COVER STORY: PROFILE, THE ITALIAN GRID on two 150kV lines, in three separate locations in the region of Campania, in southern Italy; 12MW in Benevento province, 12MW in Flumeri and 10.8MW in Scampitella, which are both in Avellino province. For its 40MW of power-intensive demands, Terna has, so far, chosen lithium ion as well as sodium nickel chloride batteries from various suppliers. Saft is supplying 2MW (2MWh) of lithium ion, Samsung 2MW (2MWh), in a consortium that includes energy storage software controls provider Younicos, BYD 2MW (2MWh), Toshiba 2MW (2MWh) and LG Chem 1 MW (0.5MWh), with Siemens building the energy storage system. Fiamm is supplying 2.4MW (8.3MWh) and GE 1MW (2MWh) of sodium nickel chloride batteries. The batteries are being installed on Codrongianos, in Sassari province on Sardinia and in Ciminna and Casuzze, both in Palermo on Sicily, in two phases. NGK was selected by Terna, based on its global installations which amounted to some 200MW, reflecting the company’s experience and references. In comparison, at the time, technologies such as lithium ion had a much smaller installed base, mainly in pilots and demonstrations. “These companies were chosen as part of a worldwide tender, based on whether the technical specifications were high enough to meet with our demands,” says Tortora. “But, as part of requirements set out by the economic development ministry and the energy and gas authority, Terna must test out different technologies, to reduce the single supplier risk and gain experience by gathering knowledge on the state-of-the-art electrochemical storage.” Terna is in the process of procuring the remaining 28MW of energy storage for its power-intensive needs. In its tenders the TSO specified a maxi-
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mum of 4MW of flow batteries as well as lithium supercapacitors. However, most of the storage under Terna’s Grid Safety and Defence plan will be lithium ion, followed by sodium nickel chloride batteries.
Calculating ROI Because different end services are potentially possible with batteries the whole process of calculating the return on investment is complex, based on the battery’s energy capacity, speed of response, efficiency, its ability to perform as primary or secondary reserve and so on. For wind curtailment, specifically, the return on investment is proving elusive to calculate. “There are many different variables that can affect this ultimate outcome, such as battery capacity, grid developments and factor-
ing in works deferral and so on,” says Tortora. Terna is modelling return on investment with the regulator and also McKinsey. The nearest comparison on investment returns might be solar PV technology. “PV is not as complicated as energy storage, as it only generates energy,” she says. “However, PV panels have been very expensive and policy measures and subsidies have helped bring down the cost by stimulating market demand. Batteries are capitalintensive. But, like PV, their operational costs may not be as high as with other technologies.” According to the Italian National Renewable Action Plan (NREAP) by 2020 some 8GW of PV will have to be installed. At the end of 2013 PV generation produced over 17GW. “This
STORAGE IN THE PIPELINE As a partner in the EU-funded Grid 4EU project, Enel Distribuzione will also be installing an energy storage system, approximately 1MWh, in Forlì-Cesena, in the Emilia Romagna region. The demonstrator will increase the medium voltage network’s hosting capacity for distributed energy resources, by introducing active control and demand response of generators on the medium voltage network. The existing grid is designed for power flowing in one direction. The connection of lots of distributed energy resources to the grid can affect power quality, create imbalances between load and generation and can lead to grid congestion as well. Forlì-Cesena is a rural area, but with a high penetration of renewable energy production, including about 40MW of capacity split over some 24 producers, but power consumption is also low. The whole Grid 4EU project runs until January 2016. Companies working with Enel on the demonstrator include Siemens as well as Cisco. Acea Distribuzione a local DSO that operates the distribution network in Rome is also commissioning two small storage systems, both lithium ion battery based, from NEC. These installations are at secondary substation in the capital city, one inside, which interfaces with the grid at low voltage and the other
outdoor, which interfaces with the grid at medium voltage. The main functionality of the LV 90kWh system is for backup, to reduce or avoid electric outages, depending on the length of interruptions, to the end user when damage on the medium voltage cable, where the secondary substation is connected, occurs. The system discharges the battery to avoid outages or to reduce, or downgrade, longer interruptions. In Italy, as with some other countries in Europe, utilities face financial penalties if outages are too frequent or too long, the point being to reduce interruptions and power cuts. The main functionality of the other medium voltage 45kWh storage system, outside, is for renewables integration. The batteries will stabilise electricity fed onto the grid by a nearby PV power plant to increase hosting capacity and improve overall power quality.
Batteries International • Summer 2014 • 57