EPB Chattanooga — America's First Citywide Gig-Fibre Smart Grid

Chattanooga's municipal utility EPB had one of the region's least reliable power grids, serving over 170,000 customers with no way to detect faults without dispatching a truck, and frequent, lengthy outages.

The goal was to modernise the grid with automated sensing and switching, backed by a dedicated fibre-optic communications network, to isolate faults and reroute power automatically within seconds instead of hours.

In 2009 the US Department of Energy awarded EPB a $111.5 million Smart Grid Investment Grant under the American Recovery and Reinvestment Act — at the time the largest ARRA stimulus grant to a municipal utility — enabling EPB to compress a planned 10-12 year rollout into about 2.5 years. Using roughly $48.4 million of that funding, EPB installed 1,200 automated sensors and circuit switches across 171 circuits, paired with a citywide fibre-optic network completed in September 2010. By the end of 2012, automated switching covered EPB's full service territory of roughly 174,000 customers.

According to EPB's own reporting cited by the US Department of Energy, the programme delivered a 40-60% reduction in total customer outage minutes and roughly $26.8 million a year in avoided outage costs under normal conditions, plus about $23 million avoided during severe-weather events — figures that EPB says paid back the $48.4 million distribution-automation investment within a few years. In 2014 the DOE designated Chattanooga a national 'Smart Grid Living Laboratory,' and by 2020 the same infrastructure had attracted more than $110 million in additional smart-city research partnerships. A later economic-impact study by University of Tennessee at Chattanooga economist Bento Lobo, covering the network's first ten years (2010-2020), credited the fibre-and-smart-grid combination with $2.69 billion in total community benefit and roughly 9,516 jobs created or retained.

The Tennessee study reflects one economist's modelling of a single city's experience rather than a randomised or multi-site comparison, so the causal share attributable to the smart grid specifically, versus the fibre network or other factors, is not cleanly separated out; the case is best read as strong observational evidence rather than experimental proof.