One major problem holding back hydrogen today is the Delegated Act rules, which are complicated and burdensome and essentially have the effect of blocking hydrogen from the grid.
Because the EU grid is very likely to fully decarbonise by 2035 or sooner, these rules will be irrelevant in a few years.
The objective it is argued is that if electrolysers connect to the grid, they may use some electricity that is derived from fossil fuels - which could increase emissions. The other objection is that electricity should instead be used directly, rather than going straight to hydrogen production.
Ultimately, they severely limit the potential of the industry to expand and develop, and worse than this the rules regarding the issuance of subsidies allotted to hydrogen carry a degree of uncertainty, with developers still waiting for promised subsidies to arrive.
The objections (as I have written about) mostly come from NGOs and policy groups who have an agenda - to maintain the status quo and preserve the oil market and its subsidisation (on average €60bn per year in the EU).
https://medium.com/@danielrwilliams/policy-groups-ngos-and-lobbyists-a38cb486bfaa
Unfortunately, the rules have also been adopted in the US, which could significantly slow down the industry as a whole. As many have written, such strict rules have never been applied to other clean energy technologies.
https://utilitydive.com/news/lets-get-hydrogen-right-from-the-start-production-tax-credit-45V/696953
Hopefully these rules will be challenged, but until the Commission revises their stance the industry is going to have a difficult time taking off and reducing costs.