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Title: Using probabilistic solar power forecasts to inform flexible ramp product procurement for the California ISO

Abstract

How can independent system operators (ISOs) take advantage of probabilistic solar forecasts to lower generation costs and improve reliability of power systems? We discuss one three-step approach for doing so, focusing on how such forecasts might help the California Independent System Operator (CAISO) prepare unexpected net load ramps, where net load equals gross demand minus wind and solar production. First, we enhance an existing solar forecasting system to provide well-calibrated hours-ahead probabilistic forecasts. We then relate the degree of uncertainty reflected in the forecasted prediction intervals (independent variables) to error distributions for net load ramp forecasts for the CAISO real-time market (dependent variable) using machine learning and quantile regression. Projected ramp forecast errors conditioned on solar uncertainty are translated into flexible ramp requirements that therefore reflect real-time meteorological and solar conditions, improving on typical ISO procedures. Detailed descriptions are provided on the quantile regression and kth-nearest neighbor categorization methods for accomplishing that translation. Finally, a multiple time-scale look-ahead market simulation model is applied to a 118-bus IEEE Reliability Test System, modified to represent the CAISO generation mix and demand distributions. The model runs quantify how solar-conditioned ramp requirements can, first, decrease operating costs by reducing requirements compared to often conservative unconditional methods and, second, decrease generation scarcity events and consequently improve reliability by increasing flexibility requirements at times when unconditional forecast-based requirements understate actual ramp uncertainty. Solar-conditioned ramp requirements are found to reduce generation operating costs by about 2% for the test system (which would be equivalent to over $$\$$100$ million per year for a CAISO-size system).

Authors:
ORCiD logo [1];  [2];  [3]; ORCiD logo [3];  [3]; ORCiD logo [2];  [4];  [4];  [4];  [5]; ORCiD logo [5]; ORCiD logo [5]
  1. Johns Hopkins University, Baltimore, MD (United States); Market Surveillance Committee of the California Independent System Operator, Folsom, CA (United States)
  2. University of Texas at Dallas, Richardson, TX (United States)
  3. IBM Thomas J. Watson Research Center, Yorktown Heights, NY (United States)
  4. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
  5. Johns Hopkins University, Baltimore, MD (United States)
Publication Date:
Research Org.:
Johns Hopkins University, Baltimore, MD (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
OSTI Identifier:
1991262
Grant/Contract Number:  
EE0008215
Resource Type:
Accepted Manuscript
Journal Name:
Solar Energy Advances
Additional Journal Information:
Journal Volume: 2; Journal ID: ISSN 2667-1131
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 97 MATHEMATICS AND COMPUTING; 29 ENERGY PLANNING, POLICY, AND ECONOMY; Probabilistic solar power forecasts; Flexible ramp product requirements; California; Production cost; Reliability; Machine learning

