What is actually on the roof, and in the plant room
Forty-four solar panels, and behind them one of the most capable off-grid systems Victron Energy builds: a bank of MultiPlus-II inverter/chargers, MPPT solar charge controllers, a monitored lithium battery bank and the switchgear to tie it all together.
It is not a token installation bolted on for a certificate. On a sunny day the house runs 100% off-grid — everything you use, from the induction hob to the air conditioning, is coming off the roof. Across the year as a whole, the system generates around 80% of all the power the house needs.
Hot water, from the sun as well
Separately from the panels that make electricity, the house has solar thermal collectors that heat the water directly. For most of the year, every hot tap and every shower in the house is heated by the sun — and nine bedrooms' worth of showers is not a small load.
When the weather will not do it, an electric immersion heater takes over — and that heater is itself running off the solar system. Only if both of those fall short does the house draw from the grid, and it does so as a last resort rather than a default.
What this means while you are staying
Nothing, and that is the point. The batteries cover the house overnight and ride straight through the regional power cuts that are a normal part of rural Istrian life. Guests do not get a dimmed-lights, save-the-power holiday, and they do not get an outage either — the changeover is seamless and there is nothing to switch, monitor or ration.
The practical upside is a quiet house. No generator, no hum, and a garden that is not competing with machinery.
Why two things are still charged separately
Almost everything at Villa Bucks is included in the rate. Two things are not: EV charging at €0.50 per kWh and pool heating at €20 per day. Both are optional, both are published rather than sprung on you at the door.
They are charged because they are the two loads large enough to move the needle on a system this size, and because building it was a significant investment. Asking the guests who actually use those two things to contribute is what keeps the rate itself honest for everyone who does not.
Where we are trying to get to
The target is 100% carbon neutral. Eighty per cent of the way there is good, and it is not finished — the array has been extended, and the intention is to keep closing that last stretch rather than declare victory early.
Alongside the energy side we are working on what the property contributes locally: the olive garden and its planting, the wildlife the grounds support, and spending with the businesses in Višnjan and the villages around it rather than importing everything from the coast.
A day on the system, hour by hour
The chart below is a real reading rather than a brochure illustration — midnight to midday on 26 August 2026, taken straight off the monitoring dashboard.
Overnight the house draws well under a kilowatt-hour an hour and the battery sits on its reserve. From six in the morning the roof starts producing, and by seven it has already overtaken the house. Between nine and eleven the panels make roughly twice what the whole property is using, and everything spare goes into the battery — which climbs from 2.4 kWh to over 14 kWh by midday. That stored surplus is exactly what runs the house after dark.