This is a useful article.  There are 2 obvious questions.

1) Carbon taxes in Europe are detailed in 

Oil Refineries in Europe are shown in 

So the carbon taxes, by and large, are where the refineries are not.  Britain and Germany do not have a carbon tax, nor does Italy, and the one in Spain is low.  The one in France is higher, but there are relatively few refineries there.  Aside from planning for the future, and goodwill, do the refineries have an economic incentive to start developing green hydrogen now?

2) There is still likely to be very extensive import of Russian natural gas by European countries.  Statista shows this for 2021 in 

and it is not reassuring.  Could the effort the European majors are making be considered an alternative to the heavy dependence, assuming they can get LNG from elsewhere?

There is a good reason why the investment in "green hydrogen" by the oil majors is so tiny: as things stand, it's very difficult -- and very uneconomic -- to produce any significant amount of green hydrogen.

Oh, you can pretend to be producing green hydrogen. You can show off a factory floor with ranks of electrolyzers busy splitting water into hydrogen and oxygen. You can even point to a solar or wind farm somewhere and claim "that's where the electricity powering our electrolyzers is coming from. We paid for the clean energy credits it's generating."  But if the state of the power grid is such that marginal load is being served by fossil-fueled generation, then you are not producing green hydrogen.

What you're producing is "fools' green" hydrogen. The electricity you're using to power your electrolyzers has to be replaced by electricity from fossil-fueled generation. And because you need so much electricity, the carbon footprint for your fools' green hydrogen is more than double what it would be if you were producing unmitigated gray hydrogen from natural gas.

The oil majors are not fools.