Alternative Energy Links

France's Areva SA is known mostly as a designer of light-water nuclear reactors, builder of transmission and distribution systems, and a miner of uranium, so the announcement today that it has purchased 100 per cent of concentrated solar power company Ausra Inc. came as a surprise. Ausra, based in Mountain View, Calif., was founded by Canadian inventor Dr David Mills. Mills developed the underlying technology as a student and professor in Australia, but located the company in Silicon Valley as part of a major venture capital infusion from Khosla Ventures and Kleiner Perkins Caufield & Byers. Mills is currently the company's chief scientific officer.

Areva said today that the acquisition marks its entry into the solar thermal power market, where it intends to be the leader. The market itself is expected to grow 20 per cent annually over the next decade. This is just the latest in a string of acquisitions and deals aimed at broadening Areva's portfolio of renewable energy products and services. The company has been pushing heavily into biomass power and has been building biomass/biogas plants in the U.S., Brazil, India, Thailand and other countries. It is dabbling in hydrogen production and fuel cell systems, and through its acquisition of Germany's Multibrid is trying to establish itself as a future leader in offshore wind.

It's going to take big, deep-pocketed companies like Areva to really push deployment of solar thermal and other promising renewables, so this acquisition of Ausra is a good sign of where the market is heading. Given that the nuclear renaissance simply isn't materializing as expected, it's wise for Areva and other big energy conglomerates to hedge their bets.

Clean energy is one of the top topics in the world these days, in presidential speeches, economic growth plans and projections, international competition and cooperation, and even in Hollywood. We have seen rapid growth in wind power, rooftop solar, innovative financing, and much more recently.

Here is my list of the Top 10 “Clean Energy” Topics (some aren't what I would consider the cleanest) to keep an eye on.

1. International Clean Energy Race

The “international clean energy race” may well determine who will lead the world economy in the future — “the nation that leads the clean energy economy will be the nation that leads the global economy” (Obama, State of the Union 2010). China is about to make the largest solar and wind projects in the world look like little LEGO projects and it seems like it is #1 or fast-approaching #1 right now. “Every day we wait in this nation China is going to eat our lunch. The Chinese don’t need 60 votes.  I guess they just need 1 guy’s vote over there – and that guy’s voted” (Republican Senator Lindsey Graham to 200 business leaders, 2010); “China now leads world in clean tech. Time for a Sputnik program to reclaim leadership” (Representative Steve Israel of New York, January 2010).

On the flip side of that, the cooperation-focused (rather than competition-focused) United Nations climate conference in Mexico that is supposed to keep the ball rolling from the Copenhagen Accord is something to keep an eye on as well (along with all of its lead-in and follow-up activity). In a sense, this can be combined with the clean energy race topic because it is intended to put everyone on the same track.

2. Climate & Clean Energy Bill in Congress

The US’ best bet at getting ahead in the global clean energy race and at providing a livable environment for our children and grandchildren might be the climate and clean energy bill that is inching its way through Congress. The public supports it. Hollywood is trying to get people to put the pressure on their representatives in Congress. And big business is putting the pressure on Congress. However, the coal and oil lobby and its Congressional robots are constantly trying to undermine the bill.

3. PACE Funding

Property Assessed Clean Energy funding started in Berkeley, California in October of 2007 and is on the move. What’s so special about it? It “allows private property owners to pay for energy efficiency and renewable energy projects through an addition to their property tax bill, overcoming the high upfront costs that prevent most property owners from investing in such retrofits.” People can avoid the high upfront costs of solar technology but can capitalize on the long-term benefits of it and save them money!

This is also a less controversial tool than broader initiatives like cap and trade, so one hopes that this becomes a real federal priority soon. Our own Susan Kraemer writes: “One very effective way to transition fast to clean power in a way that can bypass our Senate block on cap and trade, is to make PACE funding for renewable energy available to homeowners nationwide in the budget. Budget funding can be passed with a majority of just 51 votes like in other democracies.”

