Normal solar- and wind- powered systems do not have that intermediate hydrogen section. They use storage batteries but the nationall grid may also be helped, where feasible, by pumped-storage hydro-electric plant; and of course in many countries still by nuclear or non-nuclear, base-load power-stations.
There is no hydrogen-sequence in that chain at all.
The national grid supply may also feed separate electrolysers, as "customers" producing hydrogen. Or we might see solar / wind installations whose primary or only task is powering electrolysers. Either way, that hydrogen is for applications not using electricity from the national system: e.g. earth-moving equipment, railway locomotives for non-electrified routes. Possibly too, producing hydrogen as a future partial or complete replacement for natural-gas in the public gas supply.
Not as shown, adding needless complexity and inefficiency to the primary electricity-supply chain.
Where did you find that that drawing? You don't cite its source. It seems made by someone who has muddled up two entirely separate services; but whether by ignorance or ill-will only they know. Either that or someone really has designed such a system somewhere, but that seems very unlikely.
Hydrogen is simply less efficient than batteries. It is only useful in circumstances where batteries are inconveniently heavy and bulky. Such as earth moving machinery in remote areas.
@ArishMell The end to end efficiency of a hydrogen fuelled internal combustion engine is less than the end to end efficiency of modern batteries. When you burn the hydrogen the efficiency is limited by Carnot's Theorem [1] [2]:
The autoignition temperature of hydrogen is 535 C, 808 K [3]. If we assume that the exhaust temperature is 50 C, 323 K then the maximum possible efficiency is
1 - 323 / 808 = 0.6
Lithium ion batteries have an efficiency of about 0.9 [4]
So the battery vehicle is more efficient than the H2 ICE vehicle. This analysis also omits the efficiency of the H2 production process which further reduces the end to end efficiency of hydrogen. Such a high flame temperature also increases the production of NOx to greater degree than for a diesel engine so that more urea is required.
That mathematics is remarkably simple for something so profound; but I find the concepts of entropy (and enthalpy) hard to understand.
I think for practical purposes the question of relative efficiency, is not sufficient. We'd need consider all those other factors such as production, transport or supply of electricity, etc. Environmentally too, it would come to which is the more sustainable, or more accurately perhaps the less unsustainable.
It's also worth considering that the battery manufacturers are all trying to make ever better batteries, especially searching for active ingredients better than lithium.
The JCB earth-movers might use i.c. engines but I think the locomotives being developed use fuel-cells. I have wondered if electric multiple unit trains using batteries and control systems similar to those in road vehicles could be effective, especially on relatively short routes like the Leeds-Settle-Carlisle that climb over big fells but the descent can partially re-charge the batteries. (Even over the fjells North of Trondheim?) It may need some trade-off between sustained speed, so lengthening journey time, and electricity consumption. One option may be use the overhead lines as far as they go (presently Leeds to Skipton in that first example), then switch to the batteries.
However, the OP shows a diagram of a (presumably national) electricity supply system with a complicated hydrogen "middle-man" stage that must make the overall system, from sunlight or wind-force to 13A mains socket, a lot less efficient overall than it should be.
What that proposed system does do, is remove the need for huge battery-banks; but whether that would make the system relatively more desirable on environmental grounds is anyone's guess.
In the end, the old saw about the "free lunch being a myth" is right!.
We'd need consider all those other factors such as production, transport or supply of electricity, etc.
That's what end to end is intended to convey.
Assuming solar power the process for H2 ICE is something like this
Solar panels -> inverter -> transformer -> transmission lines -> transformer -> electrolysis -> compression -> road and/or rail transport -> transfer to static tanks -> transfer to vehicle
The are more steps in the H2 process all of which introduce additional losses. Each step requires more land and creates more pollution.
The OP's diagram simply replaces grid connected batteries used for peak power supply and frequency control with electrolysis and fuel cells. The only advantage there is that the fuel cells and H2 store probably occupy less space than a battery of equivalent capacity. But remember that they also need a supply of water. For every molecule of hydrogen produced you need a molecule of water, H2O. The atomic mass of oxygen is 16 so a molecular mass of water is 18, that's 9 times as much as a molecule of hydrogen, H2. So to produce a ton of hydrogen you need 9 tons of water.
The Hornsdale Power Reserve battery supplied by Tesla is a 150 MW (194 MWh) grid-connected energy storage system [1].
To run a 200 kW fuel cell for 8 hours, (200 kW x 8 hours x 3600s) / (51% x 120,000 kJ / kg) = 94 kg of hydrogen is required. [2]
That's a capacity of 1.6 MWh. To get the same capacity as the Hornsdale battery you will need 194 / 1.6 * 95 kg = 11.5 tonne of hydrogen and therefore 104 tonne of water.
I haven't been able to find any information on the average actual output of the Hornsdale installation so i don't know how big an impact the water requirement would be but as it is in Australia I imagine that it would be at least worth considering. I don't know how fast the electrolysis cells work either but that must also be a consideration as the entire capacity of the battery can be depleted in less than 90 minutes. I imagine that the electrolysis cells would have to be significantly over dimensioned in order to cope with the peak demand.
How has that diagram proven that hydrogen is "not a source of energy"? Although having said that, your written English is so bad that perhaps you meant "It is a source of energy"
@SW-User you need chemistry classes[media=https://youtu.be/yFPnT-DCBVs]
SW-User
@OriginalDumbMan I don't believe any of the lies that come out of his mouth, especially as he has a vested interest in ensuring green hydrogen fails. I won't be watching it.
it’s a energy storage. Not energy source. Free hydrogen is not available.
I'm going to guess you mean where to store hydrogen, then the diagram you had up, is not exactly how the most likely mass distribution scenario.
For the short to medium term, energy companies will be modifying the natural gas distribution networks to sustain delivery of hydrogen in its gas form, to fuel cell facilities.
A new industry, specializing in solving these problems, is quickly developing and will solve these problems over the next few years.
The Exxons of the world are incentivized to solve this problem, not only because they like clean energy, bur because they're sitting on massive deposits of natural gas, and the latter is going to be the primary source of Hydrogen for the foreseeable future: Methane: CH4 with H2O, example is the already operational Baytown, TX facility.
@Northwest [media=https://youtu.be/yFPnT-DCBVs] You need chemistry classes
SW-User
@OriginalDumbMan A simple energy-efficient process allows us to use the most abundant element in the entire universe as a source of energy. Nuclear fission is also a source of energy.
