Gas Boiler Extinction

[tjh290633]

Howard, that's a shame. BG (or any of the large companies) will have you believe any boiler more than half an hour old is inefficient, gobbles gas, is hard to get parts for and in dire need of replacement. Rarely is this true as you have found.

Thing is, their sales department employ gas registered technicians as their lead generators. They arrive ostensibly to service your boiler, but their primary goal is to find something wrong with it and label it up as dangerous and send a saleman around to quote for a new one. If they can't manage to condemn it then they scare you with stories about how you can't get the parts and its wasting gas and guess what, you should let them send a bloke around to quote you for a new one....

Cynical? Moi?

No, you are not cynical. The British Gas system of service contracts seems to ensure that unnecessary work is carried out, usually leading to s subsequent event requiring a call out. Modern gas boilers only need attention when they go wrong, in my experience. Experience of others who have regular servicing leads me to think that British Gas are to be avoided at all costs.

TJH

[scotia]

The Gas industry in the UK and Europe currently have trials underway injecting Biogas and also Hydrogen produced by Renewable Energy sources into the gas network. Both are currently being added to standard natural gas in various trials in limited quantities without the need for major changes to the gas boiler. Hydrogen & Biogas have the advantage that it can be stored after production from a Renewable Energy source. A complete replacement of natural gas by Renewable sourced Hydrogen would require large a changeover programme similar to what happened in the 60's & 70's.

So how do we get the Hydrogen? It needs electricity. I'm assuming by electrolysis of water. And if so the Hydrogen production simply adds a further inefficiency into the fuel cycle. OK - if (less) electricity is used to extract the Hydrogen from Natural Gas, then you produce Carbon Dioxide - just what you are trying to avoid by burning Natural Gas. As for Biogas - its simply Methane (as in Natural Gas) and Carbon Dioxide. So this is no solution to our desire to eliminate Carbon Dioxide production.

[jfgw]

So how do we get the Hydrogen? It needs electricity. I'm assuming by electrolysis of water. And if so the Hydrogen production simply adds a further inefficiency into the fuel cycle.

A quick Google suggests that electrolysis is similar in efficiency to pumped storage. Gas holders in the UK are being dismantled though so I'm not sure where we would store the hydrogen. I can see how this would be viable for producing gas for use directly as a fuel. Hydrogen production for conversion back into electricity would be very inefficient as a means of storage.

As for Biogas - its simply Methane (as in Natural Gas) and Carbon Dioxide. So this is no solution to our desire to eliminate Carbon Dioxide production.

The raw materials for biogas have to grow. The net production of carbon dioxide can be no greater than zero. Waste organic matter releases carbon dioxide when it rots in any case so digesting it anaerobically and burning the methane is just releasing carbon dioxide that would eventually be released anyway.

Julian F. G W.

[JohnB]

Gasholders are no longer needed as they use variable pressure levels in the high pressure pipe network to buffer supply and demand. This wouldn't change for hydrogen, though I suspect hydrogen is more inherintly dangerous than methane, so I'm not keen on any switchover. I think boilers will go with methane, and it will be heatpumps, the 3.5 to 4 heater multipler is too attractive.

[tjh290633]

Don't forget that there is well over a century's experience of handling a gas, with a high hydrogen content, in both domestic and industrial situations. The big difference from natural gas is the flame speed, which is why there had to be a conversion programme as NG was introduced, back in the 1970s. Electrolysis is not the only method of producing hydrogen. It also produces Oxygen, which could be (is already) used to enhance combustion.

I have a feeling that a new revolution could be coming in the gaseous fuels business.

TJH

[JohnB]

I found this government report: Appraisal of domestic hydrogen appliances, A study exploring the engineering challenges of developing domestic gas hobs, ovens, fires and boilers that can run on 100% hydrogen.

https://www.gov.uk/government/publicati ... appliances

I skimmed it, and it suggests it can be done by modifying existing appliances, but its not easy. No economic numbers are provided. I don't think the report's remit included the distribution network, just the appliances.

[jfgw]

though I suspect hydrogen is more inherintly dangerous than methane...

Probably not by much, but much safer than LPG which most people are happy to use.

