| 1. |
- Aliabadi, Danial Esmaeili, et al.
(author)
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Abandoning the Residual Load Duration Curve and Overcoming the Computational Challenge
- 2022
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In: 1st International Workshop on Open Source Modelling and Simulation of Energy Systems, OSMSES 2022 - Proceedings.
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Conference paper (peer-reviewed)abstract
- As the importance of variable energy sources in-creased in the power sector, employing the Residual Load Duration Curve (RLDC) method became standard practice in many energy system models. RLDCs allow modelers to integrate temporally high-resolution data sets in the energy system while keeping the underlying model tractable. Although the RLDC approach can assist us in simplifying calculations, this comes at a cost: RLDCs disregard the inter-relations between time slices. In this manuscript, we elaborate on our strategy to overcome the computational burden caused by abandoning the RLDC method in the BioENergy OPTimization model (BENOPT). For that purpose, the available resources are utilized efficiently to reduce the run-time.
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| 2. |
- Chan, Katrina, et al.
(author)
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How diet portfolio shifts combined with land-based climate change mitigation strategies could reduce climate burdens in Germany
- 2022
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In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 376
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Journal article (peer-reviewed)abstract
- Many studies have analysed the environmental impact of vegan, vegetarian, or reduced meat diets. To date, literature has not evaluated how diet shifts affect environmental impacts by utilising portfolios which reflect personal nutrition preferences. Further, changing diets could alter the available land for non-food uses. This paper defines novel diet portfolios to outline alternative diet transitions and choices within the population and finds their effect on greenhouse gas (GHG) emissions, primary energy use, and land use in Germany. The aim of this study is to capture how these diet shifts affect land availability and increase the options for land-based climate change mitigation strategies. To do so, a contextualisation is made to compare the use of freed-up land for afforestation or biomethane production (with and without carbon capture and storage). The investigated diet portfolios lead to a reduction of the investigated impacts (GHG emissions: 7–67%; energy use: 5–46%; land use: 6–64%). Additionally, afforestation of freed-up land from each diet portfolio leads to further emission removals of 4–37%. In comparison, using the land to produce energy crops for biomethane production could lead to 2–23% further CO2-eq emission reductions when replacing fossil methane. If biomethane production is paired with carbon capture and storage, emission abatement is increased to 3–34%. This research indicates various short-term pathways to reduce GHG emissions with portfolio diet shifts. Utilising freed-up land for climate change mitigation strategies could prove essential to meet climate targets, but trade-offs with, e.g. biodiversity and ecosystem services exist and should be considered.
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| 3. |
- Millinger, Markus, 1984, et al.
(author)
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A model for cost- and greenhouse gas optimal material and energy allocation of biomass and hydrogen
- 2022
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In: SoftwareX. - : Elsevier BV. - 2352-7110. ; 20
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Journal article (peer-reviewed)abstract
- BENOPT, an optimal material and energy allocation model is presented, which is used to assess cost-optimal and/or greenhouse gas abatement optimal allocation of renewable energy carriers across power, heat and transport sectors. A high level of detail on the processes from source to end service enables detailed life-cycle greenhouse gas and cost assessments. Pareto analyses can be performed, as well as thorough sensitivity analyses. The model is designed to analyse optimal biomass and hydrogen usage, as a complement to integrated assessment and power system models.
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| 4. |
- Millinger, Markus, 1984, et al.
