| 1. |
- Goop, Joel, 1986, et al.
(författare)
-
Distributed solar and wind power - Impact on distribution losses
- 2016
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Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 112, s. 273-284
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Tidskriftsartikel (refereegranskat)abstract
- Introducing renewable electricity as distributed generation may be an attractive option in the shift towards a more sustainable electricity system. Yet, it is not clear to what extent an increased use of distributed generation is beneficial from a systems perspective. We therefore investigate the impacts from increased employment of distributed solar and wind power on losses and transformer capacity requirements in distribution systems. The analysis is based on a dispatch model with a simple representation of typical voltage levels in the distribution system. When electricity is transferred between voltage levels, we subtract losses estimated as the transferred energy times a constant loss factor. Our results show that the losses depend on how load is distributed between voltage levels. For total penetration levels up to 40–50% on an energy basis, we find that wind and solar power could potentially reduce distribution losses. Results further indicate that solar photovoltaic capacity in the low voltage level has a limited potential to decrease peak power flows between voltage levels in a setting where seasonal variations in demand and solar output are opposite to each other. Thereby distributed solar generation also has limited potential to defer investments in transformer capacity between voltage levels.
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| 2. |
- Goop, Joel, 1986, et al.
(författare)
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The effect of high levels of solar generation on congestion in the European electricity transmission grid
- 2017
-
Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 205, s. 1128-1140
-
Tidskriftsartikel (refereegranskat)abstract
- The increasing levels of solar power affect the usage and development of electricity grids, both at local distribution level and with respect to potential congestion within the transmission grid. We use a cost-minimising investment model (ELIN) to determine the development of the European electricity generation system up to Year 2050, for two renewable-dominated scenarios: the Green Base scenario, with a Europe-wide, technology-neutral renewable certificate scheme; and the Net Metering scenario, with an additional net metering support scheme for solar power. The system compositions are extracted from the ELIN results for the years 2022 and 2032, and analysed in an hourly dispatch model (EPOD) to study the effects of solar power on marginal electricity costs and transmission congestion. From the results of the investment model, it is clear that the presence of a net metering subsidy scheme significantly affects both the pace at which solar power continues to expand and the geographical distribution of the new capacity. In the dispatch modelling, it can be seen that high penetration levels of solar power have a strong effect on the marginal costs of electricity, since production is concentrated around a few hours each day. At penetration levels of 20–30% of annual electricity demand, solar power production entails a predictable daily marginal cost difference between the solar peak and the evening price peak, which could make short-term storage competitive. Transmission congestion during summer is consistently higher in the systems from the Net Metering scenario than in those from the Green Base scenario, while the opposite is true during winter. Solar power production correlates strongly with congestion 6–9 h after the solar peak, whereas wind power correlates with congestion with respect to more slowly evolving and longer-term variations.
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| 3. |
- Göransson, Lisa, 1982, et al.
(författare)
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Impact of thermal plant cycling on the cost-optimal composition of a regional electricity generation system
- 2017
-
Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 197, s. 230-240
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Heinisch, Verena, 1991, et al.
(författare)
-
Interconnection of the electricity and heating sectors to support the energy transition in cities
- 2019
-
Ingår i: International Journal of Sustainable Energy Planning and Management. - 2246-2929. ; 24, s. 57-66
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Tidskriftsartikel (refereegranskat)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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| 5. |
- Heinisch, Verena, 1991, et al.
(författare)
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Organizing prosumers into electricity trading communities: Costs to attain electricity transfer limitations and self‐sufficiency goals
- 2019
-
Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 1099-114X .- 0363-907X. ; 43:13, s. 7021-7039
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Heinisch, Verena, 1991, et al.
(författare)
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Prosumers in the Electricity System—Household vs. System Optimization of the Operation of Residential Photovoltaic Battery Systems
- 2019
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Ingår i: Frontiers in Energy Research. - : Frontiers Media SA. - 2296-598X. ; 6
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Tidskriftsartikel (refereegranskat)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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| 7. |
- Johansson, Viktor, 1991, et al.
