| 1. |
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| 2. |
- Harahap, Fumi, 1983-, et al.
(författare)
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Meeting the bioenergy targets from palm oil based biorefineries : An optimal configuration in Indonesia
- 2020
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 278
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Tidskriftsartikel (refereegranskat)abstract
- Biorefineries provide opportunities to improve the economic, environmental, and social performance of bio-based production systems. Prudent planning of plant configuration and localization is however of great merit to obtain maximum benefits from biorefineries. This study investigates optimal deployment of palm oil-based biorefineries on the two major islands of Indonesia, Sumatra and Kalimantan. In addition, the results of the optimal bioenergy (bioelectricity, biodiesel, ethanol) production are used to calculate the potential contribution of the palm oil industry according to the national bioenergy targets from 2020 to 2030. This work also offers a new perspective of analyzing the role of bioenergy in the palm oil industry in relation to meeting the bioenergy targets through the development of spatially explicit optimization model, BeWhere Indonesia. Results show that the palm oil-based biorefineries in Sumatra and Kalimantan can produce 1–1.25 GW of electricity, 4.6–12.5 bL of biodiesel, and 2.8–4.8 bL of ethanol in 2030. Significant efforts in terms of mobilization of resources and economic instruments are required to harness the full potential offered by the palm oil-based biorefineries. This study provides an important insight on how palm oil biorefineries can be developed for their enhanced roles in meeting global sustainability efforts.
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| 3. |
- Harahap, Fumi, 1983-, et al.
(författare)
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Opportunities to Optimize the Palm Oil Supply Chain in Sumatra, Indonesia
- 2019
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- Significant amounts of biomass residues were generated in Indonesia. While untreated, residues emit greenhouse gases during the decomposition process. On the other hand, if efficiently utilized, these residues could be used to produce value-added products. This study investigates opportunities for harnessing the full potential of palm oil residues (i.e., empty fruit bunches, kernel shells, fiber, and mill effluent). As far as we are aware, the study is the first attempt to model the palm oil supply chain in a geographically explicit way while considering regional infrastructures in Sumatra Island, Indonesia. The BeWhere model, a mixed integer linear programming model for energy system optimization, was used to assess the costs and benefits of optimizing the regional palm oil supply chain. Different scenarios were investigated, considering current policies and new practices leading to improved yields in small-scale plantations and power grid connectivity. The study shows that a more efficient palm oil supply chain can pave the way for the country to meet up to 50% of its national bioenergy targets by 2025, and emission reductions of up to 40 MtCO2eq/year. As much as 50% of the electricity demand in Sumatra could be met if residues are efficiently used and grid connections are available. We recommend that system improvements be done in stages. In the short to medium term, improving the smallholder plantation yield is the most optimal way to maximize regional economic gains from the palm oil industry. In the medium to long term, improving electricity grid connection to palm oil mills could bring higher economic value as excess electricity is commercialized.
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| 4. |
- Harahap, Fumi, 1983-, et al.
(författare)
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The role of oil palm biomass to meet liquid biofuels target in Indonesia
- 2019
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Ingår i: Proceedings of the 32nd International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. - Poland : Institute of Thermal Technology. - 9788361506515 ; , s. 1509-1524
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Konferensbidrag (refereegranskat)abstract
- Indonesia aims at reducing the dependence on oil import by liquid biofuels consumption (i.e., biodiesel and bio-ethanol) in industry, transport and power sectors. The palm oil industry has played significant role in the development of biodiesel in the country producing crude palm oil (CPO) and palm fatty acid distillate (PFAD) based biodiesel. Opportunity exists for the industry to contribute to the development of bio-ethanol program by utilising the lignocellulosic biomass such as the empty fruit bunches (EFB). This study evaluates the potential of liquid biofuels production from oil palm biomass and the domestic demand for biofuels as per biofuel blending target set by the Indonesian government. The existing infrastructures as well as the investment opportunity of each type of biofuel are analyzed. While technology for biodiesel production is proven at large scale, the bio-ethanol production from EFB is not commercialized yet. The study shows that meeting the biodiesel blending target is at risk if Indonesia continues to solely reliance on the production of CPO and PFAD based biodiesel. Palm oil industry can produce nearly 7 billion litres biodiesel from CPO and PFAD in 2025 but the biodiesel domestic demand is 30% higher. The bio-ethanol program faces higher risk. EFB based ethanol through gasification and synthesis of alcohol can contribute to around 13% of the target in 2025, however the infrastructure is not ready yet. Feedstock diversification to produce liquid biofuels should be prioritized. We recommend a review of the current plan to a more achievable targets or prolong the timeline in order to secure domestic biofuels demand while continuing export. The study provides database for future modelling exercise on multi-period optimization study of palm biofuels supply chain in Indonesia in a geographically explicit way.
