Behold: The World's Largest Battery

In an isolated state, Fairbanks is an isolated city. Unlike fellow Alaskan urban centers Juneau and Anchorage, it's landlocked, resting in a wide valley not far from the Arctic tree line. From here, most everything in the world lies south—the rivers and pipelines and roads, everything heading south (mostly). It must be a weird feeling.

Like the rest of Interior Alaska, Fairbanks, a region of nearly 100,000, is separated from the power grid of the contiguous US and Canada. Electricity is produced locally and regionally from coal- and oil-fired power plants and power outages within this remote microgrid are frequent. In Fairbanks, it's winter more than it isn't and snow is a frequent culprit.

This weekend, the city will celebrate the anniversary of a battery. On August 27, 2003, the Golden Valley Electric Association (GVEA), the cooperative that provides power to the Fairbanks area, powered up BESS, aka the Battery Energy Storage System. Larger than a football field and weighing 1,500 tons, BESS exists to ensure continuity of electric service. If the supply of electricity coming in from relatively distant coal plants to the south is interrupted, BESS kicks in until local power plants can be put online.

BESS can hold things down powerwise for all of seven minutes. It functions as what's known as a spinning reserve. It's a bridge between primary and backup power and is generally taken to mean some amount of excess generating capacity that is at any given time pre-synchronized to the grid. If power goes down, switching the spinning reserve on should be seamless.

In Fairbanks, having this layer of protection is critical. Many area residents live remotely and wintertime temperatures can routinely fall to minus 50°F—in these conditions, an outage can have deadly consequences. According to GVEA, the system has prevented an average of between two and nine outages (per meter) annually since its 2003 inception. It hasn't eliminated outages, but it has prevented a great many of them, which means preventing them from cascading into widespread blackouts. That's sort of the idea: grid stability. Propping up a part of the grid for even a few minutes can mean heading off severe consequences.

BESS consists of 13,760 individual nickel-cadmium cells, with each one roughly the size of a desktop PC and weighing 165 pounds. The batteries have a lifespan of between 20 and 30 years.

Power grids all over the world are facing some interesting challenges right now, given ever-increasing power demands and decreased grid decentralization thanks to green energy projects. Grid destabilization is poised to become more and more of a threat as trends continue to advance. Local and regional megabatteries a la Fairbanks—and, sure, household battery packs—are almost certain to be part of the solution to that problem.

from Behold: The World's Largest Battery