Suffolk Brian
Established Member
Fascinating. Altered my viewpoint.
Petrol Stations
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Fascinating. Altered my viewpoint.
Jacob
What goes around comes around.
Or a government on something like a war footing in order to deal with an urgent emergency. Democracy temporarily suspended for the duration, as per WW2 by means of a truce between the parties. https://link.springer.com/chapter/10.1007/978-1-349-01707-2_7
And that too. But based on the science, not limited by "that which is generally supported".
For instance; I think we are at the end of the age of the car. Personal powered transport may not be sustainable in any form.
This is not a popular idea!
Easy to forget; it's only been going en masse for one generation i.e. mine (born 1944). There were no car owners on our street when ar worra lad. Now every household will have one or more with solid banks of parking everywhere. It's a very recent phenomenon and a major generator of CO2.
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John Brown
Freeloading Social media influenza
I agree. In my experience hydrogen is usually championed by petrol heads.
It's an appealing idea, of course - surplus electricity from solar or wind, used to electrolysize(sp?) water - so interesting, if somewhat disappointing to learn about the drawbacks.
A bit of a skewed presentation. There are a number of instances where she cherry picks stuff that is not at all representative to make her point. Like the Wiesbaden buses. Not suggesting there are not issues with it, but nothing like as negative as this would lead you to believe.
Have a look at our very own Wrightbus, British company who are a world leader in manufacturing green buses, both battery and Hydrogen powered, and converting existing ones.
Contrary to what the lady in the video would have you believe it seems most hydrogen bus operators are expanding their fleets rapidly, not getting rid of them. So they have presumably overcome the various issues successfully, and find it cost effective.
Given that if it were adopted more widely the cost of both the fuel and the hardware would be likely to fall considerably, I think it should get more attention.
At the moment I think there is far to much emphasis on battery EV. They certainly have a place in the grand scheme of things, but have some serious drawbacks.
Contrary to what the lady in the video would have you believe it seems most hydrogen bus operators are expanding their fleets rapidly, not getting rid of them. So they have presumably overcome the various issues successfully, and find it cost effective.
Given that if it were adopted more widely the cost of both the fuel and the hardware would be likely to fall considerably, I think it should get more attention.
At the moment I think there is far to much emphasis on battery EV. They certainly have a place in the grand scheme of things, but have some serious drawbacks.
Why would petrol heads have a particular liking for hydrogen? They are usually ICE fans, and hydrogen vehicles are electric, with no engine.
As I have already said elsewhere quite a bit of what she says is at best a little disingenuous.
artie
Sawdust manufacturer.
How does the hydrogen get turned to electric?
Terry - Somerset
Established Member
The Prolongation of Parliament act passed in 1940 was a response to an immediate, real threat with a high level of political and public support for actions which could win the war. The invasion of Poland and France, and the prospect of Dunkirk and the Blitz would be mighty motivators!
I doubt the same level of support would be forthcoming based on the threat of climate change.
Even were political agreement forthcoming, society has radically changed since 1940 with much less respect for established authority. Suspending democracy would be perceived as a real threat to personal freedom - in 1940 it would have been a real threat to public and nation..
Suspension of parliament to meet a climate threat could create a very high risk of public unrest at a level far exceeding (for instance) the poll tax riots.
Using force to suppress unrest would reduce the UK to a single party police state using force to implement policy where possible. Putin would look on in admiration. A complete non-starter.
Fuel cell produces electricity and the vehicle is driven by electric motors like a battery EV. Only emissions are pure water.
Jacob
What goes around comes around.
If we have to wait until the s**t hits the fan it will be too late
So you are resigned to CC taking it's course and life on earth changing drastically quite soon?
John Brown
Freeloading Social media influenza
I don't know, it's just an observation.
To be honest, I get the impression that they don't realise that hydrogen vehicles use fuel cells.
Jacob
What goes around comes around.
niall Y
Established Member
The crux of the matter regarding the use of clean hydrogen, is that it is not the actual energy source, Energy ( electricity ) has to be used to produce it, so it's more akin to a battery in this regard. If using electricity to produce it, then why not cut to the chase and simply charge a battery?
John Brown
Freeloading Social media influenza
Indeed.
Yorkieguy
Established Member
I spent my 40 year career in the gas industry, and in 1967/68 work in the British Gas laboratory on the design teem which designed burners to enable appliances designed for use of coal gas to be converted to work on natural gas. Hence, I have more than a passing interest in the topic, but I've been retired many years so claim no current experience or knowledge than anyone else can glean from internet.
