Abstract

Given the escalating carbon emission crisis, there is an urgent need for large-scale adoption of renewable energy generation to replace traditional fossil fuel-based energy generation for a smooth energy transition. In this regard, distributed photovoltaic power generation plays a crucial role. Predicting the GHI in advance to predict the power of photovoltaic power generation has become one of the methods to solve the grid-connected stability in recent years, which enables the grid staff to dispatch and plan in advance through the forecast results, reduce fluctuations, and maintain grid stability. In this study, we present a deep learning-based method to assess photovoltaic output potential by solar irradiance forecasting and rooftop segmentation. First, we utilize a multivariate input Transformer model that incorporates various data to predict GHI; Second, using remote sensing images to train Swin-Transformer to identify the potential area of rooftop photovoltaic panel; Finally, the potential assessment was achieved by calculating the array output through the GHI and area data we generated in the first two parts. Our evaluation methodology and results provide technical support for the transition of energy structure.

Abstract

This research paper presents the review of two renewable energy strategies, Feed In Tariff (FIT) and Renewable Portfolio Standards (RPS), in China and other countries. The two FIT schemes, which are Erneuerbare Energien Gesetz (EEG) in Germany and Benchmark Grid Electricity Prices (BGEP) in China, are compared. On the other hand, three RPS schemes, which are California’s RPS Program, Australia’s Renewable Energy Target (RET), and China’s Weighting of Responsibility for Renewable Energy Electricity Consumption (WRREEC) framework are reviewed and discussed. Based on the review and findings, recommendations on the future development of renewable energy strategies in China are presented.

Abstract

Carbon microspheres (CMSs) derived from corn starch were successfully obtained under hydrothermal carbonization (HTC). A 6-blade Pitched blade turbine (PBT) was employed to introduce the controllable shear rate and F127 as the soft template was ultized to find out their effect on the CMSs. The combination of shear rate and soft template method, introducing a controlled flow pattern based on fluid dynamics, provides an alternative to obtain CMSs with wider distribution of pore size and more mesopores, thereby enhancing their adsorption capability. The products were characterized using Scanning Electron Microscopy (SEM), Thermal Gravimetric (TG), and Brunauer-Emmett-Teller (BET) model. The results revealed that the morphology and structure of CMSs were strongly influenced by the shear rate induced by the rotated PBT during the hydrothermal reaction. At a rotating speed of 60rpm, the CMSs showed the maximum CO2 adsorption rate at 25 °C and 0.15 bar CO2, with a specific surface area of 475 m2/g and an average pore diameter of 2nm. Furthermore, the diameter of CMSs decreased with an increase of rotating speeds. The assembly of F127 resulted in products with low degree of sphericity forming a chain, which significantly increased the BJH Adsorption/Desorption average pore width (4V/A). Hence, the controllable shear rate offers an alternative approach to explore the property of CMSs.

Abstract

The kinetic law of natural gas hydrate (NGH) growth is highly significant for the application of NGH technology. In this work, we observed the process of methane hydrate film thickening at the gas-liquid interface by X-ray Computed Tomography (X-CT). Our results showed that the methane hydrate film growth process at the gas-liquid interface can be divided into three stages. Firstly, the methane hydrate film formation process was controlled by heat transfer; secondly, the thickening process was controlled by mass transfer. Above all, the transport of water below the hydrate film caused fractures in the hydrate film, and new hydrate grows at the fractures. The proposed hydrate film formation and growth mechanism at the gas-liquid interface in this study provided theoretical support and research methodology for future studies of the gas-liquid interface growth process of NGH.

Abstract

The flexible adjustment of the air conditioning system can help smooth the load curve and absorb renewable energy. However, the quantification of building air conditioning flexibility (Air-conditioning Virtual Energy Storage，AVES) is still in its early stages. This study takes the climate and architecture of Shanghai as an example to study the changes in VES characteristics of air conditioning under different fence structures. Based on regression analysis and correlation analysis, the main factors affecting the VES of air conditioning are analyzed and quantified. This study can provide theoretical reference for the study of flexible air conditioning regulation in specific regions.

