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Ollas, P., Thiringer, T., Persson, M. & Markusson, C. (2023). Battery loss prediction using various loss models: A case study for a residential building. Journal of Energy Storage, 70, Article ID 108048.
Open this publication in new window or tab >>Battery loss prediction using various loss models: A case study for a residential building
2023 (English)In: Journal of Energy Storage, ISSN 2352-152X, E-ISSN 2352-1538, Vol. 70, article id 108048Article in journal (Refereed) Published
Abstract [en]

This work compares and quantifies the annual losses for three battery system loss representations in a case study for a residential building with solar photovoltaic (PV). Two loss representations consider the varying operating conditions and use the measured performance of battery power electronic converters (PECs) but differ in using either a constant or current-dependent internal battery cell resistance. The third representation is load-independent and uses a (fixed) round trip efficiency. The work uses sub-hourly measurements of the load and PV profiles and includes the results from varying PV and battery size combinations. The results reveal an inadequacy of using a constant battery internal resistance and quantify the annual loss discrepancy to −38.6%, compared to a case with current-dependent internal resistance. The results also show the flaw of modelling the battery system’s efficiency with a fixed round trip efficiency, with loss discrepancy variation between −5 to 17% depending on the scenario. Furthermore, the necessity of accounting for the cell’s loss is highlighted, and its dependence on converter loading is quantified.

Keywords
Battery energy storage system, Lithium-ion batteries, Solar photovoltaic system, Battery performance, Applied research
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-65662 (URN)10.1016/j.est.2023.108048 (DOI)
Funder
Swedish Energy Agency, 43276-1Swedish Energy Agency, 47273-1Swedish Energy Agency
Note

Funded by the Swedish Energy Agency (’’Energimyndigheten’’) through grant numbers: 43276-1 and 47273-1.

Available from: 2023-07-12 Created: 2023-07-12 Last updated: 2023-08-28Bibliographically approved
Ollas, P., Thiringer, T., Persson, M. & Markusson, C. (2023). Energy Loss Savings Using Direct Current Distribution in a Residential Building with Solar Photovoltaic and Battery Storage. Energies, 16(3), Article ID 1131.
Open this publication in new window or tab >>Energy Loss Savings Using Direct Current Distribution in a Residential Building with Solar Photovoltaic and Battery Storage
2023 (English)In: Energies, E-ISSN 1996-1073, Vol. 16, no 3, article id 1131Article in journal (Refereed) Published
Abstract [en]

This work presents a comparison of alternating current (AC) and direct current (DC) distribution systems for a residential building equipped with solar photovoltaic (PV) generation and battery storage. Using measured PV and load data from a residential building in Sweden, the study evaluated the annual losses, PV utilization, and energy savings of the two topologies. The analysis considered the load-dependent efficiency characteristics of power electronic converters (PECs) and battery storage to account for variations in operating conditions. The results show that DC distribution, coupled with PV generation and battery storage, offered significant loss savings due to lower conversion losses than the AC case. Assuming fixed efficiency for conversion gave a 34% yearly loss discrepancy compared with the case of implementing load-dependent losses. The results also highlight the effect on annual system losses of adding PV and battery storage of varying sizes. A yearly loss reduction of 15.8% was achieved with DC operation for the studied residential building when adding PV and battery storage. Additionally, the analysis of daily and seasonal variations in performance revealed under what circumstances DC could outperform AC and how the magnitude of the savings could vary with time. © 2023 by the authors.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
battery storage, building energy system, direct current, energy savings, power electronic converter, solar photovoltaic, Digital storage, Electric batteries, Electric impedance measurement, Electric power distribution, Energy dissipation, Housing, Power converters, Power electronics, Solar concentrators, Solar power generation, Alternating current, Building energy systems, Direct current distributions, Direct-current, Energy-savings, Power electronics converters, Residential building, Solar photovoltaics, Energy conservation
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-64102 (URN)10.3390/en16031131 (DOI)2-s2.0-85147846467 (Scopus ID)
Note

 Correspondence Address: Ollas P, RISE, Sweden; email: patrik.ollas@ri.se; Funding details: Energimyndigheten, 43276–1, 50986–1; Funding text 1: The Swedish Energy Agency funded this research through the national project “From photovoltaic generation to end-users with minimum losses—a full-scale demonstration” (2018–2020, grant number 43276–1) and the national project “Flexibility and energy efficiency in buildings with PV and EV charging” (2020–2023, grant number 50986–1).

