Grid Ancillary Services


FRIEM ESS are designed to respond to the new requirements of generating and distributing energy in the network,

with a fast time responsive and efficient management of the power flows between the storage system and the point of interconnection. Based on the modular concept of FRIEM Hybrid Inverters, the solution is extremely flexible and allows to optimise the cost/performance ratio. With over 65 years of experience in High Power Converters and Automation, the ESS includes all the necessary components from the DC side (storage means) to the MV or HV connection point, with local and remote control and monitoring systems.

FRIEM ESS main advantages:

  • Design and technologies based on 65+ years experience;
  • Flexible and tailored solution through modular concept;
  • AC or DC links for complete integration of all the energy sources;
  • Different type of storage technology available:
    • Lead batteries;
    • Li-Ion batteries;
    • Red-Ox flow batteries;
    • Hidrogen storage;
  • Integrated solution including all the main components;
  • Frequency regulation: in case of Grid frequency increase or decrease, the Energy Storage System is charged or discharged with an extremely rapid time response.
  • Spinning reserve: the Energy Storage System is charged and ready to respond to a Grid (generation or transmission) outage. The time response is adjustable according to the network requirements. The operation of the generators can be optimised since idle capacity is no more necessary.
  • Voltage regulation: in case of Grid voltage increase or decrease, the Energy Storage System is charged or discharged with an extremely rapid time response.
  • Capacity firming: power generation by a renewable source can be maintained at a defined level for a period of time having the ESS compensating the energy. Voltage and power swings on the network are smoothed as well.
  • Load leveling: the excess of the energy produced can be stored and be released during high demand periods. Therefore grid or generators upgrades can be postponed and the price of energy can be maximised.
  • Peak shaving: in case of variable loads, the energy peak demand can be supplied by the ESS. Therefore network or generation investments can be avoided or postponed and the cost of energy can be minimised. A typical application is in Railroad (Railway, Metro, Tramway and Trolleybus) where the accelerating or breaking of trains generate peaks (in demand or supply) that can be absorbed by the ESS.
  • Power quality: thanks to the fast response time, the ESS helps to protect the loads against short duration events (voltage dips, frequency variation, etc.) that affect the quality of the energy.


Download FRIEM Energy Storage brochure