| 1. |
- Abdallah, Mohammed, et al.
(author)
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Daily global solar radiation time series prediction using variational mode decomposition combined with multi-functional recurrent fuzzy neural network and quantile regression forests algorithm
- 2023
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In: Energy Reports. - 2352-4847. ; 10, s. 4198-4217
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Journal article (peer-reviewed)abstract
- Global solar radiation (GSR) prediction capability with a reliable model and high accuracy is crucial for comprehending hydrological and meteorological systems. It is vital for the production of renewable and clean energy. This research aims to evaluate the performance of combined variational mode decomposition (VMD) with a multi-functional recurrent fuzzy neural network (MFRFNN) and quantile regression forests (QRF) models for GSR prediction in daily scales. The hybrid VMD-MFRFNN and QRF models were compared with standalone MFRFNN, random forest (RF), extreme gradient boosting (XGB), and M5 tree (M5T) models across the Lund and Växjö meteorological stations in Sweden. The meteorological data from 2008 to 2017 were used to train the models, while the prediction accuracy was verified by using the data from 2018 to 2021 under five different input combinations. The various meteorological-based scenarios (including the input are air temperatures (Tmin, Tmax, T), wind speed (WS), relative humidity (RH), sunshine duration (SSH), and maximum possible sunshine duration (N)) were considered as input of predictor models. The current study resulted that the M5T model exhibited higher accuracy than RF and XGB models, while the QRF model showed equivalent performance with the M5T model at both study sites. The MFRFNN model outperformed QRF and M5T models across all input combinations at both study sites. The hybrid VMD-MFRFNN model showed the best performance when fewer input variables (Tmin, Tmax, T, WS at Lund station and Tmin, Tmax, T, WS, SSH, RH at Växjö station) were used for GSR prediction. We conclude that the MFRFNN model best predicts average daily GSR when combining all meteorological variables (Tmin, Tmax, T, WS, SSH, RH, N).
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| 2. |
- Abugabbara, Marwan, et al.
(author)
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How to develop fifth-generation district heating and cooling in Sweden? : Application review and best practices proposed by middle agents
- 2023
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In: Energy Reports. - : Elsevier Ltd. - 2352-4847. ; 9, s. 4971-4983
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Journal article (peer-reviewed)abstract
- Sweden has an ambitious plan to fully decarbonise district heating by 2030 and to contribute with negative emissions of greenhouse gases in 2050. The vagaries of the energy market associated with climate, political, and social changes entail cross-sectoral integration that can fulfill these national targets. Fifth-generation district heating and cooling (5GDHC) is a relatively new concept of district energy systems that features a simultaneous supply of heating and cooling using power-to-heat technologies. This paper presents best practices for developing 5GDHC systems in Sweden to reach a consensus view on these systems among all stakeholders. A mixed-method combining best practice and roadmapping workshops has been used to disseminate mixed knowledge and experience from middle agents representing industry professionals and practitioners. Four successful implementations of 5GDHC systems are demonstrated and the important learned lessons are shared. The best practices are outlined for system planning, system modeling and simulation, prevailing business models for energy communities, and system monitoring. A roadmap from the middle agents’ point of view is composed and can be utilised to establish industry standards and common regulatory frameworks. © 2023 The Author(s)
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| 3. |
- Abugabbara, Marwan, et al.
(author)
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Modelica-based simulations of decentralised substations to support decarbonisation of district heating and cooling
- 2021
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In: Energy Reports. - : Elsevier BV. - 2352-4847. ; 7:4, s. 465-472
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Journal article (peer-reviewed)abstract
- District heating and cooling are considered effective solutions to decarbonise the energy use in the building sector. The latest generation of district heating and cooling also increases the potential of integrating heat pumps and chillers in each building substation. The benefits of such integration are the reduction of network temperature and distribution losses; the recovery of waste heat through a bidirectional network; and the decentralised production of heating and cooling. Sizing the network depends mainly on the heat flows between connected buildings. The substation performance and technical installations determine these heat flows. We present in this paper Modelica-based simulations of two design cases for substations. The first design case involves installed heat pump, chiller, and circulation pumps. Alternatively, the second design enables the heat pump to provide direct cooling through a heat exchanger. The models for these installations were developed using the Modelica language to perform continuous-time simulations. The performance in each design case was evaluated in terms of seasonal coefficient of performance and total electric energy use. An analysis on a cluster of 11 buildings suggests that the addition of the direct cooling heat exchanger can save up to 10% of the total annual electric energy use. Additional savings can be achieved by optimising the building supply temperatures and the district network temperature.
