Offshore wind farms offer a number of benefits; many of the areas with the strongest winds are located offshore, and siting wind farms offshore ameliorates many of the land use concerns associated with onshore wind farms. Some estimates say that, if leveraged, offshore wind power could comprise as much as 4% of the United States’ electricity supply by 2030.

Engineering offshore wind power, however, is a major challenge – both in terms of construction and design optimization. Recently, a team of researchers from the University of Massachusetts and the National Renewable Energy Laboratory (NREL) published a paper describing how they used supercomputer simulations to help solve those engineering challenges.

The researchers performed simulations of offshore wind turbines to identify the differences between the wakes left by floating offshore wind turbines versus fixed-bottom offshore wind turbines. (These wakes decrease the power output and lifespan of offshore turbines.)

To run these intensive simulations, the researchers turned to two supercomputers: Comet at the San Diego Supercomputer Center (SDSC) and Stampede2 at the Texas Advanced Computing Center (TACC). Comet is rated at 2.76 peak petaflops (delivered by Intel Xeon E5 CPUs and NVIDIA K80 GPUs); Stampede2 is rated at 18.3 peak petaflops (delivered by Intel Xeon Phi CPUs) and ranked 19th on the June 2019 Top500 list.

“We looked at how these wake effects can be accurately considered when designing floating offshore wind farms,” said lead author Hannah Johlas. “At about 20,000 computer processor hours, these high-fidelity large eddy simulations are very computationally intensive and expensive, and as such, this research can only be performed using supercomputers.”

Using simulations on those supercomputers, the researchers found that the wakes of floating turbines and fixed-bottom turbines are similar – but those of floating turbines are deflected upward and have stronger turbulence at their edges.

“With global-installed capacity of offshore wind increasing from 8.9 gigawatts in 2015 to 22.5 gigawatts in 2018, this research is becoming even more prevalent,” said Johlas. “Now that we know more about how wakes behave for floating turbines, we will examine how those floating-turbine wakes affect downstream turbine power generation and structural loading.”

About the research

The paper discussed in this article, “Large eddy simulations of floating wind turbine wakes with coupled platform motion,” was published in Volume 1256 of the Journal of Physics: Conference Series. It was written by H.M. Johlas, L.A. Martinez-Tossas, D.P. Schmidt, M.A. Lackner and M.J. Churchfield. The full paper can be accessed online at this link.

The original article discussing this research was published by the University of California San Diego and can be found here.