(författare)
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Value of wind power – Implications from specific power
- 2017
-
Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 126, s. 352-360
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Tidskriftsartikel (refereegranskat)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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| 8. |
- Norwood, Zack, 1979, et al.
(författare)
-
The Future of the European Electricity Grid Is Bright: Cost Minimizing Optimization Shows Solar with Storage as Dominant Technologies to Meet European Emissions Targets to 2050
- 2017
-
Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 10:12
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Tidskriftsartikel (refereegranskat)abstract
- The European roadmap for the power sector dictates an 80–95% cut of existing levels of carbon dioxide emissions is needed by the year 2050 to meet climate goals. This article describes results from a linear cost optimization investment model, ELIN, coupled with a solar technology model, Distributed Concentrating Solar Combined Heat and Power (DCS-CHP), using published investment costs for a comprehensive suite of renewable and conventional electricity generation technologies, to compare possible scenarios for the future electricity grid. The results of these model runs and sensitivity analyses indicate that: (1) solar photovoltaics (PV) with battery storage will likely play a very large role in meeting European targets; (2) concentrating solar power (CSP) with thermal energy storage is at a slight economic disadvantage with respect to PV to compete economically; (3) the economic potential of wind power is only comparable with solar PV if high wind penetration levels are allowed in the best wind sites in Europe; and (4) carbon capture and nuclear technologies are unlikely to compete economically with renewable technologies in creating a low-carbon future grid.
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| 9. |
- Nyholm, Emil, 1984, et al.
(författare)
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An economic assessment of distributed solar PV generation in Sweden from a consumer perspective - The impact of demand response
- 2017
-
Ingår i: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 108, s. 169-178
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Tidskriftsartikel (refereegranskat)abstract
- We present an economic assessment of the impacts of Demand Response (DR) and pricing schemes on the conditions for distributed solar photovoltaics, with the focus on individual households. An optimization model has been developed that minimizes the electricity cost for individual households with the option of dispatching DR loads. DR of appliances and hydronic heating (electrical water heating for both space heating and hot water) are investigated, as well as the effects of applying a monthly, hourly or net metering pricing scheme for selling excess generated electricity and a tax reduction scheme for electricity sold to the grid. We show that for Swedish conditions a monthly net metering pricing scheme would result in the largest PV installations per household (median rated capacity of 4.21 Wpihousehold). The use of the tax reduction scheme reduces the installation per household (2.1 kWp/household), but with an installation being profitable for a larger fraction of the households. Furthermore, the tax reduction scheme retains an incentive for engaging in DR. The use of hydronic DR can support the same installations sizes as the tax reduction scheme, whilst Appliance DR is shown to have only a low impact on the profitability of a PV installation. (C) 2017 Elsevier Ltd. All rights reserved.
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| 10. |
- Nyholm, Emil, 1984, et al.
(författare)
-
Demand response potential of electrical space heating in Swedish single-family dwellings
- 2016
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Ingår i: Building and Environment. - : Elsevier BV. - 0360-1323. ; 96:1, s. 270-282
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the potential and economics of electrical space heating in Swedish single-family dwellings (SFDs) to provide Demand Response (DR) for the electricity load in Sweden.A dynamic and detailed building-stock model, is used to calculate the net energy demand by end-use of a set of sample buildings taken as representative of all Swedish SFDs with electrical heating. A new sub-model optimizes the dispatch of heating systems on an hourly basis, for each representative building, minimizing the cost of electricity purchased from the hourly spot market.The analysis of the Swedish SFD buildings indicates a technical DR capacity potential of 7.3 GW, which is considerable and can be used for the management of intermittent electricity generation. This potential could also prove to be valuable in the operating reserve market. However, this requires that the DR, rather than being governed by a single hourly electricity price signal, would instead be subject to a more centralized control. The modeling shows that DR can be expected to result in up to 5.5 GW of decreased load and 4.4 GW of increased load, if applying current Swedish electricity prices. The modeling shows that DR shifts up to 1.46 TWh of electric heating, corresponding to 1% of total Swedish electricity demand. The potential savings from DR for individual SFDs is found to be low, 0.9–330 €/year, given current Swedish electricity prices.
