Altair Nanotechnologies Completes Validation of 2MW Li-ion Battery System Grid Interconnection and Operation
8 July 2008
Altair Nanotechnologies Inc. has successfully completed a demonstration and validation program for a two-megawatt, 500 kWh battery system purchased by AES Corporation. The program was developed and validated by KEMA, Inc. and executed by AES personnel and subcontractors.
KEMA’s testing showed the battery system successfully met the program’s milestones, which was conducted to demonstrate the applicability of Altair’s large platform technology to frequency regulation, a key service currently provided by power plants to the electric grid. This demonstration also suggests that the technology could be used for several other utility applications.
The two-megawatt battery system was installed and operated at a substation owned by Indianapolis Power & Light (IPL), an AES company. The system contained two one-megawatt battery storage units each consisting of one Altairnano 250 kWh lithium titanate battery stack, AC-to-DC power conversion system, HVAC units, a control system and transformers to connect to the IPL grid.
During the validation exercise the capacity of each unit was tested by repeatedly charging and discharging at one megawatt for 15 minutes. In a second test, two megawatts of power from each of the units were used to show the capability of paralleling two separate systems. Additional testing included simulated frequency regulation, which involved switching the units from charge to discharge at up to one megawatt of power every four seconds for several hours.
Battery stack efficiency measured using cyclic charge/discharge tests (at 50% state of charge) varied from 97% at 250 kW dispatch to 91% at 1000 kW dispatch. Efficiency drops off with the power dispatch level due to internal losses that are proportional to the current squared as expected. Factoring in the DC-to-AC power conversion system, then average conversion efficiency measured varied between 93% at 250 kW dispatch to 86% at 1000 kW dispatch. This does not include HVAC or trailer auxiliary load. However, it is noted that efficiency numbers are highly dependent on the dispatch duty cycle, and need to be re-evaluated for each type of field application.—KEMA report
We are pleased with the results of the Altairnano units. This two megawatt validation project is one of the final steps in our move towards commercial deployment of grid-scale energy storage. Fast-responding, high-efficiency energy storage systems such as these will create a more resilient grid and allow for increased use of variable generating sources such as wind and solar.—Chris Shelton, Director of Energy Storage Development at AES
In March 2007, AES made a $3-million strategic investment in Altair Nanotechnologies. (Earlier post.) In August 2007, AES Corporation and Altair Nanotechnologies announced a joint development and equipment purchase agreement. Under the terms of the agreement, the companies will develop a suite of energy storage solutions. This first solution is a modular unit designed to deliver in excess of one megawatt of power and 250 kilowatt-hours of energy per unit. Multiple units can be linked together in systems to provide both more power and more energy storage.
Altair and AES are working together toward utilization of these systems to provide more efficient management of energy quality, frequency control, and real-time energy fluctuations in milliseconds at grid level.
AES is one of the world’s largest global power companies, with 2007 revenues of $13.6 billion. With operations in 29 countries on five continents, AES's generation and distribution facilities have the capacity to serve 100 million people worldwide.
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