| 1. |
- Hjalmarsson, Johannes, et al.
(författare)
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Enhancing the value of large-scale energy storage systems in congested distribution grids using service stacking
- 2023
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Ingår i: Journal of Energy Storage. - 2352-152X .- 2352-1538.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Energy storage systems (ESS) are suitable for many grid applications, where some have large seasonal variations. By combining additional services, i.e., service stacking, companies with energy storage assets may generate additional revenue as well as provide services to the power system. This paper aims to highlight and estimate the technical and economic potential of stacking services using energy storage systems in congested a distribution grid. A scheduling optimization tool was implemented for a large-scale battery ESS providing a selection of deemed relevant services over two years. The results show that there is a great potential to enhance the value of the ESS significantly depending on the service portfolio layout. A capacity life loss model was also implemented to analyse the degradation of the ESS, and the cycle aging was estimated for the chosen portfolios. The results showed that a fully stacked portfolio does not necessarily result in increased cycle aging, but that it depended on the services in the portfolio. The cycle aging was affected the most by stacking flexibility with energy arbitrage, while frequency regulation services only resulted in a few additional cycles during each year of operation.
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| 2. |
- Hjalmarsson, Johannes, et al.
(författare)
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Evaluation of centralized and distributed energy storage systems in congested distribution grids with service stacked portfolios
- 2023
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Ingår i: Applied Energy. - 0306-2619 .- 1872-9118.
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Tidskriftsartikel (refereegranskat)abstract
- The clean energy transition is expected to continue at a fast pace in the upcoming years and will imply connection of large amounts of distributed energy resources to existing distribution grids. These have the opportunity to support the power system both locally but also regionally and possibly on a system level too, which could be achieved by bundling services i.e., service stacking. The aim of this article is to compare effects on distribution grids when implementing service stacked portfolios for centralized and distributed storage capacities in congested distribution grids. The complex nature of the scheduling optimization problem motivated using a non-linear solver and for this study a meta-heuristic approach was chosen. A large number of energy storage units were connected to the IEEE European Low Voltage test feeder and load flow calculations were executed using the open-source distribution grid simulator OpenDSS. The results indicate that service stacking could be implemented successfully for both centralized and distributed storage capacities, but the possibility to target local and regional power quality measures varies for the two cases. Finally, multi-service provision using energy storage systems should be considered in more extensive simulation and real-world studies to fully capture the effects on grid dynamics and scheduling possibilities.
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| 3. |
- Hjalmarsson, Johannes, et al.
(författare)
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Large scale energy storage in Uppsala, Sweden : an analysis of voltage fluctuations and a service stacked portfolio
- 2022
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Ingår i: Proceedings of the international conference on evolving cities. - : Evolving Cities Publications. - 2754-5768. ; , s. 57-62
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Konferensbidrag (refereegranskat)abstract
- Extensive electrification has created an increased demand of electric energy and power. Congestion issues are expected to become more common as transmission and distribution grids reach their capacity limits. One of the regions in Sweden that has experienced this already is Uppsala. The distribution system operator, Vattenfall Distribution has initiated an R&D project that connects a 5 MW/20 MWh Li-ion battery energy storage system to temporarily ease the grid congestion. This study covers an analysis of grid voltage fluctuations using a large-scale battery in a distribution grid. The power quality is examined at the 10 kV connection point of the storage, where voltage and power flow are presented. Also, an example of how value stacking may be implemented is illustrated by adding a secondary service during the year. The test results indicate no significant distortion of the voltage level at the measurement point during smooth ramping. It can be concluded that smooth ramping of the BESS has very low or no impact on the local power quality, and additional services should be provided during the year to create several revenue streams. Future studies could focus on fast ramping of the BESS and stacking services in an intra-season perspective.
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| 4. |
- Hjalmarsson, Johannes, et al.
(författare)
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Optimal scheduling of energy storage system in distribution grids using service stacking
- 2023
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Ingår i: 27th International Conference on Electricity Distribution (CIRED 2023). - : Institution of Engineering and Technology. - 9781839538551 ; , s. 3077-3081
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Konferensbidrag (refereegranskat)abstract
- Energy storage systems are widely used for power system applications. By implementing service stacking, enhanced performance of storage systems can potentially be obtained. A scheduling tool based on linear programming was implemented to schedule a grid connected energy storage for two portfolios in separate periods. The results show that it is possible to provide additional services which generate value to the power system. By implementing a capacity loss life model the increased cycle aging is estimated.
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| 5. |
- Hjalmarsson, Johannes, et al.
(författare)
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Scheduling optimization of stacked grid services using energy storage system at large sport facilities in a congested distribution grid
- 2023
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Ingår i: Journal of Energy Storage. - 2352-152X .- 2352-1538.