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| 11. |
- Nyholm, Emil, 1984, et al.
(författare)
-
Solar photovoltaic-battery systems in Swedish households - Self-consumption and self-sufficiency
- 2016
-
Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 183, s. 148-159
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Tidskriftsartikel (refereegranskat)abstract
- This work investigates the extent to which domestic energy storage, in the form of batteries, can increase the self-consumption of electricity generated by a photovoltaic (PV) installation. The work uses real world household energy consumption data (measurements) as the input to a household energy consumption model. The model maximizes household self-sufficiency, by minimizing the amount of electricity purchased from the grid, and thereby also maximizing the level of self-consumption of PV electricity, i.e., the amount of PV-generated electricity that is consumed in-house. This is done for different combinations of PV installation sizes (measured in array-to-load ratio; ALR: ratio of the PV capacity to the average annual electric load of a household) and battery capacities for different categories of single-family dwellings in Sweden (i.e., northern latitudes). The modeling includes approximately 2000 households (buildings). The results show that the use of batteries with capacities within the investigated range, i.e., 0.15-100 kW h, can increase the level of self-consumption by a practical maximum of 20-50 percentage points (depending on the load profile of the household) compared to not using a battery. As an example, for a household with an annual electricity consumption of 20 MW h and a PV installation of 7 kW,,, this range in increased self-consumption of PV-generated electricity requires battery capacities in the range of 1524 kW h (actual usable capacity), depending on the load profile of the specific household. The practical maximum range is determined by the seasonality of PV generation at Swedish latitudes, i.e., higher levels of increased self-consumption are possible, however, it would require substantially larger batteries than the up to 100 kW h investigated in this work. Thus, any additional marginal increment in battery capacity beyond the range investigated results in a low level of utilization and poor additional value. Furthermore, our results reveal that when a battery is used to store PV-generated electricity in-house, self-sufficiency increases (as compared to not using a battery) by 12.5-30 percentage points for the upper range of the investigated PV capacities (ALR. of 6). (C) 2016 Elsevier Ltd. All rights reserved.
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| 12. |
- Odenberger, Mikael, 1977, et al.
(författare)
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Integrating electric vehicles in electricity system models – representing individual driving patterns
- 2018
-
Ingår i: 31st International Electric Vehicle Symposium and Exhibition, EVS 2018 and International Electric Vehicle Technology Conference 2018, EVTeC 2018. ; 2, s. 1020-1026
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Konferensbidrag (refereegranskat)abstract
- This study takes initial steps in developing a method that includes a representation of road transportation demand on individual EV level (based on GPS driving measurements) in an optimisation electricity system model to also represent the spread in the individual driving patterns. The main conclusions are that different driving profiles do have an impact on the charging and discharging back to grid depending on the individual driving distance, battery capacity and driving profile. This have shown to have an impact on, e.g. investments in peak power and the potential role of EVs facilitating the integration of more intermittent renewable power.
