| 1. |
- Beiron, Johanna, 1992, et al.
(author)
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A multiple system level modeling approach to coupled energy markets: Incentives for combined heat and power generation at the plant, city and regional energy system levels
- 2022
-
In: Energy. - : Elsevier BV. - 0360-5442. ; 254
-
Journal article (peer-reviewed)abstract
- The energy system can be subdivided into interconnected structural levels with differing boundary conditions and objectives. For heat and power generation, these levels may be the: electricity price area (regional); heat price area (city); and production site (power plant). This work presents a multi-system modeling approach for the analysis of investments and operation of combined heat and power (CHP) plants, as optimized on a regional, city, or production site energy system level. The modeling framework, comprising three energy system optimization models at the respective levels, is applied to a case study of Sweden, electricity price area SE3. The modeling levels are optimized separately but linked through electricity and heat prices. The results show that optimized CHP plant investments and operation on the three levels can both align and differ, depending on conditions. With a low biomass price and moderate congestion in transmission capacity into the city, the results from the three levels generally align. Differences arise if the biomass price is increased, which impacts the competitiveness of CHP plants in the region, while city-level CHP investments are mainly determined by the local heat demand and less-sensitive to external changes. The differences indicate a risk for diverging expectations between system levels.
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| 2. |
- Beiron, Johanna, 1992, et al.
(author)
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Flexibility provision by combined heat and power plants – An evaluation of benefits from a plant and system perspective
- 2022
-
In: Energy Conversion and Management: X. - : Elsevier BV. - 2590-1745. ; 16
-
Journal article (peer-reviewed)abstract
- Variable renewable electricity generation is likely to constitute a large share of future electricity systems. In such electricity systems, the cost and resource efficiency can be improved by employing strategies to manage variations. This work investigates combined heat and power (CHP) plant flexibility as a variation management strategy in an energy system context, considering the operation and cost-competitiveness of CHP plants. An energy system optimization model with detailed representation of CHP plant flexibility is applied, covering the electricity and district heating sectors in one Swedish electricity price area. The results show that investments in CHP plants are dimensioned based on the demand for district heating rather than electricity. In the system studied, this implies that CHP plant capacity is small relative to electricity system variations, and variation management using CHP plants has a weak impact on the total system cost of supplying electricity and district heating. However, flexibility measures increase CHP plant competitiveness in scenarios with low system flexibility (assuming low availability of hydropower or no thermal energy storage) although investments in CHP capacity are sensitive to fuel cost. It is found that while district heating is the dominant CHP product (constituting 50%–90% of the annual CHP energy output), the dispatchable electricity supply has a high value and comprises around 60% of the annual CHP plant revenue. In all scenarios, operational flexibility of the boiler is more valuable than a flexible steam cycle power-to-heat ratio.
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| 3. |
- Òsk Gardarsdòttir, Stefanìa, 1987, et al.
(author)
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Improving the flexibility of coal-fired power generators: Impact on the composition of a cost-optimal electricity system
- 2018
-
In: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 209, s. 277-289
-
Journal article (peer-reviewed)abstract
- A transformation of the electricity generation system is required to drastically reduce the associated CO2 emissions. In future systems, variable renewable energy sources (wind and solar) are expected to provide a significant fraction of the electricity supply, increasing the requirement for variation management compared with today´s situation. This paper investigates the impacts of measures designed to increase the competitiveness of coal-fired power plants in future energy systems, which are facing restrictions related to CO2 emissions and variable operation as a consequence of high penetration levels of wind and solar power. We investigate the cost-optimal compositions of three regional electricity generation systems with different conditions for generation using renewables with a linear cost-minimizing investment model. The model is applied in two energy policy scenarios: one with a tight cap on CO2 emissions, and one with a stringent requirement for generation from renewables. In a system with a stringent requirement for electricity generation from renewables but without a CO2 cap, coal-based technologies with improved cycling properties provide variation management, given that the development of measures for ensuring improved flexibility continues and reaches full-scale implementation at moderate cost. The effects of improved cycling properties on the system composition are especially relevant for regions with moderate potential for wind and solar generation, in that they reduce wind curtailment and improve the underlying conditions for investments in solar power. In the system with a tight CO2 cap, only coal-based technologies with Carbon Capture and Storage (CCS) and co-firing of biomass are feasible. Increasing the share of biomass in co-firing technologies to achieve negative CO2 emissions increases the competitiveness of these technologies to a greater extent than if simply the cycling properties are improved. A larger co-firing fraction reduces the total system costs, since it facilitates the provision of low-cost flexibility by Natural Gas Combined Cycle (NGCC) plants, and it is especially important in regions where nuclear power is otherwise cost-competitive, as low-cost flexibility stimulates investments in wind and solar power at the expense of nuclear power.
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| 4. |
- Ahlström, Johan, 1990, et al.
(author)
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The role of biomass gasification in the future flexible power system – BECCS or CCU?
- 2022
-
In: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 190, s. 596-605
-
Journal article (peer-reviewed)abstract
- In this work we study if biomass gasification for production of advanced biofuels can also play a role in managing variability in the electricity system. The idea is a CCU/power-to-gas concept to enhance methane production from biomass gasification. The suggested process is flexible in that CO2 not used for methane production can be stored through a BECCS concept that implies negative GHG emissions. For this purpose, rigorous models of three different gasification process configurations were simplified through surrogate modeling and integrated into a dynamic optimization model of regional electricity systems. The results show the diverse advantages of flexible operation between CCU and BECCS and that it is economically beneficial for the system to invest in gasification at the investigated levels of CO2 charge. The gasification option also provides value for low-priced electricity and thus stimulate increased investments in renewable electricity generation, which indicates the importance of considering geographical diversities in the assessment and highlights the importance of studying this type of concept with a time-resolved model. It is clear that the BECCS option is the most used, however, the limited quantities of CO2 used for the CCU option has a large impact on the investments made in the electricity system.
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| 5. |
- Andersson, Sara-Linnea, et al.
(author)
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Plug-in Hybrid Electric Vehicles as Regulating Power Providers - Case Studies of Sweden and Germany
- 2010
-
In: Energy Policy. - : Elsevier BV. - 0301-4215. ; 38:6, s. 2751-2762
-
Journal article (peer-reviewed)abstract
- This study investigates plug-in hybrid electric vehicles (PHEVs) as providers of regulating power in the form of primary, secondary and tertiary frequency control. Previous studies have shown that PHEVs could generate substantial profits while providing ancillary services. This study investigates under what conditions PHEVs can generate revenues using actual market data, i.e. prices and activations of regulating power, from Sweden and Germany from four months in 2008. PHEV market participation is modelled for individual vehicles in a fleet subject to a simulated movement pattern. Costs for infrastructure and vehicle-to-grid equipment are not included in the analysis. The simulation results indicate that maximum average profits generated on the German markets are in the range 30–80 h per vehicle and month whereas the Swedish regulating power markets give no profit.In addition, an analysis is performed to identify strengths, weaknesses, opportunities, and threats (SWOT) of PHEVs as regulating power providers. Based on the simulation results and the SWOT analysis, characteristics for an ideal regulating power market for PHEVs are presented.
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| 6. |
- Duvignau, Romaric, 1989, et al.