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Tidskriftsartikel (refereegranskat)abstract
- Congestion management in distribution grids is a growing challenge for network operators due to a combination of fast growing cities and electrification of transport and industry sectors. Energy storage systems connected downstream of bottlenecks have the potential to relieve parts of the peak demand, and typically does not motivate investments financially as a third-party actor alone. By stacking services it is possible for storage units to become financially viable while also enabling opportunities for providing additional local services and participation in markets for ancillary services. In this study, a large customer connected to the congested distribution grid in Uppsala, Sweden, was considered and the systematic potential of a battery connected to the facility was evaluated. A set of portfolios including the services tariff optimization, flexibility-as-a-service, and frequency containment reserve was evaluated by finding the optimal scheduling strategy using a metaheuristic optimization approach together with a capacity loss life model. The analysis was done for two separate years to illustrate the impact of yearly market fluctuations on the service allocation. Additionally, a sensitivity analysis was also performed for the rated energy capacity of the battery. The simulation results indicate that stacking services yields the most valuable portfolio with respect to both technical and economic value where the battery managed to capture several revenue streams at the cost of a small increase in cycle aging, compared to when using the BESS for tariff optimization only. From a system perspective, stacking services enables the BESS to support the power system and the local distribution grid during a large majority of the year.
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| 6. |
- Sjöström, Johan, et al.
(författare)
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Large scale exposure of fires to facade - Initial testing of proposed European method
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report describes a series of tests of the new proposed method for assessing the performance of façades when exposed to flashover fires. The tests consider the large fire exposure and consists of the 8.5 meter high incombustible walls placed in a 90° angle towards each other. The report assesses reproducibility and the effect of moisture content, stick size, wind and depth of the combustion chamber.The data from the report will be publicly available at the project website for further use and scrutiny. https://www.ri.se/en/what-we-do/projects/finalisation-of-the-european-approach-to-assess-the-fire-performance-of-facades
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| 7. |
- Vavruch, Camilla
(författare)
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Leptin and the Intersection of Cardiovascular Disease, Metabolism, and Adipose Tissue
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- According to the World Health Organization, cardiovascular disease (CVD) is a group of disorders of the heart and blood vessels, and it is the leading cause of death worldwide. The risk factors for CVD are divided into two major classes: non-modifiable (age, gender, family history) and modifiable (including tobacco use, type 2 diabetes mellitus (T2DM), physical inactivity, unhealthy diet, abdominal obesity, high cholesterol, dyslipidemia, and stress). Because CVD is a major cause of mortality and morbidity, new and clinically useful biomarkers of cardiovascular risk are of essence. Since obesity is a risk factor for CVD, new ways to achieve weight loss are also important. In this thesis, the focus is on leptin, a metabolic hormone with a pivotal function in the balance of appetite and satiety, and inducing weight loss. The adipose tissue releases leptin, with plasma levels of leptin reflecting the total adipose mass. Since it is related to both fat mass and cardiovascular risk, and is pro-inflammatory, it has been studied as a potential link between obesity, inflammation, hypertension, and vascular function. In paper I, we aimed to see if repeated cold exposure increased metabolic rate and/or brown adipose tissue (BAT) volume in humans. Out of 28 recruited participants, we allocated 16 to expose themselves to cold for one hour every day for six weeks, while 12 were controls, instructed to avoid cold exposure. Through magnetic resonance imaging, we found that supra-clavicular BAT volume had increased in an on-treatment analysis of the cold exposure group. In paper II, we used baseline data from 720 participants in “Cardiovascular Risk factors In Patients with Diabetes—a Prospective study in Primary care” (CARDIPP), all of whom had T2DM and were 55-66 years old at recruitment. We followed patients for incidence of ischemic heart disease (IHD) mortality and morbidity for 4-7 years, using the national Swedish Cause of Death and Hospitalization Registries. Our study showed that serum leptin levels related positively to the hazard ratio in both men and women, and predicted IHD independently of age, HbA1c, BMI, systolic blood pressure, and LDL/HDL-cholesterol ratio. This supports the use of serum leptin in patients with T2DM to add independent prognostic information in terms of IHD. When adding pulse wave velocity (PWV) and intima-media thickness to the model as markers of arterial stiffness, the finding of increased risk of IHD related to leptin levels remained statistically significant in men, but not in women. In paper III, we aimed to discover novel associations between leptin and circulating proteins, to possibly link leptin with the development of CVD in patients with T2DM. Using proximity extension assay, we investigated associations between 88 plasma proteins in the CARDIPP population. We replicated the associations passing the significance threshold in patients with T2DM in an independent cohort and found that adipocyte fatty acid binding protein (A-FABP) was significantly associated with leptin in both cohorts, more so in men than women. A-FABP can be found in white adipocytes and macrophages, and some studies have identified it as a circulating biomarker for metabolic syndrome, T2DM, and cardiovascular events. Finally, in paper IV, we analyzed data from 1 658 men and 1 678 women aged 50 to 65 when included in “The Swedish CardioPulmonary bioImage Study” (SCAPIS), focusing on leptin and its possible correlation with PWV. In bivariate correlations, we found log transformed leptin, and inflammatory markers IL-6, IL-18, and CRP, were all correlated in both men and women. In a multivariable linear regression, log transformed leptin correlated positively with PWV, independently of home blood pressure, smoking, non-HDL, BMI, T2DM, and IL-6, IL-18, and CRP. This suggests it may be possible to use leptin as a marker for PWV and arterial stiffness.In conclusion, this thesis provides new insights into leptin and its potential associations with other circulating proteins, and its connection to cardiovascular disease and inflammation, both in patients with T2DM and in healthy subjects. It also provides more insight into brown adipose tissue.
