With the proposal of â€œcarbon neutralityâ€, research on global warming mitigation and low-carbon transformation of energy system has been widely focused. The Integrated Assessment Model (IAM) is an important model for studying energy supply and demand, and making strategic decisions in terms of economics and policy, which can formulate reasonable and effective low-carbon development plans based on energy policies, energy structures and energy technology development levels. However, there is no knowledge mapping domain of IAMs in the context of carbon neutrality, which makes it difficult for researchers to follow the hotspots and select the appropriate IAM. In this paper, 11770 unique research papers on IAMs were retrieved from the Web of Science core database and analyzed by bibliometric mapping using VOSviewer and CiteSpace. Knowledge mapping is used to visualize the countries/regions, researchers, and journals that have made major contributions, and to analyze the network of collaborative relationships between them. The results show that the growth of relevant IAMs research is large and has been studied from multiple perspectives on climate change. Keyword analysis shows that research hotspots include “climate change”, “life cycle assessment” and “sustainability assessment”; in the burst detection, “machine learning” has been widely incorporated into research over the last two years. The paper also discusses the interplay between scientific research and policy, pointing out that policy guidance is complementary to IAMs research. This study can provide the IAMs with recommendations for future development decisions on low carbon development issues.
This study investigated utilising on-site organic waste from a large-scale dairy farm to provide sustainable electricity and heat. The 600-acre site required 65.2 kWe (electricity) and 9.54 kWth (heat). ECLIPSE software was used to simulate anaerobic digestion (AD) of livestock waste, wheat straw, and barley straw to supply biogas to a cogeneration system. AD produced sufficient biogas to meet all electrical and heating demands from a 100 kWe CHP system, alongside a biogas storage option. The study revealed that a maximum production of 1 MWe can be achieved using four 250 kWe units. Simulations of amine absorption carbon capture demonstrated that 85.1% of the CO2 could be removed from the CHP flue gases. Annual CO2 emissions are calculated by displacing current farm emissions, reducing grid usage, and implementing CCS. This results in a reduction of 117 tCO2e/year, 1692 tCO2e/year, and 6158 tCO2e/year for the 100 kWe, 1 MWe, and 1 MWe with CCS systems respectively. Economic analysis shows that the levelised cost of energy for the 100 kWe and 1 MWe options were Â£60.41/MWh and Â£47.34/MWh respectively for a lifetime of 20 years. The respective payback period ranges were calculated to be 1.9-4.4 years and 3.5-10.8 years.
Monitoring the carbon emissions of urban buildings is of great significance for assessing the benefits of emission reduction and promoting the development of energy-saving technologies in buildings. Visualizing building carbon emissions helps intuitively understand carbon intensity and enhances public awareness of environmental protection and their willingness to participate in carbon reduction. However, existing building carbon emission visualization methods are generally limited to data statistics and map visualization, lacking immersive visualization solutions from the first-person perspective and integration with street scenes. To address this issue, this paper proposes an augmented reality (AR) visualization prototype system based on urban 3D models, which achieves an immersive display of building carbon emission data by accurately aligning each frame of a street-view video from a mobile phone with the backend urban 3D model. For an arbitrary input street-view video, we first locate its position in the urban 3D model based on its location information. We then use a scene segmentation model based on deep learning to obtain segmentation results for buildings, roads, and the background in each frame of the video. Finally, using segmentation results as prior information, we optimize the photographic parameters of the frame images to achieve high-precision alignment between each frame and the urban 3D model, thereby realizing the AR display of carbon emission data in the street-view video. The prototype system developed in this paper is expected to be deployed on mobile phones or wearable devices such as virtual reality glasses, which can be considered a promising visualization technology for observing building carbon emissions from a first-person perspective.
Ammonia is a commonly used industrial chemical that is of great importance in the chemical and fertilizer production industries. It also attracts increasing attention as a green energy carrier. Haber-Bosch process is the predominant process to synthesis ammonia. However, as an energy intensive process, it can only have a low level of energy consumption when it is running on a large scale. Therefore, in this work, we present the ODSCRA process (a flue gas purification unit, a deaerator unit, a selective catalytic reduction reactor), and the NOx generated from the plasma technology can act as the alternative NOx source. ODSCAR can also decentralize the manufacture of ammonium nitrate fertilizers, making it particularly appealing for small- and medium-scale decentralized ammonia synthesis.
Battery electric taxis are progressively supplanting conventional taxis as a primary mode of transportation, promoting energy conservation and the reduction of carbon dioxide emissions. As an emergent technology, battery-swapping presents several potential advantages but also raises concerns regarding its efficacy, environmental impact, and integration with existing charging infrastructure. This paper introduces and examines four distinct energy replenishment methodologies implemented: Direct Charging, Battery Swapping, Battery Transporting, and Battery Sharing. To assess the performance of these approaches, an agent-based model was developed to simulate driver usage behavior under various mode combinations and four distinct scenario settings. The paper conducts a comparative analysis of traditional taxi charging and direct battery exchange, identifying a selection rate within 5% when ample battery-replacement stations are available. Simulation comparisons of novel charging modes reveal that battery transportation mode is superior with a smaller number of drivers, while the battery sharing mode demonstrates enhanced performance with a larger driver pool. This research provides a valuable instrument for evaluating energy replenishment strategies, facilitating the transition to low-carbon transportation in the context of future smart city development.
