I hope you'd agree that whatever wild card you may hope you find it cannot be more than 100% efficient.
That is to say you can't get more energy out of the Hydrogen than it takes you to electrolyse water.
You might want to check the following numbers because it's late and there are a lot of Zeros:
energy from burning 1 litre hydrogen 1,208 joules
energy from burning 1 litre petrol 34,000,000 joules
UK fuel sales 50 Billion litres
Equivilent H2 required 141,200,000,000,000,000 litres
17,110,000,000,000,000,000 joules
or 543,000 MW
UK peak electricity demand 60,000 MW
Electrolysing water at 100% efficiency will require an increase in electricity generation capability of 9 times our current peak.
If you want to get better than that you are suggesting that future technology is going to create energy.
Incidently because something is patented does not mean it works, A patent is a legal claim to an idea not a validation that something works - there are some Beauts out there!