Energy Station Research Articles

Optimal configuration of integrated energy station using adaptive operation mode of combined heat and power units

Operation modes of combined heat and power (CHP) units are closely related to the economic benefits of energy application in integrated energy station. In this paper, a novel bi-level optimal configuration method is proposed considering different operation modes of CHP, and a life-cycle assessment system on economic and environmental benefits is constructed using system dynamics (SD) method. Firstly, the basic structure and operation issues of a typical integrated energy station employing CHP are addressed. Secondly, the bi-level collaborative optimization model of the integrated energy station is constructed to minimize the annualized cost considering three operating modes, namely following the thermal load (FEL), following the electric load (FTL) and switching adaptively between FEL and FTL. Then, the model is solved by the column-and-constraint generation and particle swarm optimization coordination with mixed-linear integer programming respectively. Subsequently, the sensitivity of CHP units heat-to-electric ratio and electric storage to the planning results are analyzed in detail. Finally, case studies are carried out based on an actual integrated energy station. The optimization results show that, compared with FEL and FTL operating modes of the CHP units, the annualized cost of the system under adaptive operation mode is reduced by 26.5% and 42.8%, respectively. Besides, the assessment of the optimized system indicates that the total profit and carbon dioxide emission reduction of the station during its life-cycle are expected to reach 28.53 million CNY and 25.33 ten thousand tons respectively, which provides a reference for decision-making and a basis for flexible operation.

Regional collaborative planning equipped with shared energy storage under multi-time scale rolling optimisation method

Integrated energy systems (IES) have become a popular direction in the field of energy research due to their economic, efficient and environmental friendly advantages. Among them, multi-region integrated energy systems (M-RIES) are more valuable than single-region integrated energy systems (S-RIES) due to their low energy loss, high economy and reliability. At present, there is a lack of an optimisation method that integrates station-network synergy, inter-station interaction, shared energy storage configuration, overall planning of equipment configuration and multi-timescale rolling for the multi-faceted performance enhancement of M-RIES. Therefore, this paper proposes an M-RIES with station-storage interaction and inter-station interaction under the consideration of station-network synergy, and conducts a study on the optimal configuration of M-RIES from the viewpoint of economy and environmental protection. The final analysis is based on a northern region. The results show that the system achieves an energy efficiency of 1.07, a 16.9% reduction in total station equipment configuration, a 3.87% reduction in cost and a 0.76% increase in new energy consumption rate compared to a stand-alone operating system. Taking one of the energy stations as an example, under the operating conditions of 10% intra-day and 5% real-time error, the multi-timescale rolling optimisation method significantly improves the energy supply rate compared to the day-ahead dispatching method, where the error rates for the three typical days of transition, winter and summer are only 0.43%, 2.56% and 0.06%, corresponding to a reduction of 5.02%, 2.49% and 5.06%, and a smaller cost error than the ideal solution The cost error rates for the three typical days are only 1.99%, 3.60% and 3.46%. In summary, the collaborative autonomous planning and operation method proposed in this paper has great advantages in terms of economy, reliability, energy efficiency and environmental protection.

Primary Frequency Control of Wind-solar-storage Power Station Considering Discrete Control Nonlinearity

With the gradual advancement of dual-carbon goals, the wind-solar-storage power station has become the mainstream trend in constructing new energy stations due to their wind energy and luminous complementary characteristics. However, the current research on primary frequency control of new energy stations is still focused on a single-machine strategy. The communication delay and control period caused by long control links are not considered. It is difficult to describe the influence of the difference in dynamic characteristics of wind-solar-storage power on primary frequency control performance. Therefore, this paper takes the multi-layer control link wind-solar-storage power station as the research object, establishes the nonlinear control model considering the influence of control delay and control period, and puts forward the wind-solar-storage power plant primary frequency control method, which is suitable for participating in the frequency control of power grid.

