A successful month-long trial of mixing hydrogen with natural gas in the Italian province of Salerno run by utility Snam has added impetus to the growing push for greater use of hydrogen across Europe and the world, the Financial Times has reported. Although only 5% of the gas mix was hydrogen, it was a first of its kind in Europe, and will lead to further tests with higher concentrations of H₂. With many other companies, including Equinor, Vattenfall, Mitsubishi Hitachi Power Systems, the UK’s National Grid, and Toyota, having projects in the pipeline, there is a feeling of growing momentum, but with other false-starts for the elemental gas in previous decades, there is uncertainty about if hydrogen will become widely used for industry and transport. Three factors may make this push more successful, according to the article. Firstly, carbon emissions are a much higher priority, especially after the Paris Agreement of 2015, and secondly, oil prices in previous decades were low enough that there was not a sufficiently strong incentive for cars to switch from petroleum to hydrogen. Thirdly, there is the possibility that hydrogen could be used as an energy storage medium for excess power generated by renewable power generation capacity, especially as the proportion of renewables increases in energy mixes around the world. As in the past, cost will be the most (but certainly not the only) influential factor affecting the success of this push for hydrogen. Vattenfall’s project to convert the Nuon Magnum gas-fired power plant in the Eemshaven, Groningen, Netherlands, has a cost of at least €1 billion (US$1.1 billion) including production, storage and transportation of the hydrogen (which will come from natural gas), and a final investment decision will not come until 2022. The price tag gives an idea of the scale of the expense for single projects, at least at this early stage in the development of the various technologies. As with any technology, costs will fall as deployment and know-how increases, but whether they will fall sufficiently is the million, or rather billion, dollar question.