(author)
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Benefits of small-size communities for continuous cost-optimization in peer-to-peer energy sharing
- 2021
-
In: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 301
-
Journal article (peer-reviewed)abstract
- Due to ever lower cost, investments in renewable electricity generation and storage have become more attractive in recent years to electricity consumers at different scales. At the same time, electricity generation and storage have also become something that can be shared or traded locally in energy communities and microgrid systems. In this context, peer-to-peer (P2P) sharing has gained attention, since it offers a way to optimize the cost-benefits from distributed resources, making them financially more attractive. However, cooperation in practical instances still faces unclear requirements about e.g. how much predictive power is required for significant cost-saving; how many peers to contact to form efficient groups; and then, who to team up with for sharing electricity generation and storage. To answer such questions, we introduce a realistic and comprehensive cost-optimization model for P2P energy sharing communities, making continuous decisions while using only limited forecast for the input data. We provide strong evidence, based on the analysis of real household data, that the financial benefit of cooperation does not require long forecast horizons and even P2P energy sharing in small groups (with only 2–5 participants in this study) can reach a high fraction (96% in our results) of the ideal maximum gain, achievable when all input is known ahead of time. Maintaining such small communities results in much lower associated complexity and better privacy, as each participant only needs to share its data with few other peers. Our findings shed new light and motivate requirements for how to organize locally in an efficient manner prosumers and consumers into energy sharing communities in tomorrow’s real implementations.
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| 7. |
- Duvignau, Romaric, 1989, et al.
(author)
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Small-Scale Communities Are Sufficient for Cost- and Data-Efficient Peer-to-Peer Energy Sharing
- 2020
-
In: e-Energy 2020 - Proceedings of the 11th ACM International Conference on Future Energy Systems. - New York, NY, USA : ACM. ; , s. 35-46
-
Conference paper (peer-reviewed)abstract
- Due to ever lower cost, investments in renewable electricity generation and storage have become more attractive to electricity consumers in recent years. At the same time, electricity generation and storage have become something to share or trade locally in energy communities or microgrid systems. In this context, peer-to-peer (P2P) sharing has gained attention, since it offers a way to optimize the cost-benefits from distributed resources, making them financially more attractive. However, it is not yet clear in which situations consumers do have interests to team up and how much cost is saved through cooperation in practical instances. While introducing realistic continuous decisions, through detailed analysis based on large-scale measured household data, we show that the financial benefit of cooperation does not require an accurate forecasting. Furthermore, we provide strong evidence, based on analysis of the same data, that even P2P networks with only 2--5 participants can reach a high fraction (96% in our study) of the potential gain, i.e., of the ideal offline (i.e., non-continuous) achievable gain. Maintaining such small communities results in much lower associated costs and better privacy, as each participant only needs to share its data with 1--4 other peers. These findings shed new light and motivate requirements for distributed, continuous and dynamic P2P matching algorithms for energy trading and sharing.
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| 8. |
- Granfeldt, Caroline, 1991, et al.
(author)
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A Lagrangian relaxation approach to an electricity system investment model with a high temporal resolution
- 2023
-
In: OR Spectrum. - 1436-6304 .- 0171-6468. ; 45:4, s. 1263-1294
-
Journal article (peer-reviewed)abstract
- The global production of electricity contributes significantly to the release of carbon dioxide emissions. Therefore, a transformation of the electricity system is of vital importance in order to restrict global warming. This paper proposes a modelling methodology for electricity systems with a large share of variable renewable electricity generation, such as wind and solar power. The model developed addresses the capacity expansion problem, i.e. identifying optimal long-term investments in the electricity system. Optimal investments are defined by minimum investment and production costs under electricity production constraints—having different spatial resolutions and technical detail—while meeting the electricity demand. Our model is able to capture a range of strategies to manage variations and to facilitate the integration of variable renewable electricity; it is very large due to the high temporal resolution required to capture the variations in wind and solar power production and the chronological time representation needed to model energy storage. Moreover, the model can be further extended—making it even larger—to capture a large geographical scope, accounting for the trade of electricity between regions with different conditions for wind and solar power. Models of this nature thus typically need to be solved using some decomposition method to reduce solution times. In this paper, we develop a decomposition method using so-called variable splitting and Lagrangian relaxation; the dual problem is solved by a deflected subgradient algorithm. Our decomposition regards the temporal resolution by defining 2-week periods throughout the year and relaxing the overlapping constraints. The method is tested and evaluated on some real-world cases containing regions with different energy mixes and conditions for wind power. Numerical results show shorter computation times as compared with the non-decomposed model, and capacity investment options similar to the optimal solution provided by the latter model.
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| 9. |
- Göransson, Lisa, 1982, et al.
(author)
-
A comparison of variation management strategies for wind power integration in different electricity system contexts
- 2018
-
In: Wind Energy. - : Wiley. - 1099-1824 .- 1095-4244. ; 21:10, s. 837-854
-
Journal article (peer-reviewed)abstract
- Variation management strategies improve the capability of the electricity system to meet variations both in the electricity demand and in the generation that relies on variable energy sources. In this work, we introduce a new, functionality-based, categorization of variation management strategies: shifting (eg, batteries), absorbing (eg, power-to-gas), and complementing (dispatchable generation, including reservoir hydropower) strategies. A dispatch model with European coverage (EU-27 plus Norway and Switzerland) is applied to compare the benefits of shifting and absorbing strategies on wind integration in regions with different amounts of complementing strategies in place. The benefits are measured in terms of the wind value factor, wind owner revenue, and average short-term generation cost. The results of the modeling show that the reduction in average short-term generation cost and the increase in revenue earned by the wind owner from shifting strategies, such as the use of batteries, are more substantial at low wind shares than at high wind shares. The opposite situation is found for absorbing strategies, such as power-to-gas, which are found to be more efficient at reducing the average generation cost and increasing profit for the wind owner as the wind share increases. In regions that have access to complementing strategies in the form of reservoir hydropower, variation management has a weak ability to reduce the average short-term generation cost, although it can increase significantly the revenue accrued by the wind power owner.
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| 10. |
- Göransson, Lisa, 1982
(author)
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Balancing Electricity Supply and Demand in a Carbon-Neutral Northern Europe
- 2023
-
In: Energies. - 1996-1073 .- 1996-1073. ; 16:8
-
Journal article (peer-reviewed)abstract
- This work investigates how to balance the electricity supply and demand in a carbon-neutral northern Europe. Applying a cost-minimizing electricity system model including options to invest in eleven different flexibility measures, and cost-efficient combinations of strategies to manage variations were identified. The results of the model were post-processed using a novel method to map the net load before and after flexibility measures were applied to reveal the contribution of each flexibility measure. The net load was mapped in the space spanned by the amplitude, duration and number of occurrences. The mapping shows that, depending on cost structure, flexibility measures contribute to reduce the net load in three different ways; (1) by reducing variations with a long duration but low amplitude, (2) by reducing variations with a high amplitude but short duration and low occurrence or (3) by reducing variations with a high amplitude, short duration and high occurrence. It was found that cost-efficient variation management was achieved by combining wind and solar power and by combining strategies (1–3) to manage the variations. The cost-efficient combination of strategies depends on electricity system context where electricity trade, flexible hydrogen and heat production (1) manage the majority of the variations in regions with good conditions for wind power while stationary batteries (3) were the main contributors in regions with good conditions for solar power.
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| 11. |
- Göransson, Lisa, 1982, et al.
