IEEE Open Access Journal of Power and Energy (Jan 2022)

How Can Probabilistic Solar Power Forecasts Be Used to Lower Costs and Improve Reliability in Power Spot Markets? A Review and Application to Flexiramp Requirements

  • Benjamin F. Hobbs,
  • Venkat Krishnan,
  • Jie Zhang,
  • Hendrik F. Hamann,
  • Carlo Siebenschuh,
  • Rui Zhang,
  • Binghui Li,
  • Li He,
  • Paul Edwards,
  • Haiku Sky,
  • Ibrahim Krad,
  • Evangelia Spyrou,
  • Xin Fang,
  • Yijiao Wang,
  • Q. Xu,
  • Shu Zhang

DOI
https://doi.org/10.1109/OAJPE.2022.3217909
Journal volume & issue
Vol. 9
pp. 437 – 450

Abstract

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Net load uncertainty in electricity spot markets is rapidly growing. There are five general approaches by which system operators and market participants can use probabilistic forecasts of wind, solar, and load to help manage this uncertainty. These include operator situation awareness, resource risk hedging, reserves procurement, definition of contingencies, and explicit stochastic optimization. We review these approaches, and then provide a case study in which a method for using probabilistic solar forecasts to define needs for reserves is developed and evaluated. The case study has three parts. First, we describe building blocks for enhancing the Watt-Sun solar forecasting system to produce probabilistic irradiance and power forecasts. Second, relationships between Watt-Sun forecasts for multiple sites in California and the system’s need for flexible ramp capability (flexiramp) are defined by machine learning and statistical methods. Third, the performance of present methods to defining flexiramp requirements, which are not conditioned on weather and renewables forecasts, is compared with that of probabilistic solar forecast-based requirements, using a multi-timescale production costing model with an 1820-bus representation of the WECC power system. Significant potential savings in fuel and flexiramp procurement costs from using solar-informed reserve requirements are found.

Keywords