A UC Berkeley study found that there is “potentially a gigaton of greenhouse gas reductions to be made, at no cost to local, state, or federal governments from a $280 billion potential market in PACE solar funding in the US.” Cities and counties that are picking it up are seeing dramatic growth in solar power (e.g. “California’s Sonoma County which offered PACE starting in March in California recently reached an astounding 4% of power on the grid coming just from rooftop solar alone.”)

4. Distributed Solar Energy

Simply, distributed solar is “energy generated, stored and managed at the local level.” Distributed solar includes private installations (e.g. on the roofs of houses, businesses, etc.) which are actually more popular than utility-scale solar these days as well as things like small photovoltaic farms. Distributed solar projects can be combined into larger power purchase agreements for a big bang as well.

Distributed solar has several key advantages over large-scale solar projects: quicker implementation, better ability to upgrade or innovate to more efficient technologies, and much more flexibility in siting. Due to all of its benefits and increasingly cheap solar technology, distributed solar seems to be booming and is getting more and more people’s attention. As the New York Times reports, “Over the past few weeks, some 1,300 megawatts’ worth of distributed solar deals and initiatives have been announced or approved. At peak output, that is the equivalent of a big nuclear power plant.”

5. 10 Million Solar Roofs Bill

New bill just introduced to Congress from Independent Bernie Sanders proposes incentives and tax rebates aimed at getting 10 million solar roofs and 200,000 solar heaters up and running over the next 10 years. Keep your eye on that!

A California-based solar company capable of building solar facilities that put out as much energy as a plant running on non-renewable fuels is being bought by a French engineering firm best known for its nuclear capabilities.

The San Francisco Chronicle reports that Areva will buy Ausra, a startup specializing in large-scale solar power:

The deal will give Areva a way to break into the growing worldwide business for big solar facilities that can generate as much electricity as a fossil fuel power plant. Although Areva is best known for its nuclear expertise, the company has branched out into other forms of renewable power generation, such as biomass and wind.

“By combining Areva's strengths and Ausra's technology, now we have the complete package we need to go to market,” said Robert Fishman, Ausra's chief executive officer.

Ausra's business headquarters will stay in California.

Two grants totaling $1.7 million have been approved for studying offshore wind technologies in Michigan.

The Chicago Tribune reports the grants come from the state's Public Service Commission:

Grand Valley State University's Michigan Alternative and Renewable Energy Center and the University of Michigan's Memorial Phoenix Energy Institute are getting $1.3 million for jointly researching offshore wind and ice data on Lake Michigan.

The Superior Watershed Partnership is to receive $350,000 for researching sites' wind energy potential on Lake Michigan. The organization also will assess public opinion on offshore wind development.

If the last post I had about an offshore wind energy project in Lake Michigan, where Scandia Wind was proposing a 1,000 megawatt Lake Michigan wind farm, is any indication, there should be plenty of discussion about this topic … on this site and elsewhere. Let's see what people have to say.

As Congress debates (or tries to debate between blizzards) the jobs bill, the measure that would put lots biodiesel workers back on the job seems to be tied to that same bill's fate.

This post on the Des Moines Register's blog says Democrats had hoped to get the jobs bill to the floor today, but the 30+ inches of snow over the weekend plowed under that bill … and the renewal of the lapsed federal biodiesel tax subsidy:

Beth Pellett Levine, a spokeswoman for Sen. Charles Grassley, the senior Republican for the Senate Finance Committee, says he “has insisted that the biodiesel tax credit be a part of any discussions” on a jobs bill with the panel’s chairman, Montana Democrat Max Baucus. The $1-a-gallon tax credit for biodiesel “remains a top priority for Senator Grassley to extend the credit at the first available opportunity,” she added. Soybean growers are looking to Grassley to ensure that the biodiesel credit is part of any jobs bill to come out of the senate, according to John Gordley, a lobbyist for the American Soybean Association.

Renewal of the federal biodiesel tax incentive is seen as the last element to put the biodiesel industry back on track. The other two elements were the EPA's decisions to consider biodiesel low enough in carbon footprint and mandate this year of 1.15 billion gallons of the green fuel.

