Bazz re-read the first post, second sentence. As to declining yield the example I give is tar sands but fracking is a good example as well. Some commenters here steeped in market folklore think high prices create more fuel supply. True enough if consumers can afford it but not much extra energy may come with that high price.

Spindoc,

I speak here only for myself. This is supposed to be an ideas and shared information forum. I really do not need a lecture on either the implied lack of my erudition or the facts I share.

1.Fact - I have travelled on the hydrogen fuelled buses. They were discontinued here because of hydrogen transportation costs regarding distance from generation point to distribution point, although they were proved successful [through data obtained] in operation in 6 other country's who trialed them.

2. Fact - I have personally visited a community in Arizona who rely on solar and wind power for their needs. There is much data attached to these two facts, but I leave it to those who may be interested to research the associated data for themselves.

Worldwatch, at the risk of boring the others, as you being new to here,
this subject anyway, hydrogen powered buses have been tried by the
bus manufacturers.
I got this first hand from someone who was managing director of the
largest bus & fire engine manufacturer in the UK and who designed,
developed and introduced the trial buses.
I will be having Christmas dinner with him so will ask him about the
latest developments.

The lifetime of the fuel cells is not long enough to make them viable.
Hydrogen can not be stopped from leaking through connections, pipes
and through the walls of the tanks.
Hydrogen vehicles cannot be parked in underground car parks and
places where they are parked must have especially designed roof ventilation.
Then there is loss of fuel when not being used, it destroys the
economics of operating hydrogen vehicles.
The worst of the economics is in the distribution network.
It cannot be afforded.

It is a dead technology for transportation. It is no longer on the list.

Taswegian, I was making little different point.
What I was pointing out was that to make shale oil viable they have
to keep putting money into the system, to enable the next years income
to be raised. They can do it while the drilling costs can be kept down
but as the easiest are drilled and exhausted the drilling becomes more
expensive. I think this explains the falling rig count.
However with such fast decline rates a fall in rig count must mean a
fall in production.

So we are in agreement on that I think. Certainly, except for brief
volatility, lower prices are just impossible as the only new oil is expensive.

Hydrogen has safety problems. It not only contains hydrogen it contains oxygen. Therefor a tank full of this mix virtually becomes a hydrogen bomb. Good for running engines under water with no ventilation.
Some americans produce hydrogen with solar and store it for winter heating. They use old large gas tanks to store it in, but is not compressed.
Spindoc must have learning problems.

Spindoc says To worldwatcher, Rhosty, 579 and warmair,

The best advice I can offer is for you all to stop reading and start thinking. Start with reading your posts and asking yourselves, If I were someone other than myself, what on earth would I make of that
_________________________________________________________________________

I took your advice and read a fair number of your previous posts, I found some difficulty in understanding what you were trying to say, possibly due to too many long words like wheelbarrow, which nobody uses these days. The one thing that seems clear to me is that you have decided for whatever reason not accept the vast body of knowledge on climate change.
As for my own posts I found them all beautifully clear and absolutely brilliant but of course I am slightly biased.