Wind power produces over 8% of our nation’s electricity, up from less than 2% just a few years ago. One impediment to increasing reliance on this clean, sustainable power source is the vast size of many windfarms and the challenge of understanding turbine-turbine and turbine-atmosphere interactions. These interactions affect wind farm performance on a variety of levels—from power output to turbine loading and maintenance.
High performance computer simulations can help by providing detailed insights into fluid mechanical effects associated with turbine placement, layouts, and environmental factors. But these simulations are expensive and produce huge datasets comprising tens to hundreds of terabytes, putting them out of reach of researchers without the requisite computational skills, substantial financial resources, and/or access to technology required.
An initiative spearheaded by researchers in the Johns Hopkins Ralph O’Connor Sustainable Energy Institute, ROSEI, is poised to change that. Dennice Gayme, an associate professor in the Whiting School of Engineering’s Department of Mechanical Engineering and Charles Meneveau, the Louis M. Sardella Professor in Mechanical Engineering at WSE, have started a new project to create a public database of windfarm simulations, which will allow anyone with an internet connection to easily access and analyze the data in order to conduct research, generate knowledge, and evaluate models or wind field data to be used in wind farm planning or development projects. Potential users of the database therefore span academia and national laboratories to engineers working on wind farm projects.
“Each type of user will be able to very easily access and analyze data that is of interest to them,” Meneveau said. “They will be able to take data from a synthetic windfarm and explore all of its spatio-temporal facets, at a level of detail that is impossible to achieve with existing datasets. The fact that you can come back and look at one location in detail and ask some very specific questions within this big simulation will be unprecedented and be very exciting for many researchers. We expect it to give access to scientists of many backgrounds and facilitate a variety of different types of science and engineering.”
The Hopkins researchers are at present preparing the first simulations that will comprise the database. They say it’s tricky work because making simulations either too general or specific will limit the broad range of potential utility of the data.
“The idea is to have a couple benchmark test cases that people can use to start testing and evaluating their models and design decisions,” Gayme said. “We want a couple simulations that are similar but vary by one factor, such as atmospheric stability, or the placement of turbines. That way you can run your model and see the effects each factor has and use this to better understand the conditions affecting not only power output, but wind turbine loading. People will have interest in a wide variety of things like atmospheric stability conditions, or inter-turbine distance, and how they affect their model or flow field, so we’re trying to take all of that into account when creating the simulations.”
Gayme and Meneveau are using as a model the Johns Hopkins Turbulence Database, JHTDB, which is hosted by the Institute for Data Intensive Engineering and Science, IDIES.
“The hope is it will have a similar look and feel, and that researchers will be able to perform similar tasks, just with wind velocity and wind turbine data instead of fundamental turbulence datasets,” said Meneveau, who is IDIES associate director.
In fact, IDIES researchers and staff will play a critical role in JHWFDB, according to Meneveau.
“We are also working in close collaboration with IDIES, and utilizing their infrastructure of resources, ranging from computers and servers to a staff of system managers and programmers that have data from all sorts of fields,” he said.
Gayme credits the creation of ROSEI with making her longtime goal of finding support for the new database project a reality.
“A lot of people thought it was a good idea, but it seemed that nobody wanted to put money forward for it,” Gayme said. “Johns Hopkins is known for these databases, so ROSEI provided a vehicle for funding, but more than that, ROSEI correctly viewed this as an opportunity to showcase what sort of work Hopkins can do in this area. This database has the potential to be a great tool that will hopefully help researchers all over the world and help harness the most we can get out of wind energy.”