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| 13. |
-
PERSPEKTIV PÅ FÖRNYBAR EL
- 2015
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- El driver en ökande mängd mänskliga aktiviteter och har utvecklats till industrisamhällets livsnerv. Trots energieffektiviserande åtgärder kommer den globala efterfrågan på elkraft sannolikt att fortsätta att växa i årtionden framöver. I sig är el en ren och lättanvänd energibärare, men produktionen av elenergi från icke-förnybara energikällor leder till klimatförändringar och miljöproblem och skapar inte sällan sociala och politiska dilemman. En radikal omställning till förnybar elkraft är därför önskvärd. Omställningen till förnybar elenergi är dock inte problemfri. Det finns många frågor som kräver svar: Finns det tillräckligt med förnybar energi för att ersätta alla icke förnybara energikällor? Vilken miljöpåverkan har produktion och användning av nya typer av kraftverk? Hur balanseras tillgång och efterfrågan när solen inte lyser och vinden inte blåser? Vad krävs av beslutsfattare och investerare för att en storskalig expansion av den nya tekniken skall komma till stånd och hur genomförs förändring om etablerade maktstrukturer hotas av det nya som vill in? Det saknas slutgiltiga svar på dessa och andra viktiga frågor. Men om vi studerar förnybar el från olika perspektiv kan vi berika bilden, döda myter, klargöra konflikter och fördjupa förståelsen. Perspektiv på förnybar el är en levande e-bok med regelbundna uppdateringar. Du kanske också vill läsa böckerna "Perspektiv på eldrivna fordon" och "Perspektiv på förädling av bioråvara".
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| 14. |
- Reichenberg, Lina, 1976, et al.
(författare)
-
Tailoring large-scale electricity production from variable renewable energy sources to accommodate baseload generation in Europe
- 2018
-
Ingår i: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 129, s. 334-346
-
Tidskriftsartikel (refereegranskat)abstract
- This work investigates the possibility of combining large-scale penetration (around 50% of annual demand) of variable electricity production (wind and solar power) with baseload generation of electricity (e.g., via nuclear power or coal burning). A new methodology is developed that focuses on renewable resource and variation management in combination with transmission expansion and curtailment of excess electricity generation. Using the Conditional Value-at-Risk (CVaR) measure in the objective function, the optimization model targets the residual load and tailors it to fit the baseload generation. Using Europe as an example, the results show that it is possible to tailor the residual load to fit the baseload with only a small sacrifice (∼1%) of output of generation from variable renewable energy sources (VRES). Expansion of the electricity transmission system is an important factor in accommodating baseload generation in systems with a high penetration level of VRES, whereby, for example, 50 GW of transmission capacity opens the way for baseload generation to increase from 20% to 32% of annual demand. The results show that wind power is the main contributor to VRES production, even in the case of exceptionally low future costs for solar PV.
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| 15. |
- Reichenberg, Lina, 1976, et al.
(författare)
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The marginal system LCOE of variable renewables Evaluating high penetration levels of wind and solar in Europe
- 2018
-
Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 152, s. 914-924
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Tidskriftsartikel (refereegranskat)abstract
- The marginal levelized cost of electricity (LCOE) for increasing the share of Variable Renewable Energy (VRE) is estimated using the electricity investment model greenVRE, which entails a detailed representation of the time dimension to account for variability and variation management. The model is applied to Europe (EU-27 + Norway and Switzerland), which the model divides into ten electricity balance regions and runs with 2920 time-steps The model is applied in a greenfield setting, in which the share of renewables (VRE + Hydro) varies between 0% and 100%. The results show that the system LCOE for VRE increases linearly with the penetration level range of 20%-80%, above which it increases sharply. Systems that have a high penetration of VRE are characterized by using wind power as the major generating technology and having strong expansion of transmission capacity. A sensitivity analysis for the cost of VRE and variation management capacity (storage and transmission) reveals that the point of increase in marginal LCOE is robust under different future scenarios regarding technology costs. We conclude that VRE could constitute the bulk of electricity generation at a reasonable cost, given that there is availability of variation management, especially with respect to transmission. (C) 2018 Published by Elsevier Ltd.
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| 16. |
- Romanchenko, Dmytro, 1988, et al.
