Its analysis shows the reduction in commercial and industrial use would outweigh an upsurge in domestic demand.
The prediction was included in an update from the Energy Networks Association (ENA), in which it sought to reassure the public that contingency plans are in place to ensure services are unaffected by the coronavirus spread.
The body, which represents the UK's electricity and gas network companies, said "robust measures" had been put in place to protect control rooms and contact centres. To provide additional resilience, engineers have been trained across multiple disciplines and backup centres exist should operations need to be moved if, for example, deep cleaning is required, the ENA said.
Networks also have industry-wide mutual aid arrangements for people and the equipment needed to keep gas and electricity flowing.
ENA chief executive, David Smith, said: "The UK's electricity and gas network is one of the most reliable in the world and network operators are working with the authorities to ensure that their contingency plans are reviewed and delivered in accordance with the latest expert advice. We are following this advice closely and reassuring customers that energy networks are continuing to operate as normal for the public."
Utility Week spoke to a senior figure at one of the networks who reiterated the robust measures in place to keep the lights on. However, they pleaded for more clarity from Ofgem and government on how its workers will be treated if the coronavirus spread becomes a pandemic in the UK.