| 1. |
- Naqvi, Muhammad, et al.
(författare)
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Polygeneration system integrated with small non-wood pulp mills for substitute natural gas production
- 2018
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 224, s. 636-646
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Tidskriftsartikel (refereegranskat)abstract
- This study aims to examine the potential substitute natural gas (SNG) production by integrating black liquor gasification (BLG) island with a small wheat straw-based non-wood pulp mills (NPM), which do not employ the black liquor recovery cycle. For such integration, it is important to first build knowledge on expected improvements in an overall integrated non-wood pulp mill energy system using the key performance indicators. O2-blown circulating fluidized bed (CFB) gasification with direct causticization is integrated with a reference small NPM to evaluate the overall performance. A detailed economic analysis is performed together with a sensitivity analysis based on variations in the rate of return due to varying biomass price, total capital investment, and natural gas prices. The quantitive results showed considerable SNG production but significantly reduced electricity production. There is a substantial CO2 abatement potential combining CO2 capture and CO2 mitigation from SNG use replacing compressed natural gas (CNG) or gasoline. The economic performance through sensitivity analysis reflects significant dependency on both substitute natural gas production and natural gas market price. Furthermore, the solutions to address the challenges and barriers for the successful commercial implementation of BLG based polygeneration system at small NPMs are discussed. The system performance and discussion on the real application of integrated system presented in this article form a vital literature source for future use by large number of small non-wood pulp industries.
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| 2. |
- Zhang, Chi, et al.
(författare)
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Purchase Intention for Crowd-funded Milk Products with Integrated Photovoltaic Water Pumping Systems in China
- 2019
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Ingår i: Renewable Energy Integration with Mini/Microgrid. - : Elsevier. ; , s. 503-508, s. 503-508
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Konferensbidrag (refereegranskat)abstract
- In comparison with current financing mechanisms for renewable energy systems, crowd-funding financing mechanism offers a new potential source of financing with recent use of social media. Crowd-funding financing mechanism can also increases the social supports for renewable energy systems as users and investors turn to be more actively engaged in energy systems. As a new potential source of financing, crowd-funding mechanism has different forms, including donation, lending, equity and product reward approaches. In this paper, discrete choice model was used to explore whether crowd-funding financing with a novel sociotechnical product reward practice, has the attractions for potential customers to pay for a more sustainable milk product with distributed photovoltaic (PV) system. We empirically investigated the reward-base crowd funding with the specific integrated photovoltaic water pumping (PVWP) system in dairy milk production in China. 48 in-depth interviews were adopted for qualitative analysis of determinants of customer milk purchase decision. The ordered probit regression was employed with 357 online surveys to systematically estimate the purchase intention for the online-crowd-funding sustainable milk. Customer behaviours, environmental consciousness, and the individual socio-demographic factors were tested as potential explanatory variables. In the survey and depth interview samples, we found interviewees as potential customers showed strong purchase intentions to the crowd funding dairy milk for noticing milk quality and nutritious improvement, emission reduction and environmental benefits by the integrated PVWP system. In our findings of the regression results, the females, customers with young children or planning to have children were found with higher willing to purchase than other customers for crowd funding the sustainable dairy milk. The familiarity and popularity with online shopping and pre-sale purchase in China made customers more open and active towards pre-pay and crowd-funding mechanism.
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| 3. |
- Huang, L., et al.
(författare)
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Carbon footprint of oil products pipeline transportation
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier B.V.. - 0048-9697 .- 1879-1026. ; 783
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Tidskriftsartikel (refereegranskat)abstract
- As climate issues gradually attract public attention worldwide, the operation and construction of oil product pipelines have been attached with new energy-saving and emission-reduction targets. Though previous studies concerning Life Cycle Assessment of oil and gas pipelines have estimated the carbon footprint to some extent, there is a lack of researches that take the characteristics of oil products pipelines into consideration. Oil products pipelines undertake the task of delivering various products to downstream demand locations, which differs greatly from other pipeline transportation systems as back-to-back sequential delivery is adopted. In this paper, a detailed Life Cycle Assessment model is established to analyze carbon emissions of oil products pipeline system from construction to disposal as well as its impact on soil environment. Data from practical pipes is adopted as the case study to reflect emissions produced in different stages, and the amount of total and unified emissions of different pipes provided through the proposed model is within the range of 2.78 to 4.70 tCO2e/t·km. Then, sensitivity analysis is carried out to identify the driving factors of emissions. According to the calculation results, pipe length, diameter and throughput turn out to be the dominating factors, and an empirical formula is derived for future planned pipes. Relevant recommendations are put forward based on the results to help reduce emissions from oil product pipe transportation.
