Wind Power Changes Research Articles

Short-Term Power Fluctuations of Large Wind Power Plants*

To evaluate short-term wind power fluctuations and their impact on electric power systems, the National Renewable Energy Laboratory, in cooperation with Enron Wind, has started a project to record output power from several large commercial wind power plants at the 1-Hertz rate. This paper presents statistical properties of the data collected so far and discusses the results of data analysis. From the available data, we can already conclude that despite the stochastic nature of wind power fluctuations, the magnitudes and rates of wind power changes caused by wind speed variations are seldom extreme, nor are they totally random. Their values are bounded in narrow ranges. Power output data also show significant spatial variations within a large wind power plant. The data also offer encouraging evidence that accurate wind power forecasting is feasible. To the utility system, large wind power plants are not really random burdens. The narrow range of power level step changes provides a lot of information with which system operators can make short-term predictions of wind power. Large swings of wind power do occur, but those infrequent large changes (caused by wind speed changes) are always related to well-defined weather events, most of which can be accurately predicted in advance.

On the potential change in wind power over the US due to increases of atmospheric greenhouse gases

Wind power (WP) is a likely source of renewable energy to reduce fossil CO 2 atmospheric emissions. However, WP availability might be affected by climate changes induced by such emissions. In this study a refined regional climate model, appropriate for resolving near-surface flows, was used to generate WP climatologies for the US consistent with present and mid-21st century enhanced atmospheric CO 2 level. In both cases the regional climate simulation was forced by lateral boundary conditions based on simulations of the Hadley Centre general circulation model. Simulated present WP showed reasonable general agreement with patterns observed in most locations. In most of the US the enhanced CO 2 simulation showed a trend of decreased daily average WP availability in the range of 0–30%. However, in limited areas in the southern and northwestern US, an increase in WP, peaking at 30%, was simulated. Under the enhanced CO 2 climate scenario, the present relatively high WP availability in northern Texas and western Oklahoma, as well as in the northwest US, are almost unaffected. A decline in WP is simulated in the north–central US and the western mountainous region.

A Modified Unit Commitment and Generation Control for Utilities with Large Wind Generation Penetrations

A modified unit commitment is proposed in this paper that would be updated on three different cycles (daily, quarter-hourly and every minute). The 24 hour updated unit commitment would include the effects of load and slow trend wind power change that could be predicted 24 hours ahead. The quarter- hourly updated unit commitment would handle the fast trend and cyclic change in wind power that could be predicted one hour ahead and would commit peaking, regulation, and quick pickup and possibly economic units to handle these wind power changes.

Methods of Reducing Wind Power Changes from Large Wind Turbine Arrays

Previous results have [1,2,3] been concerned with establishing (1) whether operating problems could exist when WECS generation is significant and (2) the proper modification of unit commitment, regulation, and economic dispatch required to provide sufficient system security and alleviate the operating problems caused by WECS generation changes. This paper discusses methods of reducing the WECS generation change through selection of the wind turbine model for each site, selection of an appropriate siting configuration, and wind array controls. An analysis of wind generation change from an echelon and a farm for passage of a thunderstorm is presented to establish the factors concerning the wind turbine model and ; siting configuration that contribute to these variations. Detailed simulation results indicate more. precisely how these factors can be exploited to. minimize the WECS generation changes observed. Reduction of the wind generation change over ten minutes is shown to reduce the increase in spinning reserve, unloadable generation and load following requirements on unit commitment when significant WECS generation is present and the farm penetration constraint is satisfied. Controls on the blade pitch angle of all wind turbines in an array or a battery control are shown to reduce both the wind generation change out of an array and the effective farm penetration in anticipation of a storm so that the farm penetration constraint may be satisfied.

Methods of Reducing Wind Power Changes from Large Wind Turbine Arrays

Methods of Reducing Wind Power Changes from Large Wind Turbine Arrays

Limits to wind-power

Simple formulas are given for the change in wind-power, frictional stress and vertical energy transport in the atmospheric boundary layer, caused by the erection of windmill arrays. The limit to wind-power conversion appears to be around 1 W/m 2 of terrain in both coastal and inland areas.