Solar-driven steam methane reforming (SMR) is a promising technology for hydrogen production. However, current solar thermochemical and photochemical reactions have different limitations. The former often requires high temperatures to achieve desired yield and neglects the strong activation ability of photons in short-wavelength spectrum, while the latter cannot use solar energy in the long-wavelength spectrum due to catalyst drawbacks, resulting in low solar energy utilization efficiency. To overcome these drawbacks, photo-thermal synergetic catalytic hydrogen production is proposed to achieve higher solar-to-hydrogen efficiency under relatively mild condition. In this work, the photo-thermal synergetic effect of solar hydrogen production from SMR using Co/Al2O3 catalyst is experimentally investigated. Results show the H2 yield by photo-thermochemical reaction (221.7 mmolÂ·h-1Â·g-1) can be increased by 42.8% at 650Â°C compared with that of the thermochemical reaction (155.2 mmolÂ·h-1Â·g-1), and the activation energy of the photo-thermochemical reaction is significantly reduced. The high activity is mainly attributed to photoactivation effect of light in photo-thermochemistry. These findings provide valuable guidance for hydrogen production from steam methane reforming using solar energy.
Article 6 of the Paris Agreement enables Parties to achieve their Nationally Determined Contributions (NDCs) through direct cooperation or Internationally Transferred Mitigation Outcomes (ITMOs). Current researches on Article 6 are mostly based on the assumption of unlimited global carbon market link, which may lead to large price volatility and cause concern of policy makers. Here, we designed carbon market link scenarios with different degrees of trading volume limits, and simulated the global and regional carbon markets under different scenarios from 2025 to 2060 using the Global Change Assessment Model (GCAM). The ï¬ndings suggest that as the link limit tightens, both the price volatility of global carbon market and the cumulative mitigation costs saved by carbon market links decrease. The price volatility under the unlimited global carbon market scenario is about 30% higher than that with link limits implemented. At the national level, a total of 15 regions are constrained in different link limit scenarios, among which China, the United States, EU and India are the most sensitive regions to link limits. Based on the scenario results, we discuss the design and impact of different international carbon market link limit mechanisms, such as absolute link limits and relative link limits.
This paper discusses the potential of small-scale distributed vertical farming in buildings to be a more sustainable and energy-efficient alternative to large-scale centralized vertical farming. While vertical farming has the potential to revolutionize urban agriculture by providing fresh produce year-round and reducing transportation emissions, the energy consumption required to power the lighting systems can be significant, particularly in centralized systems. The study compares the energy consumption and growth of pak choi cabbage plants between centralized and distributed vertical farming systems while adopting a traditional cultivation process as a reference. The data from the experiment are used to simulate the carbon emissions generated by vertical farms. The paper concludes that distributed vertical farming offers higher energy efficiency, with a potential 60% reduction in energy consumption and a 30% decrease in carbon footprint relative to large-scale integrated vertical farms. Yielding over twice the crop output compared to conventional agriculture, this approach may serve as a potential solution to address global food challenges.
To facilitate the decarbonization of the energy sector and promote the market penetration of hydrogen, exploring the feasibility of using ammonia as an energy carrier in existing combustion equipment becomes an important topic. Partial cracking or mixing with other fuels is currently the common strategy to improve ammoniaâ€™s slow chemistry and low reactivity.
We conducted an experimental study of ammonia addition to an existing low-pollution hydrogen gas turbine combustor, observing flame structure changes, measuring NOx emissions, and investigating flashback boundaries. The results show that after adding only 5% ammonia, the flame structure changed significantly, and the flame expansion angle became more extensive, but it did not affect the flame stability and working condition regulation. Also, no ammonia escape occurs. Meanwhile, the addition of ammonia expanded the flashback boundary to some extent. However, the main issue facing the addition of ammonia is the significant increase in NOx emissions. The practice of this paper provides a reference for the feasibility of adding ammonia gas to the low-pollution hydrogen gas turbine combustor.
This paper presents a numerical investigation of the
potential of a 4-lobed swirl generator for enhancing the
thermal performance of an active Solar Water Heater
(SWH). The hydro-thermal performance of the generator
was thoroughly evaluated using the code ANSYS FLUENT
2021 R1, and the results were validated against available
experimental data in the literature. The predicted results
demonstrated that the proposed swirl generator was
capable of giving a higher Performance Evaluation
Criteria (PEC) compared to twisted tape as it enhanced
the heat transfer at the expense of a much lower
pressure loss than the twisted tapes. However, with only
one swirl generator, the PEC value for the swirl generator
was only slightly higher than 1 and the analysis with the
field synergy principle revealed that the thermal
enhancement produced only prevails for 30D to 40D
downstream. To achieve optimal thermal enhancement
in the SWH, strategic placement regimes were examined
by regularly placing 2, 3 and 4 swirl generators,
respectively, inside the SWH. Simulation results
indicated that, with an optimal placement of the swirl
generator, the heat transfer coefficient is increased by
9.9% with an extra pressure drop of 26.9% more than a
plain circular tube. This increase in heat transfer
coefficient can reduce the overall pumping time and,
more importantly, can make the SWH more reliable in