Solar energy captured by solar photovoltaic (PV) systems has great potential to meet the high demand for renewable energy sources in urban areas. A photovoltaic noise barrier (PVNB) system, which ...integrates a PV system with a noise barrier, is a promising source for harvesting solar energy to overcome the problem of having limited land available for solar panel installations. When estimating the solar PV potential at the city scale, it is difficult to identify sites for installing solar panels. A computational framework is proposed for estimating the solar PV potential of PVNB systems based on both existing and planned noise barrier sites. The proposed computational framework can identify suitable sites for installing photovoltaic panels. A deep learning-based method is used to detect existing noise barrier sites from massive street-view images. The planned noise barrier sites are identified with urban policies. Based on the existing and planned sites of noise barriers in Nanjing, the annual solar PV potentials in 2019 are 29,137 MW h and 113,052 MW h, respectively. The estimation results show that the potential PVNB systems based on the existing and planned noise barrier in 2019 have the potential installed capacity of 14.26 MW and 57.24 MW, with corresponding potential annual power generation of 4662 MW h and 18,088 MW h, respectively.
•A photovoltaic noise barrier system is promising source for harvesting solar energy.•Detect existing noise barrier from street-view images with 96.22% accuracy.•Solar PV potentials of existing and planned noise barriers are estimated.•Installed capacity of proposed PVNB systems reach 14.26 MW and 57.24 MW.•Potential annual power generation are 4662 MW h and 18,088 MW h.
Solar PV has seen a spectacular market development in recent years and has become a cost competitive source of electricity in many parts of the world. Yet, prospective observations show that the ...coronavirus pandemic could impact renewable energy projects, especially in the distributed market. Tracking and attributing the economic footprint of COVID-19 lockdowns in the photovoltaic sector poses a significant research challenge. Based on millions of financial transaction records and 44 thousand photovoltaic installation records, we tracked the spatio-temporal sale network of the distributed photovoltaic market and explored the extent of market slowdown. We found that a two-month lockdown duration can be assessed as a high-risk threshold value. When the lockdown duration exceeds the threshold value, the monthly value-added loss reaches 67.7%, and emission reduction capacity is cut by 64.2% over the whole year. We show that risks of a slowdown in PV deployment due to COVID-19 lockdowns can be mitigated by comprehensive incentive strategies for the distributed PV market amid market uncertainties.
This study investigates the use of CaO-CeO2 mixed oxides as solid base catalysts for the transesterification of Pistacia chinensis oil with methanol to produce biodiesel. These CaO-CeO2 mixed-oxide ...catalysts were prepared by an incipient wetness impregnation method and characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. The cerium improved the heterogeneous catalytic stability remarkably due to the defects induced by the substitution of Ca ions for Ce ions on the surface. The best catalyst was determined to be C0.15-973 (with a Ce/Ca molar ratio of 0.15 and having been calcined at 973 K), considering its catalytic and anti-leaching abilities. The effects of reaction parameters such as the methanol/oil molar ratio, the amount of catalyst amount and the reaction temperature were also investigated. For the C0.15-973 regenerated after five reuses, the biodiesel yield was 91%, which is slightly less than that of the fresh sample. The test results revealed that the CaO-CeO2 mixed oxides have good potential for use in the large-scale biodiesel production.
lRevealing highly class-imbalance and non-concentrated distribution of PV panel image data.lFinding the notable resolution threshold for effective PV panel semantic-segmentation.lExploring ...homogeneous texture feature and heterogenous color feature of PV panel image data.lProviding recommendations on further improvements of PV panel semantic-segmentation.
The photovoltaic (PV) industry boom and increased PV applications call for better planning based on accurate and updated data on the installed capacity. Compared with the manual statistical approach, which is often time-consuming and labor-intensive, using satellite/aerial images to estimate the existing PV installed capacity offers a new method with cost-effective and data-consistent features. Previous studies investigated the feasibility of segmenting PV panels from images involving machine learning technologies. However, due to the particular characteristics of PV panel semantic-segmentation, the machine learning tools need to be designed and applied with careful considerations of the issue formulation, data quality, and model explainability. This paper investigated the characteristics of PV panel semantic-segmentation from the perspective of computer vision. The results reveal that the PV panel image data has several specific characteristics: highly class-imbalance and non-concentrated distribution; homogeneous texture and heterogenous color features; and the notable resolution threshold for effective semantic-segmentation. Moreover, this paper provided recommendations for data obtaining and model design, aiming at each observed character from the viewpoints of recent solutions in computer vision, which can be helpful for future improvement of the PV panel semantic-segmentation.
The preparation of a Li-doped MgO for biodiesel synthesis has been investigated by optimizing the catalyst composition and calcination temperatures. The results show that the formation of strong base ...sites is particularly promoted by the addition of Li, thus resulting in an increase of the biodiesel synthesis. The catalyst with the Li/Mg molar ratio of 0.08 and calcination temperature of 823
K exhibits the best performance. The biodiesel conversion decreases with further increasing Li/Mg molar ratio above 0.08, which is most likely attributed to the separated lithium hydroxide formed by excess Li ions and a concomitant decrease of BET values. In addition, the effects of methanol/oil molar ratio, reaction time, catalyst amount, and catalyst stability were also investigated for the optimized Li-doped MgO. The metal leaching from the Li-doped MgO catalysts was detected, indicating more studies are needed to stabilize the catalysts for its application in the large-scale biodiesel production facilities.
