Basically: the Inflation Reduction Act has a tax credit for ‘clean’ hydrogen to encourage the chemicals industry (eg: nitrate fertilizer manufacturing) from using methane as a hydrogen source to using renewable energy + electrolysis of water to as their hydrogen source.

A team at Princeton wrote a paper showing that for this to offer a climate benefit, you need to make sure that they’re using only renewable energy, and not displacing other users of renewable energy in order to do this and have a net greenhouse gas emission reduction which is to say that they’ve installed new or additional renewable energy and time-matched their use of electricity to production of the additional renewables. This is of course more expensive than just buying whatever electricity you can at the moment.

So industry is running an ad campaign to confuse the heck out of people and environmental groups are pushing back.