Citation Formats

Hobbs, Benjamin F., Zhang, Jie, Hamann, Hendrik F., Siebenschuh, Carlo, Zhang, Rui, Li, Binghui, Krad, Ibrahim, Krishnan, Venkat, Spyrou, Evangelia, Wang, Yijiao, Xu, Qingyu, and Zhang, Shu. Using probabilistic solar power forecasts to inform flexible ramp product procurement for the California ISO. United States: N. p., 2022. Web. doi:10.1016/j.seja.2022.100024.
Hobbs, Benjamin F., Zhang, Jie, Hamann, Hendrik F., Siebenschuh, Carlo, Zhang, Rui, Li, Binghui, Krad, Ibrahim, Krishnan, Venkat, Spyrou, Evangelia, Wang, Yijiao, Xu, Qingyu, & Zhang, Shu. Using probabilistic solar power forecasts to inform flexible ramp product procurement for the California ISO. United States. https://doi.org/10.1016/j.seja.2022.100024
Hobbs, Benjamin F., Zhang, Jie, Hamann, Hendrik F., Siebenschuh, Carlo, Zhang, Rui, Li, Binghui, Krad, Ibrahim, Krishnan, Venkat, Spyrou, Evangelia, Wang, Yijiao, Xu, Qingyu, and Zhang, Shu. Thu . "Using probabilistic solar power forecasts to inform flexible ramp product procurement for the California ISO". United States. https://doi.org/10.1016/j.seja.2022.100024. https://www.osti.gov/servlets/purl/1991262.
@article{osti_1991262,
title = {Using probabilistic solar power forecasts to inform flexible ramp product procurement for the California ISO},
author = {Hobbs, Benjamin F. and Zhang, Jie and Hamann, Hendrik F. and Siebenschuh, Carlo and Zhang, Rui and Li, Binghui and Krad, Ibrahim and Krishnan, Venkat and Spyrou, Evangelia and Wang, Yijiao and Xu, Qingyu and Zhang, Shu},
abstractNote = {How can independent system operators (ISOs) take advantage of probabilistic solar forecasts to lower generation costs and improve reliability of power systems? We discuss one three-step approach for doing so, focusing on how such forecasts might help the California Independent System Operator (CAISO) prepare unexpected net load ramps, where net load equals gross demand minus wind and solar production. First, we enhance an existing solar forecasting system to provide well-calibrated hours-ahead probabilistic forecasts. We then relate the degree of uncertainty reflected in the forecasted prediction intervals (independent variables) to error distributions for net load ramp forecasts for the CAISO real-time market (dependent variable) using machine learning and quantile regression. Projected ramp forecast errors conditioned on solar uncertainty are translated into flexible ramp requirements that therefore reflect real-time meteorological and solar conditions, improving on typical ISO procedures. Detailed descriptions are provided on the quantile regression and kth-nearest neighbor categorization methods for accomplishing that translation. Finally, a multiple time-scale look-ahead market simulation model is applied to a 118-bus IEEE Reliability Test System, modified to represent the CAISO generation mix and demand distributions. The model runs quantify how solar-conditioned ramp requirements can, first, decrease operating costs by reducing requirements compared to often conservative unconditional methods and, second, decrease generation scarcity events and consequently improve reliability by increasing flexibility requirements at times when unconditional forecast-based requirements understate actual ramp uncertainty. Solar-conditioned ramp requirements are found to reduce generation operating costs by about 2% for the test system (which would be equivalent to over $\$100$ million per year for a CAISO-size system).},
doi = {10.1016/j.seja.2022.100024},
journal = {Solar Energy Advances},
number = ,
volume = 2,
place = {United States},
year = {Thu Sep 15 00:00:00 EDT 2022},
month = {Thu Sep 15 00:00:00 EDT 2022}
}

Works referenced in this record:

The value of day-ahead solar power forecasting improvement
journal, May 2016


Real-Time Markets for Flexiramp: A Stochastic Unit Commitment-Based Analysis
journal, March 2016


Optimizing the Spinning Reserve Requirements Using a Cost/Benefit Analysis
journal, February 2007

  • Ortega-Vazquez, Miguel A.; Kirschen, Daniel S.
  • IEEE Transactions on Power Systems, Vol. 22, Issue 1
  • DOI: 10.1109/TPWRS.2006.888951

Application of probabilistic wind power forecasting in electricity markets
journal, March 2012

  • Zhou, Z.; Botterud, A.; Wang, J.
  • Wind Energy, Vol. 16, Issue 3
  • DOI: 10.1002/we.1496

A review on the integration of probabilistic solar forecasting in power systems
journal, November 2020


Sizing ramping reserve using probabilistic solar forecasts: A data-driven method
journal, May 2022


The combined value of wind and solar power forecasting improvements and electricity storage
journal, March 2018


An Extended IEEE 118-Bus Test System With High Renewable Penetration
journal, January 2018

  • Pena, Ivonne; Martinez-Anido, Carlo Brancucci; Hodge, Bri-Mathias
  • IEEE Transactions on Power Systems, Vol. 33, Issue 1
  • DOI: 10.1109/TPWRS.2017.2695963