Fiedler Holiday Homes PV Battery Demand Charges (2022)

A techno-economic study of grid-connected PV and battery systems for holiday homes in Sälen (Dalarna, SE3), with a focus on demand charges (effektavgifter), funded by Dalarna University, Tillväxtverket and Region Dalarna. Open access.

Method

• Hourly use for four randomly chosen holiday homes in 2019; load 2 has peaks all year, the others mainly in the winter ski season. Systems sized and compared by 30-year net present cost in HOMER Grid, with battery sizes 5, 10 and 15 kWh, against a grid-only reference and PV-only.
• Three real tariffs for small customers with a 16 A three-phase connection: utility 1 with high demand charges, utility 2 with moderate ones, and a third without (the tariff table is not in the extracted text). Spot prices for SE3, 2019.
• Incentives modelled: a 0.6 SEK tax credit per exported kWh, 0.05 SEK/kWh grid compensation, a 15 % tax reduction on PV and a 50 % tax reduction on batteries.
• The battery dispatch is HOMER Grid’s advanced strategy, which forecasts peaks and prices; the authors say such control is not yet fully in available products.

Results

• PV and PV-plus-battery both have much lower cost than the reference; payback 12 to 17 years (utility 1) and 13 to 19 years (utility 2).
• A battery adds clear value over PV alone only where demand charges are high and the load peaks across the year. With the moderate tariff (utility 2), PV plus battery was less profitable than PV alone for all four loads, with barely any difference for 10 and 15 kWh. Without demand charges a battery gave no extra savings.
• The battery’s effect is on the demand charge; energy costs barely differed with or without a battery because the 0.6 SEK credit made a self-used kWh worth the same as an exported one.
• With the tax credit, net savings against grid-only were 32 to 42 %; without it, 10 to 22 %. Doubling the demand charges raised the battery’s savings and lowered PV-only savings; the biggest savings were with a 15 kWh battery, high demand charges and no tax credit.
• Abstract versus conclusions: the abstract says systems with batteries were “equally profitable” as PV alone when demand charges applied and slightly better in the high-peak case; the conclusions call battery systems “highly profitable” in these environments, depending on demand-charge level, tax credits and load profile. Both statements refer to savings against the grid-only case.
• The authors expect batteries to become profitable for single-family homes as demand charges spread, especially with regular peaks such as EV charging, and say further revenue from frequency control or peak-hour demand reduction was not modelled.

Relevance

The main Swedish study of a battery against demand charges; it shows the saving depends on the size of the charge and on peaks across the year. Cited through Rinio in Source - Swedish Household PV-BESS Studies (Rinio 2025, Ollas et al 2026); see Elnätsavgift — What Determines Your Bill and Energy Storage. The study predates the 2025 wave of effektavgifter and the 2027 changes.

Limits of this summary

The tariff table and figures were not in the extracted text; savings are quoted as given in the running text. The load-profile and cost details in the figures were not read.