The UK energy cap this winter is about £700 for 3,100kWh (up from £650), so 1kWh cost 23p. Things that now cost 1p: modern light bulb for 3 hours, laptop on for 45 mins, microwave or heater for 3 mins, kettle for 90 seconds. https://www.ofgem.gov.uk/publications/default-tariff-cap-level-1-october-2021-31-march-2022