I have been "playing" with banks of 20kW hydrogen fuel cells for a couple of years so have an insight to how they work best.

They are far more efficient hot - so short journeys are wasteful.
The gas flows are fun to increase/decrease rapidly, you need lots of damp warm air, so getting the humidity to 90% with varying air flow is fun.

This leads to an electric vehicle with a fair sized battery, and a hydrogen re-charging system that tends to run at it's optimum rather than follow the load.

Now fuel, our 20kw fuel cells use a full size BOC bottle of hydrogen every 15 minutes, granted they are "only" filled to 150bar, and you could in theory fill to 600bar, but the fuel tank is going to be heavy.

You could in theory fill with low pressure liquid hydrogen (4 bar and minus 250C), but it leaks as it warms up, so you loose it as you are parked - lets say 70% loss if parked up for 3 days.

It's a great idea for vehicles like busses, with large storage (on the roof), predictable energy use, and running for hours on end.

It feels like groundhog day, when I was newly out of my time service engineers drove 1.3 petrol vans (Viva HB) then we all got diesels, looks like petrol is back in as the flavour of the month at present. Tangiers Orange - gone, missing her
Replaced by Ewok what a mistake - now a happy Disco Sport owner

Here is a handy tool that tells you the proportion of UK power from various sources.

http://www.gridwatch.templar.co.uk/ 3 x FL1 2 manual + 1 auto
5 x FL2 4 manual + 1 auto
Now Discovery Sport P250 MHEV SE

Worms wrote:

Perhaps liquid batteries are the answer!