| 1. |
- Beiron, Johanna, 1992, et al.
(författare)
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A Case Study of the Potential for CCS in Swedish Combined Heat and Power Plants
- 2021
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Ingår i: 15th Greenhouse Gas Control Technologies Conference 2021, GHGT 2021.
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Konferensbidrag (refereegranskat)abstract
- The global need to reduce anthropogenic CO2 emissions is imminent and might be facilitated by carbon capture and storage (CCS) technologies. Sweden has a goal to reach net-zero emissions by 2045, where negative emissions – and bio-CCS (BECCS) in particular - have been proposed as an important strategy to reach this target at the lowest cost. The Swedish district heating sector constitutes a large potential for BECCS since there is a large number of relatively large biogenic point sources of CO2 in the form of combined heat and power (CHP) plants burning biomass residues from the forest industry. This study provides a multi-level estimation of the impact and potential of CO2 capture and negative emissions in 110 existing Swedish biomass or waste-fired CHP plants, located in 78 local district heating systems. Process models of CHP steam cycles give the impact of absorption-based CCS integration on CHP plant heat and electricity production. The propagation of the plant-level impact to the unit commitment of CHP plants in district heating systems is modelled, and the potential for CO2 capture in each system is estimated. The results indicate that 45-70% of nominal steam cycle district heating generation is retained when integrating carbon capture, depending on the power-to-heat ratio; although the reduced heat output can be moderated by sacrificing electricity generation. In the district heating system context, CCS integration can lead to increased utilization and fuel use of CHP plants, in synergy with increased CO2 capture, but might also lead to greater need for peak heat and/or electricity generation. The total CO2 captured from the 45 CHP plants with modeled CO2 emissions exceeding 150 kton/year could be sufficient to meet a proposed target of 3-10 Mton/year of BECCS by Year 2045.
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| 2. |
- Biermann, Max, 1989, et al.
(författare)
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Partial capture from refineries through utilization of existing site energy systems
- 2021
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Ingår i: 15th Greenhouse Gas Control Technologies Conference 2021, GHGT 2021. - : Elsevier BV.
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Konferensbidrag (refereegranskat)abstract
- Many studies indicate that carbon capture and storage operations need to be ramped up in the coming decades to limit global warming to well-below 2°C. Partial CO2 capture from carbon-intensive industrial processes is a promising starting point for initial CO2 transport and storage infrastructure projects, such as the Norwegian full-chain CCS project “Northern Lights”, since specific capture cost (€/t CO2) for single-stack capture can be kept low compared to full capture from all, often less suitable stacks. This work highlights the importance of utilizing existing site energy systems to avoid significant increase in marginal abatement cost when moving from partial to full capture. A systematic and comprehensive techno-economic approach is applied that identifies a mix of heat supply sources with minimum cost based on a detailed analysis of available heat and capacity within the existing site energy system. Time-dependent variations are considered via multi-period, linear optimization. For single-stack capture from the hydrogen production unit (~0.5 Mt CO2 p.a.) of a Swedish refinery in the context of the current energy system, we find avoidance cost for the capture plant (liquefaction, ship transport, and storage excluded)of 42 €/t CO2-avoided that is predominantly driven by steam raised from available process heat in existing coolers (~6 €/t steam). For full capture from all major stacks (~1.4 Mt CO2 p.a.), the avoidance cost becomes twice as high (86 €/t CO2-avoided) due to heat supply from available heat and existing boiler capacity (combustion of natural gas) at costs of ~20€/t steam. The analysis shows that very few investments in new steam capacity are required, and thus, that the utilization of existing site energy systems is important for lowering capture cost significantly, and thus the whole-chain cost for early CCS projects.
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| 3. |
- Cintas Sanchez, Olivia, 1982, et al.
(författare)
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Geospatial supply-demand modeling of lignocellulosic biomass for electricity and biofuels in the European Union
- 2021
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 144
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Tidskriftsartikel (refereegranskat)abstract
- Bioenergy can contribute to achieving European Union (EU) climate targets while mitigating impacts from current agricultural land use. A GIS-based modeling framework (1000 m resolution) is employed to match biomass supply (forest and agricultural residues, complemented by lignocellulosic energy crops where needed) with biomass demand for either electricity or bio-oil production on sites currently used for coal power in the EU-28, Norway, and Switzerland. The framework matches supply and demand based on minimizing the field-to-gate costs and is used to provide geographically explicit information on (i) plant-gate supply cost; (ii) CO2 savings; and (iii) potential mitigation opportunities for soil erosion, flooding, and eutrophication resulting from the introduction of energy crops on cropland. Converting all suitable coal power plants to biomass and assuming that biomass is sourced within a transport distance of 300 km, would produce an estimated 150 TW h biomass-derived electricity, using 1365 PJ biomass, including biomass from energy crops grown on 6 Mha. Using all existing coal power sites for bio-oil production in 100-MW pyrolysis units could produce 820 PJ of bio-oil, using 1260 PJ biomass, including biomass from energy crops grown on 1.8 Mha. Using biomass to generate electricity would correspond to an emissions reduction of 135 MtCO2, while using biomass to produce bio-oil to substitute for crude oil would correspond to a reduction of 59 MtCO2. In addition, energy crops can have a positive effect on soil organic carbon in most of the analyzed countries. The mitigation opportunities investigated range from marginal to high depending on location.
