College of Engineering News • Iowa State University

An end-to-end approach to advancing wind energy

When you sit down with the Iowa State faculty members who have gathered under the College of Engineering’s Wind Energy Initiative (WEI), you soon realize the group has developed a multifaceted, yet well constructed, plan to contribute to expanding the viability of wind energy in the US energy portfolio.

As they talk about their role in the effort, you can feel the excitement build as they highlight several pieces that are quickly coming together to move their ideas forward.

These pieces, which include a National Science Foundation (NSF) Research Experience for Undergraduates (REU), an NSF Integrative Graduate Education and Research Traineeship (IGERT) program, multiple research projects, and key industry partnerships, are collectively helping Iowa State make its mark as a leader in advancing wind energy science, engineering, and policy.

Beginnings of a strong program

While WEI was officially established in March 2011 under the Dean’s Research Initiative, research and teaching that explores wind energy has been active on campus for quite some time. These efforts were accelerated in 2008 when Iowa State President Gregory Geoffroy asked the College of Engineering to help put wind energy at the forefront of the university’s research focus.

Sri Sritharan
Sri Sritharan

“That’s when we really started assessing all the work going on related to wind energy and began figuring out how each part could collectively impact the charge given to us by President Geoffroy,” says Sri Sritharan, lead of WEI, Wilson Professor of Engineering, and professor of civil, construction, and environmental engineering.

Preliminary efforts by a group of faculty interested in wind energy included a national symposium in December 2008, with representatives from the U.S. Department of Energy, national laboratories and the American Wind Energy Association, as well as industry leaders from Siemens, Mid-American Energy, and Clipper Windpower.

Since then, research projects and courses have been added, covering everything from wind resource characterization to design and construction of tall towers to blade manufacturing to wind energy penetration and integration.

The group also co-hosted a conference in 2010 in conjunction with the Iowa Alliance for Wind Innovation and Novel Development (IAWIND) and Iowa Wind Energy Association’s (IWEA) annual meeting and conference.

Taken together, these activities are creating a name for the College of Engineering and Iowa State in wind energy research, laying the foundation for WEI, and establishing key partnerships for future endeavors.

A vested interest

Members of WEI say they formally established the initiative because of a desire to solve important problems facing our nation. “When you look at the state of Iowa, we are a leader in wind energy production, so we have a sense of responsibility in making sure wind energy will continue to advance and become a dependable energy source for the state and nation over the long term,” says Sritharan.

According to the American Wind Association, Iowa is ranked first in the U.S. in 2010 for percentage of electricity derived from wind. This year through April, Iowa is generating 20 percent of the state’s electricity from wind, which is comparable to that of Denmark—a nation known for generating the highest percentage of electricity by wind power. Iowa also has the second most installed wind capacity of any state and has attracted many major manufacturers of towers, blades and turbines.

“We have companies coming to our state to manufacture all three components of the wind energy system, and with that growth and development comes an expectation that our state participates in the research and education related to wind energy,” Sritharan says, adding that Iowa State’s science and technology roots make the institution a key part of such advancements.

“With the right experience and knowledge, we can prepare future engineers with sufficient knowledge to build, operate, and manage the wind energy industry in Iowa,” he says. “It’s fitting for us to focus on wind energy given our physical location (central Iowa), our state’s potential for producing wind energy, and the likelihood of this industry adding jobs and stimulating Iowa’s economy.”

Lisa Brasche, associate director of the Center for Nondestructive Evaluation (CNDE) and a member of WEI, adds that a formalized approach to studying wind energy offers an opportunity for students to stay in the state and contribute to Iowa’s economic development. “Our education efforts will prepare engineering, meteorology, and policy graduates for successful careers in the wind energy industry, and our research efforts will help the industry continue to move forward both in Iowa and the nation,” she says.

Establishing an identity

As a project within the Dean’s Research Initiative, WEI will receive $500,000 in “pursuit funding” over a three-year period from the Engineering Venture Fund, which blends private and public funding in support of key research efforts. To determine which projects and proposals will add value to the group’s efforts, WEI first established its mission as “facilitating the nation’s achievement of 20 percent of energy from wind by 2030 and strategically drive heavy wind energy growth in Iowa and the nation.”

Such an extensive goal will be met by combining the interests of researchers both on and off campus. Currently, WEI consists of seven faculty and research staff from Iowa State, and three organizations from outside the university, including Sandia National Laboratories, the University of Maine, and Michigan State University. The group will also join forces with industry partners, utility companies, and state agencies.

