Quantitative Measures for Evaluating Grid Variability Reduction Due to Diversity, Storage or DSM

摘要

Integration of large-scale of variable generation brings challenges to the supply and demand balance at different timeframes, and has impacts on correspondent planning, operation and market practices. While the power output variability of individual variable generation source (e.g. a wind farm) is dominated by its local conditions (e.g. local weather and wind pattern), the overall aggregate variable generation output variability can be smoothed by the diversification of variable generation developments across a bigger footprint with diversified variability patterns. In order to evaluate the benefit of variable generation variability reduction against related cost incurred due to increasing diversity of developing across bigger footprint, some form of quantitative measures is needed for analysing related variable generation variability reduction in the context of electric grid planning, operation and market. In this paper, based on Alberta historical wind power output data of each individual wind farm and overall aggregation, we investigate the wind diversity benefit of variability reduction within the context of grid planning, operation and market; propose a new concept and its quantitative measures - generation output shape factor and shaping factor based on normalized generation duration curve. While the generation shape factor is to measure the variability of individual wind farm's generation output profile itself, the generation shaping factor is to measure the improvement (reducing variability) of the shape factor of the aggregate wind generation output profile that caused by the diversity effect of aggregation of wind farms with more diversified variability patterns across bigger footprint. We also describe the calculation method of proposed quantitative measures. Then we adopt, calculate and validate the concept and the proposed quantitative measures by using the Alberta historical wind power output data. Next, through examples, we demonstrate and discuss the method of using the proposed quantitative measures to quantify the wind power diversity benefit in market, grid planning and operation context Last, we extend the discussion of adopting the proposed concept and quantitative measures into broader application to evaluate the economic impact on overall system for other technologies, such as diversify between different variable generation resources, storage or DSM that can reshape and improve the overall system supply and demand balance situation.