July 18, 2014
Living in Alaska is living on the edge. Both geography and climate conspire to challenge service providers. One such provider is the Golden Valley Electrical Association (GVEA), a cooperative headquartered in Fairbanks, Alaska’s second largest city. It supplies electricity to some 90,000 customers spread over 5,700km2 in the interior of the state.
Here, because of the harsh climate, failures, if prolonged, can cause more than just inconvenience.
This concern led to the planning and building in 2003 of BESS: the Battery Energy Storage System. BESS was, at the time, the largest battery facility in the world when, during a December 2003 test of its capacity, it maintained a discharge of 46MW for five minutes. In more normal circumstances BESS can provide 27MW for 15 minutes. This is made possible by 13,760 71kg flooded NiCd cells.
In 2013, BESS responded so seamlessly to 60 interruptions of supply that many of the 34,202 members of the cooperative were probably unaware that there had been a problem. Because of BESS, an average of 6.9 outages per electricity meter in the GVEA system was avoided as the system operated at 99.86% reliability in 2013.
Dan Bishop, engineer at GVEA, reports that BESS was designed to enhance reliability without burning petroleum-based fuel. “The BESS is not cheap, but reduces purchases of expensive fuel. It also has eliminated the need for another Static VAR [volt ampere reactive] Compensation system because in addition to energy storage it provides reactive compensation (voltage regulation) for GVEA’s 138kV transmission system. BESS has eliminated about 90% of all power supply outages, higher than the design goals. Our current expectation is that BESS will exceed its 20 year life before battery replacement needs to be considered. We are delighted to have BESS backing us up.”