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| 5. |
- Jafri, Yawer, 1988-, et al.
(författare)
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Combining expansion in pulp capacity with production of sustainable biofuels – Techno-economic and greenhouse gas emissions assessment of drop-in fuels from black liquor part-streams
- 2020
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 279
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Tidskriftsartikel (refereegranskat)abstract
- Drop-in biofuels from forest by-products such as black liquor can help deliver deep reductions in transport greenhouse gas emissions by replacing fossil fuels in our vehicle fleet. Black liquor is produced at pulp mills that can increase their pulping capacity by upgrading some of it to drop-in biofuels but this is not well-studied. We evaluate the techno-economic and greenhouse gas performance of five drop-in biofuel pathways based on BL lignin separation with hydrotreatment or black liquor gasification with catalytic synthesis. We also assess how integrated biofuel production impacts different types of pulp mills and a petroleum refinery by using energy and material balances assembled from experimental data supplemented by expert input. Our results indicate that drop-in biofuels from black liquor part-streams can be produced for ~80 EUR2017/MWh, which puts black liquor on the same footing (or better) as comparable forest residue-based alternatives. The best pathways in both production routes have comparable costs and their principal biofuel products (petrol for black liquor gasification and diesel for lignin hydrotreatment) complement each other. All pathways surpass European Union's sustainability criteria for greenhouse gas savings from new plants. Supplementing black liquor with pyrolysis oil or electrolysis hydrogen can improve biofuel production potentials and feedstock diversity, but better economic performance does not accompany these benefits. Fossil hydrogen represents the cheaper option for lignin hydrotreatment by some margin, but greenhouse gas savings from renewable hydrogen are nearly twice as great. Research on lignin upgrading in industrial conditions is recommended for reducing the presently significant performance uncertainties. © 2020 The Authors
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| 6. |
- Kraxner, Florian, et al.
(författare)
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Planning the future forests: managing for wildlife in a climate constrained landscape
- 2017
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Ingår i: Book of Abstracts. - 9783902762887 ; , s. 655-
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Konferensbidrag (refereegranskat)abstract
- Multipurpose functionality is a paradigm when it comes to forest management. This includes sustainability, resilience, stand stability, wildlife management, recreation, clean water and air, or healthy soils - to name a few. The world is aiming at a maximum global warming of 2-deg by 2100, but cumulative emissions are still rising. Higher temperatures are associated with higher risks of extreme events such as storm, flood, droughts, pests and fires etc. - and at the same time, forest systems are key for any mitigation activity to avoid such dangerous climate change. But how will a managed forest look like in the future? How can we understand the underlying dynamics and make our forests fit for the increased need for carbon storage, biomass for energy and sustainable wood and non-wood forest products like game, while maintaining biodiversity, recreational and protected areas. Moreover, we need to address all challenges on limited land and establish action from policy development allthe way to their implementation within a short time frame. Based on Sweden's forests, traditionally considered a role model for successfully bridging a multitude of demands, we present a modeling approach that should serve as a planning tool for enhancing forests' risk resilience and capacity of integrating diverse demands and different ecosystem-services. Guided by the expertise of Sweden's Environmental Protection Agency, national forest and habitat shift models from SLU and KTH will be linked with global land use models and engineering tools from IIASA. Hereby, special emphasis will be put on ecosystem services from wildlife, different scenarios of forest intensification and the optimization of biomass for bioenergy production. First estimates show that spatially explicit modeling can substantially support decision making by optimizing multipurpose use of both managed and protected areas and steering habitat shift for maintaining biodiversity and improving wildlife (game)management.
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| 7. |
- Meng, Ying, et al.