(author)
-
Cost-optimized allocation of wind power investments: a Nordic-German perspective
- 2013
-
In: Wind Energy. - : Wiley. - 1099-1824 .- 1095-4244. ; 16:4, s. 587-604
-
Journal article (peer-reviewed)abstract
- Using a linear cost minimization model with a 1h time resolution, we investigated the influence of geographic allocation of wind power on large-scale wind power investments, taking into account wind conditions, distance to load, and the nature of the power system in place (i.e. power generation and transmission capacities). We employed a hypothetical case in which a 20% wind power share of total electricity demand is applied to the NordicGerman power system. Free, i.e. geographically unrestricted, allocation of new wind power capacity is compared with a case in which national planning frameworks impose national limitations on wind power penetration levels. Given the cost assumptions made in the present work, the prospect of increasing the wind power capacity factor from 20 to 30% could motivate investments in transmission capacity from northern Scandinavia to continental Europe. The results obtained using the model show that the distribution of wind farms between regions with favorable wind conditions is dependent upon two factors: (i) the extent to which existing lines can be used to transmit the electricity that results from the new wind power and (ii) the correlation for wind power generation between the exporting region and the wind power generation already in place. In addition, the results indicate that there is little difference, i.e. just over 1%, in total yearly cost between the free allocation of new wind power and an allocation that complies with national planning frameworks. However, on a national level, there are significant differences with respect to investments in transmission and wind power capacities and the replacement of conventional power generation.
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| 12. |
- Göransson, Lisa, 1982, et al.
(author)
-
Dispatch modeling of a regional power generation system - Integrating wind power
- 2009
-
In: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 34:4, s. 1040-1049
-
Journal article (peer-reviewed)abstract
- A modeling tool has been developed which can be used to analyze interaction between intermittent wind power generation and thermal power plant generation in a regional electricity grid system. The model uses a mixed integer programming (MIP) approach to determine the power plant dispatch strategy which yields the lowest systems costs. In the model, each large thermal plant is described separately, including properties such as start-up time, start-up cost and minimum load level. The model is evaluated using western Denmark as a case study.For western Denmark, it is found that the inclusion of start-up performance (i.e. start-up time and related costs) and minimum load level of the power generating units have a significant impact on the results. It is shown that the inclusion of these aspects influences the analysis of the effect of wind power variations on the production patterns of thermal units in the system. The model demonstrates how the introduction of wind power production and associated variations change the dispatch order of the large thermal power plants in the western Denmark system so that the unit with the lowest running costs no longer has the highest capacity factor. It is shown that this effect only is detected if start-up performance and minimum load level limitations are included in the optimization. it can also be concluded that start-up performance and minimum load level must be taken into account if the total system costs and emissions are not to be underestimated. The simulations show that if these aspects are disregarded, both total costs and total emissions of the power system are underestimated, with 5% in the case of western Denmark. Models such as the one developed in this work can be efficient tools to understand the effects of large-scale wind power integration in a power generation system with base load plants.
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| 13. |
- Göransson, Lisa, 1982, et al.
(author)
-
Elbilar och förnyelsebar elproduktion
- 2014
-
In: Perspektiv på eldrivna fordon 2014. - 9789198097443 ; , s. 20-21
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Book chapter (other academic/artistic)
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| 14. |
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| 15. |
- Göransson, Lisa, 1982, et al.
(author)
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Impact of thermal plant cycling on the cost-optimal composition of a regional electricity generation system
- 2017
-
In: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 197, s. 230-240
-
Journal article (peer-reviewed)abstract
- A regional cost-minimizing investment model that accounts for cycling properties (i.e., start-up time, minimum load level, start-up cost and emissions, and part-load costs and emissions) is developed to investigate the impact of thermal plant cycling on the cost-optimal composition of a regional electricity generation system. The model is applied to an electricity system that is rich in wind resources with and without accounting for cycling in two scenarios: one with favorable conditions for flexible bio-based generation (Bio scenario); and one in which base load is favored (Base load scenario) owing to high prices for biomass. Both scenarios are subject to a tight cap on carbon dioxide emissions, limiting the investment options to technologies that have low or no carbon emissions. We report that in the Bio scenario, the cost-optimal system is dominated by wind power and flexible bio-based generation, whereas base-load generation dominates the Base load scenario, in line with the assumptions made, and the level of wind power is reduced. In the Base load scenario, 19% of the capacity is cycling-dependent, i.e., for this share of installed capacity, the choice of technology is different if cycling properties are included, compared to a case in which they are omitted. In the Bio scenario, in which flexible bio-based generation is less costly, 9% of the capacity is cycling-dependent. We conclude that it is critical to include cycling properties in investment modeling, to assess investments in thermal generation technologies that compete at utilization times in the range of 2000–5000 h.
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| 16. |
- Göransson, Lisa, 1982, et al.
(author)
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Integration of plug-in hybrid electric vehicles in a regional wind-thermal power system
- 2010
-
In: Energy Policy. - : Elsevier BV. - 0301-4215. ; 38:10, s. 5482-5492
-
Journal article (peer-reviewed)abstract
- This study investigates consequences of integrating plug-in hybrid electric vehicles (PHEVs) in a windthermal power system supplied by one quarter of wind power and three quarters of thermal generation. Four different PHEV integration strategies, with different impacts on the total electric load profile, have been investigated. The study shows that PHEVs can reduce the CO2-emissions from the power system if actively integrated, whereas a passive approach to PHEV integration (i.e. letting people charge the car at will) is likely to result in an increase in emissions compared to a power system without PHEV load. The reduction in emissions under active PHEV integration strategies is due to a reduction in emissions related to thermal plant start-ups and part load operation. Emissions of the power sector are reduced with up to 4.7% compared to a system without PHEVs, according to the simulations. Allocating this emission reduction to the PHEV electricity consumption only, and assuming that the vehicles in electric mode is about 3 times as energy efficient as standard gasoline operation, total emissions from PHEVs would be less than half the emissions of a standard car, when running in electric mode.
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| 17. |
- Göransson, Lisa, 1982, et al.
(author)
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Intermittent renewables, thermal power and hydropower - complements or competitors?
- 2014
-
In: Systems Perspectives on Renewable Power 2014. - 9789198097405 ; , s. 119-127
-
Book chapter (other academic/artistic)abstract
- Around 80% of the electricity demand in the world is still supplied by fossil fuelledpower or nuclear, i.e. thermal generation. Wind and solar power is integrated intothe electricity generation systems to decrease the amount of carbon dioxide emissionsassociated with the generation of electricity as well as to enhance security ofsupply. Wind and solar power plants differ from thermal generation in two importantways: they have very low running costs (and high capital costs) and a generationlevel that depends on external elements. Due to the low running costs thereare strong economic incentives for the employment of wind and solar power tosupply the electricity demand once the capacity has been put in place. However,the share of the load that can be supplied by wind and solar power in a certainhour or second varies irregularly since it depends on prevailing wind speeds, solarirradiation and cloudiness.Thermal units are most efficiently run continuously at rated power. However, in amixed renewable-thermal system they may have to compensate for fluctuations in wind and solar generation. Thus, depending on the characteristics of the renewable-thermal system, part of the decrease in fuel costs and emissions realised bywind and solar power may be offset by a reduced efficiency in the operation of thethermal plants. This chapter discusses the interaction between intermittent renewablepower and thermal power, and investigates briefly the impact of including amore controllable renewable source such as hydropower in these mixed systems.
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| 18. |
- Göransson, Lisa, 1982, et al.
