Energy companies have started preparing emergency plans to cope with coronavirus disruption, including the possibility of operating with only a fifth of their usual staff numbers.

The UK’s regional energy networks held talks last week with government ministers, senior officials and the energy regulator over plans to maintain the energy system’s power lines and gas pipes if 80% of their staff are unable to work.

The Guardian understands that energy network bosses have agreed to postpone all nonessential maintenance on the UK’s critical energy infrastructure after the government warned that up to four-fifths of Britons could be infected by the Covid-19 virus over the coming months.

The energy companies are in talks to hire extra contractors to help keep the UK’s energy grids and control rooms running. The regional monopolies also plan to train staff to cover other roles, retrain staff members to step back into former roles, and share engineering staff between them.

Planning applications for UK clean energy projects hit new high Read more

The contingency plans use modelling that includes major storm damage to overhead lines and substations on top of the disruption to staffing as engineers fall sick, self-isolate or stay at home to care for sick family members.

The plans have raised concern among trade unions, which fear a repeat of the blackouts experienced during the widespread winter storms over Christmas 2013, which were exacerbated by staff holidays and insufficient plans to share staff between regions.

A government spokesman said the UK was “extremely well-prepared for these types of outbreaks” just days after Boris Johnson, the prime minister, described the coronavirus pandemic as the worst public health crisis in a generation.

The GMB national secretary, Justin Bowden, who took part in the talks last week, said the “energy network contingency plans are likely to be tested to the limit” if the government’s modelling of the levels of infection and sickness at the peak of the pandemic is correct.

“There is still time to update and uprate those plans before infection and illness levels take off,” he said. “As we are in largely uncharted territory – particularly with the potential duration and intensity of the outbreak – it would be prudent to do so.” Bowden added.

The central energy system operator, National Grid, said it had fully operational backup locations for the control centres that operate the central nervous system of the UK’s energy networks, and added that it was restricting access to its sites to help protect staff from infection.

A spokesperson for Ofgem said the regulator was “aware that the current situation will present a number of challenges” and is “working with government and closely engaging industry to discuss their readiness, including at senior levels”.