The Chairman of the National Biodiesel Board is Ed Heglund, seen here as a guest on today's AgriTalk show.

Ed says that attendance was something they were very concerned about here at the Conference due to the state of the industry and the weather but they had to bring in 100 extra chairs to the opening general session so he thinks attendance is better than expected. He's optimistic for the future because of the EPA RFS-2 ruling and the expectation that the biodiesel fuel credit will be re-instated soon.

You can listen to my interview with Ed below.

National Biodiesel Conference Photo Album

Last week, the Southern California Association of Governments turned down $11 million in stimulus money for Pearson Fuels to install 55 E85 stations. Huh. And this shortly after the expanded rules were announced for the Renewable Fuels Standard not to mention the Low Carbon Fuel Standard that went into effect on January 1.

What would cause the most notorious state, hailed around the world for its progressive environmental policies, to shun a lower carbon fuel? Hmmm…could it maybe, just possibly be that it is blinded by it's Big Love for Big Oil?

Let us for a moment, take some time to reflect on California's torrid affair with oil.

Last year California Lawyer Magazine Awarded its Clay Awards which are given to lawyers who show extraordinary achievements. Lawyers John Daum and Mary Nichols both won a Clay Award for two very different achievements. Daum won for his co-counsel regarding the worst oil spill in environmental history – the Exxon Valdez. But he didn't win for his work to hold Exxon accountable for its actions – he won the award because he was able to lower the punitive damages that were to be paid to fisherman, landowners and others by one-tenth of the original damages. The magazine writes, “This was truly a signature punitive damages case, and it could have major implications for environmental and other torts in the future.”

While Daum was given an award for his work in defending Big Oil's environmental offenses, Mary Nichols, who is the chairman of the California Air Resources Board and Daum's wife, was given an award for her role in passing the Global Warming Solutions Act of 2006. This piece of legislation is intended to reduce CO2 emissions to 1990 levels by 2020. While the final rules are just now coming through the pipeline, the policy could potentially regulate all areas of energy use including land use and will be enforced through a “cap-and-trade” program. It is important to note that through this program, Big Oil doesn't have to reduce its CO2 emissions solely through alternative fuels. If they bring to market technology that reduces CO2 but still uses fossil fuels, the technology will still meet policy requirements.

Not allowing to let the relationship fizzle, the state rekindeled its love with its latest proffering and now its sizzling once again.Less than two weeks ago, Governor Schwarzenegger appointed oil lobbyist Cathy Reheis-Boyd, “a global warming advocate” and currently the President of the Western States Petroleum Association, as chair of the Marine Life Protection Act (MLPA) Blue Ribbon Task Force. The MLPA is a debacle in and of itself (23 percent of all off shore oil reserves are believed to be off the coast of California) and it is important to note that Reheis-Boyd has been tasked with monitoring marine protection at the same time oil companies are in a lobbying frenzy to expand drilling operations off the California coast.

The affair has become more sordid indeed.

The state of California seems to be taking on a new mistress – the environment — and like most people having an affair, is making promises of divorce while buying his wife (or husband) more elaborate and expensive gifts with no intentions of ever leaving. This relationship is doomed. Eventually someone has got to go, but in the meantime, we're caught in the middle of a bad reality TV show yet we can't look away.

I'm all for balancing environmental policy with a comprehensive energy policy that favors clean energy. But we're never going to reach our clean energy and security goals if we keep kowtowing to Big Oil and creating policies that are too difficult for developing clean energy technologies to achieve. There is a divorce in order. California needs to walk away from its failed relationship with oil (it was good while it lasted) and marry his mistress – the environment.

BTW – I'm dedicating this week to oil so check in tomorrow for my book review of “Crude World: The Violent Twilight of Oil.”