•Erythritol and SAT are two of the most concerned materials for M-TES.•The shell-and-tube container is the most versatile type in an M-TES system.•The energy cost of an M-TES system is in a range of ...0.02–0.08 € kW h−1.
The transportation of thermal energy is essential for users who are located far away from heat sources. The networks connecting them achieve the goal in efficient heat delivery and reasonable cost, especially for the users with large heat demands. However, it is difficult to satisfy the heat supply of the detached or emergent users with the existing pipelines. Therefore, a promising alternative, called mobilized thermal energy storage (M-TES), was proposed to deliver the heat flexibly without the restriction of networks. In this paper, a review of studies on M-TES is conducted in terms of materials, containers and economic evaluation. The potential candidates of materials, such as sugar alcohols, hydrated salts, alkalies and zeolite are reviewed and compared based on their thermophysical properties, price, advantages and disadvantages. Various containers, including the shell-and-tube, encapsulated, direct-contact, detachable and sorptive types, are discussed from the aspects of configuration, performance and utilization. Furthermore, the studies on the economic evaluation of M-TES systems are summarized and discussed based on the analysis of the economic indicators, including initial cost, operating cost, revenue, subsidy and energy cost. Finally, the challenges and future perspectives for developing M-TES are presented.
► We study synthetic gas production from dry black liquor gasification system. ► Direct causticization eliminates energy intensive lime kiln reducing biomass use. ► Results show large SNG production ...potential at significant energy efficiency (58%). ► Substantial CO2 capture potential plus CO2 reductions from natural gas replacement. ► Significant transport fuel replacement especially in Sweden and Europe.
Synthetic natural gas (SNG) production from dry black liquor gasification (DBLG) system is an attractive option to reduce CO2 emissions replacing natural gas. This article evaluates the energy conversion performance of SNG production from oxygen blown circulating fluidized bed (CFB) black liquor gasification process with direct causticization by investigating system integration with a reference pulp mill producing 1000 air dried tonnes (ADt) of pulp per day. The direct causticization process eliminates use of energy intensive lime kiln that is a main component required in the conventional black liquor recovery cycle with the recovery boiler. The paper has estimated SNG production potential, the process energy ratio of black liquor (BL) conversion to SNG, and quantified the potential CO2 abatement. Based on reference pulp mill capacity, the results indicate a large potential of SNG production (about 162MW) from black liquor but at a cost of additional biomass import (36.7MW) to compensate the total energy deficit. The process shows cold gas energy efficiency of about 58% considering black liquor and biomass import as major energy inputs. About 700ktonnes per year of CO2 abatement i.e. both possible CO2 capture and CO2 offset from bio-fuel use replacing natural gas, is estimated. Moreover, the SNG production offers a significant fuel replacement in transport sector especially in countries with large pulp and paper industry e.g. in Sweden, about 72% of motor gasoline and 40% of total motor fuel could be replaced.
•The PV+HSR system which incorporates station and railway PV systems is proposed.•A techno-economic assessment of PV potential of the Beijing-shanghai high-speed railway is performed.•Case study ...shows that the PV+HSR system is promising to cover bullet trains’ most electricity consumption and achieve high-penetration renewable energy operation.
Cities worldwide are stepping up efforts to reshape their infrastructure to ensure a carbon-neutral and sustainable future, leading to the rapid electrification of transportation systems. The electricity demand of this sector, particularly that of high-speed railways, is increasing. Application of the existing infrastructures of railway stations and available land along rail lines for photovoltaic (PV) electricity generation has the potential to power high-speed bullet trains with renewable energy and supply surplus electricity to surrounding users. In this work, a methodology based on a geographic information system was established to evaluate the PV potential along rail lines and on the roofs of train stations. The Beijing-Shanghai high-speed railway (HSR) was used as a case study. Its total PV potential reached 5.65 GW (of which the station potential accounted for 264 MW, approximately 4.68%, of the total potential), with a lifelong generation capacity of 155 TWh, which corresponds to approximately 12% of the total new installed capacity of China in 2020. Although electricity prices and solar resources differed along the railway line, all PV systems were profitable. Moreover, a comparison between the electricity consumption and generation shows that the PV+HSR system can cover most of the electricity demand of the Beijing-Shanghai HSR without a storage system. This concept can be further expanded to other rail lines and stations. Within the context of global carbon peaks and carbon neutrality, the integration of PV and railway systems should be promoted.
The membrane wetting by amine absorbents results in performance deterioration of membrane gas absorption system for CO
2 post-combustion capture. To solve this problem, in this study, the ...polypropylene membrane fiber was modified by depositing a rough layer on the surface to improve its hydrophobicity. Weighing the coating homogeneity, hydrophobicity and modification process efficiency, the mixture of cyclohexanone and MEK system was considered as the best non-solvent. The contact angle increased dramatically from 122° to 158° by the modification, thereby obtaining superhydrophobic membrane surface. The membrane–absorbent interaction results demonstrated that the modification treatment effectively enhanced the stability and maintained the superhydrophobicity of fibers contacting with the absorbent. In addition, continuous CO
2 absorption experiments for up to 20
days were carried out in untreated and modified polypropylene hollow fiber membrane contactors, using 1
mol
L
−1 MEA solution as the absorbent. The long-term system operation results indicated that, even though additional mass transfer resistance was introduced by the surface coating, the modified polypropylene hollow fiber membrane contactor was still technically feasible for CO
2 capture from the power stations.
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