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The use of clean electricity to replace fossil energy burning for heating is an important emission reduction way to achieve carbon neutrality. Without a good business model, it is very difficult to promote electric heating as a replacement for coal-fired systems in some areas with abundant coal resources. This study proposed a new business model for electric heating with stakeholders that included the government, the power grid company, and heat users. Based on this model, a specific tri-objective optimization model was proposed with the electric heating promotion power, heating electricity price, and government subsidy as variables to characterize the game relationship of the stakeholders, and the components of the stakeholder benefit function were analyzed in detail. A classical multi-objective genetic algorithm was used to solve the model. Finally, an “electrical heating” project for a typical area in China was analyzed, and four promotion cases were examined. The results showed that the power grid company and users had an antagonistic relationship in relation to the electricity price, but the best solution was found for all three stakeholders due to the high financial subsidies provided by the government.

Under the traditional control strategy, UHVDC transmission system is lack of inertia and damping characteristics, so it can't effectively adjust the frequency of AC system dynamically. Virtual synchronous generator (VSG) technology can simulate the operation characteristics of traditional synchronous generator, making the converter have inertia and damping characteristics, so as to slow down the frequency change of AC system, but it belongs to differential frequency modulation method. To solve the above problems, in this article, we propose a two-terminal converter station control strategy for UHVDC transmission system based on VSG technology. Two key parameters of synchronous generator rotational inertia and damping coefficient are retained in this method. Meanwhile, the calculation method of frequency in virtual rotor is improved, and secondary frequency regulation is added. Aiming at the situation of load mutation, a two terminal VSG system model is built in Matlab/ SIMULINK for simulation. The results show that the control strategy has the characteristics of inertia and damping, which can reduce the amplitude, speed and overshoot of frequency fluctuation, suppress the voltage fluctuation of DC system, and realize secondary frequency modulation.

In this paper, an advanced analytical model for an electric vehicle (EV) powertrain has been developed to illustrate the vehicular dynamics by combining electrical and mechanical models in the analysis. This study is based on a Nissan Leaf EV. In the electrical system, the powertrain has various components including a battery pack, a battery management system, a dc/dc converter, a dc/ac inverter, a permanent magnet synchronous motor, and a control system. In the mechanical system, it consists of power transmissions, axial shaft, and vehicle wheels. Furthermore, the driving performance of the Nissan Leaf is studied through the real-world driving tests and simulation tests in MATLAB/Simulink. In the analytical model, the vehicular dynamics is evaluated against changes in the vehicle velocity and acceleration, state of charge of the battery, and the motor power. Finally, a number of EVs involved in the power dispatch is studied. The greenhouse gas emissions of the EV are analyzed according to various energy power and driving features, and compared with the conventional internal combustion engine vehicle. In this case, Nissan Leaf is a pure EV. For a given drive cycle, Nissan Leaf can reduce CO2 emissions by 70%, depending on the way electricity is generated and duty cycles.

Owing to intermittency of wind power and slow ramp rates of conventional generators, a considerable amount of wind energy cannot be effectively utilized during frequency control processes. This paper proposes a technique for power system planners and operators to select or commit power capacity and energy capacity of battery energy storage system (BESS) for mitigating the effects of intermittent wind speeds on reliability and economics. A novel procedure is proposed to determine intermittent wind speeds based on the chaos theory and intermittency-related parameters. The frequency-related reliability and economic indices of a power system with BESS are formulated based on frequency control processes. The effects of BESS on dynamic reliability and economics of a practical power system are investigated using the proposed techniques and models.

Green hydrogen is used as fuel or raw material in power systems, transportation, and industry, which is expected to curb carbon emissions at the root. First, a unified energy system consisting of clean power generation systems, hydrogen energy systems (HESs), and transmission systems was proposed, and the characteristics of hydrogen load in different fields are analyzed. Possible business models for HESs in industry and transportation are then presented, cost and benefit functions for stakeholders of HES were created, and a business model with multi-party participation was modeled as a multi-objective optimization model. In a power system, the business model of combining two operating modes for hydrogen storage was proposed at the power generation side as well. Finally, three HESs were designed for a chemical plant with a hydrogen demand of 1000 Nm3/h, a hydrogen refueling station with a daily hydrogen load of 600 kg, and a 100% clean power generation system, respectively. The results of the case study show that one or more feasible business models (i.e., all stakeholders are profitable) can be found in both industrial and transportation by the HES planning approach proposed, while the internal rate of return of HES installed on the generation side is less than 5% due to high investment cost at this stage and low utilization rate; nonetheless, the profitable strategies are shown by 3D graphics.

