Households across the UK are being advised to expect higher energy bills this winter as European nations work to refill their natural gas reserves before colder weather sets in. Natural gas prices have reached three-year highs, which could lead to increased costs for both businesses and consumers. This situation has been compounded by delays in summer gas stockpiling due to high wholesale prices, which were driven up by tensions involving Iran. European countries had hoped the conflict would ease before winter, allowing prices to drop, but storage levels are now much lower than normal for this time of year. This means countries may need to buy gas at higher prices now or risk paying even more when the winter arrives. The European benchmark natural gas price reached €75 per megawatt-hour (MWh) on Wednesday, the highest since late 2022, following a spike caused by Russia's invasion of Ukraine. In the UK, natural gas prices have also climbed to 185p per therm, the highest since late 2022. These price increases have been driven by renewed hostilities between the US and Iran, which have raised fears that the Strait of Hormuz, a critical waterway for global oil and liquefied natural gas (LNG) transport, will remain closed for longer. Around a fifth of the world's oil and LNG passes through this strait. Hamad Hussain, a senior climate and commodities economist at Capital Economics, said he does not expect the strait to reopen until early 2027. Even then, it will take time for energy supplies to stabilize and for prices to ease. "The risks to gas prices are definitely tilted towards the upside," Hussain told the BBC, warning that prices could rise to €80 by the end of the year. He noted that gas storage operators had hoped for a quicker resolution to the crisis, but six months have passed since the conflict began with no significant improvement. Higher wholesale gas prices influence the energy price cap set by regulator Ofgem, which has already risen in July and will increase by 4% in October. A typical household is expected to pay £1,723 this winter. Analysts at energy consultancy Cornwall Insight predict a further 9% rise in domestic energy prices in the new year, adding to household concerns during the colder months. However, they also noted that there is still time for prices to fall if the situation improves. The UK government has dismissed criticism of its low gas storage levels, emphasizing that gas prices are determined by international markets. Meanwhile, British Gas owner Centrica's chief has called for government support to expand the Rough storage facility in the North Sea, warning it may close without a deal.