Quite apart from the challenges posed by production, storage transmission and distribution of hydrogen, it's way more complex to design burners and control equipment for hydrogen than many realise. It poses immense challenges in burner design for any appliance using gas, whether domestic or industrial. I doubt it will be possible (as it was when converting to natural gas) to convert existing appliances to hydrogen, as the characteristics of hydrogen are very different from those of natural gas.
For example:
The heat value of gas 'in British Thermal Units' (Btus) per cubic foot' (old measure) or 'megajoules per cubic metre' of coal gas, natural gas and hydrogen vary widely, which means that the volume of gas needed to produce the same amount of heat differs.
Coal Gas: Btu/Cu ft: 483 Btu. MJ/Cu Mtr 18 MJ
Natural Gas (US) Btu/Cu ft 1,090 Btu. MJ/Cu Mtr: 40.6 MJ
Hydrogen Btu/Cu ft 341 Btu. MJ/Cu Mtr: 12.7 MJ
So when converting from coal gas to natural gas, only half the volume was needed for a given amount if heat, which had the benefit of doubling the capacity of the transmission and distribution system at a time when demand for natural gas was rapidly increasing. Hydrogen has only a third the calorific value of natural gas.
Flame Speeds:
This is the rate at which a gas will burn.
The combustion characteristics of H2 are vastly different from those of natural gas. The flame speed in H2 combustion is approximately 1.7 metres per second, while the flame speed of natural gas is significantly slower at only 0.4m/s. Most people will at some time found that when a gas cigarette lighter is turned up too high, the gas comes out of the jet at a faster rate than it will burn and the flame 'lifts off'. Burners designed for natural gas are thus designed for 'flame retention' to prevent 'lift-off'.
In a normal gas burner, air and gas are premixed in a combustion tube, and additional secondary air also surrounds the flame as it burns. Hydrogen’s flame speed is nearly five times that of natural gas, so burners become more susceptible to flashback into the burner, which needs to be designed to avoid this. Flashback occurs when the gas velocity exiting the burner nozzle is slower than the flame speed in a premixed application. Damage to the burner components can result when flashback occurs. The increased flame temperature of hydrogen requires upgrading the steel used for nozzle construction, throat construction, and flame stabilizers to a higher grade stainless or alloy.
Flame Failure Devices:
All current boiler operating codes require flame detection as a critical burner safeguard. When H2 is present in the combustion process, it generates water vapor. As the H2 content approaches 80% in the fuel stream, most flame scanners available today have difficulty distinguishing and verifying the flame due to the high level of water vapor present. Selecting the proper flame detection equipment is crucial.
Source: https://cea.org.uk/practical-consid...mbustion characteristics of H2,at only 0.4m/s
The flame failure device used in modern domestic natural gas boilers is invariably 'flame rectification'. Gas emerges from a pilot jet and is ignited by a spark generator. A minute AC current flows through the pilot flame, which rectifies the current to AC, opening the main gas burner. If for example, a fragment of metal fell onto the pilot, the metal may well conduct AC current across the pilot burner but the main gas valve wouldn't open as it needs to see an AC voltage. When the main burner cycles on an off, so does the pilot.
The steel used in burners firing H2 should not be susceptible to hydrogen embrittlement and high-temperature hydrogen attack. Both phenomena can prematurely degrade an improperly chosen steel, leading to early failure of the burner parts. Any region with elevated temperatures above 1,371°C is conducive to NOx formation. Field and test facility data have shown that standard low-NOx burners firing H2 typically exhibit an increase in NOx emission rates by up to a factor of three.
Many will repeat the mantra that 'hydrogen is a 'clean gas' as it combining with oxygen when it burns, creating water vapour'.
Well yes, but air is roughly 4/5ths nitrogen and 1/5th oxygen, so you don't get one without the other.
In the most recent annual air quality assessment (for 2022), the UK was non-compliant with the annual mean concentration limit value for NO2 (as set in the Air Quality Standards Regulations (2010) at a number of roadside locations in urban areas. It 's estimated that, on average in 2022, 65 per cent of the NOx concentrations at the roadside originate as NOx emissions from road transport.
Short-term exposure to concentrations of NO2 can cause inflammation of the airways and increase susceptibility to respiratory infections and to allergens. NO2 can exacerbate the symptoms of those already suffering from lung or heart conditions. In addition, NOx can have environmental impacts. Deposition of nitrogen to the environment both directly as a gas (dry deposition) and in precipitation (wet deposition) can change soil chemistry and affect biodiversity in sensitive habitats.
