Now showing 1 - 4 of 4
  • Publication
    Accommodating Variability in Generation Planning
    (Institute of Electrical and Electronics Engineers, 2013-02) ; ;
    Many of the most commonly used generation planning models have been formulated in a way that neglects the chronological sequence of demand and the mixed-integer nature of generating units. The generator schedules assumed by these models are inaccurate and become increasingly divorced from real schedules with increasing variability. This paper seeks to characterize and quantify the limitations of these models over a broad set of input parameters. For an illustrative set of test systems, wind capacities and generator types, annual system costs are determined for all combinations of generating units using a unit-commitment model, which captures the chronological behavior of units and a dispatch model which does not. It is seen that the relative performance of the dispatch model is highly system specific but generally degrades with increasing variability. The difference in cost estimates between the models is decomposed into start costs, starts avoidance and average cost estimation error. The impact on least-cost portfolios is shown and finally sensitivities are performed with the addition of hydro and nuclear power to assess their impact.
      1702Scopus© Citations 78
  • Publication
    Short-Term Energy Balancing With Increasing Levels of Wind Energy
    (Institute of Electrical and Electronics Engineers, 2012-10) ; ; ;
    Increasing levels of wind energy are adding to the uncertainty and variability inherent in electricity grids and are consequently driving changes. Here, some of the possible evolutions in optimal short-term energy balancing to better deal with wind energy uncertainty are investigated. The focus is mainly on managing reserves through changes in scheduling, in particular market structure (more regular and higher resolution scheduling), reserve procurement (dynamic as opposed to static), and improved operational planning (stochastic as opposed to deterministic). Infrastructure changes including flexible plant, increased demand side participation, more interconnection, transmission, larger balancing areas, and critically improved forecasting can also be significant and are dealt with in the discussion. The evolutions are tightly coupled, their impact is system-dependent and so no “best” set is identifiable but experience of system operators will be critical to future developments.
      1918Scopus© Citations 53
  • Publication
    Impact of wind power on the unit commitment, operating reserves, and market design
    This article highlights and demonstrates the new requirements variable and partly unpredictable wind power will bring to unit commitment and power system operations. Current practice is described and contrasted against the new requirements. Literature specifically addressing questions about wind power and unit commitment related power system operations is surveyed. The scope includes forecast errors, operating reserves, intra-day markets, and sharing reserves across interconnections. The discussion covers the critical issues arising from the research.
      956Scopus© Citations 39
  • Publication
    Variability of load and net load in case of large scale distributed wind power
    Large scale wind power production and its variability is one of the major inputs to wind integration studies. This paper analyses measured data from large scale wind power production. Comparisons of variability are made across several variables: time scale (10-60 minute ramp rates), number of wind farms, and simulated vs. modeled data. Ramp rates for Wind power production, Load (total system load) and Net load (load minus wind power production) demonstrate how wind power increases the net load variability. Wind power will also change the timing of daily ramps.