Last week, I wrote a story regarding President Obama's executive order for the federal government to reduce its greenhouse gas emissions 28 percent by 2020. One goal of this program is to get other companies to follow suit, but many companies don't know where to start. Enter the Hondo Green Assessment Tool (HGAT). To learn more about how companies can become more sustainable, I spoke with the Hondo Group's CEO Lynn Balinas.

HGAT is an internet based tool for small to mid-sized companies that can measure a company's carbon footprint, manage its carbon footprint and maintain carbon footprint goals, explained Balinas. The tool measures five categories: water, energy, transportation, materials and waste. Ultimately the tool helps companies become not only more sustainable but more profitable as well.

“People usually first think, it's about the environment, it's about global warming. That's part of it,” said Balinas. “But it's good governance and it's actually profitable for organizations.”

A few years ago, people perceived that going green meant going broke. That is actually not the case. Going green will actually help you make more green. For example, if all small to mid-sized businesses turned off their computers and printers at night (unplug the electronics) nearly $2.1 billion could be saved annually.

Here is how it works. After 35 days of metrics based on the five categories outlined above, the HGAT will tell a company how to reduce the carbon footprint and give suggestions that a company can choose to integrate. Ultimately, the tools that are put into place will help a company manage its program and save money.

Companies can implement the program alone or partner with other small to mid-sized companies. Balinas said that the average cost to a company with less than 50 employees is around $50 per month but the return is much greater.

Listen to my interview with Lynn below to learn more about HGAT.

Economist Don Reynolds was the keynote speaker at the opening general session here at the National Biodiesel Conference. He appeared on stage two years ago and predicted the problems in our economy. Today he started out on a very optimistic note in part due to his belief that we'll continue to see a growing recovery of the economy. His comments were meant to help participants define what is the “new normal” in today's business environment.

His style is very entertaining and filled with facts and figures that help you better understand what the future may look like. He thinks it's looking very good.

You can listen to his speech below.

National Biodiesel Conference Photo Album

In November 2009, I had talked about how the first of the 20 BC Transit hydrogen fuel cell buses were arriving in Whistler, British Columbia in time for the 2010 Vancouver Winter Olympics.

The 20 BC Transit hydrogen buses, powered by Ballard fuel cells, are the largest single bus fleet anywhere. Besides being zero emissions vehicles, the BC hydrogen buses have a range of over 300 miles and can be refueled in 8 to 10 minutes. Air Liquide will be supplying the compressed hydrogen gas for refueling.

Once the Olympics are over with the buses will continue to be part of the BC Canada Hydrogen Highway system, which is part of the West Coast hydrogen highway system that is being built from Whistler, BC all the way down the coast to around the San Diego area.

The 2009 Hydrogen Road Tour that took place this past summer featured a procession of hydrogen cars traveling from Chula Vista, CA (south of San Diego) to Vancouver, BC with many stops at H2 fueling stations along the way.

Joining the 20 BC Transit H2 buses at the Olympics will be a hydrogen fuel cell hybrid bus from the University of South Carolina and a fleet of Chevy Equinox fuel cell vehicles. The 2010 Vancouver Winter Olympics will begin this Friday, February 12, 2010.

There has been a lot of development and commercialization of hydrogen fuel cell forklifts over the past couple of years. I’ve talked about FCV forklifts in the U. S. food industry, including Coca-Cola and FCV forklifts for Walmart. Outside the U. S. I’ve talked about fuel cell forklifts in Scandinavia and Germany.

This past summer I had talked about the H2 Mobility plan for Germany in which eight large companies had signed onto in order to rollout enough H2 fueling stations for the commercialization of hydrogen vehicles by 2015.

One of the companies that had signed on to this agreement for Germany to become a hydrogen transportation corridor is Daimler which is producing 200 FCVs in the next couple of years with aims at commercialization by 2015.

Another of these eight companies is Linde, which is not only a major supplier of hydrogen gas in Germany but is also now in the business of building H2 forklifts. The forklifts or “trucks” as they are being called are replacing two diesel forklifts at the Linde plant.

