Without the panels, last winter’s import need would have been almost 9 TWh. It was 6.8 TWh. That is Swissolar’s calculation from BFE data in Solarmonitor Schweiz 2026, presented at the Batteriekongress on 20 October. Over winter 2025/26, Switzerland’s 9.5 GW of photovoltaics on roofs, façades and infrastructure produced about 2.2 TWh. Per the report, that is «über 55 Prozent des mittleren Importsaldos der letzten 10 Winter». Most people still picture Swiss solar as a summer flood. It is now a winter instrument too.

According to Swissolar, annual output rose 33 % in 2025 to about 8 TWh, or 13.7 % of 58 TWh of final consumption. Mean specific yield rose from 820 to 900 kWh/kW. The association expects about 17 % for 2026. New installations fell in 2025 for the first time since 2017, which the report calls «eine Phase der Konsolidierung».

The physics of a May noon

From April to August 2026, by Swissolar’s analysis, PV covered more than 23 % of domestic consumption on average, and about 27 % in July. In the same months some nuclear units were throttled or taken offline because their river water ran too warm. The record feed-in of about 6.6 GW did not come in a heatwave. It came at 13:00 on 22 May. The report cites Swiss Energy-Charts for the reason: «Grosse Hitze reduziert die Leistung von Solarmodulen». As a silicon cell heats up, its open-circuit voltage drops, and crystalline modules typically lose about 0.3–0.4 % of power per kelvin. A cool, clear spring noon beats a July afternoon.

←TODAY: 9.5 GW of Swiss PV made 2.2 TWh last winter, and 93,500 behind-the-meter batteries hold 1.4 GWh.
→3012: Every Zurich envelope is metered by the hour, and buildings trade their timing, not their kWh.
Fulcrum: Once a kilowatt-hour is priced by the hour, the drawing has to show the hour too.

The battery turn

Behind-the-meter storage capacity grew by almost 70 % in 2025. The total is now about 1.4 GWh across roughly 93,500 units. The share of PV systems with a battery rose from 18 % in 2023 to about 28 % at the end of 2025. The BFE price observation study puts the median for 20–30 kWh PV-coupled storage at about 504 CHF/kWh. Daniel Schäubli, key account at Krannich Solar AG, says it in the report: «Jetzt kommt die Speicherzeit». The people who made that happen are rarely named: the installers and electricians who wired in 93,500 systems, and the grid-operator staff who registered each one.

Where it lands on the drawing

The new feed-in rule pays small producers the day-ahead spot price at the moment of injection, with transition rules running to end 2027. Systems up to 30 kW get a minimum premium of 6 Rp./kWh. Local electricity communities (LEG) have been allowed since early 2026, and Swissolar extrapolates about 1,860 of them by end June. Together, these make when a building produces, stores and consumes power part of the design brief. Swissolar’s yield factors are 950 kWh/kW for roofs and 550 kWh/kW for façades. A façade kilowatt therefore delivers under 60 % of a roof kilowatt’s annual energy. Specify it knowingly, for the surface it adds, not on the annual total alone.

Atelier: For a Zürich studio detailing a multi-family block, the battery cabinet and the energy-management system are now plan decisions, not something added after handover. They need a room and a cable route. Monday move: ask your electrical engineer for the client’s winter evening load profile (17:00–21:00) before the next design review, and pin it next to the PV layout.

Hack: Size the battery against the winter evening hours, not the annual kWh. Take four evening hours from a smart-meter export, allow for round-trip loss and usable depth of discharge, and price the result at the BFE median. Replace the placeholder loads with the meter’s own numbers. The same lines run inside a GhPython component next to your Grasshopper roof model.

evening_kwh = [3.1, 2.8, 2.6, 2.2]   # 17-21 h, winter weekday (placeholder)
need = sum(evening_kwh) / 0.90        # round-trip efficiency
size = need / 0.90                    # usable depth of discharge
print(f"{size:.1f} kWh, about CHF {size*504:,.0f}")  # 13.2 kWh, about CHF 6,658

2030, by scenario

Swissolar lays out three paths. The Bundesrat target path reaches 18.7 TWh of PV and needs about 3.3 GW of new capacity a year. The Minimalszenario reaches about 14.7 TWh, misses the 2030 target by 4 TWh, but stays on track for 2050. The Bremsszenario reaches about 13.3 TWh. Seen from the late 2070s, the lesson was never the panel count. It was the timing. The executive summary, signed by Matthias Egli, Wieland Hintz and Maja Schoch, names what matters more: «wie gut Solarstrom, Speicher, Netze und flexible Verbraucher zusammenspielen».

Open your current project and plot its hourly solar curve against its winter evening load before the battery gets specified.