You need at least 4% hydrogen in air for it to burn. If there is a leak, it floats upwards, as does methane. Both butane and propane are more dense than air so can accumulate in drains and basements. They require a concentration of 1.86% and 2.1% in air respectively to burn.

Julian F. G. W.

[scotia]

A quick Google suggests that electrolysis is similar in efficiency to pumped storage.

Yes - but its the stage after electrolysis that is more wasteful - compression or liquification for storage.

Gas holders in the UK are being dismantled though so I'm not sure where we would store the hydrogen.

Possibly compressed underground in salt mines, as is currently used for natural gas. Although the seepage rate is likely to be higher due to the smaller molecules.

I can see how this would be viable for producing gas for use directly as a fuel.

Maybe - but electrical heating with heat pumps may be a more economical use of electricity - albeit I would certainly prefer a gas boiler

Hydrogen production for conversion back into electricity would be very inefficient as a means of storage.

Agreed

The raw materials for biogas have to grow. The net production of carbon dioxide can be no greater than zero. Waste organic matter releases carbon dioxide when it rots in any case so digesting it anaerobically and burning the methane is just releasing carbon dioxide that would eventually be released anyway.

That's the theory - but energy is used in planting, growing and cropping for Biogas which is not recoverable. So Biogas is not 100% net zero in carbon dioxide production. More seriously it takes over useful agricultural land. Pumped storage uses high ground of little agricultural value.

[dspp]

You can put up to 25% hydrogen into the existing gas network. Gasometers aren't needed as linepack has been substituting since the 1980s. Below 25% appliance mods are only (from memory) the burner nozzle change.

Doing wind > hydrogen allows timeshifting and gets some reuse out of existing stranded North Sea pipeline infrastructure. But it is fairly old infrastructure.

I am doubtful about the economics, but things could develop in usual ways and even a partial conversion may be a piece of the jigsaw puzzle. Personally I think the ASHP route is more likely. Around the world's major petrochemical complexes I think H2 gas networks are more likely, but they are special cases.

Some extra reading if you are interested, there is plenty more out there including by these two orgs:

https://www.kiwa.com/en/service/hydrogen-leeds-h21/
https://www.gov.uk/government/publicati ... conversion

regards, dspp

[tjh290633]

You can put up to 25% hydrogen into the existing gas network. Gasometers aren't needed as linepack has been substituting since the 1980s. Below 25% appliance mods are only (from memory) the burner nozzle change.

The differences lie in the flame speed of hydrogen and the amount of Oxygen needed for combustion.

Hydrogen has a higher flame speed, so nozzle design has to avoid the risk of backfire, and the natural gas version has to avoid flame lift off.

Methane CH4 needs 2 molecules of Oxygen O2 to burn completely, providing 1 molecule of carbon dioxide CO2 and two of water H2O. Hydrogen H2 needs just half a molecule of oxygen O2 to make water H2O. So allowing for the other gases in air, we need about 10 parts of air to 1 of methane for combustion, and 2.5 parts of air for hydrogen. The calorific value of the two is different, so the burner nozzle(s) and the means of introducing the air for a premix burner are different. Town's gas, of course, also contained carbon monoxide, so direct comparisons with the situation pre-natural gas do not work.

TJH

[scotia]

Some extra reading if you are interested, there is plenty more out there including by these two orgs:
https://www.kiwa.com/en/service/hydrogen-leeds-h21/
https://www.gov.uk/government/publicati ... conversion

Thanks for the links. The kiwa report on switching Leeds to hydrogen is going to need a bit of thought - particularly since it proposes producing the hydrogen by steam methane reforming (SMR) - which produces carbon dioxide - and consequently requires the carbon dioxide to be captured and transmitted to underground storage for ever. The kiwa proposal leaves this problem of carbon capture to be solved sometime in the future. It dismissed the no-carbon solution of generating the hydrogen by electrolysis of water, since it estimates that it would require about three times the Electrical energy of the SMR solution (provided you ignore the SMR need for carbon capture). I think there needs to be some hard thinking about a UK wide generation of the hydrogen.
The second, more mundane link, I found interesting - as it outlined the costs, manpower and timescales involved in switching over from natural gas to hydrogen - without specifying how the hydrogen would be obtained. Since there is past experience of switching to natural gas from coal gas, their projections of costs (about £1000 per house conversion of a gas hob and CH boiler) and timescales (a few years to around 16 years, depending on whether or not to train an additional 100,000 gas engineers) are probably reasonably accurate. However unlike the earlier switch to natural gas, there is no monetary pay-off in switching to hydrogen - only costs - but it should help reduce global warming. And that is something the general public don't seem to have been warned about - all of the proposed changes to produce a zero carbon emitting society are going to be expensive.

