Major utilities in the US are spending around $51 billion (£39bn) annually on upgrading electricity distribution systems.
That’s an increase from around $31 billion (£24bn) a year – a 54% rise over the last two decades, according to latest analysis by the US Energy Information Administration (EIA).
The rise is said to have been largely driven by increases in capital investment, which has almost doubled from 1996 to 2017.
Electricity distribution networks deliver power from the high voltage transmission grid to homes and businesses across the country.
The EIA states capital investment accounts for the largest share of distribution costs as utilities work to upgrade ageing equipment.
According to a 2015 report from the Department of Energy, 70% of power transformers are 25 years or older, 60% of circuit breakers are 30 years or older and 70% of transmission lines are 25 years or older.
Utilities are upgrading poles, wires and substation transformers with advanced materials and new technology to better withstand extreme weather events, allow easier frequency and voltage control during system emergencies and accommodate greater use of variable renewable generation.
Investment in customer meters has also more than doubled over the past decade as companies have upgraded them to smart meters that can be accessed remotely and provides near real-time energy data.