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Is there money in timing? - Parameter based comparison of energy storage alternatives within a Swedish residential context

Engström, Jesper LU (2025) AEBM01 20251
Division of Energy and Building Design
Abstract
This study provides a simulation-based comparison of two energy storage alternatives, lithium-ion battery storage and a timer controlled domestic hot water (DHW) tank, within a Swedish residential context. The timer strategy explores the use of low-cost thermal storage to reduce electricity costs, especially in light of changing photovoltaic (PV) incentives. Different scenarios are modelled to compare strategies for storing PV generation versus selling the surplus, but also for utilizing price variations during off-peak hours with or without PV systems. TRNSYS is used to model and simulate varying system configurations for loads, PV generation and energy storage capacities. Consumer costs are calculated based on real consumption,... (More)
This study provides a simulation-based comparison of two energy storage alternatives, lithium-ion battery storage and a timer controlled domestic hot water (DHW) tank, within a Swedish residential context. The timer strategy explores the use of low-cost thermal storage to reduce electricity costs, especially in light of changing photovoltaic (PV) incentives. Different scenarios are modelled to compare strategies for storing PV generation versus selling the surplus, but also for utilizing price variations during off-peak hours with or without PV systems. TRNSYS is used to model and simulate varying system configurations for loads, PV generation and energy storage capacities. Consumer costs are calculated based on real consumption, irradiation and spot-prices matched for SE4 in 2022. After the removal of tax deduction, the results indicate that electricity costs without any energy storage ranged from 324 SEK/year to 4 293 SEK/year. In contrast, matching DHW heating with PV generation using the timer, resulted in savings ranging from 141 SEK/year to 6 796 SEK/year. Battery storage, which adopted both PV generation and off-peak charging, saved between 488 SEK/year to 2 483 SEK/year. When evaluated without PV system, timer for off-peak hours saved between 1 546 SEK/year and 7 245 SEK/year compared to purchasing electricity without timer. Importantly, the PV matching timer outperformed the battery storage in 19 % of the cases and achieved savings that were more than double of the battery’s savings limit, in 11 % of the cases. (Less)
Popular Abstract
"Affordable energy storage: How timers can help Swedish PV homeowners cut electricity costs"
Can a cheap timer, connected to a domestic hot water tank, be more profitable than Lithium-ion battery storage? Energy storage is considered key in the renewable energy transition. But with upcoming policy changes, Swedish PV homeowners’ risk having the financial return of their PV systems reduced. This study compares two energy storage solutions for cutting costs in various system configurations and system sizes. The goal with the project was to help homeowners find an affordable way to save money and improve their investment in PV modules.
The findings from the calculations are:
• Without energy storage, the removal of tax benefits connected... (More)
"Affordable energy storage: How timers can help Swedish PV homeowners cut electricity costs"
Can a cheap timer, connected to a domestic hot water tank, be more profitable than Lithium-ion battery storage? Energy storage is considered key in the renewable energy transition. But with upcoming policy changes, Swedish PV homeowners’ risk having the financial return of their PV systems reduced. This study compares two energy storage solutions for cutting costs in various system configurations and system sizes. The goal with the project was to help homeowners find an affordable way to save money and improve their investment in PV modules.
The findings from the calculations are:
• Without energy storage, the removal of tax benefits connected to selling electricity from PV modules could increase PV homeowners’ electricity bills anywhere from 324 SEK to
4 293 SEK per year.
• Battery storage offers savings of 488 SEK to 2 483 SEK per year, depending on sizes and systems.
• The timer used for shifting water heating to sunny hours, saved up to 6 796 SEK per year.
• When set to heating at night using cheaper off-peak electricity, the timer saved 1 546 SEK to 7 245 SEK per year of bought electricity costs. This option is also possible for homes without PV-modules.
This study shows that a low-cost timer can be a cost-effective alternative to batteries, especially in homes with high hot water usage. The timer solution cuts electricity costs and does so at a much lower investment cost than battery systems. (Less)
Please use this url to cite or link to this publication:
author
Engström, Jesper LU
supervisor
organization
course
AEBM01 20251
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Parametric, TRNSYS, energy, storage, battery, tank, timer, PV, spotprice
language
English
id
9213633
date added to LUP
2025-10-09 14:24:43
date last changed
2025-10-09 14:24:43
@misc{9213633,
  abstract     = {{This study provides a simulation-based comparison of two energy storage alternatives, lithium-ion battery storage and a timer controlled domestic hot water (DHW) tank, within a Swedish residential context. The timer strategy explores the use of low-cost thermal storage to reduce electricity costs, especially in light of changing photovoltaic (PV) incentives. Different scenarios are modelled to compare strategies for storing PV generation versus selling the surplus, but also for utilizing price variations during off-peak hours with or without PV systems. TRNSYS is used to model and simulate varying system configurations for loads, PV generation and energy storage capacities. Consumer costs are calculated based on real consumption, irradiation and spot-prices matched for SE4 in 2022. After the removal of tax deduction, the results indicate that electricity costs without any energy storage ranged from 324 SEK/year to 4 293 SEK/year. In contrast, matching DHW heating with PV generation using the timer, resulted in savings ranging from 141 SEK/year to 6 796 SEK/year. Battery storage, which adopted both PV generation and off-peak charging, saved between 488 SEK/year to 2 483 SEK/year. When evaluated without PV system, timer for off-peak hours saved between 1 546 SEK/year and 7 245 SEK/year compared to purchasing electricity without timer. Importantly, the PV matching timer outperformed the battery storage in 19 % of the cases and achieved savings that were more than double of the battery’s savings limit, in 11 % of the cases.}},
  author       = {{Engström, Jesper}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Is there money in timing? - Parameter based comparison of energy storage alternatives within a Swedish residential context}},
  year         = {{2025}},
}