GT - Was it Andy or the market who identified that Green Hydrogen is the Holy Grail?
To answer your question below: The most common method for separating Hydrogen from Methane (natural gas) is Steam Methane Reforming.
Using this process, it takes 3 units of Natural Gas to produce 1 unit of Hydrogen.
So grey Hydrogen is at least 3 times more expensive than natural gas at the point of processing.
By comparison, it takes about 50 kWh of electrical energy to convert 9 kg of water into 1 kg of Green Hydrogen and 8 kg of O2 by means of commercially available electrolyers.