The fuel cell forklifts are being used to haul compressed gas tanks between warehouses and trucking points. Now, granted, hydrogen fuel cell forklifts may not be as sexy as hydrogen cars, but they are practical, economical, environmentally friendly and being commercialized now.

Proton Power Systems and Smith Electric Vehicles have teamed up to produce an electric car with fuel cell range extender. This terminology will most likely go over better with battery electric vehicle fans than the term hydrogen fuel cell hybrid vehicle.

Most likely the term electric car with fuel cell range extender was chosen because the electric car without the range extender has a range of about 100 miles. By adding the Proton Power PM200 fuel cell the car picks up another 86 miles in range. Had those numbers been swapped, however we’d most likely be calling this a fuel cell hybrid electric vehicle.

The first commercial EV with FC range extender will be rolled out in Germany in the last quarter of 2010. The first customers will be fleet operators and local authorities. It makes sense that the first vehicles would rollout in Germany which is part of the European Union Hydrogen Highway system.

Germany, which has an area of 137,000 square miles has 30 hydrogen fueling stations in place with a commitment to the acceleration in building more H2 stations over the next 5 years. By comparison, California has an area of 164,000 square miles and has 27 hydrogen fueling stations operational, but not all are open to the public.

This is a little futuristic and still in the concept phase but I’d like to talk about it since it ranks high on my “coolness” gauge. A British design company called Seymourpowell was commissioned by Samsung Construction and Trading (C&T) to come up with a futuristic design for hydrogen powered air travel.

The Seymourpowell Aircruise is the result of this futuristic thinking. The idea behind the Seymourpowell Aircruise Concept is that it will be a floating luxury hotel that is over 800 feet tall and will float like a large balloon over cityscapes or dramatic landscapes like the watching of the migration of the wildebeests in Kenya. An ocean trip from New York to London would take 37 hours.

The Seymourpowell Aircruise would accept up to 100 guests, and 10 luxury apartments would be up for grabs. The photos on this page do not do the Seymourpowell Aircruise concept justice so here’s a video on the vision.

Now, I don’t want any hydrogen haters helping to harbor comparisons to the Hindenburg here. The Seymourpowell Aircruise will above all be safe. Hydrogen gas will provide the lift. The airship will also be powered by solar energy plus several hydrogen fuel cells which will provide not only the motivation but also safe drinking water for the customers.

This serene type of air travel will include large spaces within the craft for dining, lounging and a bar for entertainment. The crew at Seymourpowell anticipate that the Aircruise hotel could be ready as early as 2015 if the project is a go. This may be a bit pie-in-the-sky as far as how future hydrogen travel may go. Then again, perhaps the sky is the limit and we are only limited by our current imaginations.

It’s Groundhog’s Day, again. And as a sign of the times, the famous Punxsutawney Phil stepped out of his burrow, saw his shadow and apparently text messaged all of this friends that there will be six more weeks of winter.

Now, just as Phil text messaging all of his friends doesn’t seem to go together, neither does electricity and hydrogen. But, this is what researchers in Virginia and China are proposing.

Scientists at the Virginia Commonwealth University (VCU), the Chinese Academy of Science in Shanghai and Peking University in Beijing are proposing the use of an outside electrical field to contain hydrogen molecules efficiently and reversibly at ambient temperatures.

According to Puru Jena, Ph.D at VCU, “Using an external electric field as another variable in our search for such a material will bring a hydrogen economy closer to reality. This is a paradigm shift in the approach to store hydrogen. Thus far, the efforts have been on how to modify the composition of the storage material. Here we show that an applied electric field can do the same thing as doped metal ions.”

Right now there has been much research on metal hydride storage. Hydrogen clings to the metal at low pressures and ambient temperatures because of a weak electrical charge that bonds the molecules. The new proposal says that a weak electrical charge can be applied from the outside to “contain” the hydrogen inside some sort of fueling tank and when the electricity is shut off the hydrogen is released for the vehicle to use.

Now, this may seem counterintuitive to many, who think that hydrogen and electricity go together about as well as a flame and gasoline. But, the scientists aren’t talking about a spark to ignite the H2 fuel but rather charge polarization at the molecular level.