(författare)
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Hydropower Production Benefits More From 1.5 °C than 2 °C Climate Scenario
- 2020
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Ingår i: Water resources research. - : Blackwell Publishing Ltd. - 0043-1397 .- 1944-7973. ; 56:5
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Tidskriftsartikel (refereegranskat)abstract
- Hydropower plays an important role as renewable and clean energy in the world's overall energy supply. Electricity generation from hydropower represented approximately 16.6% of the world's total electricity and 70% of all renewable electricity in 2015. Determining the different effects of 1.5 and 2 °C of global warming has become a hot spot in water resources research. However, there are still few studies on the impacts of different global warming levels on gross hydropower potential. This study used a coupled hydrological and techno-economic model framework to assess hydropower production under global warming levels of 1.5 and 2 °C, while also considering gross hydropower potential, power consumption, and economic factors. The results show that both global warming levels will have a positive impact on the hydropower production of a tropical island (Sumatra) relative to the historical period; however, the ratio of hydropower production versus power demand provided by 1.5 °C of global warming is 40% higher than that provided by 2 °C of global warming under RCP6.0. The power generation by hydropower plants shows incongruous changing trends with hydropower potential under the same global warming levels. This inconformity occurs because the optimal sites for hydropower plants were chosen by considering not only hydropower potential but also economic factors. In addition, the reduction in CO2 emissions under global warming of 1.5 °C (39.06 × 106 t) is greater than that under global warming of 2 °C (10.20 × 106 t), which reveals that global warming decreases the benefits necessary to relieve global warming levels. However, the hydropower generation and the reduction in CO2 emissions will be far less than the energy demand when protected areas are excluded as potential sites for hydropower plants, with a sharp decrease of 40–80%. Thus, government policy-makers should consider the trade-off between hydropower generation and forest coverage area in nationally determined contributions. © 2020 The Authors.
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| 8. |
- Mesfun, Sennai, et al.
(författare)
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Black liquor fractionation for biofuels production : A techno-economic assessment
- 2014
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 166, s. 508-517
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Tidskriftsartikel (refereegranskat)abstract
- The hemicelluloses fraction of black liquor is an underutilized resource in many chemical pulp mills. It is possible to extract and separate the lignin and hemicelluloses from the black liquor and use the hemicelluloses for biochemical conversion into biofuels and chemicals. Precipitation of the lignin from the black liquor would consequently decrease the thermal load on the recovery boiler, which is often referred to as a bottleneck for increased pulp production. The objective of this work is to techno-economically evaluate the production of sodium-free lignin as a solid fuel and butanol to be used as fossil gasoline replacement by fractionating black liquor. The hydrolysis and fermentation processes are modeled in Aspen Plus to analyze energy and material balances as well as to evaluate the plant economics. A mathematical model of an existing pulp and paper mill is used to analyze the effects on the energy performance of the mill subprocesses.
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| 9. |
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| 10. |
- Mesfun, Sennai, et al.
(författare)
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Electrification of Biorefinery Concepts for Improved Productivity—Yield, Economic and GHG Performances
- 2023
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Ingår i: Energies. - : MDPI. - 1996-1073. ; 16:21
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Tidskriftsartikel (refereegranskat)abstract
- Demand for biofuels will likely increase, driven by intensifying obligations to decarbonize aviation and maritime sectors. Sustainable biomass is a finite resource, and the forest harvesting level is a topic of ongoing discussions, in relation to biodiversity preservation and the short-term role of forests as carbon sinks. State-of-the-art technologies for converting lignocellulosic feedstock into transportation biofuels achieves a carbon utilization rate ranging from 25% to 50%. Mature technologies like second-generation ethanol and gasification-based processes tend to fall toward the lower end of this spectrum. This study explores how electrification can enhance the carbon efficiency of biorefinery concepts and investigates its impact on energy, economics and greenhouse gas emissions. Results show that electrification increases carbon efficiency from 28% to 123% for gasification processes, from 28% to 45% for second-generation ethanol, and from 50% to 65% for direct liquefaction processes. Biofuels are produced to a cost range 60–140 EUR/MWh-biofuel, depending on the chosen technology pathway, feedstock and electricity prices. Notably, production in electrified biorefineries proves cost-competitive when compared to pure electrofuel (E-fuels) tracks. Depending on the selected technology pathway and the extent of electrification, a reduction in GHG emissions ranging from 75% to 98% is achievable, particularly when powered by a low-carbon electricity mix.
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| 11. |
- Mesfun, Sennai, et al.