Available from: 2023-02-28 Created: 2023-02-28 Last updated: 2023-08-28Bibliographically approved
Ollas, P., Ghaem Sigarchian, S., Alfredsson, H., Leijon, J., Döhler, J. S., Aalhuizen, C., . . . Thomas, K. (2023). Evaluating the role of solar photovoltaic and battery storage in supporting electric aviation and vehicle infrastructure at Visby Airport. Applied Energy, 352, Article ID 121946.
Open this publication in new window or tab >>Evaluating the role of solar photovoltaic and battery storage in supporting electric aviation and vehicle infrastructure at Visby Airport
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2023 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 352, article id 121946Article in journal (Refereed) Published
Abstract [en]

Following the societal electrification trend, airports face an inevitable transition of increased electric demand, driven by electric vehicles (EVs) and the potential rise of electric aviation (EA). For aviation, short-haul flights are first in line for fuel exchange to electrified transportation. This work studies the airport of Visby, Sweden and the effect on the electrical power system from EA and EV charging. It uses the measured airport load demand from one year’s operation and simulated EA and EV charging profiles. Solar photovoltaic (PV) and electrical battery energy storage systems (BESS) are modelled to analyse the potential techno-economical gains. The BESS charge and discharge control are modelled in four ways, including a novel multi-objective (MO) dispatch to combine self-consumption (SC) enhancement and peak power shaving. Each model scenario is compared for peak power shaving ability, SC rate and pay-back-period (PBP). The BESS controls are also evaluated for annual degradation and associated cost. The results show that the novel MO dispatch performs well for peak shaving and SC, effectively reducing the BESS’s idle periods. The MO dispatch also results in the battery controls’ lowest PBP (6.9 years) using the nominal economic parameters. Furthermore, a sensitivity analysis for the PBP shows that the peak power tariff significantly influences the PBP for BESS investment. 

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Gotland; Sweden; Visby; Battery storage; Charging (batteries); Economic analysis; Electric discharges; Electric load dispatching; Investments; Secondary batteries; Sensitivity analysis; Solar concentrators; Solar power generation; Battery control; Battery energy storage systems; Battery storage; Battery storage system; Electric aviation; Electric vehicle charging; Multi objective; Peak power shaving; Solar photovoltaics; Techno-Economic analysis; airport; control system; economic analysis; electrical power; electrification; energy storage; photovoltaic system; Airports
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-67969 (URN)10.1016/j.apenergy.2023.121946 (DOI)2-s2.0-85171863677 (Scopus ID)
Note

The Swedish Energy Agency financially supported the work (GrantNo’s. 52433-1, 50986-1 and P2022-01305). The authors would alsolike to thank Swedavia for collaborating on sharing data and discussingfeasible system configurations.

Available from: 2023-11-24 Created: 2023-11-24 Last updated: 2023-12-20Bibliographically approved
Leijon, J., Hagman, J., Alfredsson, H., Ghaem Sigarchian, S., Ollas, P., Aalhuizen, C., . . . Thomas, K. (2022). Airports with increased electrification – an ongoing project with case studies in Sweden. In: 35th International Electric Vehicle Symposium and Exhibition (EVS35) Oslo, Norway, June 11-15, 2022: . Paper presented at 35th International Electric Vehicle Symposium and Exhibition (EVS35) Oslo, Norway, June 11-15, 2022., 2022.
Open this publication in new window or tab >>Airports with increased electrification – an ongoing project with case studies in Sweden
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2022 (English)In: 35th International Electric Vehicle Symposium and Exhibition (EVS35) Oslo, Norway, June 11-15, 2022, 2022Conference paper, Published paper (Other academic)
Keywords
charging, electric drive, electricity, infrastructure, energy consumption, Electrical Engineering, Electronic Engineering, Information Engineering, Elektroteknik och elektronik
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-62539 (URN)
Conference
35th International Electric Vehicle Symposium and Exhibition (EVS35) Oslo, Norway, June 11-15, 2022., 2022
Available from: 2023-01-24 Created: 2023-01-24 Last updated: 2023-12-20Bibliographically approved
Ollas, P., Thiringer, T., Chen, H. & Markusson, C. (2021). Increased photovoltaic utilisation from direct current distribution: Quantification of geographical location impact. Progress in Photovoltaics, 29(7), 846-856
Open this publication in new window or tab >>Increased photovoltaic utilisation from direct current distribution: Quantification of geographical location impact
2021 (English)In: Progress in Photovoltaics, ISSN 1062-7995, E-ISSN 1099-159X, Vol. 29, no 7, p. 846-856Article in journal (Refereed) Published
Abstract [en]

