| 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. |
- Heinisch, Verena, 1991, et al.
(författare)
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Interconnection of the electricity and heating sectors to support the energy transition in cities
- 2019
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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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| 7. |
- 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
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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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| 8. |
- 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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| 9. |
- Heinisch, Verena, 1991, et al.
(författare)
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Smart electric vehicle charging strategies for sectoral coupling in a city energy system
- 2021
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Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 288
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Tidskriftsartikel (refereegranskat)abstract
- The decarbonization of city energy systems plays an important role to meet climate targets. We examine the consequences of integrating electric cars and buses into the city energy system (60% of private cars and 100% of public buses), using three different charging strategies in a modelling tool that considers local generation and storage of electricity and heat, electricity import to the city, and investments to achieve net-zero emissions from local electricity and heating in 2050. We find that up to 85% of the demand for the charging of electric cars is flexible and that smart charging strategies can facilitate 62% solar PV in the charging electricity mix, compared to 24% when cars are charged directly when parked. Electric buses are less flexible, but the timing of charging enables up to 32% to be supplied by solar PV. The benefit from smart charging to the city energy system can be exploited when charging is aligned with the local value of electricity in the city. Smart charging for cars reduces the need for investments in stationary batteries and peak units in the city electricity and heating sectors. Thus, our results point to the importance of sectoral coupling to exploit flexibility options in the city electricity, district heating and transport sectors.
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| 10. |
- Heinisch, Verena, 1991, et al.
(författare)
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The impact of limited electricity connection capacity on energy transitions in cities
- 2021
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Ingår i: Smart Energy. - : Elsevier BV. - 2666-9552. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- We study the impacts of the connection capacity for electricity transfer between a city and a regional energy system on the design and operation of both systems. The city energy system is represented by the aggregate energy demand of three cities in southern Sweden, and the regional energy system is represented by Swedish electricity price area SE3. We minimize the investment and running costs in the electricity and district heating sectors, considering different levels of connection capacity between the city and the regional energy systems; connection capacities equal to 100%, 75%, 50% and 0% of the maximum city electricity demand. We find that a system design with 50% connection capacity is only 3% more expensive in terms of total costs than a system with 100% connection capacity. However, shifting electricity generation capacity from the regional to the city energy system with 50%, as compared to 100%, connection capacity leads to a higher marginal cost for electricity in the city than in the region. With the highest connection capacities, 75% and 100%, the district heating sector in the city can support wind power integration in the regional energy system by means of power-to-heat operation. Modeling systems with different connection capacities makes our results applicable to other fast-growing cities with potential to increase local electricity production and sector coupling between the electricity, district heating and electrified transport sectors.
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