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| 4. |
- Zhang, Chi, et al.
(författare)
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Economic assessment of photovoltaic water pumping integration with dairy milk production
- 2018
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Ingår i: Energy Conversion and Management. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0196-8904 .- 1879-2227. ; 177, s. 750-764
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Tidskriftsartikel (refereegranskat)abstract
- As dairy consumption grows, domestic dairy farms face challenges in reducing the cost of feeds and the production of high-quality milk for market demands. This paper aims to introduce and integrate solar energy into the milk production chain to investigate its economic performance. By collecting data on milk production processes from 11 dairy farms in China, we quantified electricity usage and costs of milk production to identify the best and worst cases. Crop yields response to the water demand and the electricity requirements of the dairy farms were considered. The study simulated scenarios of self-sufficiency at 20%, 80%, and 100%, in the identified farms by integrating a photovoltaic water pumping (PVWP) system to provide both power and water for alfalfa and other feeds' irrigation and subsequent milk production. We evaluated annual discounted cost, revenue and net profit under each scenario and case. The results showed that a dairy farm with an integrated PVWP system and self-sufficient feeds would lead to value add-ins, such as electricity saving with solar energy generation, economic cost saving of crops, and CO2 emission reduction. The analysis on return on investment (ROI) and internal rate of return (IRR) revealed that not all the self-sufficient feeds can bring positive marginal profit. Among the investigated scenarios and cases, the dairy farm marked out by the highest ROI with 3.12 and IRR with 20.4%, was the farm where the integrated PVWP system was used to reach 20% self-sufficiency (self-production of only alfalfa). The other scenarios and cases with higher levels of self-sufficiency showed lower ROIs and IRRs. This indicates that high self-production levels of feeds decrease the total profit due to high investment cost. Sensitivity analyses of crop price and operational cost were conducted for ROI with single and double factor approaches. Scale and production of feeds proportions should be carefully considered in improving the economic performance of dairy milk production.
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| 5. |
- Zhang, R., et al.
(författare)
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Pore-scale study of effects of relative humidity on reactive transport processes in catalyst layers in PEMFC
- 2022
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 323
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Tidskriftsartikel (refereegranskat)abstract
- High surface area carbon (HSC) particles can be adopted to increase the specific surface area of catalyst layer (CL) in proton exchange membrane fuel cells. Relative humidity (RH) has a significant effect on the Pt activity inside HSC particles, and the underlying mechanisms need to be further investigated. In this study, a pore-scale model considering the effects of RH on the reactive transport processes inside the CLs is developed. Two kinds of liquid water distributions affected by the RH, including capillary condensation in pores and ultra-thin liquid film on Pt surface, are considered. The liquid water distribution, Pt activity and local oxygen transport resistance (Rlocal) under different RH are studied in detail. It is found that as RH increases from 0.3 to 1.0, the condensed water in micropores of HSC particles increases, resulting in an increase in reactive surface area by about 43 %. Combined effect of the RH, Pt loading, I/C ratio and different kinds of carbon particles is investigated. It is found that due to the lack of sufficient reaction sites, compared with that under a high Pt loading, Rlocal under a low Pt loading is more sensitive to the RH. Besides, since the Pt activity inside HSC particles depends on the condensed water, the Rlocal of HSC particles is more sensitive to the RH than solid carbon particles. Finally, the Rlocal at low ionomer content is more sensitive to RH due to low ionomer coverage on Pt particles. The present study provides a pore-scale model for investigating the coupled effects of RH and CL porous structures on local transport processes, and can facilitate the optimization of CL nanoscale structures for better cell performance.
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| 6. |
- Ding, Y., et al.
(författare)
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Economical flexibility options for integrating fluctuating wind energy in power systems : The case of China
- 2018
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 228, s. 426-436
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Tidskriftsartikel (refereegranskat)abstract
- The inherent stochastic nature of wind power requires additional flexibility during power system operation. Traditionally, conventional generation is the only option to provide the required flexibility. However, the provision of the flexibility from the conventional generation such as coal-fired generating units comes at the cost of significantly additional fuel consumption and carbon emissions. Fortunately, with the development of the technologies, energy storage and customer demand response would be able to compete with the conventional generation in providing the flexibility. Give that power systems should deploy the most economic resources for provision of the required operational flexibility, this paper presents a detailed analysis of the economic characteristics of these key flexibility options. The concept of “balancing cost” is proposed to represent the cost of utilizing the flexible resources to integrate the variable wind power. The key indicators are proposed respectively for the different flexible resources to measure the balancing cost. Moreover, the optimization models are developed to evaluate the indicators to find out the balancing costs when utilizing different flexible resources. The results illustrate that exploiting the potential of flexibility from demand side management is the preferred option for integrating variable wind power when the penetration level is below 10%, preventing additional fuel consumption and carbon emissions. However, it may require 8% of the customer demand to be flexible and available. Moreover, although energy storage is currently relatively expensive, it is likely to prevail over conventional generation by 2025 to 2030, when the capital cost of energy storage is projected to drop to approximately $ 400/kWh or lower.
