The Isles of Scilly has the second highest electricity use per household in the UK.
Scilly is second only to the Shetland Islands, according to the most recent data on Local Authority electricity consumption.
The statistics are quoted in a report by Sarah Harris from the Office for National Statistics, who visited the islands in February 2017 to investigate whether household expenditure in the Isles of Scilly is different from Cornwall.
She wrote: "There is no mains gas piped into the Isles of Scilly and residents reported the cost of other fuels being high. Although electricity is the main fuel source, residents also reported the use of coal, oil, bottled gas and wood for fuel, which has additional freight costs.
"Residents reported that although electricity prices are the same, as they are national rates, they are having to use more. Heating costs are higher because of the condition of houses; lots of houses are not well insulated and there were comments about old equipment and the community not benefitting from insulation programmes.
"A resident on St Agnes highlighted that some properties are drafty, porous granite cottages in a damp, exposed environment. Another resident did, however, comment on the good insulation in their social housing."
The report continued: "Some residents do not have central heating (or storage heaters) and one individual only had central heating installed three years ago. For one resident without central heating they find it hard to heat their house so they do not heat it until needed; they felt fuel would cost more if they were heating their house more of the time."
Statistics show the proportion of households affected by fuel poverty in the Isles of Scilly in 2016 (15.5%) was higher than Cornwall (12.8%) and England (11.1%). The islands' local authority area ranks 8th in England for fuel poverty.
However, Sarah said that "expenditure on power in the Isles of Scilly is something that may change" with the Smart Energy Islands Project, which aims to cut fuel bills by 40% by 2025.
She added: "Therefore, any assumptions or estimations of differences between residents’ spending on power (compared with Cornwall) may need to be reconsidered in line with progress on the Smart Energy Islands Project."