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| 4. |
- Agar, David, et al.
(author)
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Combining behavioural TOPSIS and six multi-criteria weighting methods to rank biomass fuel pellets for energy use in Sweden
- 2023
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In: Energy Reports. - 2352-4847. ; 10, s. 706-718
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Journal article (peer-reviewed)abstract
- EU energy and climate policies continue to drive interest in biomass fuel pellets which can be produced from a wide variety of feedstock. The use of multi-criteria decision analysis (MCDA) to support feedstock selection has the potential for more transparent and better decision-making. This study applies the behavioural TOPSIS, a prominent MCDA technique, to rank pellets for energy use in Sweden produced from under-utilised forest and agricultural biomass. Seven criteria were used to assess and rank the biomass pellets. The alternatives include 88 types of pellets from 11 biomass materials. Possible attitudes of an expert towards the risk of losses (risk averse, risk neutral and risk-seeking) were combined with six sets of criteria weights obtained using six weighting methods – a total of 18 input settings (scenarios). Despite having different input settings, almost identical results were obtained in all scenarios, meaning that the rankings were stable and consistent. Across all 18 scenarios, pellets produced from a reference spruce/pine sawdust blend are ranked ahead of other pellet types. Pellets produced from Scots pine bark exhibited stable and consistent rankings across all scenarios; and thus this biomass is the second-best overall. The next best materials overall are poplar, reed canary grass and wheat straw, whereas torrefied pellets (torrefied beech, poplar and wheat straw) were ranked last in all scenarios. Combining behavioural TOPSIS and a variety of criteria-weighting methods is a meaningful way of improving decision-making with respect to producing a more valid and reliable ranking of biomass fuel pellets for energy use in Sweden.
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| 5. |
- Agyekum, Ephraim Bonah, et al.
(author)
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Towards a reduction of emissions and cost-savings in homes: Techno-economic and environmental impact of two different solar water heaters
- 2024
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In: Energy Reports. - : ELSEVIER. - 2352-4847. ; 11, s. 963-981
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Journal article (peer-reviewed)abstract
- South Africa currently has the highest carbon emission intensity per kilowatt of electricity generation globally, and its government intends to reduce it. Some of the measures taken by the government include a reduction of emissions in the building sector using solar water heating (SWH) systems. However, there is currently no study in the country that comprehensively assesses the technical, economic, and environmental impact of SWH systems across the country. This study therefore used the System Advisor Model (SAM) to model two different technologies of SWH systems (i.e., flat plate (FPC) and evacuated tube (EPC) SWH) at five different locations (i.e., Pretoria, Upington, Kimberley, Durban, and Cape Town) strategically selected across the country. According to the study, the optimum azimuth for both the evacuated tube and flat plate SWH system in South Africa is 0 degrees. Installing FPC and EPC at the different locations would yield payback periods of 3.2 to 4.4 years and 3.5 to 4.3 years, respectively. Comparably, levelized cost of energy for the FPC and EPC will range from 7.47 to 9.62 cents/kWh and 7.66 to 9.24 cents/kWh, respectively, based on where the SWH system is located. Depending on where the facility is located, the annual cost savings for the FPC system would be between $486 and $625, while the EPC system would save between $529 and $638. Using SWHs can reduce CO2 emissions by 75-77% for the evacuated tube system and 69-76% for the flat plate system annually, depending on the location.
