At least, that was the suggestion that grew out of a recent conversation between Renewable Energy Magazine and Josh Paquette of Sandia National Laboratories in Albuquerque, New Mexico.
Sandia is one the United States' foremost research facilities when it comes to the future of wind energy, and Paquette is the laboratory's Task Leader for Laboratory and Field Testing of Wind Turbine Blades.
When REM caught up with him, Paquette was running between meetings on various ongoing research projects. One was with a study group called the blade reliability collaborative, a research team that is looking at the intersection of materials and manufacturing, and how materials get put into wind turbine blades.
At the same time the group is taking a hard look at the reliability of blades that are currently coming out of the factory and during their operational life.
Another of the meetings on Paquette's busy schedule involved a long-term project where we are looking into the feasibility of putting very large, floating, vertical- axis wind turbines in the offshore environment off the US coast.
Given your meeting schedule, it seems like wind energy-related research is very robust right now...
Yes, I would say so. I mean, the US Dept of Energy has been conducting research into wind turbines since the mid-1970s and European research entities and universities have been at it for at least that long, if not longer. So, yes, there is a lot going on.
And yet,, here in America at least, the hand-wringing continues over the fate of the federal production tax credit. Does research ebb and flow with the fate of the PTC?
I couldn’t really speak to what manufacturers do. Probably many of them handle it in different ways. As for the US Dept. of Energy, while I'd say it's somewhat more insulated from what happens with the production tax credit, there have been times, particularly in the 1990s, when the industry had a bit of a hard time, and that ultimately would lead the government to question why they are spending money on research for an industry that they view as being on its way out.
Thankfully, research budgets at the DOE have gone up consistently for the past five to 10 years…
What percentage of the research done under the DOE's auspices involves composites and materials, and what percentage is devoted purely to new technologies?
I don’t know the exact percentages. At Sandia we have several different projects going, each of which has its own components. I would say 10 to 20 percent goes to composites. But our budget is roughly 10 percent of the DOE’s total wind program budget. The National Renewable Energy Laboratory in Colorado gets a large part of the rest, as do competitive solicitations that have been awarded to universities and industry.
With composites, is that research mainly driven by people wanting to make bigger blades?
The thing that makes composites for wind different from the use of composites in a lot of other industries is that the price composites structures, namely blades, have to be delivered at, is generally at least an order of magnitude less than for, say, aerospace components.
So where in aerospace the price might be $100 a pound, wind works with something less than $10 a pound. The second part of it is wind turbine blades experience some peak loading cycles that are larger in number than just about any other composite structure that exists. A modern wind turbine blade will experience something like 100 million fatigue cycles over its lifetime.
Why the dramatic cost difference?
I think there are a variety of reasons, but mostly I think it boils down to aerospace components being life-safe designs. And so they are held to the standard that they need to support and protect human life.
Wind turbines are… well, they don’t necessarily hold that same factor. The main driving factor behind a wind turbine is competitive cost of energy. Wind turbines have to compete with fossil fuel generation, nuclear, hydro electric and things like that.
So our cost driver is fairly steep for wind. It has to be economical or else nobody is going to install it.
So that’s what makes composites difficult for wind turbines. We have big load drivers and we also have a big cost driver.
That said, I think that big strides have been made in being able to produce acceptable quality parts at very large scales. Modern wind turbine blades are being build at 50 to 60 meters, and they are some of the largest, if not the largest, composite structures that are being built currently. And they have good life times for the most part. There are some cases of manufacturing flaws that have worked their way into blades and there are consequences of that, but... the research and the technological advances continue.
So maintaining cost competitiveness and performance at those scales has been a real challenge and I think it's a real achievement of the industry.
How does your research transfer from lab to commercial application?
Obviously we produce public reports and documents and presentations we give at conferences. I think some of the most meaningful activities that Sandia has worked on have been our collaborations with Montana State University.
That relationship has been ongoing for over 20 years, and it has led to out producing the DOPE/Sandia/Montana State University composite materials database.
This is a data base that has the results of over 12,000 materials test on wind specific composite materials and it's utilized by not only the wind industry, but also the aerospace and automotive industries for co-validations and in some cases, design…
But it is a very unique database because it includes so many test results for fatigue performance for composite materials, which I mentioned before is a large driver of our research into design.
Would it be accurate to say research institutions like Sandia are the leaders of wind energy research in the US are the leaders? Are commercial entities that have located R&D facilities here on par?
I think it's very encouraging in the modern wind turbine industry that OEMs have very large research budgets and do very top notch research on their own -- In addition to the research the we and other universities and laboratories do.