(författare)
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Electrolysis Assisted Biomass Gasification for Liquid Fuels Production
- 2022
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Ingår i: Frontiers in Energy Research. - : Frontiers Media S.A.. - 2296-598X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Gasification is a promising pathway for converting biomass residues into renewable transportation fuels and chemicals needed to comply with the ambitious Swedish environmental targets. The paper investigates the integration of a molten carbonate electrolysis cell (MCEC) in biofuel production pathway from sawmill byproducts, to improve the performance of gas cleaning and conditioning steps prior to the final conversion of syngas into liquid biofuels. The energy, material, and economic performance of process configurations with different gasification technologies are simulated and compared. The results provide relevant information to develop the engineering of gas-to-liquid transportation fuels utilizing renewable electricity. The MCEC replaces the water-gas shift step of a conventional syngas conditioning process and enables increased product throughput by as much as 15%–31%. Depending on the process configuration and steam-methane reforming technology, biofuels can be produced to the cost range 140–155 €/MWh in the short-term. Copyright © 2022 Mesfun, Engvall and Toffolo.
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| 12. |
- Mesfun, Sennai, et al.
(författare)
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Integrated SNG production in a typical Nordic sawmill
- 2015
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Ingår i: ECOS 2015. - : International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. - 9782955553909
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Konferensbidrag (refereegranskat)abstract
- Advanced biomass based motor fuels and chemicals are becoming increasingly important to replace fossil energy sources within the coming decades. It is likely that the new biorefineries will evolve mainly from existing forest industry sites as they already have the required biomass handling infrastructure in place. The main objective of this work is to assess the potential for increasing the profit margin from sawmill byproducts by integrating innovative downstream processes. The focus is on the techno-economic evaluation of an integrated site for bio-SNG production. The option of using the syngas in a b-IGCC for the production of electricity (instead of SNG) is also considered for comparison. The process flowsheets that are used to analyse the energy and material balances are modelled in MATLAB and Simulink. A mathematical process integration model of a typical Nordic sawmill is used to analyse the effects on the energy flows in the overall site as well as to evaluate the site economics. Different plant sizes have been considered in order to assess the economy-of-scale effect. The technical data required as input are collected from the literature and, in some cases, from experiments. The investment cost is evaluated on the basis of conducted studies, third party supplier budget quotations and in-house database information. This paper presents complete material and energy balances of the considered processes and the resulting process economics.
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| 13. |
- Mesfun, Sennai, et al.
(författare)
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Integrated SNG Production in a Typical Nordic Sawmill
- 2016
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 9:5
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Tidskriftsartikel (refereegranskat)abstract
- Advanced biomass-based motor fuels and chemicals are becoming increasingly important to replace fossil energy sources within the coming decades. It is likely that the new biorefineries will evolve mainly from existing forest industry sites, as they already have the required biomass handling infrastructure in place. The main objective of this work is to assess the potential for increasing the profit margin from sawmill byproducts by integrating innovative downstream processes. The focus is on the techno-economic evaluation of an integrated site for biomass-based synthetic natural gas (bio-SNG) production. The option of using the syngas in a biomass-integrated gasification combined cycle (b-IGCC) for the production of electricity (instead of SNG) is also considered for comparison. The process flowsheets that are used to analyze the energy and material balances are modelled in MATLAB and Simulink. A mathematical process integration model of a typical Nordic sawmill is used to analyze the effects on the energy flows in the overall site, as well as to evaluate the site economics. Different plant sizes have been considered in order to assess the economy-of-scale effect. The technical data required as input are collected from the literature and, in some cases, from experiments. The investment cost is evaluated on the basis of conducted studies, third party supplier budget quotations and in-house database information. This paper presents complete material and energy balances of the considered processes and the resulting process economics. Results show that in order for the integrated SNG production to be favored, depending on the sawmill size, a biofuel subsidy in the order of 28–52 €/MWh SNG is required.
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| 14. |
- Mesfun, Sennai, et al.
(författare)
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Integrating the processes of a Kraft pulp and paper mill and its supply chain
- 2014
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Ingår i: 27th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. - Åbo : Åbo Akademi University Press. - 9781634391344
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the possibility of combining different forest industries (a pulp and paper mill, its supply chain, and a wood-pellet plant) into an integrated industrial site in which they share a common heat and power utility. Advanced process integration and optimization techniques are used to study the site from both material and energy viewpoints. An existing pulp and paper mill is used as the site core plant and its pulp and paper production rates are kept fixed as they are in reality, while the other material flow links among the plants are based on the current industrial situation in Sweden. Different scenarios are evaluated in order to reflect the two main objectives that can be pursued (increased electricity production or biomass resource saving) and the two technologies that can be considered for the shared CHP system (boilers and product gas fired gas turbines). The corresponding non-integrated (standalone) configurations are compared to these scenarios to quantify the potential benefits of the integration. Investment opportunity is also calculated for the considered scenarios as an indicator of the economic convenience
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| 15. |
- Mesfun, Sennai, et al.
