Campania Region, Italy

NAS Battery used for Investment Deferral


Mitigation of Transmission Congestion and Losses

Owner Terna S.p.A.
System Size Total 34.8MW/250MWh
Commissioning Operation Date 2015
Location Campania Region, Italy


  • Deployments of renewable energy sources, such as wind and PV, have increased rapidly in Italy due to aggressive incentives for renewables. Because of the environmental and geographic characteristics of Italy, most of the installed wind capacity is concentrated in southern Italy.
  • The massive growth of wind generation in the south caused congestion on the transmission lines carrying this energy to northern Italy. Terna, the Italian Transmission System Operator (TSO), was finding it increasingly difficult to manage the grid. Terna had to frequently ask wind farm operators to curtain wind generation to reduce congestion in the transmission lines.


  • Terna deployed NGK's NAS® battery system to allow excess wind energy to be stored rather than curtailed. This stored energy is shipped north when the transmission lines are not congested.
  • Terna selected the NAS system because it is the world's most proven, most widely deployed and most reliable grid-scale battery storage system. NAS system are ideally suited to the repeated deep cycling needed to capture renewables on a daily basis. Terna's deployment was of 34.8MW (250 MWh) of NAS storage (two sites of 12MW and one site of 10.8MW).

Additional Benefits

  • The NAS battery systems also provide additional functions, including primary reserve, secondary reserve, load balancing and voltage control.

NAS and the NAS logo are trademarks of NGK INSULATORS, LTD., registered in the U.S. and other countries.