(författare)
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Flexibility Potential of Space Heating Demand Response in Buildings for District Heating Systems
- 2019
-
Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 12:15
-
Tidskriftsartikel (refereegranskat)abstract
- Using an integrated demand-supply optimization model, this work investigates the potential for flexible space heating demand, i.e., demand response (DR), in buildings, as well as its effects on the heating demand and the operation of a district heating (DH) system. The work applies a building stock description, including both residential and non-residential buildings, and employs a representation of the current DH system of the city of Gothenburg, Sweden as a case study. The results indicate that space heating DR in buildings can have a significant impact on the cost-optimal heat supply of the city by smoothing variations in the system heat demand. DR implemented via indoor temperature deviations of as little as +1 degrees C can smoothen the short-term (daily) fluctuations in the system heating demand by up to 18% over a period of 1 year. The smoothening of the demand reduces the cost of heat generation, in that the heat supply and number of full-load hours of base-load heat generation units increase, while the number of starts for the peaking units decreases by more than 80%. DR through temperature deviations of +3 degrees C confers diminishing returns in terms of its effects on the heat demand, as compared to the DR via +1 degrees C.
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| 17. |
- Romanchenko, Dmytro, 1988, et al.
(författare)
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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
-
Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 204, s. 16-30
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Tidskriftsartikel (refereegranskat)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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| 18. |
- Romanchenko, Dmytro, 1988, et al.
(författare)
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Thermal energy storage in district heating: Centralised storage vs. storage in thermal inertia of buildings
- 2018
-
Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904. ; 162, s. 26-38
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Tidskriftsartikel (refereegranskat)abstract
- Heat load variations in district heating systems lead to increased costs for heat generation and, in most cases, increased greenhouse gas emissions associated with the marginal use of fossil fuels. This work investigates the benefits of applying thermal energy storage in district heating systems to decrease heat load variations, comparing storage using a hot water tank and the thermal inertia of buildings (with similar storage capacity). A detailed techno-economic optimisation model is applied to the district heating system of Göteborg, Sweden. The results show that both the hot water tank and the thermal inertia of buildings benefit the operation of the district heating system and have similar dynamics of utilisation. However, compared to the thermal inertia of buildings, the hot water tank stores more than twice as much heat over the modelled year, owing to lower energy losses. For the same reason, only the hot water tank is used to store heat for periods longer than a few days. Furthermore, the hot water tank has its full capacity available for charging/discharging at all times, whereas the capacity of the thermal inertia of buildings depends on the heat transfer between the building core and its indoor air and internals. Finally, the total system yearly operating cost decreases by 1% when the thermal inertia of buildings and by 2% when the hot water tank is added to the district heating system, as compared to the scenario without any storage.
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| 19. |
- Taljegård, Maria, 1988, et al.
(författare)
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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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Ingår i: World Electric Vehicle Journal. - : MDPI AG. - 2032-6653. ; 3, s. 1823-1834
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Tidskriftsartikel (refereegranskat)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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| 20. |
- Taljegård, Maria, 1988, et al.
(författare)
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Electric road systems in Norway and Sweden-impact on CO2 emissions and infrastructure cost
- 2017
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Ingår i: 2017 IEEE Transportation Electrification Conference and Expo, Asia-Pacific, ITEC Asia-Pacific 2017; Hotel VictoriesHarbin; China; 7 August 2017 through 10 August 2017.
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Konferensbidrag (refereegranskat)abstract
- This study investigates a large-scale implementation of electric road system (ERS) in Norway and Sweden by analysing (i) which roads, (ii) how much of the road network and (iii) what vehicle types that are beneficial to electrify based on analysis of road traffic volumes, CO2 emissions mitigation potential and infrastructure investment costs per vehicle kilometre. All European and National roads in Norway and Sweden have been included assuming different degrees of electrification in terms fraction of the road length with ERS, prioritizing high traffic roads. The results show similar effect from ERS in Norway and Sweden. Implementing ERS on 25% of the busiest European and National road length in both countries is enough to result in an electrification of approximately 70% of the vehicle kilometres on these roads and 35% of the total vehicle kilometres on all roads. An ERS on all European and National roads will include 60 and 70% of the vehicle kilometres and CO2 emissions from all heavy traffic in Norway and Sweden, respectively. The results also show that aiming to electrify more than 50% of the light vehicles with ERS implies that also county roads and private roads need to be included. For a majority of the European and National roads, the infrastructure investment cost per vehicle kilometre are low compare to the current cost for diesel per kilometre assuming a depreciation time of ERS investments of 35 years.
