| Energy

Working against the wind (part 2): Julia Menken – meteorologist and atmospheric scientist

Meteorologist Julia Menken
PhD student Julia Menken is investigating how the wake of the turbine changes under different atmospheric conditions at the WiValdi wind energy research farm.

Krummendeich. Where the dyke to the Elbe is not straight but curved. Population: 390. A flat land where wind is part of everyday life. Since summer 2023, the rotor blades of OPUS 1 and 2 at the WiValdi wind energy research farm have been turning there. When a rotor blade is vertical, its tip is 150 metres above the ground. What you can't see from a distance: the wind turbines and the measuring masts are equipped with a total of 1500 sensors from the foundation to the tip of the rotor, collecting and recording data around the clock. And if you look closely, you will see that the two wind turbines are arranged one behind the other in the main wind direction – an absolute no-go for commercial turbines, because the rear turbine stands in the wind turbulence of the first. Both are intentional, because WiValdi is a research facility, not designed to generate as much electricity as possible but to gain as much scientific knowledge as possible. Lukas Firmhofer, Kevin Gnebner and Julia Menken have all stood 90 metres up on the turbine’s large central nacelle and felt the strong headwind. In a series of three articles, we introduce the people who work at and with the wind farm.

Continuous data collection

Storms, gusts of wind, light breezes or strong gales, temperatures, humidity – at any given moment, Julia Menken, from the Institute of Atmospheric Physics, can see exactly what conditions are prevailing at the WiValdi wind energy research farm from her desk at the DLR site in Oberpfaffenhofen. "I receive very high-quality data, which I analyse," says the PhD student, who joined DLR in the summer of 2023 to work on her doctoral thesis. New data is collected every 30 seconds. "I can let the data processing run continuously."

Working with data from 90 metres up: Research at the WiValdi wind energy research farm
PhD student Julia Menken uses data from a wind lidar installed on the nacelle of one of the wind turbines as well as data from other sensors across the site.

The 29-year-old, who has already stood on the turbine housing at a height of 90 metres, uses two main sources of data: sensors on the meteorological measurement masts in front of the wind turbines and data from a lidar – an instrument that can measure wind speeds over a larger area using transmitted light pulses and their reflection – which is installed on the nacelle of the wind turbine. "The measurements on the mast show me what is happening at the turbine. The lidar measurements provide information about what is happening behind the turbine." If the instrument needs to be serviced or checked, this is, of course, done on site at the turbine.

Storms and gusts instead of standard atmosphere

DLR's WiValdi wind energy research farm
The wind turbines and the measuring masts in Krummendeich are equipped with a total of 1500 sensors from the foundation to the tip of the rotor, which collect and record data around the clock.

The goal of her research: "I’m investigating how the wake created by the turbine changes under different atmospheric conditions." Most wind turbine wake models, which are often simplified, do not represent the atmosphere very accurately. "They are based on a simulated standard atmosphere and do not take into account how dynamic the real atmosphere can be." The results of her doctoral thesis will help to select better locations for new wind turbines in the future.

During her studies in meteorology, Julia Menken had already dealt with the basics of different forms of renewable energy, and in internships and jobs she was responsible for forecasting the performance of wind turbines and solar power systems, amongst other things. Although working with a lidar was not part of her research work before joining DLR, she has always been interested in experimental methods and renewable energies. The WiValdi research farm offers an enormous advantage for her research: "In most other projects, you carry out shorter measurement campaigns and then use the data collected during that time. Here, on the other hand, I have continuous measurements from a large number of instruments over a very long period of time," explains the meteorologist. "That includes storms and gusts, which might not occur during a short measurement campaign."

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