And something that’s even more encouraging recently is that there is a real push among composite material manufacturers, both the resin suppliers and the fiber suppliers, to do their own research, and these are large companies devoting very sizable sums of money specifically to wind turbines.
I gather from what you said earlier that you also spend a fair amount of time mulling the effectiveness of manufacturing processes when it comes to blade manufacturing...
That is a very important observation. For wind materials at least as much as aerospace composite materials. I mentioned before that the intersection between materials and manufacturing is of the utmost importance.
You can take a good material and make it bad with a bad manufacturing process and so that’s way we tend to combine those in our research and our thinking. It's not enough to have a good material; you have to have a good way to put it into the blade.
So there had been research – very recent research actually - into different processing methods. And with a particular interest in automation. And what we've found in the state of the current research is that some sort of a combination of automation and human interaction looks very promising.
That's because of the nature of the way wind turbine blades are made; there are good reasons to have human beings actually inspecting the manufacturing process at various different stages and ensuring quality, but as I mentioned, we are making very large objects, so there are places where machines can definitely play a role, placing very large pieces of fabric into a mold for instance and having human beings actually have a final role in getting the material aligned correctly. So those are the things that seem to be the most promising right now. I would mention that Sandia is finishing up a project called the Advanced Manufacturing Initiative. This was a project that was a consortium Sandia National Laboratories, Iowa State University and TPI Composites, and this was a look at increasing productivity at their TPI's Newton, Iowa facility.
I should also mention, in terms of our research on specific blades, we worked on three different designs five to 10 years ago, and since that time, those designs have resulted in five to 10 spinoff blade design projects. People are taking that original research and doing something different with it, which is always promising.
What can you tell me about this project involving the offshore vertical axis turbine?
Off shore wind is sort of the new frontier in wind energy, the land based wind market having become what a lot of people would say is mature.
Along with the market factors, offshore is very compelling because there are very good resources offshore, the wind is high and consistent and also, depending on where you are at, very large portions of the population live very close to the ocean… so if you can successfully put in offshore wind turbines very close to load centers you can reduce the cost associated with transmission lines and stuff like that.
When you go offshore, there are generally three defined regions -- shallow water, intermediate water and deep water. Deep water is the most challenging because you're now considering putting in floating devices. Of course, that's not unprecedented, the oil and gas industry does it all the time when they put in offshore floating oil rigs. The question is whether that can ever be economically viable.
So the DOE had a competitive solicitation that they released and they wanted to look at offshore wind turbine concepts that had the potential to lower the cost of energy associated with offshore wind farms by 20 percent, and several projects were awarded.
The project we proposed and were successful with was one where we put a vertical axis turbine -- some people call them egg beaters -- in a floating configuration. This is conceived at a fairly large scale -- a 10 MW to maybe 20 MW turbine. The reason for this is that it is assumed that the turbine is the smaller portion of your cost offshore. The major costs tend to be the foundation of the turbine, and other things we call balance of station costs – all the stuff you have to do to hook the turbine up to the grid.
With offshore, you don't have the transportation constraints you encounter on shore. You don't have to haul the turbines and blades over the interstate and under overpasses and things like that. So you have that to your advantage and signs point to the idea that you want to put as big a turbine as possible offshore, so that turbine can sort of lower those balance of station costs.
The other issue with offshore wind is you have higher maintenance costs. Its just more difficult to get personnel and equipment out to fix turbines. So you would also like to have a very robust and reliable turbine out there. So our projects seeks to exploit the relative simplicity of vertical axis turbines and their scalability to large sizes to hopefully produce a concept that would reduce anticipated offshore wind energy costs by 20 percent.
But this technology has actually been around for quite some time, Why haven't we seen more of it?
I think there are a variety of reasons for that. One is that there was only one company producing vertical axis wind turbines at one point in time and that company went out of business. Also, I think designing vertical axis wind turbines is very difficult. There are a lot of structural resonances that have to be dealt with; there are some scaling issues in relation to the size of bearings and so on. In our concept, having the turbine spin in the water eliminates the need for a bearing like you would have onshore.
Theoretically, there is no reason a vertical access would perform less well than a horizontal wind turbine. That said the name of the game in energy is the cost of energy; so how all the bits and pieces fit together and what the machine costs -- along with its performance -- is what’s important.
It sounds like economics plays a large role in your science...
It is everything. I mean, when we talk about optimization problems, what we optimize to is the cost of energy. So it's equal parts, how much does the machine cost? How reliable is it? How much energy does it generate? Theoretical performance is almost identical for both machines, but the integration into an actual engineered design is a challenge.
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