On 20/01/2020 11:21, Pancho wrote:
On 20/01/2020 11:05, The Natural Philosopher wrote:
On 20/01/2020 11:02, Pancho wrote:
On 20/01/2020 08:16, Chris Hogg wrote:
On Sun, 19 Jan 2020 20:17:29 +0000, Pancho
wrote:

On 19/01/2020 14:42, Chris Hogg wrote:
On Sun, 19 Jan 2020 13:37:34 +0000, Chris Hogg
wrote:

On Sun, 19 Jan 2020 13:17:14 +0000, Pancho
wrote:

On 19/01/2020 12:53, Chris Hogg wrote:

Lots of 'potential' storage solutions, such as compressed air into
underground caverns, trundling very heavy weights on rail
tracks up
mountains, Tesla-type batteries everywhere and so on. But none
of it
comes near to pumped storage in terms of capacity, and that's very
dependent on the right topography, most of which has already been
used. Those other solutions may be OK for very short term
peak-lopping, but none are capable of storing the amounts of
energy
needed to run the country for a several days at this time of year,

OK, I was seeing quotes of hydrogen storage providingÂ* months
energy
supply as opposed to a few hours for pumped storage. The main
difference
being hydrogen is 40% efficient where as pumped is 80% efficient.


But how and where are they going to store a month's worth of
hydrogen?
The volume would be absolutely huge, even if compressed. The phrase
'greens don't do sums' is occasionally trotted out on this NG. That
looks like a classic example of just that.

AND:

Where is the capacity coming from? Unreliables, supported by nuclear?
Bear in mind that whatever unreliable is being used as the primary
generator, when the 'battery' (in whatever form that might be) gets
substantially discharged, not only will the primary generators
have to
supply the ongoing day-to-day demand, they will also have to recharge
that 'battery' PDQ, in anticipation of another generation-free period
in a week or so's time. How much extra generating capacity that might
need, I don't know, but substantial, I would think.
Â* That problem doesn't arise with nuclear.

A large battery gives plenty of time for a battery to recharge, two
months is a big battery.

I don't understand what you're saying there. A large 'battery', of
whatever type, would take a long time to recharge from flat, when
speed would be of the essence in time for the next lull in the weather
with no generation from unreliables.

The idea of a battery is to smooth out variance. To allow for supply
to match demand. With a big enough battery we just need average
energy production to match average energy demand. Without a big
enough battery we need overcapacity. Hasn't this point been made many
times?


Actually the problem does occur with nuclear, too. You need rapid
dispatch to counter the variability of demand.

But nuclear is dispatchable; not ideal (they're best run flat-out
AIUI), but it's not difficult.

Yes, but is it optimal? You would need enough nuclear capacity to
match maximum demand, also turning it down can cause difficulty.

At some point it might be cheaper to have fewer nuclear power
stations generating full all the time. When they have spare capacity
they generate hydrogen, in periods of high demand they use the
hydrogen to fuel rapid dispatch generators.

No point. Cheaper to add a little more pumped storage
Or gas.


I'm pretty sure you have already pointed out we cannot have months of
energy stored in pump storage.

We donmt NEED to. we just need enough for daily peaks, with nuclear.
Only with renewable energy do we need a winters worth.



Yes we could use natural gas or burn coal, but the idea we are
discussing is to avoid CO2 emissions.

Then use nukes.

And pumped strorage. That is all you actually NEED.


--
If I had all the money I've spent on drink...
...I'd spend it on drink.

Sir Henry (at Rawlinson's End)