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| 21. |
- Taljegård, Maria, 1988, et al.
(författare)
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Electric vehicles as a flexibility management strategy in Europe
- 2018
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Ingår i: 31st International Electric Vehicle Symposium and Exhibition, EVS 2018 and International Electric Vehicle Technology Conference 2018, EVTeC 2018.
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Konferensbidrag (refereegranskat)abstract
- This study investigates how an electrification of road transportation impact investments and operation of the electricity system in Sweden, Germany, Great Britain and Spain under a stringent CO2 constraint. A scenario with full electrification of the road transport sector, including also dynamic power transfer for trucks and buses, decreases the need for investments in peak power and curtailment of wind power compared to the scenario without EVs, provided that an optimal charging strategy and vehicle-to-grid is applied for the passenger vehicles. Flexibility from EVs can facilitate an increase of investments in renewable electricity, especially solar PVs in sunny regions.
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| 22. |
- Taljegård, Maria, 1988, et al.
(författare)
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Electric Vehicles as Flexibility Management Strategy for the Electricity System-A Comparison between Different Regions of Europe
- 2019
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 12:13
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Tidskriftsartikel (refereegranskat)abstract
- This study considers whether electric vehicles (EVs) can be exploited as a flexibility management strategy to stimulate investments in and operation of renewable electricity under stringent CO2 constraints in four regions with different conditions for renewable electricity (Sweden, Germany, the UK, and Spain). The study applies a cost-minimisation investment model and an electricity dispatch model of the European electricity system, assuming three types of charging strategies for EVs. The results show that vehicle-to-grid (V2G), i.e., the possibility to discharging the EV batteries back to grid, facilitates an increase in investments and generation from solar photovoltaics (PVs) compare to the scenario without EVs, in all regions except Sweden. Without the possibility to store electricity in EV batteries across different days, which is a technical limitation of this type of model, EVs increase the share of wind power by only a few percentage points in Sweden, even if Sweden is a region with good conditions for wind power. Full electrification of the road transport sector, including also dynamic power transfer for trucks and buses, would decrease the need for investments in peak power in all four regions by at least 50%, as compared to a scenario without EVs or with uncontrolled charging of EVs, provided that an optimal charging strategy and V2G are implemented for the passenger vehicles.
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| 23. |
- Taljegård, Maria, 1988, et al.
(författare)
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Electric vehicles as power and energy provider for the European electricity system - an electricity systems modelling study
- 2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study analysis the potential for electric vehicles (EVs) to contribute with power and energy to the electricity system by means of demand response, storage of electricity and contribution to the power reserve. The work applies real-time measurements of driving patterns and a cost-minimisation model of the electricity system assuming zero CO2 emission and run for selected European regions. The results shows that EVs can (i) substantially reduce investments in peak power capacity, (ii) replace investments in other both short-term and long-term storage technologies (e.g., stationary batteries and hydrogen storage), and (iii) participate in the power reserve with large additional power capacity.
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| 24. |
- Taljegård, Maria, 1988, et al.
