Improving operational flexibility of integrated energy system with uncertain renewable generations considering thermal inertia of buildings

Abstract

Insufficient flexibility in system operation caused by traditional "heat-set" operating modes of combined heat and power (CHP) units in winter heating periods is a key issue that limits renewable energy consumption. In order to reduce the curtailment of renewable energy resources through improving the operational flexibility, a novel optimal scheduling model based on chance-constrained programming (CCP), aiming at minimizing the lowest generation cost, is proposed for a small-scale integrated energy system (IES) with CHP units, thermal power units, renewable generations and representative auxiliary equipments. In this model, due to the uncertainties of renewable generations including wind turbines and photovoltaic units, the probabilistic spinning reserves are supplied in the form of chance-constrained; from the perspective of user experience, a heating load model is built with consideration of heat comfort and inertia in buildings. To solve the model, a solution approach based on sequence operation theory (SOT) is developed, where the original CCP-based scheduling model is tackled into a solvable mixedinteger linear programming (MILP) formulation by converting a chance constraint into its deterministic equivalence class, and thereby is solved via the CPLEX solver. The simulation results on the modified IEEE 30-bus system demonstrate that the presented method manages to improve operational flexibility of the IES with uncertain renewable generations by comprehensively leveraging thermal inertia of buildings and different kinds of auxiliary equipments, which provides a fundamental way for promoting renewable energy consumption. (Y. Li).the most important choices for ensuring secure and sustainable energy supply [1], due to the advantages of renewable energies such as cleanness, easy availability, low cost, and abundance [2]. Unfortunately, the increasing uncertainties of renewable generations will pose huge challenges in the operation of today's power systems [3]. Furthermore, the traditional 'heat-set' constraints and growing curtailment of renewable energy resources greatly limit the flexibility and economy of the system operation [4]. At the same time, the presence of an integrated energy system (IES), which comprehensively utilizes multiple energies in a region to achieve coordinated planning and operations among multiple energy forms [5], provides more regulatory means available for enabling greater consumption of renewable energies [6]. By utilizing the time and space complementary characteristics of energy and power of multiple power sources such as wind turbines (WT) and photovoltaic (PV) units, coordinated scheduling of a multi-energy system can improve the operational flexibility of the system and expand the space for renewable energy consumption, thereby providing a new way to ensure secure and sustainable energy supplies. Therefore, how to improve the flexibility of IES to promote renewable energy consumption is of great significance [7]. Literature reviewUp to now, some pioneering works regarding IES h...

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