Like I’ve stated before it is this kind of outside-the-box thinking we will need in order to solve the issues, getting in the way of rolling out a full-fledged hydrogen transportation system in the near future.

The importance of a clean energy economy was visited time and again in President Obama's State of the Union address.  With such strong support coming from the White House, we here at SunRun are very excited about what 2010 will bring for solar.  SunRun's president, Lynn Jurich, spoke to Fox Business on Thursday about the future of the solar energy sector, as well as the hundreds of green jobs the solar industry has been able to create.





Not only has home solar become an affordable option for millions of homeowners, but it has also been able to create clean, permanent jobs.  According to research, for every six homes that goes solar, a green job is created — and that's not including the other jobs created down the supply line.  And these are jobs created within the nation – here and at present.

Watch the Fox Business clip to hear more about green jobs, federal subsidies, and the future of solar.

This week’s WindEnergyUpdate news brief includes: Cape Wind & the MMS; EWEA; London Array, MPI & A2SEA; Siemens; AMSC; Scotland’s offshore wind manufacturing potential; Wind grant to North England; APS; GWEC; General Electric; and the UK’s small-scale FiTs.

read more

The weight of wind turbine generators is a significant issue because weight translates to costs. The structural weight of a direct-drive generator, for example, can exceed 80% of the total weight on the tower. The structure is needed to overcome the force of magnetic attraction between stationary and moving parts. The attraction force, a result of the normal component of Maxwell stress, can be 10 times the torque producing shear stress. The function of the generator structure is to maintain an airgap between the rotor and stator.

Ideally, a directly-driven generator should produce moderate to high shear stress while negating the effect of the magnetic attraction. A new topology has potential to meet that challenge, without resorting to exotic structural or magnetic materials such as superconductors. The concept takes the active materials in the machine – copper, magnets and steel – and changes their relative positions to minimize the normal-force effects. The result is a structure that need only support the weight of the active components, leading to a reduction of about 55% compared to conventional permanent magnet (PM) machines. Results show the weight reduction while maintaining high efficiency at all loads. Experimental results from a 20kW, 100 rpm prototype verify the expected performance.

Design details

The new design is air-cored, meaning there is no iron in the stator so there is little attraction between rotor and stator. In two-sided axial-flux air-cored machines, the two rotors attract each other. Because the airgap-flux density, B, is lower than for an iron-cored machine, the shear stress, σ, is lower as shown by

σ ∝ BJ (1)

where J = current density, A/mm2. The current density in the generator coils is limited by copper losses and cooling requirements. To produce the same torque, T, the outer radius, ro, of an axial-flux machine must increase to accommodate the lower shear stress because

where kr = ratio of inner to outer radii.

The increase in machine radius, when moving from iron-cored to air-cored designs can cancel the expected reductions in structural weight. One wind turbine design from Goliath Wind OU, Estonia, proposes an ironless radial-flux generator which has no airgap closing force. This is accomplished with an ironless outer stator. Its generator has a large radius, R, held in place by a lightweight spoked structure. The ironless stator produces a large airgap, so its flux density and shear stresses are small. A large air-gap radius is needed because of the low shear stress. Equation 3 is the radial-flux equivalent of Equation 2,

where L = axial length. A previous simple study showed that air-cored machines are potentially lighter for a range of power ratings.

Developing a C-core machine

A logical development of such axial-flux disc machines is to increase the rotor-shaft radius. Because airgap normal forces act near the junction of shaft and discs, the discs can be made thinner and therefore lighter. Taking this further leaves a C-shaped cross section, where the limbs carry magnets and the stator winding is held independently between them. A further step lets flux cross the web of the C and makes the rotor out of modules each carrying a pair of magnets. Rotating the C-core modules 90° produces a radial flux machine. Increasing the axial length allow increasing the radial-flux generator’s torque rating without increasing the outer diameter.

