CEAM eventually produced over 1,000 research papers and well over a dozen patents as a result of the research of over 150 scientists, engineers and product designers, from 93 participating laboratories in 13 countries. Crucially, CEAM produced enduring relationships and collaborative efforts among key research groups within Europe, who to this day continue to work together in areas of magnetics research. Just as important, CEAM enabled the creation of a new generation of research scientists and engineers, whose Ph.D. studentships and activities were made possible in whole or in part by CEAM.

I put it to you that the CEAM approach is potentially an effective model for the creation of a framework for reviving rare earths research and development, and the subsequent “incubation” of new technical talent for this sector, in the USA, Canada, Europe and beyond. It is imperative that the Western rare earths supply chain [such as it exists today] realizes that its constituent members are part of a single international “ecosystem”, and that the most effective way to challenge the People’s Republic of China in this area, is to work together within a framework NOT motivated strictly by profit or limited by national borders.

To learn more about CEAM, why it was so successful, and the six steps that could be taken to apply the CEAM model to the revival of rare earths research and development in the West, you can download a copy of my new paper on the subject: “The Concerted European Action on Magnets: A Model for Facing the Rare Earths Challenge?” in PDF format.

Take a read, and let me know what you think by adding comments below.

Since then, I’ve had the chance to play with a number of their prototypes.  I had initially been a little confused as to what the technology was all about, but having a chance to play with the different configurations gave me a better feel.  In addition, earlier this week, Design World magazine published an article with an update on the correlated magnetics technology, with a couple of videos. I had some difficulties getting the first video to play, but the second gives a good overview of the products and how they work.

As the Design World article says:

You can program, or code, the behavior of complementary magnetic structures by varying the polarity (and optionally the field strengths) of each source of the arrays of magnetic sources making up each structure. This capability, along with a cost-effective manufacturing capability, provides a multi-dimensional framework for design and development of magnets having unique spatial force functions that meet specific alignment, coupling, and release criteria.

Check out the new article today. I am told that a team from Correlated will be attending the Magnetics 2010 Conference in Florida, and will be bringing a bunch of prototypes with them.  If you’re attending the meeting, take the chance to have a play with these magnets.

Disclosures: none.

The use of algae as a potential source of fuels is nothing new within the world of renewable energy. As Siemens says:

Algae are a valuable source of raw material. For millions of years throughout the history of the world, they have transformed CO2 into valuable organic molecules. Some species specialized in the production of fatty acids and lipids. Their fossilized remains from the dawn of time are the foundation for the petroleum and natural gas extracted today. Algae continue to harbor enormous potential today as suppliers of biomass, biogas, or biodiesel. They are also easy to cultivate. They don’t need anything more than CO2 and water, and preferably wastewater at that because of the nutrients it contains.

The problem is that while it is relatively easy to grow algae, harvesting it is a real pain. Within a liter of water, only a few grams of algae grows at a time, and so the water has to be filterd and drained, which is time consuming.

The solution, according to Siemen’s Manfred Ruehrig, is to add a fine powder of magnetite – iron oxide – into the water.  The algae latch onto the magnetite and, after stirring, the algae-magnetite combination can be easily removed by using an external permanent magnet. Although this has only been done in the laboratory so far, results have been promising, and could lead to the scaling up of the process, using similar processing equipment to that used for industrial magnetic separation. The magnetite would be re-used after separating it from the algae.

According to Siemens, the process would result in less water loss, and thus it could be used for drying in drier areas.

The use of magnetic particles in this way is not dissimilar to well-establish biomagnetic separation techniques used in the medical sector, to separate blood cells, DNA and other biological entities, using combinations of chemically-active magnetic nanoparticles, and powerful magnetic fields generated by specially-shaped magnetic configurations.

The tool was developed by the magnetics engineering group at Dexter, specifically by a team led by my colleague Chris Ras, Dexter’s Product Development Manager, and with the support of the U.S. Department of Energy’s National Energy Technology Laboratory (NETL).  The tool, shown in Figure 1, is approximately 67 inches (170 cm)  long and provides over 200 watts of high density electrical power at a regulated 24 VDC, for a variety of downhole drilling, measurement and logging systems, in environments up to 250 °C (480 °F) of temperature and greater than 20,000 psi (140 kPa) of pressure.  As we drill ever-deeper into the earth,  the temperature and pressure inside the resulting wells generally increase with depth.

This type of turbine generator works by drawing energy from the drilling fluid that is pumped down under pressure from the surface, which is used to lubricate the drill bit and to remove the rock cuttings as drilling proceeds. This fluid passes through a set of turbine blades in the generator tool [shown in the cutaway schematic in Figure 2], which connects with a special permanent magnet generator that then generates power.