(författare)
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Integrating the processes of a Kraft pulp and paper mill and its supply chain
- 2015
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 103, s. 300-310
-
Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the possibility of combining different forest industries (a pulp and paper mill, its supply chain, and a wood-pellet plant) into an integrated industrial site in which they share a common heat and power utility. Advanced process integration and optimization techniques are used to study the site from both material and energy viewpoints. An existing pulp and paper mill is used as the site core plant and its pulp and paper production rates are kept fixed as they are in reality, while the other material flow links among the plants are based on the current industrial situation in Sweden. Different scenarios are evaluated in order to reflect the two main objectives that can be pursued (increased electricity production or biomass resource saving) and the two technologies that can be considered for the shared CHP system (boilers and product gas fired gas turbines). The corresponding non-integrated (standalone) configurations are compared to these scenarios to quantify the potential benefits of the integration. Investment opportunity is also calculated for the considered scenarios as an indicator of the economic convenience
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| 16. |
- Mesfun, Sennai, et al.
(författare)
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Integration of an electrolysis unit for producer gas conditioning in a bio-SNG plant
- 2017
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Ingår i: 30th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2017. - : International Measurement Confederation (IMEKO).
-
Konferensbidrag (refereegranskat)abstract
- Producer gas from biomass gasification contains impurities like tars, particles, alkali salts and sulfur/nitrogen compounds. As a result a number of process steps are required to condition the producer gas before utilization as a syngas and further upgrading to final chemicals and fuels. Here, we study the concept of using molten carbonate electrolysis cells (MCEC) both to clean and to condition the composition of a raw syngas stream, from biomass gasification, for further upgrading into SNG. A mathematical MCEC model is used to analyze the impact of operational parameters, such as current density, pressure and temperature, on the quality and amount of tailored syngas produced. Investment opportunity is evaluated as an economic indicator of the processes considered. Results indicate that the production of SNG can be boosted by approximately 50% without the need of an additional carbon source, i.e. for the same biomass input as in standalone operation of the GoBiGas plant.
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| 17. |
- Mesfun, Sennai, et al.
(författare)
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Integration of an electrolysis unit for producer gas conditioning in a bio-synthetic natural gas plant
- 2019
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Ingår i: Journal of energy resources technology. - : ASME Press. - 0195-0738 .- 1528-8994. ; 141:1
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Tidskriftsartikel (refereegranskat)abstract
- Producer gas from biomass gasification contains impurities like tars, particles, alkali salts, and sulfur/nitrogen compounds. As a result, a number of process steps are required to condition the producer gas before utilization as a syngas and further upgrading to final chemicals and fuels. Here, we study the concept of using molten carbonate electrolysis cells (MCEC) both to clean and to condition the composition of a raw syngas stream, from biomass gasification, for further upgrading into synthetic natural gas (SNG). A mathematical MCEC model is used to analyze the impact of operational parameters, such as current density, pressure and temperature, on the quality and amount of syngas produced. Internal rate of return (IRR) is evaluated as an economic indicator of the processes considered. Results indicate that, depending on process configuration, the production of SNG can be boosted by approximately 50-60% without the need of an additional carbon source, i.e., for the same biomass input as in standalone operation of the GoBi-Gas plant.
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| 18. |
- Mesfun, Sennai, et al.
(författare)
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Optimization of process integration in a Kraft pulp and paper mill : Evaporation train and CHP system
- 2013
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 107, s. 98-110
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Tidskriftsartikel (refereegranskat)abstract
- A great interest has been arising about the production of fuels and advanced chemicals from renewable resources such as wooden biomass in the so-called biorefineries. Pulp and paper mills are often seen as the most obvious fundamental module of such industrial sites, because of the common feedstock and the chemical transformations that already occur in the process. In this paper the model of real Kraft pulp and paper mill is developed and optimized from energetic point of view using process integration techniques, in order to assess the potential for energy saving and to establish a starting point for future research on biorefinery sites. Improvements to the configurations of the multi-effect evaporator and of the steam cycle in the CHP system have been introduced, and three different levels of heat integration boundaries have been considered (multi-effect evaporator, mill sub-processes, and total site). Results indicate a significant potential for the decrease in thermal energy requirement and/or the increase in power production for the same pulp and paper production.
