Search Results (310)

This study proposes the SMR Smart Net-Zero City (SSNC) framework—a scalable model for achieving carbon neutrality by integrating Small Modular Reactors (SMRs), renewable energy sources, and sector coupling within a microgrid architecture. As deploying renewables alone would require economically and technically impractical energy storage systems, SMRs provide a reliable and flexible baseload power source. Sector coupling systems—such as hydrogen production and heat generation—enhance grid stability by absorbing surplus energy and supporting the decarbonization of non-electric sectors. The core contribution of this study lies in its real-time data emulation framework, which overcomes a critical limitation in the current energy landscape: the absence of operational data for future technologies such as SMRs and their coupled hydrogen production systems. As these technologies are still in the pre-commercial stage, direct physical integration and validation are not yet feasible. To address this, the researchers leveraged real-time data from an existing commercial microgrid, specifically focusing on the import of grid electricity during energy shortfalls and export during solar surpluses. These patterns were repurposed to simulate the real-time operational behavior of future SMRs (ProxySMR) and sector coupling loads. This physically grounded simulation approach enables high-fidelity approximation of unavailable technologies and introduces a novel methodology to characterize their dynamic response within operational contexts. A key element of the SSNC control logic is a day–night strategy: maximum SMR output and minimal hydrogen production at night, and minimal SMR output with maximum hydrogen production during the day—balancing supply and demand while maintaining high SMR utilization for economic efficiency. The SSNC testbed was validated through a seven-day continuous operation in Busan, demonstrating stable performance and approximately 75% SMR utilization, thereby supporting the feasibility of this proxy-based method. Importantly, to the best of our knowledge, this study represents the first publicly reported attempt to emulate the real-time dynamics of a net-zero city concept based on not-yet-commercial SMRs and sector coupling systems using live operational data. This simulation-based framework offers a forward-looking, data-driven pathway to inform the development and control of next-generation carbon-neutral energy systems. Full article

Heating, ventilation, and air-conditioning (HVAC) systems account for the largest share of energy consumption in European Union (EU) buildings, representing approximately 40% of the final energy use and contributing significantly to carbon emissions. Latent thermal energy storage (LTES) using phase change materials (PCMs) has emerged as a promising strategy to enhance HVAC efficiency. This review systematically examines the role of latent thermal energy storage using phase change materials (PCMs) in optimizing HVAC performance to align with EU climate targets, including the Energy Performance of Buildings Directive (EPBD) and the Energy Efficiency Directive (EED). By analyzing advancements in PCM-enhanced HVAC systems across residential and commercial sectors, this study identifies critical pathways for reducing energy demand, enhancing grid flexibility, and accelerating the transition to nearly zero-energy buildings (NZEBs). The review categorizes PCM technologies into organic, inorganic, and eutectic systems, evaluating their integration into thermal storage tanks, airside free cooling units, heat pumps, and building envelopes. Empirical data from case studies demonstrate consistent energy savings of 10–30% and peak load reductions of 20–50%, with Mediterranean climates achieving superior cooling load management through paraffin-based PCMs (melting range: 18–28 °C) compared to continental regions. Policy-driven initiatives, such as Germany’s renewable integration mandates for public buildings, are shown to amplify PCM adoption rates by 40% compared to regions lacking regulatory incentives. Despite these benefits, barriers persist, including fragmented EU standards, life cycle cost uncertainties, and insufficient training. This work bridges critical gaps between PCM research and EU policy implementation, offering a roadmap for scalable deployment. By contextualizing technical improvement within regulatory and economic landscapes, the review provides strategic recommendations to achieve the EU’s 2030 emissions reduction targets and 2050 climate neutrality goals. Full article