The new generator system can replace disposable lithium and rechargeable lithium ion batteries, which are commonly used in these systems.  Because these batteries do not operate above 200 °C (390 °F), they limiting the cycle time and depth of drilling for systems that use them.  Using the turbine generator means that in addition to oil & gas well drilling, the tool could also have applications for geothermal drilling, which can experience even more demanding conditions.

My colleague Tim Price, Dexter’s Business Development Manager for the oil & gas industry, said:

“The development of HPHT measurement and logging tools has outpaced the availability of safe and reliable HPHT power supplies. Dexter’s HPHT downhole generator was developed specifically to fill that void. We have a downhole power supply that provides regulated power from subzero surface temperatures to 250 °C (480 °F) bottom hole formation temperatures. No other single commercially-available technology can provide power over that operating range as of this date.”

Tim went on to say that:

“The need for such HPHT power supplies appears to be greater now more than ever, with the high temperature, extended reach horizontal drilling experienced in plays such as the Haynesville Shale.”

Performance data on the HPHT downhole generator products can be acquired directly from Courtney Stone, Marketing Manager at Dexter, or from me.  We are now actively looking for partners in the well drilling industry, to participate in field trials and qualification of the new HPHT downhole generator tool, in wells with formation temperatures expected to exceed 175 °C (350 °F).

Get in touch with me if that describes you or your company!

Flywheels work on the basis of imparting energy into a rapidly rotating mass, which can then be tapped for later use.  They are a well-established method of providing back up power for commercial power utilities, and more recently, they have started to see use in regenerative braking applications for vehicles, where the energy from braking is transferred into a flywheel [instead of the alternative electrical generator approach].

It is to this latter application that the Kinergy is apparently being applied.  In Figure 1 we can see a cutaway model showing the insides of the device. The blue-and-yellow components represent the magnetic gear system.

The Ricardo Web site says that:

[t]he range of potential Kinergy applications is significant not least due to its comparatively very low projected production costs. The technology is thus ideally suited for use in road vehicles where regenerative braking and torque assist is employed as a means of improving efficiency and hence reducing fuel consumption and CO2 emissions. Such potential applications range from small, price-sensitive mass-market passenger cars to large luxury SUVs, buses and trucks. Across all of these vehicle categories, Kinergy offers the prospect of enabling effective hybridisation extending into market sectors where the use of conventional electro-chemical battery systems technology would be prohibitively expensive.

They go on to say that:

Further potential Kinergy applications also include low-cost, compact energy management and storage systems for use in industrial and construction equipment, elevators, railway rolling stock, and local electrical substations and power distribution systems.

Magnetic gears of this type are relatively new, and there are not too many commercialized applications for them as yet. The systems generally consist of three concentric sub-systems which allow for the conversion of speed into torque and vice versa, without contact between the sub-systems.  They can also be combined with electrical motors and generators to form some very interesting electrical machines.

Ricardo says in the excerpts above that they anticipate “very low projected production costs“. Magnetic gears are not cheap to build, because of the labour involved, so one would have to surmise from this statement that in relation to the system as a whole, the gear sub-system is not a major cost driver. Certainly there are some significant advantages to magnetic gears over and above mechanical gears, to make them worth considering.

Ricardo is working on the use of the Kinergy concept in a demonstrator FLYBUS vehicle based on an Optare Solo bus, as shown in Figure 2.

Figure 2. FLYBUS demonstration concept, using the Ricardo Kinergy flywheel system. Courtesy of Ricardo (2009)

I’ll be posting more on magnetic gears in the near future, and I will be presenting a review of magnetic gears and related electrical machines at the Magnetics 2010 conference in Florida, next January. In the meantime, you can read the rest of the article on Kinergy here.

The Times Online has just published a story on a technology that apparently “has the potential to revolutionise the renewable energy industry by making wind power cheaper and more reliable and greatly increasing the efficiency of wind turbines for electricity companies.”

The driver behind the work, conducted by Dr Markus Mueller and Dr. Alasdair McDonald of the University of Edinburgh’s Institute of Energy Systems, is the goal of effectively eliminating the gearbox from off-shore wind turbines. Being able to achieve this would increase reliability and reduce maintenance costs, given that off-shore wind turbines are out at sea.

The researchers claim to have been able to reduce the weight of conventional direct-drive generators by up to a half, and have developed a system that is apparently simpler to assembly and manufacture. Unfortunately at this point, there appears to be little in the public domain on the new technology. I was able to find a paper presented at the 2008 European Wind Energy Conference that looks to describe the technology.

