| 1. |
- Goop, Joel, 1986, et al.
(författare)
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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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Impact of electricity market feedback on investments in solar photovoltaic and battery systems in Swedish single-family dwellings
- 2021
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Ingår i: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 163, s. 1078-1091
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Tidskriftsartikel (refereegranskat)abstract
- The profitability of investments in photovoltaics (PVs) and batteries in private households depends on the market price of electricity, which in turn is affected by the investments made in and the usage of PVs and batteries. This creates a feedback mechanism between the centralised electricity generation system, and household investments in PVs and batteries. To investigate this feedback effect, we connect a local optimisation model for household investments with a European power generation dispatch model. The local optimisation is based on the consumption profiles measured for 2104 Swedish households. The modelling compares three different scenarios for the centralised electricity supply system in Year 2032, as well as several sensitivity cases. Our results show total investment levels of 5–20 GWp of PV and 0.01–10 GWh of battery storage capacity in Swedish households in the investigated cases. These levels are up to 33% lower than before market feedback is taken into account. The profitability of PV investments is affected most by the price of electricity and the assumptions made regarding grid tariffs and taxes. The value of investments in batteries depends on both the benefits of increased self-consumption of PV electricity and market arbitrage.
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| 3. |
- 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
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Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 205, s. 1128-1140
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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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| 4. |
- 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
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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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| 5. |
- Göransson, Lisa, 1982, et al.
(författare)
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Linkages between demand-side management and congestion in the European electricity transmission system
- 2014
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Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 69, s. 860-872
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Johansson, Viktor, 1991, et al.
(författare)
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Value of wind power – Implications from specific power
- 2017
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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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| 7. |
- Kjärstad, Jan, 1956, et al.
(författare)
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Development of a methodology to analyze the geographical distribution of CCS plants and ramp-up of CO2-flow over time
- 2014
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 63, s. 6871-6877
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Konferensbidrag (refereegranskat)abstract
- Development of large scale CO2 transport systems will obviously depend on geographical distribution of CCS installations and CO2 volumes over time and their location relative to appropriate storage sites with sufficient injectivity. However, installation of CCS at any facility is likely to be based on company specific planning and company specific strategies with the risk that there will be a considerable geographical spread of such installations over time leading to several small scale and single source-sink transport systems which will be more costly, affect the surroundings more and potentially also lead to increased local opposition to CCS. Additionally, such a development is also likely to require longer overall lead times since each system will have to be treated individually by for instance permitting authorities. This paper presents a methodology to distribute capture installations and captured volumes geographically over time in order to identify, analyze and visualize potential problems related to large scale build-up of CCS installations within Europe.
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| 8. |
- Nyholm, Emil, 1984, et al.
(författare)
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Solar photovoltaic-battery systems in Swedish households - Self-consumption and self-sufficiency
- 2016
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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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| 9. |
- Reichenberg, Lina, 1976, et al.
(författare)
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Maximizing Value of Wind Power Allocation: a Multi-objective Optimization approach
- 2012
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Ingår i: Proceedings 11th International Workshop on Large-Scale Integration of Wind Power.
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Konferensbidrag (refereegranskat)abstract
- The trade-off between average output and standard deviation of the aggregated wind power output in Europe was investigated using a multi-objective optimization approach. By varying the allocation of wind power to different regions in Europe and aggregating the output, emphasis can be shifted between variability and average output. In the optimization, the objective of minimizing standard deviation is related to maximizing the aggregated capacity factor. A case where the capacity of wind power was five times the present installation was investigated. It was found, that the standard deviation of the aggregated output for the optimal aggregations range between 8.1 % and 19.5 % with a corresponding range in average output between 18.4 % and 37.3 %.
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