(author)
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Are biofuel mandates cost-effective? - An analysis of transport fuels and biomass usage to achieve emissions targets in the European energy system
- 2022
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In: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 326
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Journal article (peer-reviewed)abstract
- Abatement options for the hard-to-electrify parts of the transport sector are needed to achieve ambitious emissions targets. Biofuels based on biomass, electrofuels based on renewable hydrogen and a carbon source, as well as fossil fuels compensated by carbon dioxide removal (CDR) are the main options. Currently, biofuels are the only renewable fuels available at scale and are stimulated by blending mandates. Here, we estimate the system cost of enforcing such mandates in addition to an overall emissions cap for all energy sectors. We model overnight scenarios for 2040 and 2060 with the sector-coupled European energy system model PyPSA-Eur-Sec, with a high temporal resolution. The following cost drivers are identified: (i) high biomass costs due to scarcity, (ii) opportunity costs for competing usages of biomass for industry heat and combined heat and power (CHP) with carbon capture, and (iii) lower scalability and generally higher cost for biofuels compared to electrofuels and fossil fuels combined with CDR. With a -80% emissions reduction target in 2040, variable renewables, partial electrification of heat, industry and transport, and biomass use for CHP and industrial heat are important for achieving the target at minimal cost, while an abatement of remaining liquid fossil fuel use increases system cost. In this case, a 50% biofuel mandate increases total energy system costs by 123–191 billion €, corresponding to 35%–62% of the liquid fuel cost without a mandate. With a negative -105% emissions target in 2060, fuel abatement options are necessary, and electrofuels or the use of CDR to offset fossil fuel emissions are both more competitive than biofuels. In this case, a 50% biofuel mandate increases total costs by 21–33 billion €, or 11%–15% of the liquid fuel cost without a mandate. Biomass is preferred in CHP and industry heat, combined with carbon capture to serve negative emissions or electrofuel production, thereby utilising biogenic carbon several times. Sensitivity analyses reveal significant uncertainties but consistently support that higher biofuel mandates lead to higher costs.
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| 5. |
- Millinger, Markus, 1984, et al.
(author)
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Electrofuels from excess renewable electricity: costs, emissions, carbon use
- 2022
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In: International Conference on the European Energy Market, EEM. - 2165-4077 .- 2165-4093. ; 2022-September
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Conference paper (peer-reviewed)abstract
- Large shares of variable renewable electricity (VRE) generation are pursued in order to achieve emissions targets in the energy sectors. This results in increased excess renewable electricity (ERE) at times when supply exceeds conventional inflexible electricity demand. ERE can be utilized as a low-emission energy source for sector coupling through e.g. hydrogen production via flexible electrolysis, Which can be used directly or combined With a carbon source to produce electrofuels. Such fuels are crucial for the transport sector, where renewable alternatives are scarce. However, while ERE increases With raising VRE shares, carbon emissions decrease and may become a limited resource with several usage options, including carbon storage (CCS). Here We perform a model based analysis for the German case until 2050, with a general analysis for regions with a high VRE reliance. The capital expenditure of electrolysers was found not to be crucial for the cost, despite low capacity factors due to variable ERE patterns. Carbon will likely become a limiting factor when aiming for stringent climate targets and renewable electricity-based hydrocarbon electrofuels replacing fossil fuels achieve up to 70% more greenhouse gas (GHG) abatement than CCS. Given (1) an unsaturated demand for renewable hydrocarbon fuels, (2) a saturated renewable hydrogen demand and (3) unused ERE capacities which would otherwise be curtailed, we find that carbon used for renewable fuel production abates more GHG than if the carbon would be stored. This effect may increase substantially if shale oil or gas is displaced.
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| 6. |
- Musonda, Frazer, et al.
(author)
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Modelling assessment of resource competition for renewable basic chemicals and the effect of recycling
- 2024
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In: GCB Bioenergy. - 1757-1707 .- 1757-1693. ; 16:4
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Journal article (peer-reviewed)abstract
- This work assesses pathways towards a net-zero greenhouse gas (GHG) emissions chemical industry sector in Germany until 2050, focusing on the ammonia, methanol, ethylene and adipic acid subsectors and the effect of the recycling of C embedded in chemical end products on the GHG abatement cost and primary resource demand. This was done using a bottom-up mathematical optimization model, including the energy sectors and the chemicals sector, with electricity and biobased options considered. Results show that net-zero GHG emissions for the considered chemicals in 2050 are attainable at a marginal cost of 640–900 €/tCO2-eq, even with 26%–36% of demand being satisfied by fossil production routes. This is possible because renewable organic chemicals can act as carbon sinks if, at their end of life, C is permanently stored via landfilling or passed on to the next value chain via recycling. Nonetheless, considering the cost implications, the practical deployment of renewable chemicals is a challenge. The considered renewable chemicals cost 1.3–8 times more than their fossil counterparts, resulting in a marginal CO2 price of 480 €/tCO2-eq when all primary resources (energy crops, forest residues and renewable electricity) are considered, or 810 €/tCO2-eq when the availability of arable land is restricted. In the transition to net-zero emissions for the chemicals under study, a circular economy is important not only for reducing demand for primary resources as is typically the case but also reduces GHG abatement costs by 13%–24% through carbon capture and utilization effects.
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