(author)
-
Large scale integration of wind power: moderating thermal power plant cycling
- 2011
-
In: Wind Energy. - : Wiley. - 1099-1824 .- 1095-4244. ; 14:1, s. 91-105
-
Journal article (peer-reviewed)abstract
- Power plant cycling in thermal plants typically implies high costs and emissions. It is, therefore, important to find ways to reduce the influence of variations in wind power generation on these plants without forsaking large amounts of wind power. Using a unit commitment model, this work investigates the possibility to reduce variations by means of a moderator, such as a storage unit or import/export capacity. The relation between the reduction in CO2-emissions and the power rating of the moderator is investigated, as well as the benefit of a moderator which handles weekly variations compared with a moderator which has to be balanced on a daily basis. It is found that a daily balanced moderator yields a decrease in emissions of about 2% at 20% wind power grid penetration. The reduction in emissions is mainly due to an avoidance of start-up and part load emissions and a moderator of modest power rating is sufficient to achieve most of this decrease. In the case of a weekly balanced moderator, emissions are reduced as the moderator power rating increases. At 40% wind power grid penetration, a weekly balanced moderator reduces emissions with up to 11%. The major part of this reduction is due to the avoidance of wind power curtailment. The simulated benefit (CO2-emissions and costs) from adding a general moderator is compared with emissions from Life Cycle Assessment (LCA) studies and cost data of five available moderator technologies; transmission capacity, pumped hydro power, compressed air energy storage, flow batteries and sodium sulphur batteries. Copyright (C) 2010 John Wiley & Sons, Ltd.
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| 19. |
- Göransson, Lisa, 1982, et al.
(author)
-
Linkages between demand-side management and congestion in the European electricity transmission system
- 2014
-
In: Energy. - : Elsevier BV. - 0360-5442. ; 69, s. 860-872
-
Journal article (peer-reviewed)abstract
- We evaluate the possibility to reduce congestion in the transmission grid through large-scale implementation of demand-side management (DSM) in the form of load shifting for the EU-27 countries, Norway, and Switzerland for Year 2020. A linear, cost-minimising, dispatch model that includes a DC load-flow description of the transmission system and a general representation of load shifting is used. It is assumed that the EU Member States fulfil the targets for Year 2020 in their national renewable energy action plans. In the model calculations, a reference case without load shifting is compared with cases in which the load shifting is 5%, 10%, 15% or 20% of the load. The possibility to shift load in time is added exogenously and economic incentives for DSM are not evaluated. Three types of congestion are identified: peak-load-hour congestion, low-load-hour congestion and all-hour congestion. Peak-load-hour congestion is reduced as the DSM share of the load increases, whereas low-load-hour congestion, which is typically associated with a high level of wind generation, persists at all the DSM penetration levels investigated. We show that all-hour congestion occurs between systems that have large differences in supply structure, and that the impact of DSM on all-hour congestion is low. (C) 2014 Elsevier Ltd. All rights reserved.
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| 20. |
- Göransson, Lisa, 1982, et al.
(author)
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Management of Wind Power Variations in Electricity System Investment Models. A Parallel Computing Strategy
- 2021
-
In: Operations Research Forum. - : Springer Science and Business Media LLC. - 2662-2556. ; 2
-
Journal article (peer-reviewed)abstract
- Accounting for variability in generation and load and strategies to tackle variability cost-efficiently are key components of investment models for modern electricity systems. This work presents and evaluates the Hours-to-Decades (H2D) model, which builds upon a novel approach to account for strategies to manage variations in the electricity system covering several days, the variation management which is of particular relevance to wind power integration. The model discretizes the time dimension of the capacity expansion problem into 2-week segments, thereby exploiting the parallel processing capabilities of modern computers. Information between these segments is then exchanged in a consensus loop. The method is evaluated with regard to its ability to account for the impacts of strategies to manage variations in generation and load, regional resources and trade, and inter-annual linkages. Compared to a method with fully connected time, the proposed method provides solutions with an increase in total system cost of no more than 1.12%, while reducing memory requirements to 1/26’th of those of the original problem. For capacity expansion problems concerning two regions or more, it is found that the H2D model requires 1–2% of the calculation time relative to a model with fully connected time when solved on a computer with parallel processing capability.
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| 21. |
- Göransson, Lisa, 1982, et al.
(author)
-
Plug-in hybrid electric vehicles as a mean to reduce CO2 emissions from electricity production
- 2009
-
In: 24th International Battery, Hybrid and Fuel Cell Electric Vehicle Symposium and Exhibition 2009, EVS 24; Stavanger; Norway; 13 May 2009 through 16 May 2009. - 9781615674558 ; 4, s. 2614-2624
-
Conference paper (other academic/artistic)abstract
- In this study we have investigated the consequences of integrating plug-in hybrid electric vehicles (PHEV:s) in a wind-thermal power system supplied by one quarter of wind power and three quarters of thermal generation. A fleet of PHEV:s with an electricity consumption corresponding to 3%, 12% and 20%of the total electricity consumption has been integrated to the system (i.e. the total electricity consumption remains unaffected while the non-PHEV consumption is 97%, 88% and 80% in the three cases). Four PHEV integration strategies, with different impacts on the total electric load profile, have been investigated by means of a mixed integer model which can model the effects of the new load profiles on the dispatch of the units in the system and, thus, on the CO2-emissions from the system. The study shows that PHEV:s canreduce the CO2-emissions from the power system if actively integrated, whereas a passive approach to PHEV integration (i.e. letting people charge the car at will) is likely to result in an increase in emissions compared to a power system without PHEV load.The model simulations give that CO2 emissions of the power sector are reduced with up to 4.7% compared to a system without PHEV:s. If the reduction in emissions is allocated to the electricity consumed by the PHEV:s, the emissions from generation of this electricity are reduced from 588 kg CO2/MWh (windthermal system without PHEV:s) down to 367 kg CO2/MWh (PHEV:s actively integrated). Under the assumption that electric mode is about 3 times as efficient as standard gasoline operation, emissions from PHEV:s would then be less than half the emissions of a standard car, when running in electric mode.
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| 22. |
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| 23. |
- Göransson, Lisa, 1982, et al.
(author)
-
The benefit of collaboration in the North European electricity system transition - System and sector perspectives
- 2019
-
In: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 12:24
-
Journal article (peer-reviewed)abstract
- This work investigates the connection between electrification of the industry, transport, and heat sector and the integration of wind and solar power in the electricity system. The impact of combining electrification of the steel industry, passenger vehicles, and residential heat supply with flexibility provision is evaluated from a systems and sector perspective. Deploying a parallel computing approach to the capacity expansion problem, the impact of flexibility provision throughout the north European electricity system transition is investigated. It is found that a strategic collaboration between the electricity system, an electrified steel industry, an electrified transport sector in the form of passenger electric vehicles (EVs) and residential heat supply can reduce total system cost by 8% in the north European electricity system compared to if no collaboration is achieved. The flexibility provision by new electricity consumers enables a faster transition from fossil fuels in the European electricity system and reduces thermal generation. From a sector perspective, strategic consumption of electricity for hydrogen production and EV charging and discharging to the grid reduces the number of hours with very high electricity prices resulting in a reduction in annual electricity prices by up to 20%.