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| 19. |
- Mesfun, Sennai, et al.
(författare)
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Power-to-gas and power-to-liquid for managing renewable electricity intermittency in the Alpine Region
- 2017
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Ingår i: Renewable energy. - : Elsevier. - 0960-1481 .- 1879-0682. ; 107, s. 361-372
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Tidskriftsartikel (refereegranskat)abstract
- Large-scale deployment of renewable energy sources (RES) plays a central role in reducing CO2 emissions from energy supply systems, but intermittency from solar and wind technologies presents integration challenges. High temperature co-electrolysis of steam and CO2 in power-to-gas (PtG) and power-to-liquid (PtL) configurations could utilize excess intermittent electricity by converting it into chemical fuels. These can then be directly consumed in other sectors, such as transportation and heating, or used as power storage. Here, we investigate the impact of carbon policy and fossil fuel prices on the economic and engineering potential of PtG and PtL systems as storage for intermittent renewable electricity and as a source of low-carbon heating and transportation energy in the Alpine region. We employ a spatially and temporally explicit optimization approach of RES, PtG, PtL and fossil technologies in the electricity, heating, and transportation sectors, using the BeWhere model. Results indicate that large-scale deployment of PtG and PtL technologies for producing chemical fuels from excess intermittent electricity is feasible, particularly when incentivized by carbon prices. Depending on carbon and fossil fuel price, 0.15−15 million tonnes/year of captured CO2 can be used in the synthesis of the chemical fuels, displacing up to 11% of current fossil fuel use in transportation. By providing a physical link between the electricity, transportation, and heating sectors, PtG and PtL technologies can enable greater integration of RES into the energy supply chain globally.
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| 20. |
- Mesfun, Sennai
(författare)
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Process integration to increase woody biomass utilization for energy purposes
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Woody biomass is an abundant renewable energy resource in Sweden, and the Swedish government has been promoting research and development programs for the exploitation of this resource as a mean to meet the targets on the reduction of the carbon dioxide emissions from the industrial, energy and transportation sectors. This thesis aims at expanding the knowledge on the efficient utilization of the available woody biomass, so that a larger amount of this renewable resource can be used for energy purposes. The thesis presents a collection of studies following the main two policies that have been identified for the reduction of carbon dioxide emission, i.e. the implementation of measures improving energy conservation and efficiency and a deep decarbonization of the energy sector. Process integration and optimization techniques are applied to forest industry sites in order to improve the resource and energy efficiency, the benefits of the integrated design configurations being evaluated by both technical and economic analyses. The integration of woody biomass with intermittent renewable energy sources is also studied in order to enable a large share of non-fossil sources in the energy mix.The results of the investigations show a significant potential for improving biomass resource utilization in the forest industry sites strictly from the energetic point of view. Optimizing the process integration in sites including Kraft pulp and paper mills and/or sawmills and a dedicated common CHP system can lead to a much greater power generation for the same input biomass and for the same production volume, or to large amounts of excess heat to be used in nearby processes or district heating, or even to the re-routing of part of the input biomass to other conversion processes (e.g. lignin separation and hemicellulose fermentation to produce biofuels). The operational profit of the site is consequently increased, but, when the investment costs are considered, some form of subsidies to the “green” byproducts are usually still required to make the integrated design configurations economically viable. The integration of woody biomass with intermittent renewable energy sources can result in an increased efficiency of hybrid power generation plants (e.g. with concentrated solar thermal collectors), and on a large scale it could facilitate the decarbonization of the energy sector with the fundamental contribution from power-to-X technologies in order to produce chemical fuels from the excess intermittent electricity. These technologies would be clearly incentivized by a carbon tax, but the benefit deriving from the large volumes of captured CO2 that are required for the synthesis of chemical fuels through co-electrolysis should also be taken into account. Keywords: Forest industry, process integration, pinch analysis, HEATSEP method, optimization, CHP system, techno-economic, biorefinery, intermittent renewables.
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| 21. |
- Mesfun, Sennai, et al.
