The Estonian Dairy Farm Project: Enhancing Sustainability with Microgrid Solutions

The Estonian Dairy Farm Project

This project, operational since 2023, is located in a suburban area of Tallinn, Estonia, at a specialized milk processing factory. The local power grid's instability and high electricity prices have hindered the factory's development. Power supply fluctuations have led to disruptions in critical processes, resulting in waste of semi-finished products. The key process equipment at the dairy farm requires a significant load of 80 kW, including approximately 30 kW for AC motors, 30 kW for electric heating equipment, and the rest for lighting and auxiliary facilities. The client's factory roof has already been equipped with a 102 kWp photovoltaic (PV) system, with a requirement to integrate an energy storage system to support PV as auxiliary power during outages. The operating temperature ranges from -17°C to +31°C.

Client Objectives:

Peak shaving: Utilize the energy storage system to capitalize on electricity price differentials and reduce costs.

Backup power: Use the energy storage system as a backup power source during grid faults or outages.

Microgrid integration: Establish a microgrid composed of solar energy and storage to operate in parallel with or independently from the main grid.

P18 Solution (Project Design)

To meet the client's needs, we proposed a solution using a 120 kW off-grid microgrid system.

The microgrid system comprises a 102 kWp distributed PV system, two sets of 60 kW/129 kWh energy storage systems, energy storage inverters, an energy management system, and the client's distribution system. Please refer to the system diagram.

(1) Distributed PV: Utilizes 320 W monocrystalline PV modules with a total capacity of 102.4 kW, connected to the grid in AC.

(2) Battery storage: Consists of 336 units of 3.2V 120Ah lithium iron phosphate batteries with a capacity of 129 kWh.

(3) PV-battery inverters: Employing two 30 kW PV-battery inverter modules for bidirectional DC/AC conversion.

(4) Data services: Energy storage inverters upload data to the energy management system, which then transmits relevant data to cloud servers.

Solution (Configuration) - Illustrated

Microgrid Functions:

PV integration to support loads and serve as backup during outages.

(1) Peak shaving: Automatically supplements power when load exceeds set limits and stops when load decreases.

(2) Off-grid backup: Provides power to electrical devices during grid disconnection to ensure continuous operation.

(3) Remote monitoring: Receives dispatch instructions for power output from the grid.

(4) Remote upgrades: Allows remote upgrades of internal equipment.

Project Highlights/Significance:

Reliable operation in low-temperature environments.

Addressed the issue of frequent power outages, ensuring continuous production.

Cost savings for the client through peak shaving.

Challenges During Implementation:

Miscommunication during initial technical discussions with the client led to wiring modifications during implementation, resulting in additional costs. Clear technical briefings and training for agents are essential to ensure clients understand the situation and provide necessary information accurately.