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| 24. |
- Göransson, Lisa, 1982
(author)
-
The impact of wind power variability on the least-cost dispatch of units in the electricity generation system
- 2014
-
Doctoral thesis (other academic/artistic)abstract
- This thesis investigates the dynamics of electricity generation systems that involve high levels of wind power. Methods to account for wind power variability in electricity-dispatch models are explored, and the impact of wind power variability on the optimal output of the generation units, so as to meet the system load with the lowest possible cost (economic dispatch), is analyzed for several systems, for both regional and European cases. Systems that lack active variation management, as well as systems with variation management through storage, charging of plug-in hybrid electric vehicles, and trade with the hydropower-rich Nordic countries, are investigated. The work considers systems in which wind power supplies between 20 % and 40 % of the electricity demand on an annual basis. From the work of this thesis, it is concluded that the inclusion of cycling costs can have significant impacts on the capacity factor of individual generation units obtained from modeling the regional dispatch of systems with 20 % wind power penetration (i.e., annual wind power generation relative to annual demand for electricity). Whether cycling costs need to be included in the systems analysis depends on the wind penetration level and the research question being posed, as well as the relationship between the cycling costs and running costs of the thermal units in the system. Furthermore, it is shown that in a wind-thermal system, in which wind power generation corresponds to about 20% of the demand for electricity, the variations in net load (here defined as the demand for electricity reduced by wind power generation each hour) follow a diurnal pattern, and load shifting from day to night reduces the competition between wind power and thermal generation with poor cycling properties. However, in systems with about 40% wind power, the ability to store electricity or to shift the load over longer time periods (i.e., several days) confers significant advantages compared to load shifting from day to night, owing to the altered pattern of the variations in net load. Finally, this thesis shows that the role of the Nordic electricity-generation system in the European context relies heavily on the balance between investments in interconnector capacity and investments in Nordic generation capacity. If planned interconnections between Norway and the rest of Europe are established, net export of electricity is likely from the Nordic countries to Germany and the UK, whereby hydropower-rich Norway would play a central role in redistributing electricity from high-wind events to peak-load events.
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| 25. |
- Göransson, Lisa, 1982
(author)
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Wind power in thermal power systems
- 2008
-
Licentiate thesis (other academic/artistic)abstract
- AbstractWind power is a key technology in the effort to transform the power system in order to reduce its climate impact. However, the ability of wind power to reduce CO2-emissions depends on the properties of the power system. As large-scale wind power is integrated in a power system (typically 20% wind power grid penetration and beyond), the intermittent nature of wind power will result in an increase in variations in load on the other units in the system (e.g. thermal power plants). There are three main alternatives for the power system to respond to this increase in variations; by an increase in power plant cycling (i.e. starting/stopping), by an increase in part load operation hours or by wind power curtailment. In a system dominated by thermal base load units, the integration of large-scale wind power might thus result in an increase in costs and emissions related to thermal operation and/or an increase in wind power curtailment.This work investigates consequences of large-scale wind power integration in a thermal power system. Operation of units in a regional thermal power system have been investigated and quantified by means of modelling. Furthermore, the possibility to reduce the influence from wind power variations by means of introducing a variation moderator or demand side management has been evaluated. A variation moderator is a unit with the ability to reallocate power in time. Pumped hydro power stations, compressed air energy storages, batteries and transmission lines providing power exchange are examples of variation moderators which are all investigated in this work. Demand side management will allow for some flexibility in the allocation of parts of the load and in this work evaluates the ability of plug-in hybrid electric vehicles (PHEV:s) to provide such flexibility. The simulations are carried out with a simplified version of the western Denmark power system as a starting point. This, since this system already has a high share of wind power and wind power data is available.For the system studied, simulations show that for 24% wind power grid penetration, variations in wind power generation results in start-up emissions corresponding to 5% of the total CO2-emissions of the power generation system. It is also shown that the inclusion of start-up and minimum load level aspects has an impact on the dispatch of units in the system. By integration of a moderator in the wind-thermal system, emissions are reduced with 7.2% mainly due to a decrease in power plant cycling. At wind power grid penetration levels of around 20%, a daily balanced moderator is sufficient, whereas more extensive storage capacity is required at higher wind power penetration levels such as for the 40% penetration level investigated in this work.The ability of PHEV:s to manage wind power variations depends strongly on the choice of PHEV integration strategy. With a strategy where the power system is free to allocate the load in time, emissions from the power system (excluding vehicles) are up to 6% lower than a corresponding system without PHEV:s. A passive approach to PHEV integration results in increased emissions from the system. For the system studied, the PHEV share of the electricity consumption should be around 12% to obtain maximum reduction in emission. This, since this share of PHEV capacity approximately corresponds to the difference in average load between night and day (evens out variations in load profile).
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| 26. |
- Heinisch, Verena, 1991, et al.
(author)
-
Interconnection of the electricity and heating sectors to support the energy transition in cities
- 2019
-
In: International Journal of Sustainable Energy Planning and Management. - 2246-2929. ; 24, s. 57-66
-
Journal article (peer-reviewed)abstract
- The electricity, heating, and transport sectors in urban areas all have to contribute to meeting stringent climate targets. Cities will face a transition from fossil fuels to renewable sources, with electricity acting as a cross-sectorial energy carrier. Consequently, the electricity demand of cities is expected to rise, in a situation that will be exacerbated by ongoing urbanisation and city growth. As alternative to an expansion of the connection capacity to the national grid, local measures can be considered within city planning in order to utilize decentralised electricity generation, synergies between the heating and electricity sectors, and flexibility through energy storage technologies. This work proposes an optimisation model that interconnects the electricity, heat, and transport sectors in cities. We analyse the investments in and operation of an urban energy system, using the City of Gothenburg as an example. We find that the availability of electricity from local solar PV together with thermal storage technologies increase the value of using power-to-heat technologies, such as heat pumps. High biomass prices together with strict climate targets enhance the importance of electricity in the district heating sector. A detailed understanding of the integration of local low-carbon energy technologies can give urban planners and other city stakeholders the opportunity to take an active role in the city’s energy transition.
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| 27. |
- Heinisch, Verena, 1991, et al.
(author)
-
Organizing prosumers into electricity trading communities: Costs to attain electricity transfer limitations and self‐sufficiency goals
- 2019
-
In: International Journal of Energy Research. - : Hindawi Limited. - 1099-114X .- 0363-907X. ; 43:13, s. 7021-7039
-
Journal article (peer-reviewed)abstract
- Among household electricity end users, there is growing interest in local renewable electricity generation and energy independence. Community‐based and neighborhood energy projects, where consumers and prosumers of electricity trade their energy locally in a peer‐to‐peer system, have started to emerge in different parts of the world. This study investigates and compares the costs incurred by individual households and households organized in electricity trading communities in seeking to attain greater independence from the centralized electricity system. This independence is investigated with respect to: (i) the potential to reduce the electricity transfer capacity to and from the centralized system and (ii) the potential to increase self‐sufficiency. An optimization model is designed to analyze the investment and operation of residential photovoltaic battery systems. The model is then applied to different cases in a region of southern Sweden for year 2030. Utilizing measured electricity demand data for Swedish households, we show that with a reduced electricity transfer capacity to the centralized system, already a community of five residential prosumers can supply the household demand at lower cost than can prosumers acting individually. Grouping of residential prosumers in an electricity trading community confers greater benefits under conditions with a reduced electricity transfer capacity than when the goal is to become electricity self‐sufficient. It is important to consider the local utilization of photovoltaic‐generated electricity and its effect on the net trading pattern (to and from the centralized system) when discussing the impact on the electricity system of a high percentage of prosumers.
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| 28. |
- Heinisch, Verena, 1991, et al.
(author)
-
Prosumers in the Electricity System—Household vs. System Optimization of the Operation of Residential Photovoltaic Battery Systems
- 2019
-
In: Frontiers in Energy Research. - : Frontiers Media SA. - 2296-598X. ; 6
-
Journal article (peer-reviewed)abstract
- An increase in distributed small-scale generation and storage in residential prosumer households requires an understanding of how the household-controlled operation of these distributed technologies differ from a system-optimal utilization. This paper aims at investigating how residential photovoltaic (PV)-battery systems are operated, given different assumed incentives, and whether or not a prosumer induced operational pattern differs from what is desirable from a total electricity system point of view. The work combines a household optimization model that minimizes the annual household electricity bill for two price zones in southern Sweden with a dispatch model for the northern European electricity supply system. The results show significant differences in the charging and discharging patterns of residential batteries. A household annual electricity cost minimization gives many hours in which only a fraction of the battery capacity is used for charging and discharging, mainly driven by incentives to maximize self-consumption of PV-generated electricity. In contrast, in a total electricity system operational cost minimization larger fractions of the available battery capacity are utilized within single hours. In the total system optimization case, the batteries are charged and discharged less frequently and the energy turnover in the batteries is only half that of the household optimization case. For all the cases studied, the hourly electricity price provides only a limited incentive for households to operate their batteries in a system-optimal manner.
