The figures come at a time of rising energy prices, driven by a spike in the cost of gas, with energy bills predicted to double this year.
Department for Business, Energy and Industrial Strategy figures show 309 Gigawatt hours (GWh) of electricity were consumed by domestic meters in Portsmouth in 2020.
This was a four per cent rise on the 297 GWh consumed the year before and the largest change since comparable records began in 2012.
Across Great Britain electricity use by homes rose by 5.6 per cent in 2020, but while people spent more time at home, lockdowns forced many businesses to close, with non-domestic consumption dropping by 11.1 per cent.
It means overall electricity use dropped by 4.8 per cent – the largest year-on-year fall on record.
Fears have been raised about the soaring cost of energy bills – driven by rising gas prices – as work from home advice has been reintroduced throughout the UK. The disruption has been bankrupting suppliers since September, costing consumers £4bn. The News last year joined a national campaign run by its parent company JPIMedia to highlight rising costs, called Keep Us Warm This Winter.
Ms Reeves said: ‘Right now, people are being hit by a cost-of-living crisis which has seen energy bills soar, food costs increase and the weekly budget stretched.
‘We need a sustainable and ambitious approach to energy, which is why Labour would also ramp up ambition with our plan to retrofit 19 million homes, making our energy supply chain more secure without hitting household savings.’
Labour said new figures from the House of Commons Library show that rising energy, food and other bills meant the Treasury is expected to have an extra £3.1 billion in VAT receipts this year, which it could use to fund the energy bill VAT cut.
However, the Government said VAT receipts were forecast to be below pre-Covid levels, with a loss of £2 billion compared to directly before the pandemic.
The business secretary Kwasi Kwarteng met with energy companies and regulator Ofgem after Christmas to discuss how to deal with soaring gas and electricity prices.
A government spokesman said: ‘Throughout the meeting there was discussion of the issues facing the sector and an agreement for meetings to continue over the coming days and weeks to ensure UK consumers are protected.’
They added vulnerable households were being supported by initiatives such as the warm home discount, which has been extended to cover an extra 750,000 homes, as well as winter fuel payments, and cold weather payments.