Research tools for wind farms

Wind farms have become a common sight both on land and at sea – not least in Denmark, where wind turbines supply a quarter of the power. But how does it actually affect wind turbines, if you arrange them closely together, and overall, how do you get the most benefits in terms of financial outcome from a wind farm? TOPFARM, a large-scale EU project led by Risø DTU, part of the Technical University of Denmark, has been looking into these matters during the last three years. The result: a simulation platform that is said to be able to optimize the total economic benefits.

The nine participants in TOPFARM are Risø National Laboratory for Sustainable Energy, DTU (Project Manager), DTU Mechanical Engineering, DONG Energy, Vestas, Universidad Politécnica de Madrid, Cambridge Environmental Research Consultants ltd., Garrad Hassan and Partners ltd., Germanischer Lloyd Industrial Services GmbH and Teknikgruppen AB.

The recently completed EU project, TOPFARM, has focused on how a wide range of factors affect the economically optimum location of each wind turbine within the wind farms – in technical terms this is called the topology of a wind farm. And contrary to common practice, productions as well as costs associated with the establishment and operation of each wind turbine are included in the model of calculation.
 
The core of the optimization tool consists of five calculation modules. The first module consists of models (of varying complexity) that describe the wind inside a wind farm. The second module is a detailed model of how the wind affects each wind turbine in a wind farm. The input to this module is the wind field from the first module and the result is production data and load data from the individual turbines. The third module comprises models of the control system at both wind farm level and wind turbine level, while the fourth module contains cost models, which make it possible to formulate the optimization problem in economic terms. The fifth and the last module is a package of optimization algorithms that, with the input from the other four modules, generates the optimum layout of a given wind farm. This is the module that gave rise in the case story to the new location of turbines at Middelgrunden wind farm, as seen on the picture.

The TOPFARM optimization platform is currently a research tool, but the vision of the scientists at Risø DTU is to pursue opportunities with the purpose of creating a more user-friendly programme that can be used by wind farm developers in their daily work. The basic sub-models have already been developed in the TOPFARM project, and efforts will therefore primarily concentrate on a more streamlined implementation of software and on developing a suitable user interface.