Based on this paper, it appear that the NGenTec [not "NGenTech" as originally reported by the Times] technology involves the use of a “C” shaped core generator [see Figure 1] which, according to a University of Edinburgh press release sent out on Nov 23, 2009, they’re calling C-GEN. The team used it to build a 20 kW, 100 rpm prototype. They were able to show that changing the mechanical structure of the generator led to reduce required mass while maintain rigidity and structural integrity. Building on the initial concept, the team were able to show that a generator capable of producing 100 kW, based on this design, would have a total mass of approximately 2,800 kg (6,170 lb) – less than half the 6,600 kg (14,550 lb) mass of the NorthWind 100 commercially-available wind turbine generator, which also produces 100 kW of power.

Figure 1: a) schematic of a conventional permanent magnet, radial flux generator, and b) the NGenTech C core machine. From Mueller & McDonald (2008).

Dr. Mueller and Dr. McDonald have on the last couple of weeks formed a new company to market the device, called. The new company is chaired by Mr. Derek Shepherd, “a former managing director of Aggreko International, a Glasgow-based supplier of mainly diesel-fuelled generators.“

The Times article goes on to say that:

Derek Douglas, an entrepreneur specialising in raising finance for start-up companies, has joined NGenTech [sic] with the aim of raising £4 million to prove that a 6MW generator would work and then a further £10 million to set up an assembly and manufacturing operation.

Mr Douglas goes on to say that the technology has applications for both on- and off-shore systems. This makes sense, although there isn’t necessarily the same cost premium associated with maintenance on-shore, as there is for off-shore installations.

At the moment, NGenTech does not appear to have a Web site up and running yet. NGenTec does have a Web site, and  the Institute for Energy Systems also has an extensive Web site. It shows that this group is doing extensive work in the arena of generators and electrical machines for a variety of renewable energy systems, including wind turbines, wave energy convertors, tidal current systems and the like.

From the NGenTec site:

The Company is presently raising its first round of funding of £4 million. This will enable us to develop, manufacture and build a 1 MW modular unit over the next 12 months. This 1MW modular unit will be specifically designed to form part of a 6MW generator we plan to manufacture and test the following year.

According to the University’s press release, the new company was spun out of the University by Edinburgh Research and Innovation (ERI), the University’s successful research and commercialisation arm, which celebrated its 40th anniversary this month. The University retains a minority stake in the new business.

The initial proof of concept work was funded by Scottish Enterprise.

I’m looking forward to seeing how these chaps progress with this project. You can read the original Times Online article here, incorrect spellings and all…

Microfluidics involves the control of fluids in very small channels and containers. According to the article:

The NIST connector employs a ring magnet with a O-ring gasket on its bottom and a tube in its center set directly atop the inlet or outlet port of a microfluidic channel embedded in a glass chip. A disc magnet on the underside of the chip holds the first magnet — and its tubing — securely in place.

According to the abstract of the original paper on which the article was based, “interfacial forces in the range of 2-15 N” have been achieved.

The folks at NIST do warn that while these connectors are suitable for a range of microfluidic applications, they are not suitable for use with magnetic nanoparticles or at higher temperatures.

You can get more details on this application here.

Over the past few days, Australia’s ABC Radio National broadcast not one, but two items on rare earth metals, to both of which I heartily recommend listening.

The first item was broadcast on the Breakfast program on Friday, and lasts a little over 6 minutes.  It’s an introductory piece on the subject, but spends significant time discussing the environmental issues surrounding rare earth production in Australia. You can listen to the piece on the program’s Rare Earths Metals segment Web page or by clicking below:

ABC Radio National Breakfast: Rare Earth Metals

The second piece, first broadcast on the Background Briefing program this past Sunday morning, lasts for over 45 minutes and is an comprehensive, in-depth study of the rare earth metals, their markets and associated supply chain, environmental and political issues.There is also a pretty decent-sized portion on rare earth permanent magnets and their applications, for which, in the interests of full disclosure, I was interviewed :-)

As producer and narrator Stan Correy says:

China currently produces about 95% of the world’s rare earths, which are metals which are essential to modern living and used all around us every day. In business it’s a volatile mix, with complex political alchemy for every government, including Australia.

The program features several interviews of a variety of individuals from a number of different sectors, in addition to yours truly.

You can listen to the piece on the Background Briefing Rare Earths and China program Web page or by clicking below:

ABC Radio National Background Briefing: Rare Earths and China

Stan did a great job in explaining what can be a difficult subject to convey.  He also included a link back to Terra Magnetica – so thanks, Stan, for that!