RE:EBH 2 News outThis article from 2017 says there are already electrolysers at 80%.
Very roughly, a new electrolysis plant today delivers energy efficiency of around 80%. That is, the energy value of the hydrogen produced is about 80% of the electricity used to split the water molecule. Steam reforming is around 65% efficient.
· However, the capital costs of a steam reforming system are currently below the price of a new electrolyser of a similar capacity. The project report for the conversion of the Leeds area in Northern England away from natural gas and towards hydrogen for business and residential use suggested a steam reformer cost of about £600,000 per megawatt of capacity. Like much else in the low carbon economy, electrolyser costs are falling fast. Some manufacturers see electrolyser costs of around £700,000 per megawatt within the next year or so. ITM Power, the Sheffield electrolysis manufacturer, says its costs are already below €1m (about £870,000) for each megawatt of capacity. As the size of electrolysers sharply increases - we may see 10 megawatt devices soon – the cost per unit of capacity will fall. Eventually, electrolysers will be significantly cheaper than steam reforming equipment.
https://www.carboncommentary.com/blog/2017/7/5/hydrogen-made-by-the-electrolysis-of-water-is-now-cost-competitive-and-gives-us-another-building-block-for-the-low-carbon-economy