Wind power is the most promising renewable energy source, and hydrogen energy is a clean energy carrier. The combination of the two will provide a feasible solution for achieving carbon neutrality. We combine natural gas and carbon capture systems with typical wind-hydrogen coupling systems to improve system economy, and hydrogen power generation is not considered. Oxygen-enriched combustion technology uses the oxygen obtained from hydrogen production to realize the coupling of natural gas and wind energy hydrogen production systems, which improves the efficiency of gas turbines and reduces Energy consumption of carbon capture. Then, with the goal of minimizing the annualized cost including the cost of investment, maintenance, operation and wind curtailment penalty, and taking wind curtailment, carbon capture, gas storage, and power balance as constraints, construct a wind-hydrogen low carbon energy system optimal configuration model. Finally, based on CPLEX to simulate the energy supply system in a certain area, the optimal configuration plan of the system’s wind power, gas storage capacity, electrolytic cell.

Utilizing clean renewable generation and carbon capture plants (CCPs) can remarkably reduce the carbon emission from electricity production. Because operating carbon capture facility consumers additional energy, minimizing the production cost and reducing the carbon emission may conflict with each other. To compromise these two objectives and cope with uncertain wind generation, this paper proposes a robust environmental-economic dispatch (EED) method that jointly optimizes energy and reserve schedules in the upcoming dispatch period. The operating characteristic of CCP and the volatility of wind energy are considered in the proposed model. Because both objectives are convex functions, the Pareto front can be readily computed by using the e-constraint method. The Nash bargaining criterion is adopted to determine a fair trade-off between the generation cost and the carbon emission in the absence of a clear carbon tax or emission cap. A second-order cone program (SOCP) is proposed to locate the bargaining solution on the Pareto front. An adaptive scenario generation algorithm is derived to solve the robust EED problem in a tractable manner. The PJM 5-bus system is used to illustrate the obtained dispatch strategy, and demonstrate the contribution of CCPs on reducing the carbon emissions and enhancing the operational flexibility. Case studies on the IEEE 118-bus system corroborate the applicability of the proposed method.

To utilize heat and electricity in a clean and integrated manner, a zero-carbon-emission micro Energy Internet (ZCE-MEI) architecture is proposed by incorporating non-supplementary fired compressed air energy storage (NSF-CAES) hub. A typical ZCE-MEI combining power distribution network (PDN) and district heating network (DHN) with NSF-CAES is considered in this paper. NSF-CAES hub is formulated to take the thermal dynamic and pressure behavior into account to enhance dispatch flexibility. A modified DistFlow model is utilized to allow several discrete and continuous reactive power compensators to maintain voltage quality of PDN. Optimal operation of the ZCE-MEI is firstly modeled as a mixed integer nonlinear programming (MINLP). Several transformations and simplifications are taken to convert the problem as a mixed integer linear programming (MILP) which can be effectively solved by CPLEX. A typical test system composed of a NSF-CAES hub, a 33-bus PDN, and an 8-node DHN is adopted to verify the effectiveness of the proposed ZCE-MEI in terms of reducing operation cost and wind curtailment.

This paper introduces a new rotor design for the easy insertion and removal of rotor windings. The shape of the rotor is optimized based on a surrogate method in order to achieve low power loss under the maximum power output. The synchronous machine with the new rotor is evaluated in 2-D finite element software and validated by experiments. This rotor shows great potential for reducing the maintenance and repair costs of synchronous machines, making it particularly suited for low-cost mass production markets including gen-sets, steam turbines, wind power generators, and hybrid electric vehicles.

According to the analysis of the traditional multiport converter, a novel partly-isolated four-port converter topology is proposed. The proposed converter is combined by two boost converters and a bidirectional full-bridge DC/DC converter, which can realize bi-directional transfer of energy and isolated between ports, and it ensures the stability of photovoltaic power with a lithium battery energy storage system. Then the control strategies of proposed converter under different working modes are analyzed. Finally, the simulation of operating modes and the conversion between the modes are carried out to verify the feasibility of the new four-port converter.

