Abstract

The focus of this study is to conduct a techno-economic evaluation of a chemical production plant that utilizes carbon-, nitrogen- and hydrogen-containing steel mill off-gases as a material feedstock. The chemical products analyzed are acetic acid, ammonia, methanol, and urea, all of which, except ammonia, are classified under the carbon capture and utilization (CCU) concept. In order to support the investment decision-making process, a superstructure optimization model is employed, which includes the main technical plants (e.g. reactors, storages and separators) and plant layout decisions (e.g. the choice between two reactors). To determine the impact of future developments, five scenarios are considered, focusing on environmental, technical, and economic key factors for the target operational year of 2040. The scenario-dependent optimization results represent the optimal CCU concept with the highest net present value (NPV) for a German steel plant in Duisburg in 2025. These results, including the chemical plant layout with selected chemicals and plants, demonstrate that different scenarios can lead to significant changes in the NPV and chemicals produced and subsequently exported. The results of this study can be utilized as a foundation for investment decisions.

Abstract

With the integrated energy system (IES) that considers multi-energy complementarity and energy cascade utilization becoming an important trend in energy innovation, aiming at the current IES carbon emission reduction task and safe and stable operation requirements, accurately solving the maximum carbon emission capacity under the safe operation of IES can warn the working state of the system and provide references for carbon emission reduction tasks. Firstly, the steady-state IES energy flow and carbon flow model of electric-gas coupling is established. On this basis, the calculation model of IES maximum carbon emission capacity was established. Then, the mathematical model of IES carbon emission capacity curve is established. Finally, a numerical example is given to verify the effectiveness of the proposed model.

Abstract

The decarbonisation of the built environment is a critical strategy for addressing climate change and decarbonisation of heat plays a significant role in this process. However, the UK’s progress in electrifying heating with heat pumps is significantly behind that of other European countries such as Finland and Norway. This study used clustering analysis to investigate UK consumers’ energy consumption patterns and their correlation with socioeconomic characteristics to identify suitable households for heat pumps. The study optimised K-means outlier removal (K-MOR) using genetic algorithms (GA) to reveal five typical energy consumption patterns consistent with a classification of residential neighbourhoods (ACORN) socioeconomic segments. The findings of our study indicate that the highest energy consumption pattern requires about 3 times the heating demand of the lowest pattern. Notably, 50.9% of households exhibit a middle-high load pattern, among which affluent households demonstrate higher heat pump adoption potential, while 14.44% of lower-income households face greater barriers to heat decarbonisation.

Abstract

With rising summer temperatures and the increasing frequency and intensity of heatwaves, the risk of overheating in the UK is becoming a larger problem. During the heatwave affecting the country in July 2022, temperatures in London reached over 40C for the first time in recorded history. With only 2% of homes in the UK having active cooling, most residents must rely on passive strategies to combat heat. Using information obtained from deliberative workshops conducted within the EPSRC-funded ‘Flex-Cool-Store’ project, this paper makes use of a commercial building modelling software, IES VE, to simulate the effects of common passive cooling strategies and assesses the effects of each one.

Abstract

In this paper, a ZnNi2O4 anode material is prepared by a simple hydrothermal reaction process for lithium-ion capacitors. Bimetallic oxides exhibit excellent specific capacity and cycle stability based on redox reactions of different metals. The morphology, composition and structure of ZnNi2O4 are characterized by X-ray diffraction, transmission electron microscope and X-ray photoelectron spectroscopy. At a current density of 0.1 A g-1, the ZnNi2O4 has a high initial specific capacity of 1244.73 mAh g-1. Even when the current density is 1 A g-1, the specific capacity of ZnNi2O4 is still as high as 342.41 mAh g-1. It is worth noting that the excellent electrochemical results indicate that ZnNi2O4 is a promising anode candidate for lithium-ion capacitors.

Abstract

Salt hydrate-based thermochemical heat storage is a crucial technology for long-term heat storage. Sodium phosphate stands out due to its high energy storage density, lower dehydration temperature, and low cost. However, its practical application is limited by issues such as deliquescence and agglomeration. In this study, expanded graphite, known for its high thermal conductivity and rich microstructure, was used as the primary matrix. Composites with mass contents of 80%, 60%, and 40% were prepared using the impregnation method. Hydration tests were conducted at 30°C and RH 80% to examine the microstructure, thermal storage properties, and cycling stability of the pure salt and the composites. The results demonstrated that the incorporation of expanded graphite improved the adsorption kinetics of the composites and thermal conductivity mitigated the deliquescent agglomeration of pure salt, and reduced the dehydration temperature. EG80 has a maximum water absorption of 1.24 g/g, an energy storage density of 1081.8 kJ/kg and a thermal conductivity of 2.98 W/(m-K). After 10 storage discharge cycles, the thermal storage density remained above 1000 kJ/kg, indicating good stability.

