Wind Park Layout Design Using Combinatorial Optimization

Abstract

The energy sector has essential influence on climate change and atmospheric pollution. Wind energy, being a clean and renewable energy, can greatly contribute to decreasing of the air pollution negative impacts. Generally speaking, the production of renewable energy from wind can have a positive socioeconomic benefit – it not only help to reduce the climate changing but also support meeting of the long-term world economical goals. Taking that into account, many countries are encouraging the building of industrial wind parks. The building of a wind park is an expensive and complex task involving a wide range of engineering and scientific knowledge. The design of a wind park can have profound implications for its future profitability. Sustainable wind park development has to be done in an ecological way which means evaluating of the all possible positive and negative influences on the environment. The development of new wind energy projects requires also a significant consideration of land use issues. One of the most important factors in selecting a wind energy site is the availability of proper wind resources. The wind itself is a variable source of energy. The ability of a wind turbine to extract power from varying wind is a function of three main factors – the wind power availability, the power curve of the generator, and the ability of the turbine to respond to wind fluctuations (Üstüntaşa & Şahin, 2008). Wind turbines are available in various sizes and power output. They are designed to operate over a range of wind speeds (3-25 m/s) and can be erected singly by an individual property owner or grouped together to form a wind farm (wind park) connected to a public grid (Rodman & Meentemeyer, 2006). The common challenge for the wind park designer is to maximize the energy capture within the given restrictions (White et al., 1997; Kusiak & Song, 2010). As there is pressure to build more compact wind farms to optimize land utilization, an determination of array losses for very close turbine spacing is required (Smith et al., 2006). The investigations on wind energy using essentially cover four principal topics (Ettoumi et al., 2008). The first one deals with the sensors and instrumentation used for wind measurements. The second one examines the evaluation of wind energy potential for a given region using various statistical approaches. The third is focused on the design and characterization of wind energy turbines. The fourth is the design and development of wind parks. The results of investigations in those areas are used by wind park planners to develop cost-effective wind parks. The investigations discussed here concern the problems associated with the forth topic – design of the wind park layout, including choice of the turbines type, number and their placement in the wind park area. How to choose the number and the type of the turbines to install depends on a variety of factors – wind conditions, terrain, investments costs, power output, environmental influence, etc. More powerful turbine is usually preferred to the less powerful one since both the cost of a turbine and the energy it generates is usually proportional to its nominal power. The placement of wind turbines on the wind park site (i.e. wind park layout) is affected by several factors which have to be taken into account – the number of turbines, wind direction, wake interactions between wind turbines, land availability (area and shape), etc. For the goal a combinatorial design model for defining wind turbines type, number and placement is proposed. It is used for formulation of mixed- integer nonlinear discrete combinatorial optimization tasks satisfying different design requirements and restrictions. The tasks solutions results define different optimal wind park layout designs. The solutions results can be used also to evaluate the impact of alternative wind park layout schemes on the investment costs and wind park power output.