To compensate for the instability of renewable energy sources during China’s energy transition, large thermal power plants must provide critical operational flexibility, primarily through deep peaking. To investigate the combustion performance and wear and tear of a 600 MW pulverized coal boiler under deep peaking, the gas–solid flow characteristics and distributions of flue gas temperature, wall heat flux, and wall wear rate in a 600 MW tangentially fired pulverized coal boiler under variable loads (353 MW, 431 MW, 519 MW, and 600 MW) are investigated in this study employing computational fluid dynamics numerical simulation method. Results demonstrate that increasing the boiler load significantly amplifies gas velocity, wall heat flux, and wall wear rate. The maximum gas velocity in the furnace rises from 20.9 m·s⁻¹ (353 MW) to 37.6 m·s⁻¹ (600 MW), with tangential airflow forming a low-velocity central zone and high-velocity peripheral regions. Meanwhile, the tangential circle diameter expands by ~15% as the load increases. The flue gas temperature distribution exhibits a “low-high-low” profile along the furnace height. As the load increases from 353 MW to 600 MW, the primary combustion zone’s peak temperature rises from 1750 K to 1980 K, accompanied by a ~30% expansion in the coverage area of the high-temperature zone. Wall heat flux correlates strongly with temperature distribution, peaking at 2.29 × 10⁵ W·m⁻² (353 MW) and 2.75 × 10⁵ W·m⁻² (600 MW) in the primary combustion zone. Wear analysis highlights severe erosion in the economizer due to elevated flue gas velocities, with wall wear rates escalating from 3.29 × 10⁻⁷ kg·m⁻²·s⁻¹ (353 MW) to 1.23 × 10⁻⁵ kg·m⁻²·s⁻¹ (600 MW), representing a 40-fold increase under full-load conditions. Mitigation strategies, including ash removal optimization, anti-wear covers, and thermal spray coatings, are proposed to enhance operational safety. This work provides critical insights into flow field optimization and wear management for large-scale coal-fired boilers under flexible load operation. Full article

This paper proposes a ladder carbon trading-based low-carbon economic dispatch model for integrated energy systems (IESs), incorporating flexible load optimization and hybrid energy storage systems consisting of battery and thermal energy storage. First, a ladder-type carbon trading mechanism is introduced, in which the carbon trading cost increases progressively with emission levels, thereby providing stronger incentives for emission reduction. Second, flexible loads are categorized and modeled as shiftable, transferable, and reducible types, each with distinct operational constraints and compensation mechanisms. Third, both battery and thermal energy storage systems are considered to improve system flexibility by storing excess energy and supplying it when needed. Finally, a unified optimization framework is developed to coordinate the dispatch of renewable generation, gas turbines, waste heat recovery units, and multi-energy storage devices while integrating flexible load flexibility. The objective is to minimize the total system cost, which includes energy procurement, carbon trading expenditures, and demand response compensation. Three comparative case studies are conducted to evaluate system performance under different operational configurations: the proposed comprehensive model, a carbon trading-only approach, and a conventional baseline scenario. Results demonstrate that the proposed framework effectively balances economic and environmental objectives through coordinated demand-side management, hybrid storage utilization, and the ladder-type carbon trading market mechanism. It reshapes the system load profile via peak shaving and valley filling, improves renewable energy integration, and enhances overall system efficiency. Full article

Enhancing the load-adjustment flexibility of combined heat and power units facilitates the integration of renewable energy and enhances their profitability in dynamic electricity markets. However, the optimal coordination of various retrofitted combined heat and power units to maximize profitability has not been thoroughly investigated. To address this gap, this study conducts thermodynamic analysis and operation optimization for a combined heat and power plant integrated with flexibility retrofits, by developing models for the extraction-condensing unit, high back-pressure retrofitted unit, and low-pressure turbine zero output retrofitted unit. Results show that the low-pressure turbine zero output retrofitted unit achieves the largest energy efficiency (90.7%), while the extraction-condensing unit attains the highest exergy efficiency (38.0%). A plant-level optimization model is proposed to maximize profitability, demonstrating that the retrofitted combined heat and power plant increases total profit by 8.1% (CNY 86.4 million) compared to the original plant (CNY 79.9 million). The profit improvement stems from reduced coal consumption and enhanced heating capacity, enabling better power generation optimization. Furthermore, the study evaluates the profitability under different retrofit combinations. The findings reveal that an optimal profit can be achieved by reasonably coordinating the energy-saving characteristics of high back-pressure units, the heat supply capacity of low-pressure turbine zero output units, and the flexible adjustment capability of extraction-condensing units. Full article