Abstract

High-pressure environments have a significant impact on anaerobic oxidation of methane (AOM), increase in anaerobic methanotrophic euryarchaeota (ANME) growth rate at higher methane pressures. This study investigated the effect of temperature on the anaerobic methane-oxidizing and sulfate-reducing (AOM-SR) activities by a highly enriched ANME-2c community (high-pressure environments). The ANME-2c-enriched biomass was incubated at different temperature for 75 days. The most favorable condition for AOM-SR activity in the studied communities was set as the in situ temperature (4°C), suggesting that the studied ANME-2c is well adapted to conditions similar to those of its origins. Moreover, the dispersal process of the species is promoted by 4°C, whereas the symbiotic network is decreased.

Abstract

The coal-steam gasification method has been proven to be suitable for power generation. However, the low concentration of CO2 generated in the external coal combustion heating process causes significant CO2 capture energy consumption. As a carbon-neutral fuel, biomass combined with coal-steam gasification could contribute to a reduction in CO2 emissions. In this work, using the typical herbaceous biomass as the heating fuel, the energy efficiency and carbon emissions of the biomass-heating-coal-gasification power generation system (BHCG) are systematically studied. The results indicate that the coupling utilization of biomass and coal can significantly improve the emission reduction characteristics of fossil energy systems. In the no-carbon capture scenario, the power efficiency of BHCG is 50.66%, which is 5.31% higher than GE gasification power generation system. When the carbon capture process is introduced, the power efficiency of BHCG is 46.40% with -133.90 kg CO2/MWh. The biomass heating coal-steam gasification method can utilize the negative carbon utilization of fossil fuels and has high energy efficiency.

Abstract

Hydrogen is an ideal and potential energy carrier due to its high energy efficiency and low pollution. An alternative and promising approach to hydrogen generation is the chemical looping steam methane reforming (CL-SMR) over iron-based oxygen carriers. However, the process faces challenges such as high reaction temperature (>850°C) and low methane conversion. We demonstrate that Ni-mixed Fe-based oxygen carrier particles have significantly improved the methane conversion and hydrogen production rate in the range of 450-600°C under atmospheric pressure. The effect on the reaction reactivity of oxygen carrier particles with different Ni-based particles mixed mass ratios has been determined in the continuous unit. More than 85% of methane conversion has been achieved at 600oC, and hydrogen can be produced in both reduction and oxidation steps. Moreover, the iron-based oxygen carrier particles exhibited good cyclic performance during 150 consecutive redox cycles at 600°C. The mid-temperature iron-based oxygen carrier particles, integrated with a moving-bed chemical looping system, might provide a powerful approach toward more efficient and scalable hydrogen production.

Abstract

The bivalves in cold seep ecosystem can assimilate dissolves inorganic carbon (DIC) into their shell through extrapallial fluid (EPF) and methane through endosymbionts on their gills. Therefore, the DIC and methane released from cold seep can be decreased by the biological metabolism process of the bivalves, which can reduce such carbon enter into the atmosphere. Yet the contribution of cold seep bivalves are not considered hitherto. We choose three common bivalves from cold seep of South China Sea, Bathymodiolus platifrons, Gigantidas haimaensis, Archivesica marissinica and measure the carbon content as well as wet weight and dry weight. Comparing to five shellfish species the cold seep bivalves can store more carbon into their tissue. Combining the fact they feed on methane-oxidizing bacteria and sulfide-oxidizing bacteria, they can reduce the methane possibly released to the air. The Archivesica marissinica bivalves have the best carbon sequestration capacity for higher tissue weight.

Abstract

The process of methane anaerobic oxidation coupled with sulfate reduction promotes alkaline conditions and the formation of carbonate minerals in cold seep environments. The existing studies on microbial communities inhabiting carbonate rock surfaces in cold seep environments primarily revolve around in situ investigations. In this study, high-pressure enrichment cultivation was conducted using methane as the sole carbon source, and periodic monitoring of community dynamics was performed. The results revealed a selective increase in the abundance of the ANME-2c group, which is a typical type of microorganism in methane utilization, anaerobic oxidation, and the synthesis of other nutrients. Additionally, temperature was identified as a crucial factor influencing microbial populations and carbonate processes. Higher temperatures stimulated microbial metabolism, resulting in the production of acidic substances and extracellular hydrolytic enzymes, potentially leading to carbonate dissolution. Conversely, lower temperatures had minimal impact. These findings reveal the significance of methane metabolism and temperature in microbial community dynamics and carbonate kinetics in deep-sea environment.