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| 6. |
- Al-Sulttani, Ali Omran, et al.
(author)
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Thermal effectiveness of solar collector using Graphene nanostructures suspended in ethylene glycol–water mixtures
- 2022
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In: Energy Reports. - : Elsevier BV. - 2352-4847. ; 8, s. 1867-1882
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Journal article (peer-reviewed)abstract
- Flat plate solar collectors (FPSCs) are the most often used as solar collectors due to their easiness of installation and usage. The current research investigates the energy efficiency of FPSC using different mass concentration with varied base fluids containing Graphene nanofluids (T-Gr). Mass concentration of 0.1%-wt., 0.075%-wt., 0.050%-wt. and 0.025%-wt. were mixed with ethylene glycol (EG) and distilled water (DW) in different rations. The operating conditions were volumetric flowrate (1.5, 1 and 0.5) LPM 50 °C-input fluid temperature and 800 W/m2-global solar irradiation. Scanning electron microscope (SEM) and energy dispersive X-ray (EDX) were used to synthesize the thermally treated nanomaterial. The theoretical investigation indicated that using T-Gr nanosuspensions increased the FPSC efficiency in comparison with the host fluid for all examined mass concentrations and volumetric flowrates. In quantitative terms, the maximum thermal effectiveness improvement for the EG, (DW:70 + EG:30) and DW:EG (DW:50 + EG:50) and using flowrates of (1.5, 1 and 0.5) LPM were 12.54%, 12.46% and 12.48%. In addition, the research results pointed that the essential parameters (i.e., loss energy (FRUL)) and gain energy (FR (τα)) of the T-Gr nanofluids were increased significantly.
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| 7. |
- Andersson, Elias, 1989-, et al.
(author)
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Decarbonization of industry : Implementation of energy performance indicators for successful energy management practices in kraft pulp mills
- 2021
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In: Energy Reports. - : Elsevier. - 2352-4847. ; 7, s. 1808-1817
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Journal article (peer-reviewed)abstract
- Energy management is the most prominent means of improving energy efficiency, and improved energy efficiency constitutes the cornerstone in decarbonization. For successful industrial energy management, defining accurate energy performance indicators (EnPIs) is essential. Energy-intensive industries have previously been found to have an improvement potential regarding the current monitoring of EnPIs, especially at process level. While general models for developing and implementing EnPIs exist, manufacturing industries are diverse in terms of their production processes, which is why industry-tailored models for EnPI development are needed. One major outcome of this paper is a unique model specifically tailored for kraft pulp mills. The model derives from a practice-based approach for EnPI development, building on real-life experiences from a Swedish group of companies. This paper’s developed model, and the validation of the EnPIs, further increase the understanding of the kraft pulp industry’s processes and how to apply descriptive and explanatory indicators. The developed model can potentially be generalized to other sectors.
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| 8. |
- Andrei, Mariana, et al.
(author)
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Decarbonization of industry : Guidelines towards a harmonized energy efficiency policy program impact evaluation methodology
- 2021
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In: Energy Reports. - : Elsevier. - 2352-4847. ; 7, s. 1385-1395
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Journal article (peer-reviewed)abstract
- The decarbonization of EU energy system is under way, but manufacturing industry is still using approximately 25% of the EU total final energy use. To maintain long-term competitiveness while contributing to the EU goal of carbon neutrality by 2050, manufacturing industry needs to improve energy efficiency in a cost-effective way. One important way to achieve this is through energy audits. The Energy Efficiency Directive promotes member states development of energy efficiency programs to encourage industry to undergo energy audits. Previous studies have reviewed industrial energy efficiency policy program evaluations and argued that there is no harmonized way to conduct them. This leads to difficulties in: i) comparing energy efficiency and cost saving potentials throughout different programs, and ii) providing necessary information that supports the improvement of the policy program. Therefore, we argue that a harmonized methodology for industrial energy efficiency policy program evaluation is of great importance, and, we have developed a set of five-steps guidelines that lay the foundation for an ex-ante energy efficiency policy program evaluation methodology. The guidelines are to be be conducted during the lifetime of the program, in five steps, as follows: (s1) define key issues, (s2) set the objectives for each key issue, (s3) identify the options for each key issue, (s4) analyze options from an energy and environmental perspective, and (s5) compare options and select the recommended one. Our proposed methodology will support policymakers and evaluators answer questions such as: i) how can the objectives of the policy program be achieved? ii) is there any need to change the policy program? Furthermore, a comparison in terms of relevance, efficiency, effectiveness, and sustainability of all major policy options developed, including the status quo option is proposed in the methodology. This paper can be seen an important step towards the goal of creating a harmonized policy evaluation methodology. (C) 2021 The Authors. Published by Elsevier Ltd.