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| 29. |
- Heinisch, Verena, 1991, et al.
(author)
-
Smart electric vehicle charging strategies for sectoral coupling in a city energy system
- 2021
-
In: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 288
-
Journal article (peer-reviewed)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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| 30. |
- Heinisch, Verena, 1991, et al.
(author)
-
The impact of limited electricity connection capacity on energy transitions in cities
- 2021
-
In: Smart Energy. - : Elsevier BV. - 2666-9552. ; 3
-
Journal article (peer-reviewed)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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| 31. |
- Hodel, Henrik, 1995, et al.
(author)
-
Which wind turbine types are needed in a cost-optimal renewable energy system?
- 2024
-
In: Wind Energy. - 1099-1824 .- 1095-4244. ; 27:6, s. 549-568
-
Journal article (peer-reviewed)abstract
- Previous research has indicated that wind power plants can be designed to have less-variable power generation, thereby mitigating the drop in economic value that typically occurs at high wind power penetration rates. This study investigates the competitiveness of adapted turbine design and the interplay with other flexibility measures, such as batteries and hydrogen storage, for managing variations. The analysis covers seven turbine designs for onshore and offshore wind generation, with different specific power ratings and hub heights. Various flexibility measures (batteries, hydrogen storage and transmission expansion) are included in the optimization of investment and dispatch of the electricity system of northern Europe. Three driving forces for turbine design selection are identified: (1) lowest cost of electricity generation; (2) annual wind production per land area and (3) improved generation profile of wind power. The results show that in regions with good wind resources and limited availability of variation management, it is cost-efficient to reduce the variability of wind power production by adapting the turbine design. This remains the case when variation management is available in the form of batteries, hydrogen storage and transmission system expansion. Moreover, it is more cost-effective to improve variability by changing the specific power rating rather than the turbine hub height.
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| 32. |
- Holmér, Petra, 1992, et al.
(author)
-
Impacts of thermal energy storage on the management of variable demand and production in electricity and district heating systems: a Swedish case study
- 2020
-
In: International Journal of Sustainable Energy. - : Informa UK Limited. - 1478-646X .- 1478-6451. ; 39:5, s. 446-464
-
Journal article (peer-reviewed)abstract
- This study investigates how thermal energy storage (TES) influences the cost-optimal investment and operation of electricity and district heating (DH) systems in different scenarios. Greenfield energy system modelling for Year 2050 with a high time resolution shows that sensible TES strategies have a strong impact on the composition and operation of the DH system in all investigated scenarios. The introduction of TES displaces to a significant extent the heat-only boilers in all scenarios and can promote solar heating in small DH networks. The modelling shows that TES also promotes the use of power-to-heat processes and enables combined heat and power plants to increase full-load hours, with simultaneous adaptation to the variable production in the electricity system. A major benefit derived from TES is the ability to respond to rapid variations in the electricity system. Thus, the pit and tank storage systems with higher (dis)charging capacities are preferred over borehole storage.
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| 33. |
- Johansson, Viktor, 1991, et al.
(author)
-
A quantitative method for evaluation of variation management strategies for integration of variable renewable electricity
- 2017
-
In: The 16th international wind integration workshop.
-
Conference paper (other academic/artistic)abstract
- The ability of variation management strategies to increase the value of wind and solar power is evaluated by use of a regional electricity system investment model designed to account for variability. The marginal system value is applied as a quantitative measure for this evaluation. The study is carried out for two regions, one with good conditions for wind power (SE) and one with good conditions for solar power (ES). Batteries at various costs, demand-side management and hydropower (only in SE) are the variation management strategies assessed. It is found that hydropower has the largest impact on increasing the value of wind turbines at low to medium wind penetration levels. The effect of demand-side management on wind turbines in SE is smaller but even across all penetration levels. In the ES region, demand-side management does not increase the value of wind power but increase the value of solar PV for all solar penetration levels. An optimistic cost development for both batteries and solar PV is required for batteries to substantially increase the marginal system value and cost-effective penetration level of solar PV.
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| 34. |
- Johansson, Viktor, 1991, et al.
(author)
-
Biomass in the electricity system: A complement to variable renewables or a source of negative emissions?
- 2019
-
In: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 168, s. 532-541
-
Journal article (peer-reviewed)abstract
- Biomass is often assigned a central role in future energy system scenarios as a carbon sink, making negative greenhouse gas emissions possible through carbon capture and storage of biogenic carbon dioxide from biomass-fuelled power plants. However, biomass could also serve as a strategic complement to variable renewables by supplying electricity during hours of high residual load. In this work, we investigate the role of biomass in electricity systems with net zero or negative emissions of carbon dioxide and with different levels of biomass availability. We show that access to biomass corresponding to ca. 20% of the electricity demand in primary energy terms, is of high value to the electricity system. Biomass for flexibility purposes can be a cost-efficient support to reach a carbon neutral electricity system with the main share of electricity from wind and solar power. Biomass-fired power plants equipped with carbon capture and storage in combination with natural gas combined cycle turbines are identified as being the cost-effective choice to supply the electricity system with flexibility if the availability of biomass within the electricity system is low. In contrast, in the case of excess biomass, flexibility is supplied by biomethane-fired combined cycle turbines or by biomass-fired power plants.
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| 35. |
- Johansson, Viktor, 1991, et al.
(author)
-
Value of wind power – Implications from specific power
- 2017
-
In: Energy. - : Elsevier BV. - 0360-5442. ; 126, s. 352-360
-
Journal article (peer-reviewed)abstract
- This paper investigates the marginal system value of increasing the penetration level of wind power, and how this value is dependent upon the specific power (the ratio of the rated power to the swept area). The marginal system value measures the economic value of increasing the wind power capacity. Green-field power system scenarios, with minimised dispatch and investment costs, are modelled for Year 2050 for four regions in Europe that have different conditions for renewable electricity generation. The results show a high marginal system value of wind turbines at low penetration levels in all four regions and for the three specific powers investigated. The cost-optimal wind power penetration levels are up to 40% in low-wind-speed regions, and up to 80% in high-wind–speed regions. The results also show that both favourable solar conditions and access to hydropower benefit the marginal system value of wind turbines. Furthermore, the profile value, which measures how valuable a wind turbine generation profile is to the electricity system, increases in line with a reduction in the specific power for wind power penetration levels of >10%. The profile value shows that the specific power becomes more important as the wind power penetration level increases. © 2017 Elsevier Ltd
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| 36. |
- Johnsson, Filip, 1960, et al.
(author)
-
Challenges to integrate CCS into low carbon electricity markets
- 2014
-
In: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 63, s. 7485-7493
-
Conference paper (peer-reviewed)abstract
- Published by Elsevier Ltd. This paper discusses challenges for integration of CCS into competitive electricity markets by using the European electricity supply system as an example. The work is based on techno-economic modelling of the European electricity generation sector up to Year 2050, assuming a tightening cap on CO2 emissions down to almost no emissions by 2050. It is concluded that natural gas fired conventional power plants is likely to be a serious competitor to coal CCS in the short to medium term providing large emission reduction by fuel shifting from existing coal power plants to new high efficiency gas fired plants. This can be a barrier for early deployment of CCS without additional support. It is also concluded that for regions with large amount of intermittent electricity generation, short term balance in generation will impose challenges to handle CCS plants in relation to load following requirements. Yet, there are regions with good availability of coal combined with unfavorable conditions for wind power, for which CCS can operate in typical base load.
