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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Laststyrning av eluppvärmning och varmvattenberedning : En studie av potentialen för hushåll att bidra till en sänkt abonnerad effekt mot överliggande elnät / Load control of electrical space and water heating : A study of the potential in detached houses to contribute to a lower subscripted power of the overhead grid

Ahlm, Niklas January 2021 (has links)
This study has explored the potential for lowering the subscripted power of 25 MW for one of the connection points between the local power grid and its overhead power grid for a local grid owner. The potential for doing so through hard, direct load control of electrical domestic heating and domestic water heating for detached houses with a fuse size of 16-25 A is evaluated for 12 different scenarios. The scenarios are found by combining a customer participation of 25, 50, 75 and 100 percent with a maximum allowed duration for load control of two, three and four hours respectively. A function describing the need for electrical power for domestic heating as dependent of the outdoor temperature is developed and combined with a model that is used for simulating hot water usage and a model that describes the power demand of a domestic water heater. Furthermore, a control function is incorporated to ensure that households are not subjected to load control for a longer period than allowed and that all households bear the same burden in this respect.  The results show that a power of 1,0-4,1 MWh/h can be redistributed, but that the potential is heavily limited by the returning load that occurs. Due to the long duration of the critical peaks that are being redistributed, up to 5-10 hours, returning load occurs even though load control has not yet been finalized. The returning load leads to a bigger amount of power having to be redistributed and therefore limits the potential for the new subscripted power that can be achieved. Furthermore, the maximum aggregated power for the investigated year amounts to 25,9 MW. Still, a new subscripted power of 21,8–24,9 MW is theoretically deemed to be achievable. The most likely outcome however is thought to be a lowering of the subscripted power to at least 23,4–24,4 MW, having taken the composition of type of heating systems as well as the most likely customer participation into account.
2

Batterilagring För Södra Hallands Kraft : Nyttor Och Potential

Ahlgren, Alma January 2024 (has links)
With the goal of achieving 100% fossil-free electricity production by 2040 in Sweden, the electricity system is expected to undergo significant changes due to increased electrification, digitalization, and automation. Battery storage will become crucial for supporting and stabilizing the power grid, as well as balancing demand and production, which reduces the risk of overload. It also contributes to increased grid flexibility and a smoother, more efficient use of the power network. The purpose of this work is to develop a deeper understanding of battery storage technology and its potential impact on the Swedish power grid to meet current and future energy needs. The method examines the energy usage patterns of Södra Hallands Kraft to appropriately size a battery storage system and determine its operational scenario. It is essential to consider both the battery’s power (W), which describes the total amount of power that can be delivered, and storage capacity (Wh), which describes the total amount of energy that can be stored. By implementing battery storage systems, the share of renewable energy usage can increase, and dependence on external energy sources can decrease. This work examines different threshold levels: 60 MW, which requires a 33 MW/ 735 MWh battery; 65 MW, which requires a 28 MW/ 414 MWh battery; and 70 MW, which requires a 23 MW/ 153 MWh battery. These thresholds successfully reduce all power peaks between 2019 and 2023. This also leads to significant economic savings in the form of reduced grid fees. / Med målet att uppnå 100% fossilfri elproduktion till år 2040 i Sverige, förväntas elsystemet genomgå betydande förändringar på grund av ökad elektrifiering, digitalisering och automatisering. Batterilager blir viktiga för att stödja och stabilisera elnätet, samt balansera efterfrågan och produktion som minskar risken för överbelastning. Det bidrar även till en ökad flexibilitet på elnätet och en jämnare och mer effektiv användning av elnätet. Syftet med arbetet är att utveckla en djupare förståelse för batterilagringsteknik och dess potentiella påverkan på det svenska elnätet för att möta dagens och framtidens energibehov. Metoden undersöker energianvändningsmönstren för Södra Hallands Kraft, för att kunna dimensionera ett batterilager med lämplig storlek och driftscenario. Det är därför viktigt att beakta både batteriets effekt (W), som beskriver den totala mängd effekt som kan levereras, och lagringskapaciteten (Wh), som beskriver den totala mängd energi som kan lagras. Genom att implementera batterilagringssystem kan andelen förnybar energianvändning öka och beroendet av externa energikällor minska. Arbetet undersöker olika tröskelnivåer på 60 MW som kräver ett batteri på 33 MW/ 735 MWh, 65 MW som kräver ett batteri på 28 MW/ 414 MWh, samt 70 MW som kräver ett batteri på 23 MW/ 153 MWh. De lyckas minska alla effekttoppar mellan 2019 – 2023. Detta bidrar även till betydande ekonomiska besparingar i form av minskade elnätsavgifter.

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