District heating systems in northern China predominantly rely on coal-fired heat sources, necessitating sustainable alternatives to reduce carbon emissions. This study investigates a biomass combined heat and power (CHP) system integrated with cascaded absorption heat pump (AHP) technology to recover waste heat from semi-dry flue gas desulfurization exhaust and turbine condenser cooling water. A multi-source operational framework is developed, coordinating biomass CHP units with coal-fired boilers for peak-load regulation. The proposed system employs a two-stage heat recovery methodology: preliminary sensible heat extraction from non-saturated flue gas (elevating primary heating loop (PHL) return water from 50 °C to 55 °C), followed by serial AHPs utilizing turbine extraction steam to upgrade waste heat from circulating cooling water (further heating PHL water to 85 °C). Parametric analyses demonstrate that the cascaded AHP system reduces turbine steam extraction by 4.4 to 8.8 t/h compared to conventional steam-driven heating, enabling 3235 MWh of annual additional power generation. Environmental benefits include an annual CO₂ reduction of 1821 tonnes, calculated using regional grid emission factors. The integration of waste heat recovery and multi-source coordination achieves synergistic improvements in energy efficiency and operational flexibility, advancing low-carbon transitions in district heating systems. Full article

This study proposes an improved multi-objective black-winged kite algorithm (MOBKA-QL) integrating Q-learning with adaptive mutation strategies for optimizing multi-objective scheduling in integrated energy systems (IES). The algorithm dynamically selects mutation strategies through Q-learning to enhance solution diversity and accelerate convergence. First, an optimal scheduling model is established, incorporating a carbon capture system (CCS), power-to-gas (P2G), solar thermal, wind power, and energy storage to minimize economic costs and carbon emissions while maximizing energy efficiency. Second, the heat-to-power ratio of the cogeneration system is dynamically adjusted according to load demand, enabling flexible control of combined heat and power (CHP) output. The integration of CCS+P2G further reduces carbon emissions and wind curtailment, with the produced methane utilized in boilers and cogeneration systems. Hydrogen fuel cells (HFCs) are employed to mitigate cascading energy losses. Using forecasted load and renewable energy data from a specific region, dispatch experiments demonstrate that the proposed system reduces economic costs and CO₂ emissions by 14.63% and 13.9%, respectively, while improving energy efficiency by 28.84%. Additionally, the adjustable heat-to-power ratio of CHP yields synergistic economic, energy, and environmental benefits. Full article

To promote low-carbon transformation and achieve carbon peak and neutrality in the energy field, this study proposes an operational optimization model considering the energy- and load-side dual response (ELDR) mechanism for electrothermal coupled virtual power plants (VPPs) containing a carbon capture device. The organic Rankine cycle (ORC) waste heat boiler (WHB) is introduced on the energy side. The integrated demand response (IDR) of electricity and heat is performed on the load side based on comprehensive user satisfaction (CUS), and the carbon capture system (CCS) is used as a flexible resource. Additionally, a carbon capture device operation mode that makes full use of new energy and the valley power of the power grid is proposed. To minimize the total cost, an optimal scheduling model of virtual power plants under ladder-type carbon trading is constructed, and opportunity-constrained planning based on sequence operation is used to address the uncertainty problems of new energy output and load demand. The results show that the application of the ELDR mechanism can save 27.46% of the total operating cost and reduce CO₂ emissions by 45.28%, which effectively improves the economy and low carbon of VPPs. In particular, the application of a CCS in VPPs contributes to reducing the carbon footprint of the system. Full article

