A Two-Timescale Decision-Hazard-Decision Formulation for Storage Usage Values Calculation

TL;DR

This paper introduces a two-timescale decision-hazard-decision framework for calculating storage usage values, accounting for uncertainties at different operational timescales, improving the realism of storage valuation in renewable energy systems.

Contribution

It develops a novel two-timescale stochastic optimization model with a decision-hazard-decision structure, enhancing the accuracy of storage usage value calculations under uncertainty.

Findings

Usage values are sensitive to information disclosure modeling.

The proposed framework decomposes decision-making into planning and recourse steps.

Numerical results demonstrate the impact of information structure on storage valuation.

Abstract

The penetration of renewable energies requires additional storages to deal with intermittency. Accordingly, there is growing interest in evaluating the opportunity cost (usage value) associated with stored energy in large storages, a cost obtained by solving a multistage stochastic optimization problem. Today, to compute usage values under uncertainties, an adequacy resource problem is solved using stochastic dynamic programming assuming a hazard-decision information structure. This modelling assumes complete knowledge of the coming week uncertainties, which is not adapted to the system operation as the intermittency occurs at smaller timescale. We equip the twotimescale problem with a new information structure considering planning and recourse decisions: decision-hazard-decision. This structure is used to decompose the multistage decision-making process into a nonanticipative planning step in which the on/off decisions for the thermal units are made, and a recourse step in which the power modulation decisions are made once the uncertainties have been disclosed. In a numerical case, we illustrate how usage values are sensitive as how the disclosure of information is modelled.