To move forward and ensure WEI’s portfolio was comprehensive, the group mapped out eight thrust areas (TA):

  • TA1: Meteorology, siting, characterization, and prediction
  • TA2: Aerodynamics, loads, control and design, and noise
  • TA3: Blade, gearbox, and drivetrain
  • TA4: Tower, foundation, and construction
  • TA5: Materials, manufacturing, supply chain, and transportation
  • TA6: Transmission, storage, grid integration, and electrical systems
  • TA7: Reliability and nondestructive evaluation
  • TA8: Social Acceptance, policy, legal, and ecology

Within these areas, the team will address mid-sized turbines, which could consist of a smaller turbine providing a community with energy from wind; utility-scale turbines, such as the wind farms we see today; and offshore turbines, an approach used mostly in Europe but that is gaining more support in the United States.

Current research progress

As noted, faculty members at Iowa State have already been in the thick of wind energy research.

Gene Takle, professor of agronomy and of geological and atmospheric sciences and leader of TA1, has been studying the environmental effect turbines have on crops and vice versa, along with forecasting wind to make the most efficient use of the wind power that is being generated.

“One obvious connection for forecasting is getting an accurate measure of the wind potential a day ahead,” he explains. “A wind farm operator needs to know by a day in advance how much energy they are going to have so they will know how much they will have to sell on the market.”

His forecasting also looks into changes in wind patterns from year to year, and he is charting trends at 80 meters, the height where most wind turbines are currently active.

In addition, Takle says atmospheric sciences can provide insight into offshore wind energy potential by modeling and predicting wind shear, which can create problems for turbines by putting stress on blades and gearboxes. “Using the work we’ve already done in studying how wind interacts over land, we can help U.S. institutions, such as the University of Maine, where researchers are starting to ramp up efforts to investigate offshore wind energy,” he explains. “Wind shear caused by the low-level jet over Iowa is similar to off-shore conditions caused by coastal jets. We can share our expertise and experiences in measurements and forecasting over Iowa and allow these groups to fast-track some of their work.”

 Wind Energy Manufacturing Laboratory
Iowa State engineers, left to right, John Jackman, Vinay Dayal and Frank Peters conduct research in the Wind Energy Manufacturing Laboratory. Photo by Bob Elbert.

From a manufacturing perspective, associate professor of industrial and manufacturing systems Frank Peters, lead of TA 5, says the advancements he and his colleagues contribute extend to all areas of wind energy. “As we investigate improving the manufacturing processes used for these large-scale components, blades, and towers, our findings can be applied to land and offshore wind turbines of all sizes,” he explains. “That’s why being a part of WEI is so exciting—our work to make wind energy more cost competitive is now more accessible to a wider pool of people with similar goals.”

Peters, along with Vinay Dayal, associate professor of aerospace engineering and Matt Frank and John Jackman, associate professors of industrial and manufacturing systems engineering, are working together in the Wind Energy Manufacturing Laboratory to improve the manufacturing process for blades, and assess bigger opportunities that may exist within improving wind energy components’ manufacturability.

He notes that one of the requirements of the Engineering Venture Fund is to establish partnerships with outside agencies. This started conversations with the University of Maine, which has already resulted in a new research award from Department of Energy to study offshore wind turbines with the two universities, Delft University of Technology, TPI Composites with Sandia National Laboratories as the lead.

According to Peters, adding automation to the manufacturing process can help reduce the capital costs associated with the blades and also allow for more control of the overall process. “We can enable designs that reduce the costs and weight of the blades and other turbine components, which would increase reliability of the end product,” he says. “Manufacturing advances can also pave the way for taller towers that take advantage of the better wind conditions at 100 meters.”

Conceptualizing that taller tower also resides in research by Sritharan, who is the lead for TA4. He is currently exploring creating towers made of high to ultra-high strength concrete, which has competitive cost advantage for tall towers. The concrete option that provides a potential costs savings by reducing transportation and site development costs, is more corrosion resistant, and offers multiple construction options from cast in place to on site assembly of easily transportable prefabricated segments.

Sritharan says the 80-meter steel tower as constructed today has reached its practical limit. “We have to look for innovative means to increase the tower height to 100 meters and beyond,” he added. “Increasing the tower height will increase the energy production and reduce the infrastructure costs, which in turn will reduce the energy cost.”

Transmission lines
Transmission lines will be important for moving energy generated from wind across the country.

James McCalley, Harpole Professor in Electrical Engineering and leader of TA6, adds to the group’s efforts with expertise in energy distribution grid and storage technologies. As the U.S. looks to increase the amount of energy from wind, the collected energy will need to be transported over long distances, something our current system isn’t necessarily equipped to handle.

McCalley explains that because the only way to move wind energy is by electric transmission (unlike fossil-based energy, which can also be moved by rail or, for natural gas, by pipeline), he’s looking at ways to develop a future system that is heavily dependent on wind (and other renewables) and will be much more dependent on interregional transmission to move it from the wind-rich Midwest to the load centers at the East and West coasts.