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| 9. |
- Andrei, Mariana, 1981-, et al.
(author)
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Exploring the design of voluntary initiatives from the transition management perspective – A means for industrial decarbonization
- 2024
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In: Energy Reports. - 2352-4847. ; 11, s. 5894-5909
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Journal article (peer-reviewed)abstract
- Recent studies claim that national policies fall short of the ambitious goal to limit global temperature increase to well below 2°C, preferably 1.5°C, revealing an ambition gap between current commitments and those needed to reach climate neutrality. To bridge this gap, commitments must increase more than fivefold to achieve the necessary reduction in GHG emissions. Voluntary initiatives (VIs), gaining interest as an approach to support the Paris Agreement's ambition, have the potential to bridge the commitment gap and limit the expected temperature increase to 2°C if all their voluntary commitments to climate neutrality are fulfilled. While decarbonizing the manufacturing sector is crucial for climate targets, no prior study has explored the theoretical potential of industry-related VIs to bridge the gap for industrial decarbonization. This paper addresses this gap by examining the potential contribution of these VIs, analyzing criteria related to arena and agenda creation, operationalization, and accountability. By applying the transition management framework innovatively, the study investigates eighty-three industry-related VIs led by both state and non-state actors. The research process, involving the development of an analytical framework, VIs selection, data collection and validation, categorization, and analysis, provides insights into how the design affects VIs' potential for industrial decarbonization. The main findings highlight, firstly, the need for clearly defined and measurable targets, enhanced commitments, and robust accountability mechanisms, especially for non-state actor-led initiatives. Secondly, increased participation from energy-intensive sector companies due to their pivotal role for GHG emission reduction. Lastly, collaboration between state and non-state actors is critical for bridging the decarbonization gap in manufacturing industries. Additionally, the similarity between VIs and voluntary agreement programs (VAPs) is highlighted, with VAPs been overseen by governmental bodies with administrative authority. Given the urgency of addressing climate change, an unanswered question remains: Will future policies transition away from voluntariness towards more mandatory administrative character?
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| 10. |
- Asim, Muhammad, et al.
(author)
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Techno-economic assessment of energy and environmental impact of waste-to-energy electricity generation
- 2023
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In: Energy Reports. - : Elsevier. - 2352-4847. ; 9:Suppl 1, s. 1087-1097
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Journal article (peer-reviewed)abstract
- This study explored cumulative 127.5MW waste to energy (WtE) potential in five populous cities of Pakistan based on local waste characterization profiles and global standards. The 50MW WtE plant in Lahore using National electricity regulator codes and practices resulted in an attractive Levelized cost of electricity (LCOE) of US¢ 7.86/kWh over 25 years with a $151.5 million investment cost. The net savings to Lahore Waste Management Company can be $103.4 and $137.7 million respectively with and without tipping fees on account of waste disposal cost, bricks revenue using bottom ash, and waste fee. The project developers can get net savings of $16.9 and $51.5 million respectively with and without tipping fees other than LCOE. Furthermore, the greenhouse gas emissions of 216.6 million tons of CO2eq can be saved throughout plant life against 279 GWh/year energy generation, in terms of grid emission factor and current methane release into the atmosphere from the dumping site.
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