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| 7. |
- Guo, S., et al.
(författare)
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Mobilized thermal energy storage : Materials, containers and economic evaluation
- 2018
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Ingår i: Energy Conversion and Management. - : Elsevier Ltd. - 0196-8904 .- 1879-2227. ; 177, s. 315-329
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 8. |
- Hao, Y., et al.
(författare)
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Integration of concentrating PVs in anaerobic digestion for biomethane production
- 2018
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 231, s. 80-88
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Tidskriftsartikel (refereegranskat)abstract
- Biogas produced from anaerobic digestion processes is considered as an important alternative to natural gas and plays a key role in the emerging market for renewable energy. Aiming at achieving a more sustainable and efficient biomethane production, this work proposed a novel energy system, which integrates concentrating photovoltaic/thermal (C-PV/T) hybrid modules into a biogas plant with chemical absorption for biogas upgrading. The investigated energy system was optimized based on the data from an existing biogas plant, and its techno-economic feasibility was evaluated. Results show that about 7% of the heat consumption and 12% of the electricity consumption of the biogas plant can be covered by solar energy, by using the produced heat in a cascade way according to the operating temperature of different processes. The production of biomethane can also be improved by 25,800 N m3/yr (or 1.7%). The net present value of the integrated system is about 2.78 MSEK and the payback period is around 10 years. In order to further improve the economic performance, it is of great importance to lower the capital cost of the C-PV/T module.
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| 9. |
- Li, Hailong, 1976-, et al.
(författare)
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Thermo-physical properties of CO2 mixtures and their impacts on CO2 capture, transport and storage : Progress since 2011
- 2019
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 255
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Tidskriftsartikel (refereegranskat)abstract
- The knowledge of accurate thermo-physical properties is crucial for the development and deployment of CO2 capture, transport and storage (CCS). The progress on the experimental data and theoretical models regarding thermo-physical properties of CO2 mixtures as well as the property impact on the design and operation of different CCS processes has been updated. The newly published experimental data since 2011 have been collected and reviewed based on which the new knowledge gaps regarding measurements have been identified. There have also been some advanced models proposed recently, which have shown good performances. The collected model performances don't show there exist a model that is superior to others; but they still provide a good guideline regarding model selection. However, developing more-complex models as the complexity may not necessarily improve the accuracy when empirical parameters were included and well-tuned. By comparing the importance of the properties and the accuracy of existing models, suggestions were given regarding the development of property models that should be prioritized.
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| 10. |
- Li, Y., et al.
(författare)
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CO2 emissions reduction by switching conference online : Uncertainty analysis of global air travel
- 2020
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Ingår i: Energy Proceedings. - : Scanditale AB.
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Konferensbidrag (refereegranskat)abstract
- Ideally, primary data collection is recommended for every life cycle assessment (LCA) study. However, due to limited availability or accessibility to first-hand data, related sources of secondary data can be a good alternative in practice. In this work, the uncertainty of using secondary data from the Ecoinvent Life Cycle Inventory (LCI) database is illustrated with an LCA case study on global air travel. Inside the database, both parameters’ basic uncertainty from measurements and additional uncertainty from data quality criteria are considered with the pedigree approach. The effect of updated pedigree matrix coefficients is also evaluated. Furthermore, the sensitivity with respect to the choice of system boundary is studied with a hotspot analysis for air travel. Outside the database, the uncertainty associated with mapping real world processes to those available in the database is analyzed. In particular, the influence of flight specific parameters, e.g. plane type and occupancy level, is assessed by comparing the International Civil Aviation Organizations (ICAO) carbon emissions calculator with database calculations. The results show that emissions calculated by ICAO generally lie on the lower end of confidence intervals provided by uncertainty analysis of the database, especially for very long-haul flights. Finally, for the LCA case study on air travel, a two-step method combining the advantages of both the ICAO calculator and the Ecoinvent database is proposed.
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