Hydrogen home heating

What's he got to do with it?

1 litre of water weighs 1kg, the atomic weights are H = 1, O = 16, and H2O is 18 (molecular weight if we're being pedantic), so from 1 kg water you get 2/18 = 0.11 kg hydrogen and 0.89 kg oxygen.

You are part way there, Duncan, if I have interpreted google correctly, the volume increase between liquid form hydrogen and the gas is 851, and with oxygen, 860.

Ian's question was how much oxygen and hydrogen there would be, not the volume change from liquid to gas

A few inaccuracies and some mild real explanations.

Methane is less dense than air.

Phil appears to be a ‘climate change denier’ and very much pro fossil fuels.

BEVs are much the best option at the present time. The charge/discharge cycle is higher than other energy conversions.

Apparently 1kg of Hydrogen has 33KWH density which if totally recoverable through a fuel cell would give a tesla model3 type car a range of around 120miles in good conditions and save a few hundred Kg in battery weight

Electrolysis water is, at present, no better than 70% efficient. Fuel cells are likely not much better than 50% efficient. Adding in storage and delivery that is about 50kWh to deliver about 16kWh for motive power, so forget that 120 miles. Remember, too that hydrogen cannot be liquified for car use - it needs to be cooler than about 20K (-253 Celsius) before it can be liquified by pressure. Don’t forget that the gas bottle, to carry any appreciable hydrogen load, weighs a good deal, too!

Looking at last month’s wind generation, we would need about 20 times the current installed capacity. That capacity would certainly produce a lot of energy for potential storage at most times. In April, we would have needed about 140 Dinorwigs of pumped storage. Hydrogen could be stored in worked out oil wells or stored as liquid ammonia. But unfortunately not much of any of these options are available at present.

Boffins are, of course, working on it. Much more knowledgeable than the average for this forum.🙂

So do hydrogen powered vehicles always use a fuel cell or can you use it as a fuel source in a ic engine?

the hydrogen filling station in sheffield sells it at £10 per kilo and most cars/vans can load 5 kg so is that as a pressurised gas or liquid?

Interesting graphic, here: **LINK**

https://www.researchgate.net/figure/olume-of-4-kg-hydrogen-compacted-in-different-ways-with-size-relative-to-the-size-of-a_fig1_46710927

‘though I haven’t yet read the paper

MichaelG.

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P.S. __ I have no idea how they handle it, but this mentions pressures of 350 and 700 bar being available 

https://www.itm-power.com/h2-stations/rotherham-wind-hydrogen-station

Edited By Michael Gilligan on 18/05/2021 23:12:54

is that as a pressurised gas or liquid?

The answer is just before you posted (probably keying in).

Its gas at 350 bar, currently standard pressures for h2 in gaseous form is 350 and 700 bar. On current efficiencies the price of h2 needs to drop quite a bit to be competitive with derv.

Ballard HC wave marine fuel cell is quoted at 58% efficient, not found one yet that is much over 60%.

H2 can be used in an IC engine but usually as a mix with another pilot fuel.

Hydrogen in a PEM fuel cell is the only current technology that is truly zero emission. There is another fuel solution requiring a solid oxide fuel cell that is very low emission but not zero.

Fact is if you want to be green you need to dig deep in your pocket! Economies of scale may well bring prices down and the next generation solid state batteries may well improve EV capability but there is going to be at least 20 years of financial pain for the man on the street while the investors cream their profits off the top. The green revolution requires not only a change in attitudes but a change in lifestyle too.

Hydrogen is the universe's most abundant element, but here on Earth it doesn't appear pure in nature, and requires energy to separate. The most common technique is to extract hydrogen from water, which is two parts hydrogen and one part oxygen (hence H2O). Doing this is fairly simple. You can use heat and chemical reactions to release hydrogen from organic materials such as fossil fuels.

But this is enormously polluting. Worldwide hydrogen production is responsible for CO2 emissions equivalent to that of the UK and Indonesia combined. (The hydrogen is mostly used in the oil refining industry and to produce ammonia fertilisers.)

There is a cleaner way of getting hydrogen: a strong electrical current passed through a tank of water splits the molecule into its two constituent elements. This is called electrolysis. Hydrogen atoms form hydrogen molecules (H2) and oxygen molecules pair up too. Each can then be bottled and stored. If the electricity is generated from renewable sources such as solar or wind, production of hydrogen in this way emits no greenhouse gasses.

This is how we come to all the different shades of hydrogen:

• brown hydrogen is produced using coal where the emissions are released to the air
• grey hydrogen is produced from natural gas where the associated emissions are released to the air
• blue hydrogen is produced from natural gas, where the emissions are captured using carbon capture and storage
• green hydrogen is produced from electrolysis powered by renewable electricity.

Energy companies, here in Australia are planning on making hydrogen on a commercial basis from solar and wind power. Electric vehicles are not common on our roads because of the long distances travelled and lack of charging stations outside of the capital cities. (they are not green as they are still fuelled from coal fired power stations).

