Type 1: Commercial partnership

Sector of the company/organisation

Energy & Utilities

Name of activity/project (or solution offered)

Energy Storage System installed to increase the Ventotene island sustainability

Relevant urban sustainability topic

climate (mitigation, adaptation,…)
resource-efficiency (waste, water, materials, circular economy,…)
infrastructure (built environment)
sustainability strategy (strategy development at city level, urban planning,…)

Start year


End year


Brief project summary

Project aims at demonstrating a hybrid solution coupling already existing diesel engines with a new lithium-based energy storage system. The main targets are to support power generation and distribution in Ventotene isolated network through lowering fuel consumption, emissions, energy supply costs, and increasing grid hosting capabilities for new renewable energy systems.

Short activity description

Ventotene is an Italian island in the Tyrrhenian sea currently powered by four diesel generators 480kVA each, which struggles to cope with seasonal swings in demand caused by the annual influx of tourists, as well as the growing popularity of domestic solar panels. Enel’s answer has been a storage system, 300kW/600kWh, based on lithium-ion batteries which enable integration of solar power generation into the Island, enhancing the flexibility of the grid operation and optimizes use of power from existing diesel engines. The battery already installed will be in operation by the end of 2015.

Achieved impact

Storage system integration will allow 20% less fuel consumption, 20% less CO2 emissions and an increase of grid hosting capacity towards new distributed solar generation, while ensuring a stable and effective energy supply to the Ventotene habitants community.

The key innovation lies in advanced control system integrating battery and diesel operation and that was developed by Research and Innovation and Global Technical Support Units of Enel Global Generation. The system will allow the battery to provide frequency and voltage regulation, black start capability and to fully cover island demand also in case of all generation-sets shut down.

Is this project a best practice? Why?

Ventotene project is a first-of-a-kind and represents a best practice in the way the storage system is coupled to diesel generators. In fact, a true hybrid system is realized, in which storage fast dynamics are used to enable diesel even operation at full or quasi-full loads for most of the time, while grid dynamics are coped with by the batteries. This operation required the development of a specific hybrid control system with two functions: a) guarantee that grid dynamics are properly managed; b) schedule optimal operation of the storage system and of the diesel engines to minimize fuel consumption.

What are the main lessons learned during implementation?

Solutions to enable effective integration of battery and diesel dynamics are the best lessons learnt so far. Site acceptance tests are ongoing, therefore further lessons will be learnt after hybrid system operation.