Analysis of the Influence of Grid-Connected Photovoltaic Power Stations with Virtual Inertia on Low-Frequency Oscillation of Power System Based on Small Signal and Prony Analysis Methods

With the virtual synchronous generator (VSG) technology gradually becoming an emerging technology for new energy consumption, its introduction has solved the problems of weak support and weak anti-interference of traditional new energy stations. However, the practice shows that the grid-connected characteristics of VSG limit its large-scale utilization, and there is little research on the interaction between VSG and a multi-machine system. In this paper, small signal models and time domain simulation models of each link of a photovoltaic(PV) power station with the PV virtual synchronous generator (PV-VSG) are first conducted, and then the influence of the grid-connected PV power station with the PV-VSG on the low-frequency oscillation of power system and its interaction mechanism with the multi-machine system are qualitatively obtained based on the small signal analysis method and prony analysis method from two dimensions of frequency domain and time domain, respectively. The analysis and simulation show that the PV power station based on VSG technology affects the dynamic characteristics of the system by changing the electromagnetic torque of each synchronous generator. Unreasonable operating conditions and parameter settings will aggravate the phenomenon of low-frequency oscillation of the system. Before the grid connection of PV power station, the operating parameters shall be reasonably set to ensure their safe and stable grid connection.

Research on the Construction Model of Hydrogen-Electric Integrated Energy Stations in Typical Climate Regions of China

The hydrogen-electric integrated energy station will play an important role in the new power system with renewable energy as the main body. This paper establishes an optimization model for the system configuration of a hydrogen-electricity integrated energy station, further explores the differences in optimal configuration and operation modes of different station construction modes with different basic conditions in different places, and discusses the reasons. The research shows that the economy of the grid-connected mode is the best, and the economy of the off-grid mode is the worst. The local electricity price policy, wind and solar resource endowment, and stability will significantly impact the integrated energy station. At the same time, in the regions where the wind and solar resources fluctuate greatly from month to month, hydrogen can play the role of long-term energy storage.

Research on Interconnection Scheme of Renewable Energy in Substation

As one of the carriers of power transmission and transformation in the power system, the traditional substation has a relatively single function. To make full use of renewable energy to generate electricity, the rate of station power consumption needs to be reduced, and the goal of “zero-carbon” substation construction needs to be achieved. The use of renewable distributed power substation station power systems is a valuable research topic. This paper takes the substation as the research object, fully explores the characteristics of the strong flexibility of distributed solar energy, and analyzes the utilization form and access method of renewable distributed energy in the substation. The research station power microgrid system design scheme, mainly including system architecture design, the equipment selection and configuration principles along with the load in the substation station, proposes multiple new energy application scenarios, which have certain reference significance and promotion application value for the future transformation of traditional substations to integrated energy stations with energy interconnection.

Online Probabilistic Static Security Assessment for Power Systems Considering High Renewable Penetration

With the rapid development of renewable energy, a large number of renewable energy stations are connected to the power system, which leads to a decrease in the inertia of the power system and an increase in safety risks suffered. Thus, online static security assessment (SSA) is increasingly necessary. However, because of the uncertainty of renewable energy, it is not feasible to check all possible scenarios in online SSA. To reduce the number of calculations and achieve SSA in a short time, a new online SSA method based on scenario clustering for future ultra-short-term security assessment is proposed in this paper. In the offline stage, a key scenario set is constructed by Markov Chain Monte Carlo and K-means with historical data. In the online application, the initial probability distribution of renewable energy outputs is calculated by joint distribution with the output of the previous interval and corrected by weather data. Then load flow calculation with N-1 criteria is executed, and the probability for the safe operation of the system is calculated. The effectiveness of the proposed online SSA scheme has been verified in the IEEE-300 system, where one of the generators is replaced by a renewable energy station.

Dissimilar welding of austenitic SS and ferritic SS in last decades

Materials are very crucial and important factor in different industrial processes. Austenitic treated steel utilized overall in different significant businesses like synthetic, petrochemical, thermal energy station and vehicle dependent principally upon their corrosion opposition yet additionally for their formability, their solidarity, and their properties at outrageous temperatures. In any case, the expense of such steel is a significant worry to the ventures as the expense of austenitic treated steel is expanding step by step, because of the deficiency of its constituent Ni (Nickel). Thus, to keep away from this issue, the businesses could utilize a blend weld of two Steel having lower level of Ni. which would require right decision of filler material, welding method for an imperfection free sound weld. This paper endeavors an introductory survey of the most common way of joining significant contrasts among austenitic and ferritic Tempered Steel, its microstructure and corrosion opposition properties and mechanical properties in different Cycles and blends.