Solar panels on houses are now causing a new problem. Older panels that have to be replaced cannot be recycled and go to landfill.

Excess power generated from the panels during the day is fed back into the supply grid and compensates for that used during the night. The problem is that there is now too much power generated during the daylight hours and is overloading the national grid. Some houses are fitted with batteries but this is an expensive option. The manufacture and disposal of batteries is another problem.

The development of hydrogen producers for home use with solar panels could possibly be a solution.

Paul.

The problem is that there is now too much power generated during the daylight hours and is overloading the national grid.

There is a simple solution to that - turn off some of the solar farms. Happens with wind generation, in the UK, at any the time when it is extremely windy, particularly at night.

The other solution is to store that excess of energy in a different form - batteries, pumped storage, hydrogen generation, liquid ammonia to list a few alternatives.

Manchester had an interesting ‘Hydraulic Power’ main:

**LINK**

https://en.wikipedia.org/wiki/Manchester_Hydraulic_Power

... which seems a concept worth re-visiting if we need to smooth the peaks of energy availability.

MichaelG.

Don't worry.

Fusion is only 5 years away

Not the only city with hydraulic power...but Paris unique in compressed air power..
http://www.douglas-self.com/MUSEUM/POWER/airnetwork/airnetwork.htm

Also fascinating that paris had a pneumatic mail system
https://www.cix.co.uk/~mhayhurst/jdhayhurst/pneumatic/book1.html

pgk

A tad optimistic
" . ITER will begin operations with low-power hydrogen reactions in 2025. But from 2035, it will run on a 50:50 mix of deuterium and tritium. "
https://www.nature.com/articles/d41586-021-00408-1

..so if they did get it working circa 2035+ a few it'd still be (at least) another 10 years for a network of new fusion plants>

A close fit to the "fusion is only 30yrs away and always will be"

pgk

Somewhere I was reading about sealing at high pressures, hydraulics probably, but as a side comment it was stated that sealing hydrogen is near impossible. The problem seems to be that the molecule size of hydrogen is so small that no type of non-metallic sealing ring will keep it in, things like O rings. You have to use a metal to metal seal. The article also said that over about 250 bar metal to metal seals, like BSP, start to leak, you have to use O rings to seal.

Is this correct? It was long a go and just remembered the conclusions, perhaps incorrectly.

So how was the old coal gas piped if 50% hydrogen? It must have been in a mix with something to make the molecule larger? I can remember as a child the bubbles coming to the surface after rain all along the gas pipelines where we lived, all mud in those days, no hard surface. Of course the gas pressure was very low, not like what is needed in a car application.

They have always had Fusion Reactors in Star Trek so it must come to be

John

Just a little thought. It is not, apparently, a binary choice between natural gas and hydrogen in our boilers.

I understand that it is possible to blend in up to 10% hydrogen without affecting the boiler. Seen at a macro-level, that provides a significant emissions reduction for unconverted boilers.

Never let the good be the enemy of the perfect.

Cheers, Colin

When I hear about Hydrogen gas supplies, I think of the Hindenburg .

+1 to that!

There are plenty of ways Green Power can be used fruitfully, and many of the objections assume Hydrogen and other renewables must somehow be crowbarred into 20th century technologies. That's just one of many options.

A few posts mention it's difficult to seal Hydrogen, which is true. But they ignore that this old problem is well understood, that Hydrogen has been massively used on an industrial scale for well over a century, and it was the main component of the Coal Gas pumped into UK homes since Queen Victoria was a teeny bopper. Yes Hydrogen leaks a bit, but not enough to matter. Actually, everything leaks a little - there are no perfect technologies.

Dare I suggest old men shouldn't be allowed to influence the future? Long lives give us confidence, but we may not realise just how horribly dated our experiences are. Time marches on. Mankind has to keep all options open. The answer probably isn't in old-methods, future energy needs new thinking. Imagination, rather than a grey drizzle of negative objections. The older I get the more I hate change - perhaps mother nature is telling me to get out of the way?

Extending the availability of Natural Gas by supplementing it with electrolytic Hydrogen isn't difficult. True it doesn't solve the big problem in the long run, but it helps for a time, which is all that can be expected of any technology. Plenty of other ways of using electrolytic Hydrogen too - about 20% of the world's natural gas is used to make Hydrogen for fertilizer, without which we will all starve.

Or renewable energy could be used to store heat by melting common salt, and recovered as steam to drive turbines. Many options are more practical than bulldozing Hydrogen into fuelling Internal combustion engines designed to run on petrol! If the answer to fuelling cars is Hydrogen, IC engines as we know them are off the agenda.

I think it's a mistake to see the future in terms of Coal, Oil, Gas, Nuclear, Hydrogen, or any other favourite fuel. Better to think about how energy can be supplied and used in the round. All sources of energy are fair game. Quite likely the answers will change the world as much as canals zapped pack-horses, railways zapped canals, and then internal combustion zapped railways, dog carts, and horse-drawn everything. 2020 is nothing like 1920 and 1920 was nothing like 1820. I'm sure 2120 will be different again.

Dave