Multi-energy microgrids (MEMs) can achieve efficient and low-carbon energy utilization by relying on the coordination, complementarity, and coupling conversion of different energy sources, which is of great significance for new energy consumption and energy cascade utilization. In this paper, a low-carbon economic dispatch model of a multi-energy microgrid that uses a joint carbon capture–CHP-P2G operation is proposed. Firstly, the basic structure of the power–electrolysis–methanol energy (PEME) is established. Secondly, a flexible mechanism for the joint operation of CCPPs and CHP is analyzed, and a flexible joint operation model for carbon capture–CHP-P2G is proposed. Finally, considering the system’s low-carbon operation and economy, a low-carbon economic dispatch model for a multi-energy microgrid in a park is established, with the goal of minimizing the total operating cost of PEME in the park. The results illustrate that the introduction of a liquid storage tank reduces the total cost and carbon emissions of the MEM by 4.04% and 8.49%, respectively. The application of an electric boiler and ORC effectively alleviates the problem of peak–valley differences in the electric heating load. Our joint operation model realizes the dual optimization of the MEM’s flexibility and low-carbon requirement through the collaboration of multiple pieces of technology. Full article

In the age of widespread renewable energy integration, coal-fired power plants are transitioning from a primary baseload role to a more flexible peak-shaving capacity. Under frequent load changes, the thermal efficiency will significantly decrease. In order to achieve efficient dynamic operation, this study proposes a comprehensive mechanical model of a 300 MW drum-type boiler. Based on the Modelica/DYMOLA platform, the multi-domain equations describing energy and mass balance are programmed and solved. A comprehensive evaluation of the energy transformation within the boiler’s heat exchange components was performed. Utilizing the principles of exergy analysis, this study investigates how fluctuating operational conditions impact the energy dynamics and exergy losses in the drum and heating surfaces. Steady-state simulation reveals that the evaporator and superheater units account for 81.3% of total exergy destruction. Dynamic process analysis shows that the thermal inertia induced by the drum wall results in a significant delay in heat transfer quantity, with a dynamic period of up to 5000 s. The water wall exhibits the highest total dynamic exergy destruction at 9.5 GJ, with a destruction rate of 7.9–8.5 times higher than other components. Full article

The oil and gas industry has large and constant power and heat loads and usually ownership of land resources near oil and gas production, providing opportunities for onsite integration of renewable energy. In the future, a possible decrease in reliable and affordable electricity production capability by the power grid, mainly due to the penetration of intermittent renewable energy, makes seeking an alternative energy supply a wise choice for the oil and gas industry. Foreseeable carbon emission costs also drive the oil and gas industry to a less carbon-intensive way of production. However, it is not yet clear whether it is economically viable for the integration of renewable energy in the oil and gas industry. In this work, we propose a modeling and optimization framework for conceptual planning and the operation of an oilfield’s energy system, where energy demands—heat and power in particular, are supposed to be met by an integrated energy supply including both fossil fuels and renewable energy. Herein, an oilfield in Northeast China has been then taken as a case study. The results indicate that under current conditions with no power purchase limits, integrating renewable energy is not economically viable. As the power purchase limits the decrease by a certain threshold, renewable energy integration becomes essential for maintaining a stable power supply, with renewable energy capacity reaching 35% in a self-sufficient microgrid configuration. Similarly, as electricity prices rise, the deployment of renewable energy begins to exhibit economic viability at 1.5 times the current electricity price. Independent microgrids show better economic resilience compared to grid-dependent systems under rising electricity prices. When carbon prices increase, the heat electrification transformation for microgrids achieves a cost inflection point at USD 76.4 per tonne, resulting in overall cost reductions. These findings emphasize the importance of flexible, renewable energy-driven energy systems in cost-effective decarbonization and energy stability, providing insights for optimizing oilfield energy systems and supporting China’s carbon neutrality goals. Full article