Multi-parameter cooperative optimization and solution method for regional integrated energy system

As an energy system that uses the power grid and heat network to coordinate the energy interaction between subsystems in the region, the regional integrated energy system can further reduce the system's operating cost and improve the energy utilization rate. However, in the optimization of regional integrated energy systems, there is difficulty in balancing the accuracy of the results and the calculation time. Therefore, a nonlinear collaborative optimization model of a regional integrated energy system is established in this paper, which fully considers the electricity and heat sharing between energy stations. Subsequently, a three-layer-nested co-optimization method for a regional integrated energy system is proposed. The outer layer, middle layer, and inner layer optimize the rated capacity of the internal combustion engine, electric refrigeration ratio, and partial load rate of the internal combustion engine, respectively. Finally, the three-layer-nested co-optimization method is verified from the total system cost, energy utilization rate, and calculation time. The results show that compared with the exhaustive search method and genetic algorithm, the cost per unit area of the system is about 102.99 ¥/m2 (reduced by 1.00 ¥/m2), the energy utilization rate is 70.47% (increased by 2.43%), and the calculation time is about 50–100 h. The three-layer-nested co-optimization method significantly shortens the model's solution time while ensuring the optimization results' accuracy. Finally, this paper can provide a research idea for optimizing regional integrated energy system design.

A system dynamics-based life-cycle carbon footprint calculation model for integrated energy stations

In recent years, countries around the world have been placing increasing emphasis on energy saving and emission reduction. As part of the energy system, integrated energy stations play an important role in the low-carbon transition of the energy sector. However, most of the existing studies on carbon emissions from integrated energy stations focus on the operation phase or a single module within it and lack analysis and prediction of carbon emissions from all phases of the integrated energy station. In this paper, based on the perspective of life cycle assessment, system dynamics is used to establish a life cycle carbon emission model for integrated energy stations from four phases: production & materialization, construction, operation & maintenance, and disposal & recycling. This paper takes wind power integrated energy stations as an example, simulates the characteristics of the life cycle carbon emissions of integrated energy stations, and identifies the key factors affecting the carbon emissions. The simulation results show that the carbon emissions of the integrated energy station are mainly concentrated in the production and operation of the energy station, and the increase in the service life of the energy station will not have a significant impact on the total carbon emissions. This paper provides the theoretical guidance and decision-making basis for the formulation of low-carbon emission reduction measures for integrated energy stations.

Multi-year energy performance data for an electrolysis-based hydrogen refueling station

Financing, sizing, operating, or upgrading a hydrogen refueling station (HRS) is challenging and may be complex, much more so in today's rapidly changing and growing hydrogen industry. There is a significant information gap regarding experimental hydrogen station activities. A high-level perspective on such data and information may facilitate the transition between present and future HRS operations. To address the need for such high-level perspective, this paper presents a comprehensive data set on the performance of the California State University Los Angeles Hydrogen Research and Fueling Facility, based on multi-year operational data. The analysis of over 4500 refueling events and over 8800 kg of hydrogen dispensed, as well as the operation of the facility electrolyzer and of both storage and refueling compressors from 2016 to 2020, reveals a comprehensive picture of HRS energy performance and the identification of useful key performance indicators. In 2016, the station's energy efficiency was 25%, but in 2017 and the first three quarters of 2018, it dropped to 15%. Station-specific energy consumption increased during these quarters. The 2020 first quarter energy consumption was between 70 and 80 kWh/kg. At this time, the energy efficiency of the station reached 40%.This research is based on an unprecedented and unique dataset of an HRS operating under real-world conditions, with an approach that can be informative for modeling the performance of other stations, providing a dataset that HRS designers, operators, and investors may utilize to make data-driven choices regarding HRS components and their specs and size, as well as operating strategies.

Synergetic planning method for energy stations, pipeline networks, and demand response

Rational planning for energy stations and their lower-level energy supply pipeline networks is vital for improving the economy of the regional integrated energy system. Many studies have been focused on synergetic planning for energy stations and pipeline networks, but few have been oriented from the perspective of synergetic planning for energy stations, pipeline networks, and demand response, which may result in a redundant configuration of the regional integrated energy system. This paper proposes a synergetic planning method for energy stations, pipeline networks, and demand response. Initially, the impact of demand response on the traditional synergetic planning for energy stations and pipeline networks is analyzed. Subsequently, a synergetic planning method for energy stations, pipeline networks, and demand response is proposed to determine the optimal locations of energy stations, the optimal equipment capacity of energy stations, the optimal demand response configuration, and the optimal layout of pipeline networks. Finally, case studies are conducted to verify the effectiveness of the proposed method. Compared with the traditional synergetic planning method for energy stations and pipeline networks without considering demand response, the proposed method can reduce the construction cost of energy stations by approximately 4.8% and pipeline networks by around 8.5%. Thus, the proposed method can be applied for planning energy stations and pipeline networks.