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| 37. |
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| 38. |
- Karlsson, Ida, 1980, et al.
(author)
-
Roadmap for Decarbonization of the Building and Construction Industry - A Supply Chain Analysis Including Primary Production of Steel and Cement
- 2020
-
In: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 13:16
-
Journal article (peer-reviewed)abstract
- Sweden has committed to reducing greenhouse gas (GHG) emissions to net-zero by 2045. Around 20% of Sweden's annual CO(2)emissions arise from manufacturing, transporting, and processing of construction materials for construction and refurbishment of buildings and infrastructure. In this study, material and energy flows for building and transport infrastructure construction is outlined, together with a roadmap detailing how the flows change depending on different technical and strategical choices. By matching short-term and long-term goals with specific technology solutions, these pathways make it possible to identify key decision points and potential synergies, competing goals, and lock-in effects. The results show that it is possible to reduce CO(2)emissions associated with construction of buildings and transport infrastructure by 50% to 2030 applying already available measures, and reach close to zero emissions by 2045, while indicating that strategic choices with respect to process technologies and energy carriers may have different implications on energy use and CO(2)emissions over time. The results also illustrate the importance of intensifying efforts to identify and manage both soft and hard barriers and the importance of simultaneously acting now by implementing available measures (e.g., material efficiency and material/fuel substitution measures), while actively planning for long-term measures (low-CO(2)steel or cement).
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| 39. |
- Kermani, Mostafa, 1986, et al.
(author)
-
A comprehensive optimal energy control in interconnected microgrids through multiport converter under N−1 criterion and demand response program
- 2022
-
In: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 199, s. 957-976
-
Journal article (peer-reviewed)abstract
- Nowadays, the local distribution grids have been facing technical, economic, and regulatory challenges, because of the increased integration of renewable energy sources (RESs) and electrification of vehicles. The traditional solutions to the grid expansion, e.g., to build an additional power line, are utility-centered solutions, i.e., the distribution grid operators (DSOs) are the only party involved to tackle grid issues. The DSOs have to engage grid users with technology providers to develop innovative solutions that tackle one problem and overcome several cost-effectively. This paper presents a holistic solution to optimally control cross-sectoral energy flow between interconnected microgrids (MGs) consisting of different RESs, hydroelectric power plant (HPP) and wind turbines (WTs) to meet electric vehicles (EVs), residential, commercial and industrial demands with the main grid contribution. This issue will provide the advantages of community-based MGs for local energy trading which causes for an active and engaged system, however, an adequate control strategy for proper operation is required. The proposed solution is based on a new interconnection line between two MGs through a multiport converter (MPC) with the techno-economic consideration of newly installed components such as MPC, cables and the required battery energy storage system (BESS). The proposed case study is evaluated under three different conditions e.g., load increment, demand response (DR) and N-1 criterion in separate, interconnect and island modes. The CPLEX solver of GAMS software is employed to solve the mixed-integer linear programming model. The results show that the applied interconnection line for MGs compared to the separated operation mode can decrease the system's total costs, reduce the applied peak to the upstream grid, and enhance the system's reliability under different conditions. Furthermore, the applied solution provides the ability for MGs operation even in island mode under different conditions for a full day (24 h).
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| 40. |
- Kermani, Mostafa, 1986, et al.
(author)
-
Optimal Energy Control, Hosting BESS and EVs through Multiport Converter in Interconnected MGs
- 2022
-
In: 2022 IEEE International Conference on Environment and Electrical Engineering and 2022 IEEE Industrial and Commercial Power Systems Europe, EEEIC / I and CPS Europe 2022.
-
Conference paper (peer-reviewed)abstract
- This paper presents an optimal solution for energy control in interconnected microgrids (MGs) consisting of hydroelectric power plant (HPP) and wind turbines (WTs). The goal is to meet electric vehicles (EVs), residential, commercial, industrial and electric boiler demands with main grid contribution. The proposed solution is a new interconnection between MGs through a multiport converter (MPC) with the techno-economic evaluation for new components, e.g., MPC, cables and battery energy storage system (BESS). The system is investigated under different conditions e.g., load increment, demand response (DR) and N-1 criterion in separate, interconnect and island conditions. The results show that the proposed solution can decrease the total costs as well as peak demand and enhance reliability under different conditions.
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| 41. |
- Lehtveer, Mariliis, 1983, et al.
(author)
-
Actuating the European Energy System Transition: Indicators for Translating Energy Systems Modelling Results into Policy-Making
- 2021
-
In: Frontiers in Energy Research. - : Frontiers Media SA. - 2296-598X. ; 9
-
Journal article (peer-reviewed)abstract
- In this paper, we define indicators, with a focus on the electricity sector, that translate the results of energy systems modelling to quantitative entities that can facilitate assessments of the transitions required to meet stringent climate targets. Such indicators, which are often overlooked in model scenario presentations, can be applied to make the modelling results more accessible and are useful for managing the transition on the policy level, as well as for internal evaluations of modelling results. We propose a set of 13 indicators related to: 1) the resource and material usages in modelled energy system designs; 2) the rates of transition from current to future energy systems; and 3) the energy security in energy system modelling results. To illustrate its value, the proposed set of indicators is applied to energy system scenarios derived from an electricity system investment model for Northern Europe. We show that the proposed indicators are useful for facilitating discussions, raising new questions, and relating the modelling results to Sustainable Development Goals and thus facilitate better policy processes. The indicators presented here should not be seen as a complete set, but rather as examples. Therefore, this paper represents a starting point and a call to other modellers to expand and refine the list of indicators.
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| 42. |
- Malz, Elena, 1990, et al.
(author)
-
Drag-mode airborne wind energy vs. wind turbines: An analysis of power production, variability and geography
- 2020
-
In: Energy. - : Elsevier BV. - 0360-5442. ; 193
-
Journal article (peer-reviewed)abstract
- Airborne wind energy (AWE) is a wind power technology that harvests energy at high altitudes. The performance of AWE systems relative to traditional wind power turbines (WT) is of key relevance to any future commercialization. In particular, the power generation as well as its consistency over time will be key performance indicators. This study aims at identifying crucial factors that will influence the competitiveness of drag-mode AWE systems against WTs. To that end, the hourly power production of several drag-mode AWE designs is investigated using realistic wind data, and compared to the hourly power production of classical WTs. These results are then analyzed through three performance indicators: total annual power production, Gini coefficient, and correlation coefficient. The results show that AWE systems with multiple smaller wings have the highest annual production. The AWE power production of all AWE systems correlates in time at all sites with the production of WTs, and the Gini coefficients are similar. This observation challenges the belief that AWE systems will outcompete WTs thanks to a more consistent power output than WTs. However, the wing design as well as the local wind shear have a significant impact on the AWE performance.
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| 43. |
- Malz, Elena, 1990, et al.