Abstract

Sacrificial sodium-rich salts are promising pre-sodiation method to compensate the irreversible capacity of SIBs for energy density enhancement. To increase the capacity utilization ratio and decrease the decomposition potential, the particle size of sacrificial salts is generally reduced to lower than 10 um. However, large amounts of solvent are required to disperse the salts in slurry-coating electrodes, which increases the electrode production cost and limits the mass loading of electrode. This work utilizes dry-processing method to achieve sustainable and high-energy pre-sodiation cathode using Na2C2O4, which is free of using solvent and able to produce ultra-thick electrodes. The feasibility of Na2C2O4 as additive in ultra-thick dry-processing electrode has been demonstrated by electrochemical performance evaluation and electrode structure characterization. The full cells with pre-sodiation achieve large reversible capacity of 101.52 mAh g-1 at high areal capacity of 5.4 mAh cm-2 under 0.1 C as well as superior energy density of 309.3 Wh kg-1 and stable cycling. The novel electrode production strategy is promising for large-scale manufacturing of high-energy-density and low-cost SIBs.

Abstract

In recent years, the power industry has seen a significant uptick in renewable energy integration, including solar and wind farms, accompanied by energy storage systems. While this has increased overall generation capacity, it has also posed challenges to grid security and vulnerability. Key issues such as low short circuit ratios due to renewable integration and the retirement of synchronous machines have weakened grids. Grid forming inverters therefore have emerged as a vital solution, aiding solar and wind farms in maintaining stability during low short circuit ratio conditions. However, traditional Virtual Synchronous Generation (VSG) controllers, while beneficial, often introduce oscillations during disturbances, threatening network stability. This paper introduces an innovative approach that integrates Virtual Synchronous Generation Control with a Virtual Impedance Strategy to address stability challenges in solar and wind farms under low short circuit ratio conditions. By eliminating the need for Phase-Locked Loops (PLL), this method effectively mitigates oscillations during faults and voltage disturbances, thereby ensuring grid stability, with compliance to grid codes such as those of NER and AEMO Australia serving as guidelines. Implementation in PSCAD, which is widely used in the power system industry, validates its capability to meet stringent grid code requirements.

Abstract

In the present work, a simple numerical model is developed to estimate the performance of a solar flat plate collector (FPC) with water and CO2 as heat transfer fluids. An experimental test rig validates the model with water as heat transfer fluid (HTF). Though water is an excellent working fluid, it cannot be used in places where the ambient temperature falls below 0oC. Though antifreeze solutions can be added to water, this decreases the overall efficiency of the collector. In this context, using supercritical CO2 (s-CO2) in place of water can offer enhanced performance in addition to an extended operating temperature range. Hence in this study, the analysis is done with s-CO2 and water by considering four different cases under different operating conditions. The performance of both the HTFs is compared by using dimensionless quantities such as Reynolds number, Nusselt number, and Prandtl number. It has been observed that the outlet temperature and thermal efficiency of solar water heating system (SWHS) achieved are superior when the rate of mass flow is decreased, and the diameter of the riser tubes is made smaller. It has also been observed that substituting s-CO2 with water as the HTF in a solar FPC improves the overall performance. The solar collectors containing s-CO2 have high operating pressures, phase-changing potential with the change of ambient temperature, and considerable property variations around the critical point of the fluid, which are the major challenges for designing this type of SWHS. Thus, these subjects demand an extensive investigation.

Abstract

In recent years, Japanese companies and municipalities have increasingly recognized the importance of urban decarbonization. Urban areas, with their concentration of businesses, must consider not only decarbonization but also the well-being of the people working there. It is particularly important for business leaders to balance decarbonization efforts with employee well-being.
This project aims to create scenarios that achieve both decarbonization and well-being in Nihonbashi, a central business district in Tokyo.
The main focus is on long-term forecasting and management of energy demand using integrated simulation technology with an urban digital twin and developing scenarios that contribute to improving the overall well-being of employees.
Project activities include predicting and visualizing hourly energy demand for buildings within the area and assessing the effects of various decarbonization options. One decarbonization option involves implementing a system to transmit locally generated renewable energy to Nihonbashi and validating it with predictive models. 　　By collaborating with building owners to advance energy management, the project has identified the potential to achieve approximately 10% energy savings.
In addition, the project will also work to improve employee well-being by implementing a chatbot program that will educate employees about their company’s decarbonization activities and encourage behavior change to increase their sense of contribution.
The project aims to enhance sustainable urban development and comfort in the office area and is an important step in a larger decarbonization initiative that will be implemented in partnership with building owners in the Nihonbashi area.
Ultimately, the project aims to improve energy efficiency and overall community well-being and serve as a model for future urban sustainability.