Low-carbon economic scheduling for AIES considering flexible load coordination and multiple uncertainties

Guest Editorial: Situational awareness of integrated energy systems

The integrated energy system emphasizes the synergy between multiple energy sources compared with the traditional distributed energy subsystem. At present, the research on integrated energy systems is mostly the optimization research of single independent systems, which fails to give full play to the advantages of integrated energy systems. Since the mutual coupling between the electro-gas-thermal networks makes the multi-region integrated energy system optimization operation more complicated, the current research is still immature and needs further research. This paper firstly models the energy storage (storage, heat storage, gas storage) equipment and energy coupling equipment in the integrated energy system. Secondly, it establishes the objective function that considers the minimum system cost and establishes the power of the grid, and give the constraints of power balance equation and line loss equation of power grid, heat network and gas network; Finally, the simulation results show that after the grid, the heat network and the gas network are combined, the original distribution system is converted into a joint supply system through the grid, the heat network and the gas network, which improves the overall economy.

Seismic events can severely damage both electricity and natural gas systems, causing devastating consequences. Ensuring the secure and reliable operation of the integrated energy system (IES) is of high importance to avoid potential damage to the infrastructure and reduce economic losses. This article proposes a new optimal two-stage optimization to enhance the reliability of IES planning and operation against seismic attacks. In the first stage, hardening investment on the IES is conducted, featuring preventive measures for seismic attacks. The second stage minimizes the expected operation cost of emergency response. The random seismic attack is modeled as uncertainty, which is realized after the first stage. An explicit damage assessment model is developed to define the budget set of the uncertain seismic activity. Based on the survivability of transmission lines and gas pipelines of IES, an optimal system investment plan is developed. The problem is formulated as a two-stage distributionally robust optimization (DRO) model, which is tested on an integrated IEEE 30-bus system and 20-node gas network. Case studies demonstrate that the two-stage DRO outperforms robust optimization and a single-stage optimization model in terms of minimizing the investment cost and expected economic loss. This article can help system operators to make economical hardening and operation strategies to improve the reliability of IES under seismic attacks, thus managing a more robust and secure energy system.

The coupling between electricity and natural gas systems can be promoted with the emergence of power-to-gas (P2G) technology and natural gas generation units (NGGUs), which offers a potential alternative to accommodate the surplus renewable energy generation (REG). Given this background, an optimal coordinated schedule model for electricity and natural gas distribution networks with P2G facilities is first proposed. In this presented model, the objective is to minimize the overall operation costs of the integrated energy system, while the constraints include the operation ones in both the electricity distribution network and natural gas distribution network. The commercial solver IPOPT is then utilized in the AMPL environment to solve this developed optimization model. Finally, an integrated energy system consisting of a modified 54-bus electricity distribution network and a 19-bus natural gas distribution network is employed to demonstrate the feasibility of the presented model.

A negative-carbon planning method for agricultural rural industrial park integrated energy system considering biomass energy and modern agricultural facilities

Integrated energy system (IES) can realize the complementary energy supply of various energy forms such as electricity, heat and gas, so as to promote the consumption capacity of renewable energy and improve the comprehensive utilization efficiency of energy. The IES capacity planning considering multiple uncertain factors is closer to the actual situation, and it is also the basis for realizing multi-energy coordination and IES optimal operation. Aiming at the volatility of renewable energy such as wind and solar energy and natural gas prices, this paper proposes an IES capacity planning model considering multiple uncertain factors. The duality robust counterpart (DRC) algorithm is used to convert the uncertain problem into a deterministic problem. Finally, an IES capacity planning model with the minimum sum of investment and operation and maintenance costs as the objective function is obtained. The case studies show that the proposed model can economically and reliably satisfy the various types of load demands in the system throughout the planning cycle.

TimeGAN based distributionally robust optimization for biomass-photovoltaic-hydrogen scheduling under source-load-market uncertainties

Integrated energy system (IES) has advantages in improving the comprehensive utilization efficiency of energy, promoting the consumption of renewable energy and solving the problems of energy shortage and environmental pollution. An optimal planning method of IES considering photovoltaic (PV) integration is proposed in this paper. Firstly, considering PV units, the typical structure of IES containing electricity, gas, heat and cold energy is constructed, and the energy conversion and storage equipment are modeled; Then, aiming at the lowest total cost in the planning period, considering the constraints such as power balance, equipment working characteristics and upper limit of investment and construction, an optimal planning model of IES is established; Finally, an example is given to verify the effectiveness of the proposed method, and the effects of PV integration and natural gas price on the planning results are analyzed.