In this paper, the performance of a direct current (DC) distribution system is modelled for a single-family residential building and compared with a conventional alternating current (AC) system to quantify the potential energy savings and gains in photovoltaic (PV) utilisation. The modelling is made for two different climates to quantify the impact of the geographical location. Results show that the system losses are reduced by 19–46% and the PV utilisation increased by 3.9–7.4% when using a DC distribution system compared to an AC equivalent, resulting in system efficiency gains in the range of 1.3–8.8%. Furthermore, it is shown that the geographical location has some effect on the system's performance and PV utilisation, but most importantly, the grid interaction is paramount for the performance of the DC topology. © 2021 The Authors.

Place, publisher, year, edition, pages
John Wiley and Sons Ltd, 2021
Keywords
battery storage, direct current (DC), energy savings, photovoltaic, PV load correlation, residential building, Electric impedance measurement, Energy conservation, Potential energy, Alternating current, DC distribution system, Direct current distributions, Distribution systems, Geographical locations, System efficiency, System's performance, Location
National Category
Energy Systems
Identifiers
urn:nbn:se:ri:diva-52970 (URN)10.1002/pip.3407 (DOI)2-s2.0-85103655459 (Scopus ID)
Note

 Funding details: Energimyndigheten, 43276‐1, 47273‐1; Funding text 1: The authors would like to acknowledge the Swedish Energy Agency (‘Energimyndigheten’) who has funded this research through Grants 43276‐1 and 47273‐1.

Available from: 2021-04-21 Created: 2021-04-21 Last updated: 2023-06-02Bibliographically approved
Ollas, P. (2020). Energy Savings Using a Direct Current Distribution Network in a PV and Battery Equipped Residential Building. (Licentiate dissertation). Göteborg: Chalmers Tekniska Högskola
Open this publication in new window or tab >>Energy Savings Using a Direct Current Distribution Network in a PV and Battery Equipped Residential Building
2020 (English)Licentiate thesis, monograph (Other academic)
Abstract [en]

Energy from solar photovoltaic (PV) are generated as direct current (DC) and almost all of today’s electrical loads in residential buildings, household appliances and HVAC system (Heating Ventilation and Air-conditioning) are operated on DC. For a conventional alternating current (AC) distribution system this requires the need for multiple conversion steps before the final user-stage. By switching the distribution system to DC, conversion steps between AC to DC can be avoided and, in that way, losses are reduced. Including a battery storage–the system’s losses can be reduced further and the generated PV energy is even better utilised.

This thesis investigates and quantifies the energy savings when using a direct current distribution topology in a residential building together with distributed energy generation from solar photovoltaic and a battery storage. Measured load and PV generation data for a single-family house situated in Borås, Sweden is used as a case study for the analysis. Detailed and dynamic models–based on laboratory measurements of the power electronic converters and the battery–are also used to more accurately reflect the system’s dynamic performance.

In this study a dynamic representation of the battery’s losses is presented which is based on laboratory measurements of the resistance and current dependency for a single lithium-ion cell based on Lithium iron phosphate (LFP). A comparative study is made with two others, commonly used, loss representations and evaluated with regards to the complete system’s performance, using the PV and load data from the single-family house. Results show that a detailed battery representation is important for a correct loss prediction when modelling the interaction between loads, PV and the battery.

Four DC system topologies are also modelled and compared to an equivalent AC topology using the experimental findings from the power electronic converters and the battery measurements. Results from the quasi-dynamic modelling show that the annual energy savings potential from the suggested DC topologies ranges between 1.9–5.6%. The DC topologies also increase the PV utilisation by up to 10 percentage points, by reducing the associated losses from the inverter and the battery conversion. Results also show that the grid-tied converter is the main loss contributor and when a constant grid-tied efficiency is used, the energy savings are overestimated.