Another important facet of WEI’s efforts is the work done at CNDE. According to Brasche, the leader of TA7, the center has a long history of working with a number of industries regarding the structural integrity of complex engineered systems. These connections with wind energy companies add more opportunities for collaboration to WEI.

Additionally, she says researchers at CNDE are able to apply existing tools that address inspection challenges in the wind energy community. One example is with turbine blades. While blades are complicated, large-scale structures, they share similarities to aerospace components the center has worked on in the past. “Using our approaches and health monitoring tools, we can evaluate individual components and help develop solutions for the instances where wind energy generation systems or subsystems are failing much earlier than the projected life of 20 years,” she says.

WEI’s efforts will also be advanced through a $20 million, five-year grant funded through NSF’s Experimental Program to Stimulate Competitive Research (EPSCoR). The grant supports building Iowa’s research capacity in renewable energy and energy efficiency. Iowa’s public universities—Iowa State University, the University of Iowa and the University of Northern Iowa —will make up the core of the research project, which will be built on four major platforms: bioenergy, wind energy, energy utilization, and energy policy.

The wind energy platform aims to improve the reliability of wind turbines. EPSCoR funding will support a new faculty position in wind energy and also research initiatives that include establishing an outdoor laboratory to collect wind speed and turbulence data, studying the reliability of turbine blades, and improving the designs of turbine drivetrains.

“Collecting data in a real environment will be invaluable in the statewide effort of building out wind power in the state, says Takle. He adds that the group plans to install meteorological towers and one or more laser radars in a wind farm that has been used for the last two summers in the Crop/Wind Energy Experiment.

“These annual summer experiments, which study the interaction of wind turbines with agricultural crops, provide faculty and students with data for innovative projects and competitive advantages for future funding opportunities,” he says, noting that having WEI as a central group for wind energy research will help extend future opportunities even further.

Major outreach and education milestones

Equally important to research in wind energy is the need to provide opportunities for students to learn about the industry and the opportunities that lie ahead. Through several educational programs, WEI is developing students who can move the industry forward and help it endure over time.

This summer, WEI researchers, under the leadership of Takle, hosted the Wind Energy Science, Engineering, and Policy (WESEP) research experience to offer undergraduate students a unique, hands-on opportunity to investigate areas that address critical, long-term national needs in wind energy. Despite having only have a month to advertise the program, 269 students from 33 states applied.

“It has been my experience over many years that students are always looking ahead, and they see wind energy as a long-term career option,” says Takle. “In this field, they have a definite role to play and they can contribute to efficient generation and use of energy. It’s also a rewarding field, as they can benefit society by developing creative solutions to our country’s energy challenges.

The College of Engineering is also offering more courses in wind energy, with a new course added this fall called Introduction to Wind Energy: System Design and Delivery. WEI is hoping to work the courses into a minor, which is moving along in the approval process and has now received the approval of the faculty in the College of Engineering and the College of Liberal Arts and Sciences.

PhD students are also able to advance work in wind energy on Iowa State’s campus. The university will soon become the first institution to award students PhD degrees in WESEP thanks to a $3.1 million, five-year grant from the NSF’s IGERT program. The program’s research is focused on increasing wind energy growth rate, reducing costs, and extending penetration limits (or how much wind is used to meet the energy demands of a certain location), of wind energy.

McCalley, who is leading the new program, says building the WESEP PhD is an exciting opportunity. “We are doing something that has never been done before but that’s so necessary given the country’s need to find alternative energy sources. It will be an enriching experience that will also have major implications for advancing wind energy research.”

Takle expects that the group’s broad approach will attract a cadre of high-achieving undergraduates and graduates to Iowa State who are sure to become leaders in the field. “Through all of our efforts, we want to train leaders and professionals who will be recognized down the road for advancing our use of wind energy,” he says.

Continuing progress

Because of WEI’s strong foundation and the importance of the group’s efforts, the team has already made great strides in little more than six months. But, as all the members would say, there’s still so much more to be done.

As the group continues to form, it also is looking to capitalize on the investment of venture funds to create more opportunities for the university’s staff, faculty, and students to connect with funding agencies to solve bigger wind energy challenges. “There is significant talent at Iowa State and the venture funds facilitate the broad research community engaged in promising work across campus to come together and make bigger impact,” Sritharan says. “The group has grown to include more than 40 faculty and staff, and we definitely want to add more people within and outside of Iowa State as we continue to work towards our goals.”

Adding to Sritharan’s idea of collaboration is Peters, who says that looking outside the walls of the university will help grow wind energy research at Iowa State. “Bringing together individual groups that add a different strength will extend the impact of WEI and of wind energy in general,” he says. “We know that wind is a partial solution for this country’s energy independence, but the potential that exists within the home-grown option needs to be reached.”