A real-time error correction operation model for an integrated energy system is proposed in this paper, based on the analysis of the real-time optimized operation structure of an integrated energy system and the characteristics of the system. The model makes real-time corrections to the day-ahead operation strategy of the integrated energy system, to offset forecast errors from the renewable power generation system and multi-energy load system. When unbalanced power occurs in the system due to prediction errors, the model comprehensively considers the total capacity of each energy supply and energy storage equipment, adjustable margin, power climbing speed and adjustment cost, to formulate the droop rate which determines the unbalanced power that each device will undertake at the next time interval, while taking the day-ahead dispatching goals of the system into consideration. The case study shows that the dispatching strategy obtained by the real-time error correction operation model makes the power output change trend of the energy supply equipment consistent with the day-ahead dispatching plan at the next time interval, which ensures the safety, stability and economy of the real-time operation of the integrated energy system.

The integrated energy system (IES) has been studied in recent years to achieve higher energy efficiency. To minimize the total cost of investment and operation for IES, an optimal planning method for allocating Combined-Heat-Power (CHP) Unit considering the dynamics of heat and gas networks is proposed in this paper. Considering the dynamic characteristics of heat and gas networks, several differential equations are established, which describe the distribution of water temperature, gas density, velocity and pressure within pipelines. Then the Lax-Wendroff method is used to simplify the calculation and a more economical allocation result is achieved. The case study demonstrates the effectiveness of the proposed method.

Techno-economic-environmental evaluation framework for integrated gas and electricity distribution networks considering impact of different storage configurations

With the deepening coupling of power, natural gas and thermal network, the operation mode of integrated energy system has gradually become a new research hotspot. In this paper, taking the park level electric-heat-gas integrated energy system as an example, based on the study of its main characteristics, a mathematical model for the optimal operation of the integrated energy system is constructed, which mainly considers the gas turbine, energy storage and other equipment, in order to realize the economic operation of the system.

Integrated Energy Systems (IES), which leverage the synergistic coordination of electricity, heat, and gas networks, serve as crucial enablers for a low-carbon transition. Current research predominantly treats energy storage as a subordinate resource in dispatch schemes, failing to simultaneously optimise IES economic efficiency and storage operators' profit maximisation, thereby overlooking their potential value as independent market entities. To address these limitations, this study establishes an operator-autonomous management framework incorporating electrical, thermal, and hydrogen storage in IES. We propose a joint optimal dispatch model for hybrid energy storage systems in low-carbon IES operation. The upper-level model minimises total system operation costs for IES operators, while the lower-level model maximises net profits for independent storage operators managing various storage assets. These two levels are interconnected through power, price, and carbon signals. The effectiveness of the proposed model is verified by setting up multiple scenarios for example analysis.

The depleting oil reserves, air pollution and increasing energy demand, have overturned the focus of the scientific community to renewable energy sources. Among which the photovoltaic (PV) systems occupy more than half of the market share and are generally installed at the distribution level. The volatile and uncertain nature of these PV productions necessitates flexible resources in energy systems. To this end, the district heating systems have an outstanding flexibility on account of their high thermal inertia. This study investigates the optimal unit commitment scheduling for gas‐fired and non‐gas‐fired distributed generation units (NGU) in an integrated energy distribution system (IEDS) within the physical constraints of the electrical, natural gas and thermal energy distribution networks. Moreover, a planning‐based optimization framework is proposed to investigate the investment of battery storage systems in the electric distribution network under the high penetration of PV systems with the aim of enhancing flexibility and reducing the operating costs of the IEDS. In this framework, the information gap decision theory is deployed under risk‐averse and risk‐seeker strategies to deal with uncertain PV energy production. Additionally, the environmental emissions are considered in a multi‐objective approach. The IEDS is embodied through IEEE 33‐bus EDS, 20‐node natural gas network and an 8‐node district heating systems. Eventually, The proposed approach makes a noteworthy contribution to the advancement of solar energy systems in IEDS.

The existing studies on probabilistic steady-state analysis of integrated energy systems (IES) are limited to integrated electricity and gas networks or integrated electricity and heating networks. This paper proposes a probabilistic steady-state analysis of integrated electricity, gas and heating networks (EGH-IES). Four typical operation modes of an EGH-IES are presented at first. The probabilistic energy flow problem of the EGS-IES considering its operation modes and correlated uncertainties in wind/solar power and electricity/gas/heat loads is then formulated and solved by the Monte Carlo method based on Latin hypercube sampling and Nataf transformation. Numerical simulations are conducted on a sample EGH-IES working in the “electricity/gas following heat” mode to verify the probabilistic analysis proposed in this paper and to study the effects of uncertainties and correlations on the operation of the EGH-IES, especially uncertainty transmissions among the subnetworks.