This topology has advantages over existing ironless designs. A radial-flux ironless permanent magnet machine has a large effective airgap. This C core machine, however, has a smaller airgap length making possible higher flux densities and shear stresses. A corollary is that less permanent-magnet material is needed to produce the same flux density, so the design will be cheaper. This machine also has the advantage of two main flux paths, longitudinal and transversal, not just one. Because the amount of magnetically active steel depends on its non-saturation, this should be a lighter design than an axial-flux, two-disc machine.

Active and inactive material

The new topology is structurally superior to an iron-cored machine. In a conventional radial-flux machine, large airgap normal forces can act at distances of several meters from points where these forces can be reacted against. This implies that the rotor and stator structures must be stiff, large, and heavy. In contrast the new machine has no forces on the stator. Although the two limbs of the C-core are attracted to each other, normal stresses are reacted at points within the C-core – close to their point of application. This topology means that the steel in the C-core fulfills both active and inactive roles.

To test the ideas, a 20kW, 100rpm generator was designed at the University of Edinburgh and built by Fountain Design Ltd. (fountaindesign.co.uk) It is instructive to describe the build sequence and highlight topology’s manufacturing advantages. The rotor of the prototype C-core machine was made of 32 modules, each carrying a pair of permanent magnets similarly oriented. In this small machine, the C-core module was assembled from three trapezoidal pieces of mild steel, with magnets sliding onto the inner and outer pieces. For larger machines, magnetic material could be glued in place and magnetized later.

This would ease the problems of handling large magnets. Modularity allows the cheap and efficient production of large volumes. An assembled module is quite benign and safe to handle, because there is relatively little leakage flux outside the confines of the C core. The modules can be brought together and fixed to a common rotor structure. The prototype uses an aluminum disc.

Bringing together a rotor and stator can be a difficult and dangerous task in a conventional permanent-magnet machine because of the large magnetic attractions. Doing so is liable to pull either the rotor or stator off center and produce an unbalanced magnetic pull, thereby closing the airgap clearance even further.

A feature of the C core machine is that because there is no iron in the stator, there is no force of attraction between rotor and stator. This makes a straightforward task of threading the stator winding into the rotor. The stator in the prototype is made of 24 pseudo arc shaped concentrated coils, clamped between two rings. The coil’s discrete nature means they will be easy to replace. This will be a significant advantage in larger machines, as electrical faults are one of the more common causes of failure in direct-drive wind-turbine generators.

The prototype

The 20kW prototype machine generated a perfectly sinusoidal no-load voltage waveform of 26.7 Hz frequency at 100 rpm. A power-versus-efficiency chart gives the mechanical-to-electrical efficiency of the prototype generator over a range of speeds for a range of loads, typical for this size machine. Results show that the design matches the performance of conventional PM synchronous generators.

Thinking bigger

Conventional PM machines tend to have optimal aspect ratios (axial length to airgap diameter). In terms of electromagnetically active material, less of it is needed with a small aspect ratio and large airgap radius, R. This is because the active weight is almost proportional to the airgap surface area (2πRL) whereas the torque, according to Equation (3), is proportional to R2L. Increasing the radius therefore increases the specific torque (with respect to the active weight).

There are two limits to how small the aspect ratio can be. There is a practical limit to how big the airgap diameter can be so that the generator can be transported and fit into a nacelle. The second limit is the structural material: the structural weight of a radial-flux machine is proportional to the square of the airgap radius (for a constant axial length and for a deflection fixed in relation to the airgap clearance). The C-core machine follows the same scaling laws for active weight, but has a different law for the structural material.

In C-core modules, limbs deflect into the airgap by:

where y = deflection, w = uniformly distributed load and a product of the normal component of Maxwell stress and the width of the limb. l = length of the cantilevered beam, and A = the second moment of area.

For a fixed axial length and a trapezoidal cross section, the weight of structural material, wstr (needed to limit y to a fixed proportion of the airgap clearance) is related to the airgap radius by:

This means the specific torque with respect to structural weight also rises with increased airgap radius.

