On 19/01/2020 20:13, Pancho wrote:
On 19/01/2020 14:50, The Natural Philosopher wrote:
On 19/01/2020 13:37, 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.
To power the UK for a day, just on electricity, in winter, takes about
24 hours at an average of 35Gw
= 840GWh
In terms of nuclear warheads, that is 722 kilotons. 50 Hiroshimas.
Would you rather live:
(a) near a nuclear power station that cannot explode, only melt down
inside a safe containment vessel?
(b) near a megaton explosion capable hydrogen store?
Note: a megaton explosion takes outÂ* about 100 sq km absolutely.
Remind me, how many gas wells have exploded with megaton explosions.
How exactly would these explosions occur? AIUI hydrogen's dispersal rate
in air is very fast. It is quite hard to get an explosive mix.
Golly. I guess you cannot do WIKI
https://en.wikipedia.org/wiki/Hydrogen_safety
"Hydrogen possesses the NFPA 704's highest rating of 4 on the
flammability scale because it is flammable when mixed even in small
amounts with ordinary air; ignition can occur at a volumetric ratio of
hydrogen to air as low as 4% due to the oxygen in the air and the
simplicity and chemical properties of the reaction. ... The storage and
use of hydrogen poses unique challenges due to its ease of leaking as a
gaseous fuel, low-energy ignition, wide range of combustible fuel-air
mixtures, buoyancy, and its ability to embrittle metals that must be
accounted for to ensure safe operation. Liquid hydrogen poses additional
challenges due to its increased density and the extremely low
temperatures needed to keep it in liquid form. "
"Hydrogen-air mixtures can ignite with very low energy input, 1/10
that required igniting a gasoline-air mixture. For reference, an
invisible spark or a static spark from a person can cause ignition."
"Although the autoignition temperature of hydrogen is higher than
those for most hydrocarbons, hydrogen's lower ignition energy makes the
ignition of hydrogen€“air mixtures more likely. The minimum energy for
spark ignition at atmospheric pressure is about 0.02 millijoules."
"The flammability limits based on the volume percent of hydrogen in
air at 14.7 psia (1 atm, 101 kPa) are 4.0 and 75.0. The flammability
limits based on the volume percent of hydrogen in oxygen at 14.7 psia (1
atm, 101 kPa) are 4.0 and 94.0."
"The limits of detonability of hydrogen in air are 18.3 to 59
percent by volume"[6]
"Flames in and around a collection of pipes or structures can
create turbulence that causes a deflagration to evolve into a
detonation, even in the absence of gross confinement."
(For comparison: Deflagration limit of gasoline in air: 1.4€“7.6%; of
acetylene in air,[7] 2.5% to 82%) "
--
€śA leader is best When people barely know he exists. Of a good leader,
who talks little,When his work is done, his aim fulfilled,They will say,
€śWe did this ourselves.€ť
ۥ Lao Tzu, Tao Te Ching