Optimal quantity, location and capacity allocation of the additional renewable energy stations in a large-scale district heating system and comprehensive case analyses

Integrating the combined heat and power (CHP) plants with distributed renewable energy stations (RESs) is an important way to promote the low-carbon development of district heating system (DHS) and to further achieve “carbon neutrality” goal in the future. However, when the total capacity of power-to-heat devices is determined by district energy planning, different configurations (quantity, location, and installed capacity allocation) of additional RESs show various energy-saving potential in the long-term operation of DHS. In this study, an integrated optimization model consisting two independent optimization modules is proposed, aiming at maximizing the comprehensive economic benefits of distributed RESs. A novel virtual split method is also introduced to simplify the operating optimization of DHS. In addition, to ensure the reliability and accuracy of optimization calculation, a heuristic optimization tool (genetic algorithm) is applied to solve these non-linear optimization problems. Case studies from a real trans-regional DHS indicate that a reasonable configuration of additional RESs optimizes and equalizes the distribution of pressure and flow in the primary DHN, and the heat dissipation of flow energy in regulating valves and transmission pipelines can be reduced considerably. The proposed integrated optimization model and its solving processes can be migrated to other similar projects worldwide.

Energy accommodation-oriented interaction of active distribution network and central energy station considering soft open points

Energy accommodation-oriented interaction of active distribution network and central energy station considering soft open points

Share or not share, the analysis of energy storage interaction of multiple renewable energy stations based on the evolution game

With the increasing penetration of renewable energy, the traditional energy storage operation based on individual framework —users own and operate independently mode may become impracticable due to conflicting interests, insufficient utilization, and poor interoperability. Riding on the wave of the proliferation of sharing economy, storage energy sharing expands the existing storage energy without requiring costly and time-consuming infrastructure investments. However, the development path of shared energy storage (SES) mode is not clear due to the asymmetric decision-making of the owners of energy storage systems under bounded rationality. In this paper, the diffusion of the business model of SES among multiple renewable energy stations (the owners, RES) and its key factors are analyzed based on the evolutionary game. The goal is to maximize social welfare and ensure the continuous growth of the sharing market. The numerical simulation is carried out based on the data from northwest China to interpret the development path. The result shows that, in renewable energy cluster the stations with intermittent output or with the higher prediction accuracy are more willing to participate in sharing. The energy storage sharing mode fails when the energy storage capacity ratio of RES is less than 10%. While the high-level ratio (more than 30%) is not conducive to the diffusion of the sharing model in RESs with low power generation prediction accuracy.

Prelithiation Enhances Cycling Life of Lithium‐Ion Batteries: A Mini Review

During the last decade, the rapid development of lithium‐ion battery (LIB) energy storage systems has provided significant support for the efficient operation of renewable energy stations. In the coming years, the service life demand of energy storage systems will be further increased to 30 years from the current 20 years on the basis of the equivalent service life of renewable energy stations. However, the life of the present LIB is far from meeting such high demand. Therefore, research on the next‐generation LIB with ultra‐long service life is imminent. Prelithiation technology has been widely studied as an important means to compensate for the initial coulombic efficiency loss and improve the service life of LIBs. This review systematically summarized the different prelithiation methods from anode and cathode electrodes. Moreover, the large‐scale industrialization challenge and the possibility of the existing prelithiation technology are analyzed, based on three key parameters: industry compatibility, prelithiation efficiency, and energy density. Finally, the future trends of improvement in LIB performance by other overlithiated cathode materials are presented, which gives a reference for subsequent research.