The Generator weight and airgap charts show the generator weight based on the C core concept for 100 kW to 2 MW wind turbines. The electromagnetic design used the same basic pole pitch layout as the 20kW machine, with the number of poles and coils varied proportionately to the airgap radius.
The airgap clearance above and below the coil was taken as 0.1% of the airgap diameter. The magnetic flux was modeled using a simple lumped parameter magnetic circuit and the iron was not allowed to saturate.

For structural modeling, the maximum deflection of a C-core limb was restricted to 10% of the airgap clearance. Generator mass versus power show results for five different axial active lengths. As expected, designs with an active length of 0.4m are lightest because they reduce the active and structural weight. At larger ratings, these axially short machines may not be practical because of their large airgap diameters. Even the axially longest have great promise because these designs are not yet optimized for minimum weight.

Economic conditions don’t look good right now. Our nation is at war, businesses struggle to get sales going, and the future feels uncertain. To make matters worse, baby boomers, the most experienced people in your company, are thinking about retirement and some will take advantage of it. If there ever was a time that called for solid new leadership, this is it.

The question is, how do you find leaders for your company? The answer is you don’t. You train them. A good reason for doing so comes from Jim Collins’ book “From good to great”. In it, he reports on researchers who evaluated a range of similar companies led by CEOs hired outside the firm and those run by people who rose through the ranks. The good news is that the home grown CEOs generally outperformed the hired guns.

Although I’m no leadership expert, working with people over the last half century has led me to recognize several traits useful in a leader. Sooner or later you’ll be asked to head a project or department. So consider cultivating these characteristics:

For goodness sakes, show some enthusiasm. Let your people know you’re glad to be there. No one enjoys working for a stoic. When a staffer does something right, let them hear your appreciation. Remember: Praise in public, criticize in private.

Listen to your team. They are chock full of good ideas. You just have to ask for them. Ask them in small groups because people seem more willing to share in the comfort of, say, two to five peers.

Don’t underestimate quiet people. One former colleague was the quietest on staff, especially when in an audience. At press conferences she rarely asked questions or made comments. But when asked for a suggestion away from the crowd, she always offered a worthy idea.

Back up your followers because sometimes the cantankerous client is not always right. This is where your diplomatic and negotiating skills come in.

Let your team know what is going on and what you expect of them. Set clear group goals. You’ll expect them to talk to you so talk to them as well. Tell them how the department is doing and ask for ideas how it might do better. Be honest. They will know when you’re not and that can hurt your credibility.

Cultivate the peculiar genius. Most groups have one. Sometimes they are unsociable, easily riled, and may easily irritate others because of their unconventional manner. You need their special skills and out-of-the-box thinking, so let them be peculiar. And lastly:

Be nice to the gray-hairs. Maybe a few will stick around and you’ll learn something new.

Wind energy and leadership

The renewable industry is a growing endeavor with windpower in a leadership role showing what can be done with the right ideas and goals. Every company in the wind industry has an opportunity to be a leader by delivering on the promises and expectations that wind can be the world’s most efficient renewable energy. Join the sponsoring companies in this issue and me as we deliver on those expectations and promises.

The flower, by Art Energy Design, is a renewable energy display with solar cells attached to leaves while the flower petals act as a rotor to turn a 6V generator. Both charge a battery in the base that stores enough energy to keep the display lit by LEDs at night.

The Pittsburgh Power Flowers Project says it combines sustainable energy devices with a variety of artistic designs. “Power Flower public art sculptures are one example of our mission-specific design series,” says Dave Edwards, artist and spokesman for the organization. The flower is intended to demonstrate thought-provoking ways wind, solar, and recycling ideas can be built into urban landscapes.

“Understand that we are artists, not engineers,” adds Edwards. “The real power of our Power Flower is the conversation it starts about sustainable energy. We have created an educational tool that uses the universal appeal of art to meet the public at all levels of understanding.” He adds that people generally understand that if future power is generated close to where it is used, then these devices might have to blend esthetically into the urban landscape.