(författare)
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Impact of electric vehicles on the cost-competitiveness of generation and storage technologies in the electricity system
- 2019
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9318 .- 1748-9326. ; 14:12
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Tidskriftsartikel (refereegranskat)abstract
- The increasing levels of variable renewable electricity (VRE) generation-such as wind and solar power-will create important opportunities for the charging of electric vehicle (EV) batteries during low-cost hours with a lot of VRE generation and for the discharge of EV batteries back to the grid (i.e. vehicle-to-grid; V2G) during high-cost hours. This study investigates how different EV charging strategies influence the cost-competitiveness of generation and storage technologies other than EV batteries in the electricity system, using a regional electricity system investment and dispatch model. The charging requirements of the EVs, which are used as an input to the optimisation model, are derived from the yearly driving patterns of 426 vehicles measured with global positioning system. The study is carried out for four regions in Europe with different conditions for wind, solar and hydro power generation. The results show that optimised EV charging with V2G can: (i) reduce investments in peak power capacity in all the regions investigated; (ii) reduce the need for short-term and long-term storage technologies other than EV batteries (i.e. stationary batteries and hydrogen storage); and (iii) stimulate increased shares of solar and wind power generation, as compared to direct charging in some regions (mainly Hungary). This study also shows that EV battery capacities as low as 30 kWh, which are connected to the grid only at their home location, can to a large extent contribute with flexibility to the electricity system in the way mentioned. The present study also investigates the influences of different shares of the fleet participating in V2G, and shows that the additional benefits for the electricity system level off when approximately 24% of the vehicle fleet participates in V2G.
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| 25. |
- Taljegård, Maria, 1988, et al.
(författare)
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Impacts of electric vehicles on the electricity generation portfolio – A Scandinavian-German case study
- 2019
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Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 235, s. 1637-1650
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates how electrification of the Scandinavian and German road transportation sectors under a stringent CO2 cap will influence investments in new electricity generation capacity up to Year 2050 and the dispatch of the electricity generation portfolio in Year 2030. We apply a cost-minimisation investment model and an electricity dispatch model of the Scandinavian and German electricity systems, assuming both optimised charging and a vehicle-to-grid (V2G) charging strategy for passenger electric vehicles (EVs). Different EV battery sizes and EV deployment levels are investigated in 11 different scenarios, whereby two of the scenarios include also electric trucks and buses using electric road systems (ERS). The results of the modelling show that with a cap on CO2 emissions, the additional electricity demand from an electrified road transport sector is met mainly by increases in the outputs from wind power and thermal power plants, in the form of coal in combination with carbon capture and storage. In Year 2030, wind power generation in Scandinavia and Germany increases by 7–30% depending on the EV scenario, as compared to a scenario without EVs, which corresponds to a few more percentage points than the increased demand from EVs in absolute terms. Furthermore, a V2G charging strategy for passenger EVs smoothens the net load curve and almost completely reduces the need for peak power capacity in the Scandinavian-German electricity system. The value of investing in solar power is also reduced in all the EV scenarios by 22–42%, as compared to a scenario without EVs. This is due to the fact that in Northern Europe solar power competes with EVs for peak power supply. ERS for mainly trucks and buses will increase the current load profile by up to 18 GW in the Scandinavian-German electricity system.
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| 26. |
- Taljegård, Maria, 1988, et al.
(författare)
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Spacial and dynamic energy demand of the E39 highway – Implications on electrification options
- 2017
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Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 195, s. 681-692
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Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were to investigate how the energy demand from transportation on a road varies over time and with location, and to identify the impacts from electrification of the road on the stationary electricity system, assuming different electrification options and drivetrains. European highway route 39 (E39) in western Norway is used as a case study. A vehicle model, together with an analysis of detailed traffic data was used to estimate the energy and power demands for transportation work on E39. This study shows that a road with the characteristics of E39 exhibits large variation in the spatial and time distributions of its energy and power demands. The yearly electricity demand for E39, assuming a full electrification of the current traffic flow is comparable to that of a larger industry, such that the peak power demand for the dimensioning hour of the regional electricity system could be increased by 1–2% if static or electric road systems is applied. However, if all the main roads in Norway were installed with electric road systems, the corresponding peak power increase is 7%. In comparison, if instead using an indirect strategy for electrification of transportation via for instance hydrogen or synthetic diesel, the annual electricity demand for E39 would increase even further, albeit with the possibility to distribute such demand both geographically area and in time compared to electric road systems or static charging.
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