The thesis reviews the development of traditional synchronous machine design and point out one problem with the manufacture of wound rotor synchronous machines. Install and repair process of the rotor windings can be considered labor-costly and time-consuming in synchronous machine design. The conclusion indicates a new winding method would be helpful for not only the new machines but also for rewound machines. A new rotor design for the easy insertion and repair of the rotor windings is then introduced. This new asymmetrical rotor shows good potentials for reducing the maintenance and repair costs of synchronous machines, making it suitable for manufacturers within the mass production markets such as gen-sets, steam turbines, wind power generators. Simulation results from 2-D finite element analysis and experimental results from testing a 27.5 kVA prototype machine have verified the performance of the new rotor. The results show that the asymmetrical machine’s electromagnetic performance is worse than traditional design and need to be optimised. The shape of the rotor is then optimised based on novel surrogate method in order to achieve the lowest power loss under the maximum power output. This method combines surrogate optimistaion with finite element method. It significantly reduces the time cost of the optimization process and can be applied with very complicated geometry design of the rotor. The performance of the new rotor is examined in 2-D finite element software and validated by experiments. After optimisation, the efficiency of the new rotor can reach the same level of the traditional rotor in electromagnetic performance in addition to its easy insertion and repair feature.

Using multiple energy resources greatly enhances system operating flexibility and efficiency. An energy hub is a vital facility, producing, converting, and storing energy in different forms...

With the increasing penetration of renewable energy in power systems, fluctuation of renewable energy power plants has great influence on stability of the system, and renewable power curtailment is also becoming more and more serious due to the insufficient consumptive ability of local power grid. In order to maximize the utilization of renewable energy, this paper focuses on the generation scheduling optimization for a wind-solar-thermal hybrid system considering that the produced energy will be transmitted over a long distance to satisfy the demands of the receiving end system through ultra-high voltage (UHV) transmission lines. Accordingly, a bilevel optimization based on a non-cooperative game method is proposed to maximize the profit of power plants in the hybrid system. Users in the receiving end system are at the lower level of the bilevel programming, and power plants in the transmitting end system are at the upper level. Competitive behavior among power plants is formulated as a non-cooperative game and the profit of power plant is scheduled by adjusting generation and bidding strategies in both day-ahead markets and intraday markets. In addition, generation cost, wheeling cost, and carbon emissions are all considered in the non-cooperative game model. Moreover, a distributed algorithm is presented to obtain the generalized Nash equilibrium solution, which realizes the optimization in terms of maximizing profit. Finally, several simulations are implemented and analyzed to verify the effectiveness of the proposed optimization method.

With rapid development of renewable energy, especially wind and solar energy, long distance transmission will be the fundamental way for new energy consumption because of the insufficient consumptive ability of local grid. This paper proposed a wind-solar-thermal hybrid system long distance consumption by ultra-high voltage (UHV) transmission lines, which not only make full use of the complementary nature of wind and solar energy in time and region, but also take advantage of good stability of thermal power plant to improve system reliability. A bilevel optimization based on non-cooperative game method was utilized to maximize profit of power plants by changing bidding strategies, where power plants in the transmitting end system are at the upper level and receiving end system are at the lower level. Besides, cost model considering with wheeling cost, carbon emissions cost and government subsidies was presented. Finally, several simulations were implemented and used to verify the feasibility of the non-cooperative game based bilevel optimization method.

This paper proposes a new control method for a hybrid energy system. A wind turbine, a hydrogen energy storage system, and a proton exchange membrane fuel cell are utilized in the system to balance the load and supply. The system is modeled in MATLAB/Simulink and is controlled by an improved energetic macroscopic representation (EMR) method in order to match the load profile with wind power. The simulation and test results have proved that (1) the proposed system is effective to meet the varying load demand with fluctuating wind power inputs, (2) the hybrid energy storage system can improve the stability and fault-ride-through performance of the system, and (3) the dynamic response of the proposed system is satisfactory to operate with wind turbines, energy storage, and fuel cells under EMR control.

This paper presents a wind-methanol-fuel cell system with hydrogen storage. It can manage various energy flow to provide stable wind power supply, produce constant methanol, and reduce CO2 emissions. Firstly, this study establishes the theoretical basis and formulation algorithms. And then, computational experiments are developed with MATLAB/Simulink (R2016a, MathWorks, Natick, MA, USA). Real data are used to fit the developed models in the study. From the test results, the developed system can generate maximum electricity whilst maintaining a stable production of methanol with the aid of a hybrid energy storage system (HESS). A sophisticated control scheme is also developed to coordinate these actions to achieve satisfactory system performance.

The photovoltaic (PV) power surges with varied with sunlight intensity and temperature, resulting in great fluctuation of power on the side of synchronizati on on AC busbar micro-grid. Configuring an energy storage system may allow that the grid output is fallen into a specified interval for the purpose of reduction in grid transmission capacity. The energy conversion device of the energy storage system is designed with two stages. The inverter control strategy includes PQ control mode, VF control mode and constant-voltage charging/discharging mode on the battery side. The chopper control strategy uses control DC busbar voltage stability mode. The reliability of control strategies is verified by simulation, which are able to quickly follow up instruction change and suppress disturbance.