(författare)
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Spatio-temporal assessment of integrating intermittent electricity in the EU and Western Balkans power sector under ambitious CO2 emission policies
- 2018
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Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 164, s. 676-693
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Tidskriftsartikel (refereegranskat)abstract
- This work investigates a power dispatch system that aims to supply the power demand of the EU and Western Balkans (EUWB) based on low-carbon generation units, enabled by the expansion of biomass, solar, and wind based electricity. A spatially explicit techno-economic optimization tool simulates the EUWB power sector to explore the dispatch of new renewable electricity capacity on a EUWB scale, under ambitious CO2 emission policies. The results show that utility-scale deployment of renewable electricity is feasible and can contribute about 9–39% of the total generation mix, for a carbon price range of 0–200 €/tCO2and with the existing capacities of the cross-border transmission network. Even without any explicit carbon incentive (carbon price of 0 €/tCO2), more than 35% of the variable power in the most ambitious CO2 mitigation scenario (carbon price of 200 €/tCO2) would be economically feasible to deploy. Spatial assessment of bio-electricity potential (based on forest and agriculture feedstock) showed limited presence in the optimal generation mix (0–6%), marginalizing its effect as baseload. Expansion of the existing cross-border transmission capacities helps even out the variability of solar and wind technologies, but may also result in lower installed RE capacity in favor of state-of-the-art natural gas with relatively low sensitivity to increasing carbon taxes. A sensitivity analysis of the investment cost, even under a low-investment scenario and at the high end of the CO2 price range, showed natural gas remains at around 11% of the total generation, emphasizing how costly it would be to achieve the final percentages toward a 100% renewable system.
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| 22. |
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| 23. |
- Mesfun, Sennai, et al.
(författare)
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Technoeconomic assessment of hybrid organosolv-steam explosion pretreatment of woody biomass
- 2019
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 12:21
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates technoeconomic performance of standalone biorefinery concepts that utilize hybrid organic solvent and steam explosion pretreatment technique. The assessments were made based on a mathematical process model developed in UniSim Design software using inhouse experimental data. The work was motivated by successful experimental applications of the hybrid pretreatment technique on lignocellulosic feedstocks that demonstrated high fractionation efficiency into a cellulose-rich, a hemicellulose-rich and lignin streams. For the biorefinery concepts studied here, the targeted final products were ethanol, organosolv lignin and hemicellulose syrup. Minimum ethanol selling price (MESP) and Internal rate of return (IRR) were evaluated as economic indicators of the investigated biorefinery concepts. Depending on the configuration, and allocating all costs to ethanol, MESP in the range 0.53-0.95 €/L were required for the biorefinery concepts to break even. Under the assumed ethanol reference price of 0.55 €/L, the corresponding IRR were found to be in the range -1.75-10.7%. Hemicellulose degradation and high steam demand identified as major sources of inefficiencies for the process and economic performance, respectively. Sensitivity of MESP and IRR towards the most influential technical, economic and market parameters performed. © 2019 by the authors.
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| 24. |
- Nilsson, Robert, et al.
(författare)
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Techno-economics of carbon preserving butanol production using a combined fermentative and catalytic approach
- 2014
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 161, s. 263-269
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a novel process for n-butanol production which combines a fermentation consuming carbon dioxide (succinic acid fermentation) with subsequent catalytic reduction steps to add hydrogen to form butanol. Process simulations in Aspen Plus have been the basis for the techno-economic analyses performed. The overall economy for the novel process cannot be justified, as production of succinic acid by fermentation is too costly. Though, succinic acid price is expected to drop drastically in a near future. By fully integrating the succinic acid fermentation with the catalytic conversion the need for costly recovery operations could be reduced. The hybrid process would need 22% less raw material than the butanol fermentation at a succinic acid fermentation yield of 0.7 g/g substrate. Additionally, a carbon dioxide fixation of up to 13 ktonnes could be achieved at a plant with an annual butanol production of 10 ktonnes
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| 25. |
- Patrizio, Piera, et al.
(författare)
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Reducing US Coal Emissions Can Boost Employment
- 2018
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Ingår i: Joule. - : Elsevier. - 2542-4351. ; 2:12, s. 2633-2648
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Tidskriftsartikel (refereegranskat)abstract
- Concerns have been voiced that implementing climate change mitigation measures could come at the cost of employment, especially in the context of the US coal sector. However, repurposing US coal plants presents an opportunity to address emission mitigation and job creation, if the right technology change is adopted. In this study, the transformation of the US coal sector until 2050 is modeled to achieve ambitious climate targets. Results show that the cost-optimal strategy for meeting 2050 emission reductions consistent with 2°C stabilization pathways is through the early deployment of BECCS and by replacing 50% of aging coal plants with natural gas plants. This strategy addresses the concerns surrounding employment for coal workers by retaining 40,000 jobs, and creating 22,000 additional jobs by mid-century. Climate change mitigation does not have to come at the cost of employment, and policymakers could seek to take advantage of the social co-benefits of mitigation.
