UK Dairy and Grain Drying Solar PV Three Phase Integration Guide

Key Takeaways

• Dairy parlours and grain drying facilities require balanced three-phase electrical power to operate heavy inductive motors and thermal equipment.
• Under Defra's Improving Farm Productivity scheme, farms can obtain 25% grant funding for solar equipment to improve energy resilience.
• Solar grants range between £15,000 and £100,000 per business, requiring battery storage integration.
• Power diverters redirect surplus daytime solar power into thermal heat stores for parlour washdown water.
• Panels must be installed on farm buildings capable of bearing the load, or on irrigation reservoirs using floating pontoons.
• Contractors must assess connection parameters to determine whether the Distribution Network Operator (DNO) must be notified before or after installation.

Energy Dynamics: Dairy Parlours and Grain Stores

Dairy and arable farming feature distinct, energy-intensive load profiles:

• Dairy Milking Parlours: High demand occurs during twice-daily milking cycles (early morning and late afternoon), requiring simultaneous operation of vacuum pumps, bulk milk tank refrigeration compressors, and high-temperature water heaters.
• Grain Drying Facilities: Seasonal harvest periods require continuous operation of large three-phase centrifugal ventilation fans and heaters to reduce grain moisture content.

To offset high utility bills, farms utilize the installation of solar equipment to increase both energy resilience and the take-up of renewable energy generation on farms.

Defra Grant Funding Rules

Farm enterprises investing in three-phase solar can access funding under the Farming Investment Fund:

• Funding Scope: For solar equipment, the minimum grant available is £15,000 and the maximum grant available is £100,000. The grant will cover up to 25% of the cost.
• Eligibility: The grant is open to horticultural and farm businesses. Contractors from those sectors are eligible to apply for grants towards robotic equipment, but not solar equipment.
• Operational Intent: An eligible solar PV system should be mainly for farm power and installed on farm buildings, not on a residential property.

Mandatory Battery Storage and Thermal Diverters

Maximizing solar self-consumption in agricultural applications requires integrated energy storage:

• Battery Pairing: The solar energy is stored in a battery or batteries. The systems can be connected to export surplus power back to the National grid.
• Thermal Buffering: Eligible items include solar PV panels, solar batteries, inverters, utility meter, electrical grid connection, and power diverters that redirect excess solar energy to power storage (for example heat stores).
• In dairy facilities, excess midday generation is diverted into pre-heating washdown water tanks, cutting water heating costs.
• In arable operations, battery storage discharges during late-afternoon peak grid tariff windows while running grain aeration fans.

Siting Restrictions and Structural Safety

Defra establishes strict location parameters:

• Supported Mountings: Solar panels can be installed on an irrigation reservoir (including the supporting floating cradle), or on farm buildings that are able to support them.
• Structural Duty: It’s your responsibility to make sure that a roof intended to take solar panels, is able to support them.
• Exclusions: Items which are not eligible include ground base solar panels, replacement or reinforcement of roofs, construction of farm buildings, and upgrading of existing solar panels.

DNO Coordination and Agricultural Planning

Connecting three-phase solar equipment requires regulatory alignment:

• DNO Notification: If you are planning to install an energy device in your home or small business, you are required to register your energy device with your Distribution Network Operator ( DNO ), the company that is responsible for bringing electricity to the property where you are installing the device.
• Contractor Duty: Installation contractors must examine the energy device and required connection to determine whether the Distribution Network Operator needs to be informed before or after installation.
• Planning Context: Planning Class A governs agricultural development on units of 5 hectares or more.