[dspp]

Some extra reading if you are interested, there is plenty more out there including by these two orgs:
https://www.kiwa.com/en/service/hydrogen-leeds-h21/
https://www.gov.uk/government/publicati ... conversion

Thanks for the links. The kiwa report on switching Leeds to hydrogen is going to need a bit of thought - particularly since it proposes producing the hydrogen by steam methane reforming (SMR) - which produces carbon dioxide - and consequently requires the carbon dioxide to be captured and transmitted to underground storage for ever. The kiwa proposal leaves this problem of carbon capture to be solved sometime in the future. It dismissed the no-carbon solution of generating the hydrogen by electrolysis of water, since it estimates that it would require about three times the Electrical energy of the SMR solution (provided you ignore the SMR need for carbon capture). I think there needs to be some hard thinking about a UK wide generation of the hydrogen.
The second, more mundane link, I found interesting - as it outlined the costs, manpower and timescales involved in switching over from natural gas to hydrogen - without specifying how the hydrogen would be obtained. Since there is past experience of switching to natural gas from coal gas, their projections of costs (about £1000 per house conversion of a gas hob and CH boiler) and timescales (a few years to around 16 years, depending on whether or not to train an additional 100,000 gas engineers) are probably reasonably accurate. However unlike the earlier switch to natural gas, there is no monetary pay-off in switching to hydrogen - only costs - but it should help reduce global warming. And that is something the general public don't seem to have been warned about - all of the proposed changes to produce a zero carbon emitting society are going to be expensive.

Scotia,
I put the links up as an indication of the ability to use the existing gas network & existing appliances with an up to 25% hydrogen mix. Yes, you are absolutely correct, for any fossil-source there would need to be carbon sequestration for it to be a GHG benefit - I'm confident that is technically feasible, but less confident that it will ever be economically attractive on a large scale vs other generation options (with the exceptions likely being the major petrochemical complexes). However the various wind-to-hydrogen schemes might be attractive at very large scale, and they have no sequestration issues, but in any case I am (again) not holding my breath on the economics.
regards,
dspp

[MartynC27]

Vast quantities of natural gas (enough to supply a large city) are being flared off daily in USA and other oil producing countries. Pipelines are currently being constructed to take this Gas to export terminal for shipment to consuming countries. Further pipelines being constructed to increase the amount of gas being sent to Europe. I assume these pipeline will have a lifespan of at least 30 years. The UK gas industry under the direction of OFGEM has spent many millions converting local pipe systems to low maintenance plastic. With all this investment I don't think the Gas Boiler will become extinct for many years yet.

[anon155742]

https://kaikenhuippu.com/2020/02/18/why ... ectricity/

Even with free electricity, its still cheaper for Germans to heat their homes with gas

[JohnB]

Could be worse, you could have a coal fire ir wood-burning stove. Coal and wet wood sales to be banned in 12 months, only it takes 18 months to dry naturally...

[Mike4]

Could be worse, you could have a coal fire ir wood-burning stove. Coal and wet wood sales to be banned in 12 months, only it takes 18 months to dry naturally...

The coal thing is leading to great confusion. Only the retail sale of raw, unprocessed 'house coal' is being banned. Coal processed and formed into what is known as "smokeless fuel" (not sure how this is defined), e.g. "Coalite" is not being banned.

Processed 'smokeless fuel' is widely and loosely referred to as 'coal' by users and retailers of such.

[JohnB]

Living in London, we used smokeless fuel in our boiler for decades. It was less tarry than coal, and we used about 0.9 ton a year.