Combined Wind Farm Research Articles

A Multiobjective Evolutionary Programming Algorithm and Its Applications to Power Generation Expansion Planning

The generation expansion planning (GEP) problem is defined as the problem of determining WHAT, WHEN, and WHERE new generation units should be installed over a planning horizon to satisfy the expected energy demand. This paper presents a framework to determine the number of new generating units (e.g., conventional steam units, coal units, combined cycle modules, nuclear plants, gas turbines, wind farms, and geothermal and hydro units), power generation capacity for those units, number of new circuits on the network, the voltage phase angle at each node, and the amount of required imported fuel for a single-period generation expansion plan. The resulting mathematical program is a mixed-integer bilinear multiobjective GEP model. The proposed framework includes a multiobjective evolutionary programming algorithm to obtain an approximation of the Pareto front for the multiobjective optimization problem and analytical hierarchy process to select the best alternative. A Mexican power system case study is utilized to illustrate the proposed framework. Results show coherent decisions given the objectives and scenarios considered. Some sensitivity analysis is presented when considering different fuel price scenarios.

Energy Regime Choices: Nuclear or Not?

The energy system in industrialized countries is changing in what can be seen as an example of the technological regime change, reflecting a wider shift towards environmentally sustain-able technology which may impact on all sectors in the economy. In recent years, the emphasis in the UK's power generation system has increasingly been on smaller scale power plants, combined cycle gas turbine plants and wind farms of the order of 20-100 megawatts instead of giant gigawatt coal and nuclear plants. The UK is thus moving from a system in which large centralized plants send power to users down long grid lines, to one in which smaller plants are embedded in more localized grid networks. The traditional approach had its merits, since there are economies of scale and performance with larger plants, but with power plants having reached 1.3 GW, the efficiency gains have more or less been fully exploited. What has become more important is that there are energy losses (of up to 8–9%) due to transmittingpower from large centralized plants to consumers over long distances. Even more important is the very large losses (up to 70%) associated with the conventional centralized approach to the generation of electricity: the energy conversion efficiency of conventional coal and nuclear plants is only around 33%, with most of the energy being dumped as waste heat. In response, the trend is to towards decentralization, including co-generation of heat as well as power for local use (in so-called combined heat and power plants) and self generation by consumers themselves using domestic scale micro-power systems using local renewable sources. This technological regime change was central to the influential report 'Decarbonising the UK' produced by the Tyndall Centre in 2005, which, amongst other things, stressed the role that could be played by renewable energy sources. A similar view had been taken in theGovernment's Energy Review produced in 2003, which supported a scenario in which renew-ables expand to supply around 20% of electricity by 2020. By contrast, nuclear power was not seen as a very strong contender, in part because of its inflexibility. However, a new Government Energy Review, completed in July 2006, came to very different conclusions on nuclear power: 'We have concluded that new nuclear power stations would make a significant contribution to meeting our energy policy goals'. This guest editorial asks whether there has been a fundamental rethink over energy strategy and the need for a radical technological regime change.

The Economic Impacts of a Proposed Wind Power Plant in Kittitas County, Washington State, USA

This paper is an evaluation of potential impacts of a proposed wind farm on property values, tax revenues, and the local economy. The area studied was Kittitas County, (46.59° N, 120.25° W), Washington State, USA, where a combined wind farm of 261 wind turbines, total capacity 390 MW, is proposed. Studies were conducted in that area and regarding similar areas with similar projects. Of particular importance was the visual impact of the windfarm. Details of likely local employment are given (185 full and part-time direct jobs at construction, 85 direct jobs ongoing). Financial modelling considered local and other tax revenues, and associated financial benefits and disbenefits. Studies related to both the time of construction and ongoing operation. Tax revenues from the area would increase by $2.8 million/year (11% increase), of which $693,000/y would be disbursed for immediate local services (2% increase). It was concluded that: there was no evidence for reductions in property values; tax revenues would increase with associated disbursement of benefit within the locality; and associated secondary expenditure in the locality would be significant.