NOx can react with other air pollutants (e.g. NMVOCs) to form ground-level ozone. Ozone is a gas which is damaging to human health and can trigger inflammation of the respiratory tract, eyes, nose and throat, as well as asthma attacks. Ozone can also have adverse effects on the environment through oxidative damage to vegetation including crops.
Gothenburg Protocol and National Emission Ceilings Regulations (2018) (NECR) requires the UK to reduce emissions of NOx by 55% compared to emissions in 2005 by 2020 and in each subsequent year, up to and including 2029. The NECR also requires the UK to reduce emissions of NOx by 73% compared to emissions in 2005 by 2030.
Emissions of NOx have decreased by 78% since 1970, to 643 thousand tonnes in 2022. This trend was driven by a decline in coal use in power stations and by the modernisation of the road transport fleet. Emissions of NOx decreased by 4% between 2021 and 2022. This is similar to the change since 1990 as total emissions have decreased by an average of 4% per year between 1990 and 2022. The latest data shows that the UK did meet the 55 per cent emission reduction commitment for NOx in 2022. Anything which might cause a reversal of that trend would not I'm sure, be countenanced
Source:
https://www.gov.uk/government/stati...ave,affect biodiversity in sensitive habitats
I think that's quite enough for now.
For anyone who has read down to here, thanks for your time - I hope you've found it interesting.
David.
artie
Sawdust manufacturer.
From what little I've read a charge/refill time of minutes rather than hours would be a good reason.
John Brown
Freeloading Social media influenza
True!
Because the battery is very big and heavy and takes a long time to charge.
Using a fuel cell to power a vehicle there is little if any weight penalty over ICE, and you can refill with hydrogen in minutes and be on your way again.
Think of an HGV. The batteries required to move 40 tons from say London to Manchester would be huge. The weight of the vehicle is limited by law, so the weight of the battery is necessarily going to reduce the cargo carrying capacity. So more vehicles required to deliver the same amount of cargo.
Then there is turnaround time. How long would it take to charge the battery on a vehicle like this, several hours at best. This would play merry hell with logistics and drivers hours.
So battery EV very good for relatively short journeys especially if you have your own charging facilities, not so good in many other circumstances.
Then think of infrastructure. If we all had battery EV you would need to upgrade the grid to cope with demand, and need goodness knows how many charging points. So roads being dug up everywhere to install tens of thousands of miles of cables. Those cables contain copper and plastic insulation, hardly the most environmentally friendly things to produce.
None of this necessary if you adopt hydrogen. Logically you would have large hydrogen production facilities located alongside existing power stations or distribution points. Use green energy to power the production of liquid hydrogen which can then be tankered to filling stations in much the same way as petrol and diesel are now. This is already being done on a relatively small scale by bus companies etc so is entirely feasible.
The problem is you have the classic chicken and egg situation at the moment. No one is going to buy a fuel cell car if there is no where to fill it up, likewise no one is going to install Hydrogen pumps on their forecourt when there are no customers for it.
Very interesting. The scheme I was referring to was actually in Scotland. 300 homes are to be heated using Hydrogen. Not sure if they proposed to fit new boilers or modify existing ones. The project is currently on hold. Not it appears because of problems with the technology, but a row over who is paying for it.
One thing I did find interesting in the original report I saw was that they intended to feed the hydrogen as a gas through existing pipes. I did wonder how that would work regarding the potential problems with embrittlement, leakage etc. I can see that at these very low pressures the problems would be reduced, but I wouldn't have thought they would be entirely eliminated.
I would be interested to know your thoughts on that, you clearly know a lot more about it than most.
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With regard to the chicken and egg situation this is perhaps where government needs to step in and give things a nudge. Spain for example are investing €800 million in green hydrogen generation.
Important thing is to get a grip of where we are going. It would be a shame to waste huge amounts of money installing charging points if battery EV turn out not to be the answer we are looking for.
We need to decide what role the various options will play and plan accordingly.
As it stands I can't see any option but hydrogen for long haul road transport, air travel etc. if we will need to build the infrastructure to support this then just seems daft to build a whole separate system for battery EV.
Important thing is to get a grip of where we are going. It would be a shame to waste huge amounts of money installing charging points if battery EV turn out not to be the answer we are looking for.
We need to decide what role the various options will play and plan accordingly.
As it stands I can't see any option but hydrogen for long haul road transport, air travel etc. if we will need to build the infrastructure to support this then just seems daft to build a whole separate system for battery EV.