Place, publisher, year, edition, pages
Göteborg: Chalmers Tekniska Högskola, 2020. p. 101
Series
Chalmers Thesis for Licentiate of Engineering 2020, ISSN 1403-266X
Keywords
Direct-Current Distribution, Residential Buildings, Battery Energy Storage System, Battery Modeling, Solar Photovoltaic System, System Performance, Energy Efficiency, Energy Savings, PV Utilisation
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Building Technologies Energy Engineering Renewable Bioenergy Research Energy Systems
Identifiers
urn:nbn:se:ri:diva-44775 (URN)
Presentation
2020-03-13, ED, Göteborg, 10:00 (English)
Opponent
Supervisors
Funder
Swedish Energy Agency, 43276–1 och 47273–1
Available from: 2020-05-05 Created: 2020-04-30 Last updated: 2023-06-02Bibliographically approved
Ollas, P., Thiringer, T., Chen, H. & Markusson, C. (2020). Increased PV Utilisation from DC Distribution: Quantification of Geographical Impact. In: EU PVSEC Conference Proceedings: . Paper presented at 37th European Photovoltaic Solar Energy Conference and Exhibition (pp. 1432-1441).
Open this publication in new window or tab >>Increased PV Utilisation from DC Distribution: Quantification of Geographical Impact
2020 (English)In: EU PVSEC Conference Proceedings, 2020, p. 1432-1441Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, the performance of a direct current (DC) distribution system is modelled and compared fora single-family residential building with a conventional alternating current (AC) system to quantify the potential energy savings and gains in PV utilization. The modelling is also made for two different climates to quantify the impact of the geographical location. Results show that the system losses are reduced by 19-46% and the PV utilization increased by 3.9-7.4% when using a DC distribution system compared to an AC equivalent, resulting in system efficiency gains in the range of 1.3-8.8%. Furthermore, it is shown that the geographical location has some effect on the system's performance and PV utilization, but most importantly the grid interaction is paramount for the performance of the DC topology.

Keywords
Photovoltaic, DC-DC-Converter, Grid Integration, Storage, System Performance
National Category
Energy Engineering Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-51866 (URN)10.4229/EUPVSEC20202020-5EO.2.3 (DOI)3-936338-73-6 (ISBN)
Conference
37th European Photovoltaic Solar Energy Conference and Exhibition
Funder
Swedish Energy Agency, 43276-1
Available from: 2021-01-14 Created: 2021-01-14 Last updated: 2023-06-02Bibliographically approved
Ollas, P., Markusson, C., Eriksson, J., Chen, H., Lindahl, M. & Thiringer, T. (2020). Quasi-Dynamic Modelling of DC Operated Ground-Source Heat Pump. In: SINTEF Proceedings; 5: . Paper presented at Building Simulation 2020 Conference, Oslo (pp. 208-213). Oslo, 5
Open this publication in new window or tab >>Quasi-Dynamic Modelling of DC Operated Ground-Source Heat Pump
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2020 (English)In: SINTEF Proceedings; 5, Oslo, 2020, Vol. 5, p. 208-213Conference paper, Published paper (Refereed)
Abstract [en]

The performance of a conventional ground-source heat pump (GSHP) has been measured in the laboratory with alternating current (AC) and direct current(DC) operation using the standardised points fromEN14511:2018. The results from these measurements have been used to modify a variable speed heat pump model in IDA Indoor Climate and Energy (ICE) and the annual performance of AC and DC operation have been simulated for an entire year's operation at two geographical locations in Sweden. Results show that the energy savings with DC operation from laboratory measurements span between 1.4{5.2% and when simulating the performance for an entire year's operation, the energy savings vary between 2.5{3.4%. Furthermore, the energy savings from the simulations have been compared to the bin method described in EN14825:2018.

