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Publication
Featured researches published by Detlev Heinemann.
New Journal of Physics | 2016
Mehrnaz Anvari; G. Lohmann; Matthias Wächter; Patrick Milan; Elke Lorenz; Detlev Heinemann; M. Reza Rahimi Tabar; Joachim Peinke
Wind and solar power are known to be highly influenced by weather events and may ramp up or down abruptly. Such events in the power production influence not only the availability of energy, but also the stability of the entire power grid. By analysing significant amounts of data from several regions around the world with resolutions of seconds to minutes, we provide strong evidence that renewable wind and solar sources exhibit multiple types of variability and nonlinearity in the time scale of {it seconds} and characterise their stochastic properties. In contrast to previous findings, we show that only the jumpy characteristic of renewable sources decreases when increasing the spatial size over which the renewable energies are harvested. Otherwise, the strong non-Gaussian, intermittent behaviour in the cumulative power of the total field survives even for a country-wide distribution of the systems. The strong fluctuating behaviour of renewable wind and solar sources can be well characterised by Kolmogorov-like power spectra and
Journal of Physics: Conference Series | 2014
Björn Witha; Gerald Steinfeld; Martin Dörenkämper; Detlev Heinemann
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Journal of Physics: Conference Series | 2014
Martin Dörenkämper; Jens Tambke; Gerald Steinfeld; Detlev Heinemann; Martin Kühn
exponential probability density functions. Using the estimated potential shape of power time series, we quantify the jumpy or diffusive dynamic of the power. Finally we propose a time delayed feedback technique as a control algorithm to suppress the observed short term non-Gaussian statistics in spatially strong correlated and intermittent renewable sources.
Journal of Wind Engineering and Industrial Aerodynamics | 2015
Martin Dörenkämper; Björn Witha; Gerald Steinfeld; Detlev Heinemann; Martin Kühn
In this study, high-resolution large-eddy simulations of two German offshore wind farms are performed with the LES model PALM in which the turbines are parameterized with an actuator disk approach. The simulation of a single wind farm is realized by a stationary model domain with a turbulent inflow. Different atmospheric stratifications from slightly stable to unstable have been simulated and their effect on the wake characteristics is investigated. The results show a clear development of the flow within the wind farms with large differences between single, double and triple wakes. The wake deficit is increasing up to the second wake for the neutral and stable boundary layer and up to the third wake in the convective case before reaching a nearly constant value. This is explained with the turbulence intensity being much higher behind the second and subsequent turbines compared to the wake of the first turbine. With increasing atmospheric stability the wake deficits are shown to be stronger due to reduced turbulence.
European Physical Journal-special Topics | 2014
M. Reza Rahimi Tabar; Mehrnaz Anvari; G. Lohmann; Detlev Heinemann; Matthias Wächter; Patrick Milan; Elke Lorenz; Joachim Peinke
Power curves for offshore wind turbines within the German offshore wind farm alpha ventus were derived based on the IEC standard. Binning in groups of shear and turbulence intensity as measures of atmospheric stability were performed. The derived power curves show a strong dependency on these two parameters. Differences of up to 15% in power output between unstable and stable stratification in the non-wake case occur. For wind turbines within the wake of others the effects are even more pronounced. Here, the differences in power production between the stability classes approach 20%. This dependency of the power curves on stability can cause significant miscalculations of instantaneous power production, long-term energy yield and loads. Parameters other than the hub height wind speed are often not taken into account in state-of-the-art wind power forecasts. This can lead to substantial over- or underestimation of the resulting power.
29th European Photovoltaic Solar Energy Conference and Exhibition | 2014
Detlev Heinemann; O. Kramer; Annette Hammer; B. Wolff; Jan Kühnert; Elke Lorenz
Archive | 2010
Gerald Steinfeld; Jens Tambke; Joachim Peinke; Detlev Heinemann
arXiv: Physics and Society | 2015
Mehrnaz Anvari; G. Lohmann; M. Reza Rahimi Tabar; Matthias Wächter; Patrick Milan; Detlev Heinemann; Joachim Peinke; Elke Lorenz
Archive | 2014
Björn Witha; Gerald Steinfeld; Detlev Heinemann
Archive | 2012
Detlev Heinemann; Siegfried Raasch; Abha Sood