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| 26. |
- Ringkjøb, Hans-Kristian, et al.
(författare)
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Short-term solar and wind variability in long-term energy system models - A European case study
- 2020
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Ingår i: Energy. - : Elsevier Ltd. - 0360-5442 .- 1873-6785. ; 209
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Tidskriftsartikel (refereegranskat)abstract
- Integration of variable renewables such as solar and wind has grown at an unprecedented pace in Europe over the past two decades. As the share of solar and wind rises, it becomes increasingly important for long-term energy system models to adequately represent their short-term variability. This paper uses a long-term TIMES model of the European power and district heat sectors towards 2050 to explore how stochastic modelling of short-term solar and wind variability as well as different temporal resolutions influence the model performance. Using a stochastic model with 48 time-slices as benchmark, the results show that deterministic models with low temporal resolution give a 15–20% underestimation of annual costs, an overestimation of the contribution of variable renewables (13–15% of total electricity generation) and a lack of system flexibility. The results of the deterministic models converge towards the stochastic solution when the temporal resolution is increased, but even with 2016 time-slices, the need for flexibility is underestimated. In addition, the deterministic model with 2016 time-slices takes 30 times longer to solve than the stochastic model with 48 time-slices. Based on these findings, a stochastic approach is recommended for long-term studies of energy systems with large shares of variable renewable energy sources. © 2020 The Authors
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| 27. |
- Tanaka, Yasuto, et al.
(författare)
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Thermodynamic performance of a hybrid power generation system using biomass gasification and concentrated solar thermal processes
- 2015
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 160, s. 664-672
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the investigation of a hybrid power production system from biomass and solar energy. This paper suggests integration through heat exchanger network as a useful approach to obtain the synergy between biomass and solar. Biomass is first gasified in a bubbling fluidized bed (BFB) gasifier, and then syngas is used in a gas turbine. Excess heat exists in this sub-system and concentrated solar thermal process (CSTP) while there is a demand of steam for generating gasifying agent. Steam Rankine cycle exploits the heat created by these thermal streams to generate power while satisfying the steam demands. Thermodynamic performance was analyzed by process modelling with a semi-kinetic model of BFB gasifier and pinch analyses. The composition and temperature of gasifying agent showed some effect on the overall efficiency of the system. Higher overall efficiency of the system was achieved at higher temperature and higher O2 fraction in the O2-steam mixture as gasifying agent. The increase in thermal input from CSTP had positive effect on overall efficiency of the hybrid system until thermal input from CSTP becomes dominant against thermal stream related to the gasifier and the gas turbine.
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| 28. |
- Zetterholm, Jonas, et al.
(författare)
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Resource efficiency or economy of scale : Biorefinery supply chain configurations for co-gasification of black liquor and pyrolysis liquids
- 2018
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 230, s. 912-924
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Tidskriftsartikel (refereegranskat)abstract
- Biorefineries for the production of fuels, chemicals, or materials can be an important contributor to reducing dependence on fossil fuels. The economic performance of the biorefinery supply chain can be increased by, for example, industrial integration to utilise excess heat and products, increasing size to improve economy of scale, and using intermediate upgrading to reduce feedstock transport cost. To enable a large-scale introduction of biorefineries it is important to identify cost efficient supply chain configurations. This work investigates a lignocellulosic biorefinery concept integrated with forest industry, focusing on how different economic conditions affect the preferred supply chain configurations. The technology investigated is black liquor gasification, with and without the addition of pyrolysis liquids to increase production capacity. Primarily, it analyses trade-offs between high biomass conversion efficiency and economy of scale effects, as well as the selection of centralised vs. decentralised supply chain configurations. The results show the economic advantage for biomass efficient configurations, when the biorefinery investment is benefited from an alternative investment credit due to the replacement of current capital-intensive equipment at the host industry. However, the investment credit received heavily influenced the cost of the biorefinery and clearly illustrates the benefit for industrial integration to reduce the cost of biorefineries. There is a benefit for a decentralised supply chain configuration under very high biomass competition. However, for lower biomass competition, site-specific conditions will impact the favourability of either centralised or decentralised supply chain configurations.
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