(author)
-
The value of airborne wind energy to the electricity system
- 2022
-
In: Wind Energy. - : Wiley. - 1099-1824 .- 1095-4244. ; 25:2, s. 281-299
-
Journal article (peer-reviewed)abstract
- Airborne wind energy (AWE) is a new power generation technology that harvests wind energy at high altitudes using tethered wings. The potentially higher energy yield, combined with expected lower costs compared to traditional wind turbines (WTs), motivates interest in further developing this technology. However, commercial systems are currently unavailable to provide more detailed information on costs and power generation. This study estimates the economic value of AWE in the future electricity system, and by that indicates which cost levels are required for AWE to be competitive. A specific focus is put on the relation between AWE systems (AWESs) and WTs. For this work, ERA-5 wind data are used to compute the power generation of the wind power technologies, which is implemented in a cost-minimizing electricity system model. By forcing a certain share of the annual electricity demand to be supplied by AWESs, the marginal system value (MSV) of AWE is investigated. The MSV is found to be affected by the AWE share, the wind resource, and the temporal distribution of the AWES's electricity generation. The MSV of AWE is location- and system-dependent and ranges between 1.4 and 2.2 (Formula presented.) at a low share of AWE supply (0%–30%). At higher shares, the MSV drops. The power generation of WTs and AWESs are related, implying that the wind technologies present a similar power source and can be used interchangeably. Thus, the introduction of AWESs will have a low impact on the cost-optimal wind power share in the electricity system, unless an AWES cost far below the system-specific MSV is attained.
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| 44. |
- Reichenberg, Lina, 1976, et al.
(author)
-
Large scale integration of wind power – influence of geographical allocation
- 2011
-
In: Renewable Energy and Power Quality Journal. - : AEDERMACP (European Association for the Development of Renewable Energies and Power Quality). - 2172-038X. ; 1:9, s. 1344-1349
-
Journal article (peer-reviewed)abstract
- This paper investigates the influence of geographical allocation of wind power generation in Northern Europe, assuming large scale integration of wind power. The work applies a linear cost optimization model of the heat and power sector with a 1-hour time resolution. The model minimizes the sum of running costs to meet the heat and power demand and the wind power and transmission investment costs. Wind data are taken from modelled wind speed data from the Swedish Meteorological and Hydrological Institute. The Nordic countries and Germany were divided into regions and the 200 sites with the highest yearly output were chosen to represent the region. The model gives the most favourable distribution of wind power between the regions. In addition, the paper provides an assessment of the effect of geographical distribution of wind power with respect to influence on the aggregated wind power production (only considering the wind power generation itself). The modelling results show that the largest investments in wind power are made in the windy region of Southern Norway. However, depending on the cost of transmission allocating wind power near large load centers in Germany may also be favourable. As for the assessment of distribution of wind power, the wind data gives that if the 400 best sites in Europe were used, this would result in a capacity factor of 38.5% and a lowest output of 2.5 % of rated power (applying 2009 wind data).
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| 45. |
- Romanchenko, Dmytro, 1988, et al.
(author)
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Impact of electricity price fluctuations on the operation of district heating systems: A case study of district heating in Göteborg, Sweden
- 2017
-
In: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 204, s. 16-30
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Journal article (peer-reviewed)abstract
- This paper investigates the characteristics of interaction between district heating (DH) systems and the electricity system, induced by present and future price curves of the electricity system. A mixed integer linear programming unit commitment model has been developed with the objective of studying optimal operating strategies for DH systems. The model minimises the total operating cost of heat generation for a given DH system, which in this work is exemplified by the DH system of Göteborg, Sweden. The results should have important implications for operating strategies for DH systems as a response to future electricity price development. The results indicate significant changes in the operation of heat generation units in DH systems as a response to future electricity price profile with a, relative to today, high yearly average electricity price and more frequent high-electricity-price periods. The observed changes include a 20% decrease in heat generation from heat pumps (HP) and an increase of up to 25% in heat generation from combined heat and power (CHP) plants, owing to a switch in the merit order of these two technologies. We show that large fluctuations in the electricity price lead to an increased value being placed on CHP plants with variable power-to-heat ratio. The results indicate that with reoccurring high-electricity-price periods the value of sold electricity alone can become high enough to motivate investment in CHP plants, i.e. indicating that the generation and selling of heat from CHP plants may not be the core business in the future. Furthermore, there are additional opportunities for increased value of both CHP plants and HPs for time periods of less than 48 h, given that such short duration periods can be identified in a reasonable time in advance, i.e. dependent on, for instance, wind power forecasts.
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- Söder, Lennart, 1956-, et al.
(author)
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Är kärnkraften nödvändig för en fossilfri, svensk, elproduktion?
- 2020
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Reports (pop. science, debate, etc.)abstract
- Efter flera år av stöd har sol- och vind-el blivit ekonomiskt konkurrenskraftiga och börjat konkurrera ut stora termiska anläggningar för elproduktion. Det stängs nu kol- och kärnkraftverk i flera länder i världen och förespråkare för dessa teknologier hävdar, på olika sätt, att marknaden styr fel och att dessa kraftverk ”behövs” av olika skäl.I denna rapport har vi undersökt om det finns någon grund för ett sådant ”behov” av kärnkraftverk i Sverige som motiverar att det sker nyinvesteringar trots att konkurrensen på marknaden håller på att slå ut dem.Syftet med denna rapport är inte att fastslå om man bör ha ett framtida elsystem med eller utan kärnkraft, utan att analysera grunderna, dvs kunskapsläget, för påståendet att det är nödvändigt att ha kärnkraft. Alla diskussioner om framtiden är osäkra, så vi gör heller inte anspråk på att förutse hur framtiden kommer se ut. Upplägget är att gå igenom olika frågeställningar, och koppla dessa till frågan om huruvida kärnkraften är nödvändig för framtiden, så som framförts med exempelvis följande argument:a) Kärnkraft behövs av ekonomiska skälb) Kärnkraft behövs för att vi inte ska vara importberoendec) Kärnkraft behövs eftersom det finns kapacitetsbrist i t ex Malmö och Stockholmd) Kärnkraft behövs för att klara elektrifieringen av transporterna och industrine) Kärnkraft behövs för att klara klimatmåletf) Kärnkraft behövs för att vi ska få el alla timmar, dvs klara leveranssäkerheteng) Kärnkraften behövs för att klara frekvensstabilitetenh) Kärnkraft behövs för stödtjänster till elsystemetI avsnitt 2-7 finns en genomgång av dagsläget. I avsnitt 8 finns en mer detaljerad genomgång av listan a)-h) ovan. Mer tekniska detaljer om systembalansering och effektbalansberäkningar finns i Bilaga A-C.Den slutsats vi drar är att kärnkraften inte är nödvändig för att vi ska kunna få ett stabilt, säkert och fossilfritt elsystem i Sverige i framtiden. Ett elsystem med stor mängd sol- och vindkraft ser dock annorlunda ut än ett med stor mängd kärnkraft. Frågan är då om detta system blir dyrare. Ingen vet vad olika kraftslag kommer att kosta år 2045, men under senare år har det skett en kraftig minskning av kostnaderna för sol- och vindkraft. Samtidigt har kärnkraftens kostnader istället ökat kraftigt. Den är nu betydligt dyrare än ny vindkraft.
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- Taljegård, Maria, 1988, et al.
(author)
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Charging strategies-implications on the interaction between an electrified road infrastructure and the stationary electricity system
- 2016
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In: World Electric Vehicle Journal. - : MDPI AG. - 2032-6653. ; 3, s. 1823-1834
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Journal article (peer-reviewed)abstract
- This study uses a vehicle model together with detailed traffic data of the European route 39 in western Norway to estimate how the electricity demand for an electric road system varies with time and location. The aim is to better understand the impact of an electric road system on the stationary electricity system. The results show that the electricity demand for an E39 electric road system is comparable to a larger industry, potentially increasing the peak power demand in the regional electricity system with only a few percent. Yet, if all main Norwegian roads are electrified, or if vehicles can also charge their batteries while driving, there will be a significant (>10%) addition of electricity demand to the current load. © 2016 WEVA.
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