Producing solar power is not enough – it must be consumed where it is generated
Hardly any economic sector is as predestined for photovoltaics as agriculture. Large roof areas on stable buildings, machine halls, and storage barns, manageable shading, short connection paths to their own consumers. Nevertheless, many farms feed 60 to 80 percent of the generated electricity into the public grid on sunny days – at tariffs that no longer cover the actual electricity prices. At the same time, these same farms pay for expensive grid electricity in the evening when the milking robot, cooling, or feed mixing system are running.
A power storage system in agriculture solves precisely this imbalance. It shifts solar power from midday production to high-consumption evening and night hours – and suddenly turns a 200 kWp system on the stable roof into a self-sufficient energy system.
Why agricultural businesses, in particular, benefit from battery storage systems
Agricultural farms have three characteristics that make them significantly more interesting for commercial storage systems than traditional single-family homes:
Firstly, a high, continuous base load consumption. Dairy farmers, in particular, know this phenomenon: The milking robot runs 24/7, as does milk cooling, ventilation, manure removal, and lighting. An average dairy farm with 120 cows and an automatic milking system quickly consumes 30,000 to 100,000 kWh per year – distributed throughout the day and night.
Secondly, there is often a very large existing PV system that produces significantly more at times of maximum generation than the farm can currently consume. Without storage, this surplus goes into the grid for a few cents. With storage, the same kilowatt-hour in the evening costs nothing extra.
Thirdly, agricultural businesses are particularly susceptible to power outages. If the power goes out in an office building, the lights go out. If it goes out in a dairy stable, it can jeopardize animal welfare, milk quality, and economic existence within a few hours.
The storage system turns the milking robot into a solar milking robot
A typical practical example: A dairy farm with 150 cows, two milking robots, and a 250 kWp PV system generates surpluses of 400 to 900 kWh per day in summer. The milking robot itself consumes only 15 to 25 kWh daily – but 70 percent of that is when the sun isn't shining.
With a suitably dimensioned battery storage system, surplus solar power goes into the battery and powers the milking operation, milk cooling, and stable infrastructure at night. The self-consumption rate typically increases from 25–35 percent to 65–75 percent. At current electricity prices, a commercial storage system in agriculture pays for itself in five to seven years – with a lifespan of 15 years or more.
Two storage sizes that suit agricultural businesses
When dimensioning a power storage system for the farm, two factors are crucial: the installed PV output and the daily self-consumption. For most agricultural businesses, two systems are particularly suitable.
For medium-sized farms up to approx. 300 kWp PV: MONA Island 233
The MONA Island 233 offers 233 kWh storage capacity with 105 kW charging and discharging power – enough to power a dairy farm with a milking robot, cooling, and residential building completely overnight. The system uses safe lithium iron phosphate cells (LiFePO₄), is black-start capable ex works, and thanks to its IP54 protection class, is also suitable for outdoor installation at the stable. If you want to expand later, you can connect up to ten cabinets in parallel – up to 2,330 kWh. Typical applications include dairy farms with 80 to 180 cows, pig fattening farms with energy-intensive ventilation, and arable farms with cooling or drying facilities.
For large farms, cooperatives and biogas plants: MONA Island 418
If daily consumption significantly exceeds 500 kWh or if several business segments need to be supplied simultaneously, upgrading to the MONA Island 418 is worthwhile. With 418 kWh storage capacity and optionally 125 kW or 215 kW power (also at 690–800 volt level), the system is designed for large agricultural infrastructures. It easily covers milking centers, feed mixers, cold stores, and the farm workshop simultaneously. Here too, LiFePO₄ technology guarantees maximum cell safety, and IP55 on the cabinet and IP67 on the battery packs ensure robust outdoor use. The MONA Island 418 is modularly scalable up to 20 units (up to 8.36 MWh) – perfect for farming communities, machinery cooperatives, or agricultural biogas combined operations.
Emergency power: the underestimated added value for the stable
One point that particularly convinces dairy farms: Both MONA Island storage systems are black-start capable. If the public grid fails, be it due to thunderstorms, transformer station malfunctions, or construction work, the storage system takes over the supply of critical consumers within seconds. The milking robot continues to milk, cooling remains stable, and ventilation continues to run. What used to be only achievable with a diesel emergency generator is now done by the battery storage system – silently, without fuel, without maintenance on the day of failure.
Anyone who also has an existing diesel generator can parallelize it with the storage system via an ATS control to bridge even multi-day outages.
Profitability: more than just self-consumption
A power storage system on the farm pays off through several levers simultaneously:
The most important lever is the increase in self-consumption, e.g., from 30 to 70 percent. For a farm with 40,000 kWh annual consumption and the current commercial electricity price, this quickly means around 9,000 euros in savings per year. In addition, there is peak shaving, avoided grid usage fees, and, depending on the tariff model, additional revenue from flexible charging at favorable exchange electricity prices. The cloud-based energy management MONA Connect automatically controls these optimizations in the background.
Not to forget: In many federal states, there are investment subsidies for agricultural storage systems (partly through KfW, partly through state-specific programs such as Bavaria's "EigenStromBonus" model or Lower Saxony's agricultural investment funding).
Conclusion: The next logical investment after the PV system
Photovoltaics was the first major energy transition investment for farmers. Power storage is the second, and in many cases, the economically even better one. It transforms the farm from a mere electricity supplier to the grid into a largely self-sufficient energy cell. Especially for dairy farmers, poultry farms, and special crops with high continuous consumption, the combination of a PV system and battery storage is more economically viable today than ever before.
Whether the MONA Island 233 for the classic family farm or the MONA Island 418 for large structures – precise dimensioning is crucial. We would be happy to calculate with you how much solar power currently flows unused into the grid on your farm and how much of it could go into your tank, your stable, and your milking robot in the future.