Place, publisher, year, edition, pages
Oslo: , 2020
Keywords
Heat pump, direct current, energy savings
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-51865 (URN)978-82-536-1679-7 (ISBN)
Conference
Building Simulation 2020 Conference, Oslo
Funder
Swedish Energy Agency, 43276-1
Available from: 2021-01-14 Created: 2021-01-14 Last updated: 2023-06-02Bibliographically approved
Ollas, P., Persson, J., Markusson, C. & Alfadel, U. (2018). Impact of Battery Sizing on Self-Consumption, Self-Sufficiency and Peak Power Demand for a Low Energy Single-Family House with PV Production in Sweden. In: 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion, WCPEC 2018 - A Joint Conference of 45th IEEE PVSC, 28th PVSEC and 34th EU PVSEC: . Paper presented at 7th IEEE World Conference on Photovoltaic Energy Conversion, WCPEC 2018, 10 June 2018 through 15 June 2018 (pp. 618-623). Institute of Electrical and Electronics Engineers Inc.
Open this publication in new window or tab >>Impact of Battery Sizing on Self-Consumption, Self-Sufficiency and Peak Power Demand for a Low Energy Single-Family House with PV Production in Sweden
2018 (English)In: 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion, WCPEC 2018 - A Joint Conference of 45th IEEE PVSC, 28th PVSEC and 34th EU PVSEC, Institute of Electrical and Electronics Engineers Inc. , 2018, p. 618-623Conference paper, Published paper (Refereed)
Abstract [en]

This paper simulates the impact of battery sizing for an actual nearly-zero energy (NZEB) single-family house with solar PV located in Boras, Sweden. Simulations are done,° using measurement data as an input, for three different battery dispatch algorithms with two different purposes; (i) peak power shaving and (ii) maximising system self-consumption (SC) and self-sufficiency (SS) of the solar PV. The results show that the optimal battery storage size for this single-family house, given its measured electrical loads and existing solar PV system is around 7.2 kWh. System self-consumption and self-sufficiency from generated solar PV increased with 24.3 percentage points compared to a reference case without battery. Furthermore, results show that increasing the battery size beyond 7.2 kWh only results in minor performance gains.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2018
Keywords
battery sizing, dispatch algorithms, NZEB, optimisation, photovoltaic, self sufficiency, self-consumption, target zero, Digital storage, Energy conversion, Houses, Optimisations, Self- consumption, Electric batteries
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-37956 (URN)10.1109/PVSC.2018.8548275 (DOI)2-s2.0-85059917269 (Scopus ID)9781538685297 (ISBN)
Conference
7th IEEE World Conference on Photovoltaic Energy Conversion, WCPEC 2018, 10 June 2018 through 15 June 2018
Available from: 2019-04-23 Created: 2019-04-23 Last updated: 2023-06-02Bibliographically approved
Ollas, P., Markusson, C., Persson, J. & Alfadel, U. (2018). Impact of Battery Sizing on Self-Consumption, Self-Sufficiency and PeakPower Demand for a Low Energy Single-Family House With PVProduction in Sweden. In: 7th World Conference on Photovoltaic Energy Conversion (WCPEC-7), June 10-15, 2018: . Paper presented at 7th World Conference on Photovoltaic Energy Conversion (WCPEC-7), June 10-15, 2018.
Open this publication in new window or tab >>Impact of Battery Sizing on Self-Consumption, Self-Sufficiency and PeakPower Demand for a Low Energy Single-Family House With PVProduction in Sweden
2018 (English)In: 7th World Conference on Photovoltaic Energy Conversion (WCPEC-7), June 10-15, 2018, 2018Conference paper, Published paper (Refereed)
Abstract [en]

This paper simulates the impact of battery sizingfor an actual nearly-zero energy (NZEB) single-family housewith solar PV located in Bor°as, Sweden. Simulations are done,using measurement data as an input, for three different batterydispatch algorithms with two different purposes; (i) peak powershaving and (ii) maximising system self-consumption (SC) andself-sufficiency (SS) of the solar PV. The results show that theoptimal battery storage size for this single-family house, givenits measured electrical loads and existing solar PV system isaround 7.2 kWh. System self-consumption and self-sufficiencyfrom generated solar PV increased with 24.3 percentage pointscompared to a reference case without battery. Furthermore,results show that increasing the battery size beyond 7.2 kWhonly results in minor performance gains.

Keywords
battery sizing, self-consumption, selfsufficiency, photovoltaic, NZEB, optimisation, dispatch algorithms, target zero
National Category
Energy Systems
Identifiers
urn:nbn:se:ri:diva-35089 (URN)
Conference
7th World Conference on Photovoltaic Energy Conversion (WCPEC-7), June 10-15, 2018
Projects
Från solel till användare med minsta möjliga förlust – en fullskaledemonstration
Funder
Swedish Energy Agency
Available from: 2018-08-28 Created: 2018-08-28 Last updated: 2023-06-02Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-6060-5624

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