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| 8. |
- Vestin, Erika, et al.
(författare)
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Herpes simplex viral infection doubles the risk of dementia in a contemporary cohort of older adults : a prospective study
- 2024
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Ingår i: Journal of Alzheimer's Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 97:4, s. 1841-1850
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Tidskriftsartikel (refereegranskat)abstract
- Background: Evidence indicates that herpes simplex virus (HSV) participates in the pathogenesis of Alzheimer’s disease (AD).Objective: We investigated AD and dementia risks according to the presence of herpesvirus antibodies in relation to anti-herpesvirus treatment and potential APOE ε4 carriership interaction.Methods: This study was conducted with 1002 dementia-free 70-year-olds living in Sweden in 2001–2005 who were followed for 15 years. Serum samples were analyzed to detect anti-HSV and anti-HSV-1 immunoglobulin (Ig) G, anti-cytomegalovirus (CMV) IgG, anti-HSV IgM, and anti-HSV and anti-CMV IgG levels. Diagnoses and drug prescriptions were collected from medical records. Cox proportional-hazards regression models were applied.Results: Cumulative AD and all-cause dementia incidences were 4% and 7%, respectively. Eighty-two percent of participants were anti-HSV IgG carriers, of whom 6% received anti-herpesvirus treatment. Anti-HSV IgG was associated with a more than doubled dementia risk (fully adjusted hazard ratio = 2.26, p = 0.031). No significant association was found with AD, but the hazard ratio was of the same magnitude as for dementia. Anti-HSV IgM and anti-CMV IgG prevalence, anti-herpesvirus treatment, and anti-HSV and -CMV IgG levels were not associated with AD or dementia, nor were interactions between anti-HSV IgG and APOE ε4 or anti-CMV IgG. Similar results were obtained for HSV-1.Conclusions: HSV (but not CMV) infection may be indicative of doubled dementia risk. The low AD incidence in this cohort may have impaired the statistical power to detect associations with AD.
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| 9. |
- Vestin, Erika, et al.
(författare)
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Herpes Simplex Viral Infection Doubles the Risk of Dementia in a Contemporary Cohort of Older Adults : A Prospective Study
- 2024
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Ingår i: Journal of Alzheimer's Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 97:4, s. 1841-1850
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Tidskriftsartikel (refereegranskat)abstract
- Background: Evidence indicates that herpes simplex virus (HSV) participates in the pathogenesis of Alzheimer's disease (AD). Objective: We investigated AD and dementia risks according to the presence of herpesvirus antibodies in relation to antiherpesvirus treatment and potential APOE epsilon 4 carriership interaction. Methods: This studywas conducted with 1002 dementia-free 70-year-olds living in Sweden in 2001-2005 who were followed for 15 years. Serum samples were analyzed to detect anti-HSV and anti-HSV-1 immunoglobulin (Ig) G, anti-cytomegalovirus (CMV) IgG, anti-HSV IgM, and anti-HSV and anti-CMV IgG levels. Diagnoses and drug prescriptions were collected from medical records. Cox proportional-hazards regression models were applied. Results: CumulativeADand all-cause dementia incidences were 4% and 7%, respectively. Eighty-two percent of participants were anti-HSV IgG carriers, of whom 6% received anti-herpesvirus treatment. Anti-HSV IgG was associated with a more than doubled dementia risk (fully adjusted hazard ratio = 2.26, p = 0.031). No significant association was found with AD, but the hazard ratio was of the same magnitude as for dementia. Anti-HSV IgM and anti-CMV IgG prevalence, anti-herpesvirus treatment, and anti-HSV and -CMV IgG levels were not associated with AD or dementia, nor were interactions between anti-HSV IgG and APOE epsilon 4 or anti-CMV IgG. Similar results were obtained for HSV-1. Conclusions: HSV (but not CMV) infection may be indicative of doubled dementia risk. The low AD incidence in this cohort may have impaired the statistical power to detect associations with AD.
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