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| 4. |
- Cowie, A. L., et al.
(författare)
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Applying a science-based systems perspective to dispel misconceptions about climate effects of forest bioenergy
- 2021
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Ingår i: Global Change Biology Bioenergy. - : John Wiley and Sons Inc. - 1757-1693 .- 1757-1707. ; 13:8, s. 1210-1231
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Tidskriftsartikel (refereegranskat)abstract
- The scientific literature contains contrasting findings about the climate effects of forest bioenergy, partly due to the wide diversity of bioenergy systems and associated contexts, but also due to differences in assessment methods. The climate effects of bioenergy must be accurately assessed to inform policy-making, but the complexity of bioenergy systems and associated land, industry and energy systems raises challenges for assessment. We examine misconceptions about climate effects of forest bioenergy and discuss important considerations in assessing these effects and devising measures to incentivize sustainable bioenergy as a component of climate policy. The temporal and spatial system boundary and the reference (counterfactual) scenarios are key methodology choices that strongly influence results. Focussing on carbon balances of individual forest stands and comparing emissions at the point of combustion neglect system-level interactions that influence the climate effects of forest bioenergy. We highlight the need for a systems approach, in assessing options and developing policy for forest bioenergy that: (1) considers the whole life cycle of bioenergy systems, including effects of the associated forest management and harvesting on landscape carbon balances; (2) identifies how forest bioenergy can best be deployed to support energy system transformation required to achieve climate goals; and (3) incentivizes those forest bioenergy systems that augment the mitigation value of the forest sector as a whole. Emphasis on short-term emissions reduction targets can lead to decisions that make medium- to long-term climate goals more difficult to achieve. The most important climate change mitigation measure is the transformation of energy, industry and transport systems so that fossil carbon remains underground. Narrow perspectives obscure the significant role that bioenergy can play by displacing fossil fuels now, and supporting energy system transition. Greater transparency and consistency is needed in greenhouse gas reporting and accounting related to bioenergy.
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| 5. |
- Djerf, Tove, 1989, et al.
(författare)
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Solids flow patterns in large-scale circulating fluidised bed boilers: Experimental evaluation under fluid-dynamically down-scaled conditions
- 2021
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Ingår i: Chemical Engineering Science. - : Elsevier BV. - 0009-2509. ; 231
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Tidskriftsartikel (refereegranskat)abstract
- This work aims at gaining novel knowledge of the mechanisms governing the solids flow pattern in the furnace of large-scale Circulating Fluidised Bed (CFB) boilers. A fluid-dynamically down-scaled unit resembling an existing 200-MWth CFB boiler was built and validated against full-scale data. The extensive experimental campaign showed, among others, that the presence or absence of a dense bed governs the entrainment of solids from the bottom region of the furnace, and that the back-flow of solids at the exit region is negligible at low gas velocities although it quickly becomes significant with an increase in gas velocity. Thus, it is shown that the estimation of the external solids flux by the top flux in the furnace is not generally valid.
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| 6. |
- Fuss, Sabine, 1979, et al.
(författare)
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The BECCS Implementation Gap–A Swedish Case Study
- 2021
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Ingår i: Frontiers in Energy Research. - : Frontiers Media SA. - 2296-598X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The IPCC has assessed a variety of pathways that could still lead to achievement of the ambitious climate targets set in the Paris Agreement. However, the longer time that climate action is delayed, the more the achievement of this goal will depend on Carbon Dioxide Removal (CDR) technologies and practices. In the models behind these pathways, the main CDR technology is Bioenergy combined with Carbon Capture and Storage (BECCS). We review the role that BECCS could play in reaching net-zero targets based on the existing 1.5°C scenarios. Such scenarios presented in the literature typically have BECCS at a GtCO2 per year scale. We also assess the potentials and obstacles for BECCS implementation at the national level, applying Sweden as a case study. Given that BECCS deployment has scarcely started and, thus, is far from capturing 1 GtCO2 per year, with lead times on the scale of multiple years, we conclude that there will be a large implementation gap unless BECCS development is immediately intensified, emissions are reduced at a much faster pace or removals realized through other CDR measures. In the national case study, we show that Sweden has favorable conditions for BECCS in that it has large point sources of biogenic emissions, and that BECCS has been identified as one potential “supplementary measure” for reaching the Swedish target of net-zero emissions in 2045. Yet, work on planning for BECCS implementation has started only recently and would need to be accelerated to close the implementation gap between the present advancement and the targets for BECCS proposed in a recent public inquiry on the roles of supplementary measures. An assessment of two ramp-up scenarios for BECCS demonstrates that it should in principle be possible to reach the currently envisaged deployment scales, but this will require prompt introduction of political and economic incentives. The main barriers are thus not due to technological immaturity, but are rather of a socio-economic, political and institutional nature.
