Farm shop and milk vending machine on your own solar power?

Yes, if the system is sized on your machines and your opening hours. A semi-off-grid system runs the farm and the shop on solar power and a battery. The grid steps in when the sun and the battery fall short. The battery delivers the peaks of the pasteuriser, carries the evening sales and keeps the cooling going when the grid fails.

You sell milk at the gate, and maybe yoghurt, cheese or ice cream from your own milk. The shop has fridges and a freezer, the vending machine runs day and night, and the card terminal must work. All of it hangs on the same connection as the parlour and the milk tank.

What many farmers only notice later is the stacking. The pasteuriser, the ice cream machine and the milk tank want power at the same moments. That sets a new peak, or asks for a heavier connection. And one power cut on a warm day can cost you a full vending machine of milk.

A farm in Tielt faced a switch to medium voltage if it wanted to grow. It chose semi-off-grid instead: the battery gives the extra power, and the grid only tops up when the battery runs low. With 45 kVA and 123.2 kWh, the farm expects to take only 5% of its yearly use from the grid. Surplus solar power heats boilers.

What uses electricity in a farm shop and an on-farm dairy?

A few heavy machines that run for an hour, and cooling that never stops. The heavy machines set the power you need. The cooling sets the energy, day and night.

Sources: Aktro milk vending machines, Milky 100-litre pasteuriser (Coffia), electric pasteuriser 50 to 150 litres (Foodtech Process) and Coldelite batch freezers (Perfect Ice Solutions).

Heat is the big user. Batch pasteurising holds the milk hot for about half an hour, while faster systems heat it to 72 °C for at least 15 seconds. After heating, the milk must be cooled down again. So one batch of yoghurt or cheese milk asks for heating power first and cooling power right after.

Why does the farm shop push up your peak demand?

Because the dairy side business runs in the same hours as the farm. In the morning the parlour, the milk tank and the pumps already run. Start the pasteuriser and the ice cream machine then, and the loads stack up.

In Flanders, part of your grid costs depends on your highest quarter-hour peak of each month. The average of your last 12 monthly peaks counts. One busy production morning can therefore weigh on your bill for a year. Our article on how the capacity tariff works for businesses explains the calculation, and how to lower your peak demand gives the general levers.

On a UK farming forum, a dairy farmer listed his loads: the parlour, fans, an ice builder, hot water and one house. His neighbours debated whether batteries were worth it at all. That is the right question: a battery pays when it cuts a peak or saves a batch, not when it only stores surplus.

What happens to your milk vending machine in a power cut?

It stops cooling, and the rules decide what happens next. The Belgian food agency FAVV sets clear hygiene rules for raw milk vending machines.

• 0 to 6 °C. The milk in the tank and in the pipe to the tap must stay between 0 and 6 °C.
• Automatic block. The machine must block sales when that temperature is no longer respected.
• The milk is lost. After a block caused by the cooling, all milk is removed and the machine is cleaned and disinfected. That milk may not be sold for human consumption.
• Write it down. Every power cut or cooling problem is recorded and kept for at least 6 months.

Many machines send a text message with a temperature alarm. That warns you, but it does not keep the milk cold. A battery on the circuit of the vending machine and the shop fridges does. The card reader keeps working too, so you do not lose the evening sales either.

Cold rooms follow the same logic: read how long a battery keeps a cold room cold. For the choice between a battery, a UPS and a generator, see emergency power for businesses.

Solar by day, sales in the evening: how does a battery bridge the gap?

It stores the midday surplus and gives it back when the shop is busy and the sun is gone. Many farm shops sell most in the late afternoon, the evening and at the weekend. The vending machine sells around the clock.

Solar panels on a large barn roof produce much more at noon than the farm uses. Without storage, that surplus goes to the grid at a low price. With a battery it runs the evening fridges, the lights and the vending machine. Our article on whether solar panels still pay off on a business roof covers the solar side.

Winter is the weak spot. In December the panels give about a quarter of their June output, while the cooling keeps running. That is why a farm shop is usually a semi-off-grid case, not a fully off-grid one. The grid stays as the back-up for the dark months.

Heavier connection, battery behind the meter or semi-off-grid: what fits a farm with a shop?

It depends on how close you are to your connection limit and on what must keep running in a cut.

Already have two connections on the site? Read whether one battery can combine two connections. A dairy farm in Lokeren avoided medium voltage with solar, wind and a battery. Our article on solar and batteries on a farm covers the main farm system.

How big should the battery and inverter be for a farm shop and dairy?

Size the inverter on the machines that run together, and the battery on your evenings and your back-up hours.

We measure before we size. Your quarter-hour data from the digital meter shows when the farm and the shop peak, and how big the solar surplus is.

Which rules apply to a farm shop and a milk vending machine?

Food rules for the milk, electrical rules for the installation. The main points:

• FAVV. A farm registered for milk production may sell its own raw milk through a vending machine within 80 km, without an extra activity. The circular sets temperature, cleaning and records.
• Electrical inspection. A new electrical installation, including a battery system, is inspected by an accredited body before use (AREI in Flanders, RGIE in French).
• Capacity tariff (Flanders). Your monthly quarter-hour peak counts in your grid costs. Rules in Wallonia and Brussels differ.

When is a battery not worth it for a farm shop?

When the sales are small or the loads are light.

• Only a vending machine, few litres a day: a machine up to 960 W barely moves your peak. A temperature alarm and a clear plan for cuts may be enough.
• Sales that do not take off: a Belgian dairy farmer (RTBF, 2012) saw sales fall from 35 to 40 litres a day to under 10. He removed the machine.
• A shop open a few hours on Saturday: the fridges can often be bridged by keeping the doors closed.
• Plenty of room on your connection and no costly peaks: solar panels alone may do most of the work.

Is your connection too weak for new machines? Read what to do when a 3x230 V connection is too weak.

What happens when you contact us about your farm shop or dairy?

We start with your machines, your milking times and your opening hours.

1. Step 1: You tell us which machines you run and when the shop is open. Where possible, we measure the real consumption and peaks first.
2. Step 2: Our engineering office calculates the solar panels, the inverter power, the battery and the back-up circuit.
3. Step 3: We install, test and commission the system.
4. Step 4: You follow production, battery and use in the app and the VRM portal, with alerts when something is wrong.

Our semi-off-grid systems keep the farm working when the public grid fails, and can later become fully off-grid. The farm in Tielt shows how it works on a farm.