As the integration of renewable energy sources continues to increase, thermal power units are increasingly required to enhance their operational flexibility to accommodate grid fluctuations. However, frequent load variations in conventional thermal power plants result in decreased efficiency, accelerated equipment wear, and high operational costs. In this context, molten-salt thermal energy storage (TES) has emerged as a promising solution due to its high specific heat capacity and thermal stability. By enabling the storage of surplus energy and its regulated release during peak demand periods, molten salt TES contributes to improved grid stability, reduced start-up frequency, and minimized operational disturbances. This study employs comprehensive thermodynamic simulations to investigate three representative schemes for heat storage and release. The results indicate that the dual steam extraction configuration (Scheme 3) offers the highest thermal storage capacity and peak-load regulation potential, albeit at the cost of increased heat consumption. Conversely, the single steam extraction configurations (Scheme 1 and 2) demonstrate improved thermal efficiency and reduced system complexity. Furthermore, Scheme 3, which involves extracting feedwater from the condenser outlet, provides enhanced operational flexibility but necessitates a higher initial investment. These findings offer critical insights into the optimal integration of molten-salt thermal-storage systems with conventional thermal power units. The outcomes not only highlight the trade-offs among different design strategies but also support the broader objective of enhancing the efficiency and adaptability of thermal power generation in a renewable-dominated energy landscape. Full article

The electrification of energy systems is essential for carbon reduction and sustainable energy goals. However, current network asset ratings and the poor thermal efficiency of older buildings pose significant challenges. This study evaluates the impact of heat pump and electric vehicle (EV) penetration on a UK residential distribution network, considering the highest coincident electricity demand and worst weather conditions recorded over the past decade. The power flow calculation, based on Python, is performed using the pandapower library, leveraging the actual distribution network structure of the Hillingdon area by incorporating recent smart meter data from a distribution system operator alongside historical weather data from the past decade. Based on the outcome of power flow calculation, the transformer loadings and voltage levels were assessed for existing and projected heat pump and EV adoption rates, in line with national policy targets. Findings highlight that varied consumer density and diverse usage patterns significantly influence upgrade requirements. Full article

This study investigates improving district heating (DH) systems by analyzing the effects of low-temperature operation on network efficiency, heat losses, and indoor temperature stability. A mathematical model is developed to simulate building heat performance under different supply temperatures, substation connection types, and envelope materials. The methodology involves detailed hourly heat load simulations and optimization techniques to assess the impact of temperature flexibility and heat accumulation within buildings. The results reveal that a 10 °C reduction in supply temperature leads to a heat loss decrease of up to 20%, significantly improving system efficiency. Moreover, buildings with higher thermal inertia and indirect substation connections exhibit better resilience to short-term temperature fluctuations, ensuring more stable indoor conditions. The analysis also demonstrates that optimizing temperature control can reduce operational costs by 19%, primarily by minimizing excessive heat supply and utilizing stored thermal energy effectively. Despite slight temperature fluctuations in extreme conditions, the system maintains indoor comfort levels within acceptable limits. This study concludes that transitioning to a lower-temperature DH system is feasible without compromising reliability, provided heat accumulation effects and supply flexibility are carefully managed. These findings offer a replicable approach for improving DH efficiency in networks with diverse building configurations. Full article

Against the backdrop of the steady advancement of the national rural revitalization strategy and the dual-carbon goals, the low-carbon transformation of rural energy systems is of critical importance. This study first proposes a comprehensive architecture for rural energy supply systems, incorporating four key dimensions: investment, system configuration, user demand, and policy support. Leveraging the abundant wind, solar, and biomass resources available in rural areas, a low-carbon optimization model for rural energy system operation is developed. The model accounts for diverse load characteristics and the integration of elevated water towers, which serve both energy storage and agricultural functions. The optimization framework targets the multi-energy demands of rural production and daily life—including electricity, heating, cooling, and gas—and incorporates the stochastic nature of wind and solar generation. To address renewable energy uncertainty, the Fisher optimal segmentation method is employed to extract representative scenarios. A representative rural region in China is used as the case study, and the system’s performance is evaluated across multiple scenarios using the Gurobi solver. The objective functions include maximizing clean energy benefits and minimizing carbon emissions. Within the system, flexible resources participate in demand response based on their specific response characteristics, thereby enhancing the overall decarbonization level. The energy storage aggregator improves renewable energy utilization and gains economic returns by charging and discharging surplus wind and solar power. The elevated water tower contributes to renewable energy absorption by storing and releasing water, while also supporting irrigation via a drip system. The simulation results demonstrate that the proposed clean energy system and its associated operational strategy significantly enhance the low-carbon performance of rural energy consumption while improving the economic efficiency of the energy system. Full article