Configuration optimization of solar-driven low temperature district heating and cooling system integrated with distributed water-lithium bromide absorption heat pumps

Developing solar energy source for space heating and cooling contributes to achieving the target of China’s carbon emission peak by 2030. However, the conventional solar-driven heating systems integrated with heat pump or natural gas boiler are featured by short economic heat transmission distance and small solar fraction, and can’t cover the demand of the large-scale solar-driven district heating and cooling systems. To solve the problem, two configurations of solar-driven low temperature district heating and cooling system are proposed. One is integrated with distributed single-effect water-lithium bromide absorption heat pumps, and the other is integrated with distributed half-effect water-lithium bromide absorption heat pumps. The distributed absorption heat pumps are located in the energy stations for reducing return temperature of the primary network, which helps to enlarge temperature difference between supply and return and improve solar collector performance. The analyzed results indicate that, in the energy station, replacing single-effect water-lithium bromide absorption heat pump by half-effect one can improve system annual coefficient of performance by about 0.73, reduce cooling cost by about 6.04 ¥/GJ, and increase economic heat transmission distance by about 2.6 km. Thus, the proposed solar-driven low temperature district heating and cooling system integrated with distributed half-effect water-lithium bromide absorption heat pumps has an advanced energy conversion and transfer process, and its economic heat transmission distance is about 18.3 km. Thus, application of the proposed solar-driven low temperature district heating and cooling system integrated with distributed half-effect water-lithium bromide absorption heat pumps would be promising in Northern China.

Two-stage robust optimization of regional integrated energy systems considering uncertainties of distributed energy stations

For a regional integrated energy system (RIES) composed of an energy supply network and distributed energy station, the uncertainty of distributed photovoltaic (PV) output and the fluctuation of various loads pose significant challenges to the stability of system operation and the accuracy of optimal scheduling. In order to enhance the operational reliability of regional integrated energy systems and reduce the impact of photovoltaic and load uncertainties on distributed energy stations, this study proposes robust optimization method of regional integrated energy systems that takes into account the uncertainty of the distributed energy station. First, the regional integrated energy system is divided into an upper electric-gas energy supply network and a lower distributed energy station. The upper model mainly realizes energy transmission, while the lower model is a two-stage robust optimization model of distributed energy stations in the form of min–max–min, which mainly realizes flexible energy supply of different types of energy. Then, the lower two-stage robust optimization model is simplified and solved using a column and constraint generation (CCG) algorithm. After that, an alternating direction method of multipliers (ADMM) is used to solve the upper and lower models of the regional integrated energy system, and the solution scale is reduced while ensuring the correlation between the energy transmission network and the distributed energy stations. Finally, a test example is provided to illustrate the effectiveness and usefulness of the proposed method. It follows from simulation results that the robust optimization method can effectively reduce the instability of the system operation caused by uncertainty factors and improve the system’s anti-interference ability, and in addition, systems with high penetration levels of photovoltaic output will benefit more from robust optimization.

Optimal dispatch of integrated energy station considering carbon capture and hydrogen demand

To respond to the escalating contradiction between improving economy and reducing carbon emissions, a low-carbon optimal dispatch model of integrated energy station (IES) considering carbon capture and hydrogen demand is proposed. First, a wind-photovoltaic-hydrogen power (WPHP) integration model is built, giving an effective way of renewable energy accommodating and reliable hydrogen supplying of IES. The WPHP significantly improves system economy and decreases the renewable energy curtailment, especially with a high proportion integrated; Then, a coupling model of carbon capture system (CCS) and power-to-gas (P2G) is built. The model resolves the problem of carbon source of P2G and reduces the carbon net emissions, changing the carbon trading cost from expenditure to profit; Next, an integrated demand response (IDR) model is built covering electricity, gas, cooling, hydrogen load as well as the heating load with different heat grade requirements. The IDR further improves multi-energy users' satisfaction, the economy and stability of IES by decreasing the peak-valley difference and increasing load ratio of multi-energy loads. Finally, an optimal dispatch model of IES is built with the objective of minimizing the cost of economic, carbon emission trading and users’ dissatisfaction, and the effectiveness of the model is verified by a numerical example.

Stability Assessment Method for New Energy Stations Merged into the Receiving End Power Grid

Replacing thermal power with new energy is the future power grid development trend. Many distributed new energy stations are integrated into the power grid in areas with concentrated loads, such as Shandong Province. The short-circuit ratio (SCR) is often used to evaluate the system’s stability, but the short-circuit ratio index is a static index with no actual physical meaning, so it is difficult to reflect the transient stability problem after the new energy station is connected. In this paper, an analytical calculation method for the fault-clearing time of new energy power stations is proposed according to the operating state of the induction motor. The fault limit clearing time is used as an index to evaluate the system’s stability, which has practical physical significance and good results.