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| 7. |
- Goop, Joel, 1986, et al.
(författare)
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Impact of electricity market feedback on investments in solar photovoltaic and battery systems in Swedish single-family dwellings
- 2021
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Ingår i: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 163, s. 1078-1091
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Tidskriftsartikel (refereegranskat)abstract
- The profitability of investments in photovoltaics (PVs) and batteries in private households depends on the market price of electricity, which in turn is affected by the investments made in and the usage of PVs and batteries. This creates a feedback mechanism between the centralised electricity generation system, and household investments in PVs and batteries. To investigate this feedback effect, we connect a local optimisation model for household investments with a European power generation dispatch model. The local optimisation is based on the consumption profiles measured for 2104 Swedish households. The modelling compares three different scenarios for the centralised electricity supply system in Year 2032, as well as several sensitivity cases. Our results show total investment levels of 5–20 GWp of PV and 0.01–10 GWh of battery storage capacity in Swedish households in the investigated cases. These levels are up to 33% lower than before market feedback is taken into account. The profitability of PV investments is affected most by the price of electricity and the assumptions made regarding grid tariffs and taxes. The value of investments in batteries depends on both the benefits of increased self-consumption of PV electricity and market arbitrage.
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| 8. |
- Heinisch, Verena, 1991, et al.
(författare)
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Smart electric vehicle charging strategies for sectoral coupling in a city energy system
- 2021
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Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 288
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Tidskriftsartikel (refereegranskat)abstract
- The decarbonization of city energy systems plays an important role to meet climate targets. We examine the consequences of integrating electric cars and buses into the city energy system (60% of private cars and 100% of public buses), using three different charging strategies in a modelling tool that considers local generation and storage of electricity and heat, electricity import to the city, and investments to achieve net-zero emissions from local electricity and heating in 2050. We find that up to 85% of the demand for the charging of electric cars is flexible and that smart charging strategies can facilitate 62% solar PV in the charging electricity mix, compared to 24% when cars are charged directly when parked. Electric buses are less flexible, but the timing of charging enables up to 32% to be supplied by solar PV. The benefit from smart charging to the city energy system can be exploited when charging is aligned with the local value of electricity in the city. Smart charging for cars reduces the need for investments in stationary batteries and peak units in the city electricity and heating sectors. Thus, our results point to the importance of sectoral coupling to exploit flexibility options in the city electricity, district heating and transport sectors.
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| 9. |
- Heinisch, Verena, 1991, et al.
(författare)
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The impact of limited electricity connection capacity on energy transitions in cities
- 2021
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Ingår i: Smart Energy. - : Elsevier BV. - 2666-9552. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- We study the impacts of the connection capacity for electricity transfer between a city and a regional energy system on the design and operation of both systems. The city energy system is represented by the aggregate energy demand of three cities in southern Sweden, and the regional energy system is represented by Swedish electricity price area SE3. We minimize the investment and running costs in the electricity and district heating sectors, considering different levels of connection capacity between the city and the regional energy systems; connection capacities equal to 100%, 75%, 50% and 0% of the maximum city electricity demand. We find that a system design with 50% connection capacity is only 3% more expensive in terms of total costs than a system with 100% connection capacity. However, shifting electricity generation capacity from the regional to the city energy system with 50%, as compared to 100%, connection capacity leads to a higher marginal cost for electricity in the city than in the region. With the highest connection capacities, 75% and 100%, the district heating sector in the city can support wind power integration in the regional energy system by means of power-to-heat operation. Modeling systems with different connection capacities makes our results applicable to other fast-growing cities with potential to increase local electricity production and sector coupling between the electricity, district heating and electrified transport sectors.
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| 10. |
- Johnsson, Filip, 1960, et al.
(författare)
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Future applications of circulating fluidized-bed technology
- 2021
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Ingår i: CFB 2021 - Proceedings of the 13th International Conference on Fluidized Bed Technology. ; , s. 26-35
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Konferensbidrag (refereegranskat)abstract
- Considering the climate-change challenge, future thermal and chemical processes must by midcentury be net zero carbon emitting and promote circular processes, phasing out the uptake of fossil fuels from the earth’s crust. This paper discusses how circulating fluidized bed (CFB) technology can support such a future. We identify key processes and provide examples of challenges and need for research, demonstration and scale-up. Important CFB applications are both in well-established biomass combustion and gasification, and in novel concepts such as CO2 capture, plastic recycling and energy storage. It is concluded that large scale implementation of these CFB applications is primarily not a technical challenge but requires stronger climate policy as well as policies promoting a circular economy.
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