General: UK housing: Fit for the future?

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- CommentAuthorMike1
- CommentTimeFeb 24th 2019 edited
Not sure (as nobody seems to have mentioned it) if anyone saw the headline about banning new homes from connecting to the gas grid by 2025, but the Committee on Climate Change's report including that recommendation can be found at https://www.theccc.org.uk/publication/uk-housing-fit-for-the-future/ and makes interesting reading.
- CommentAuthordjh
- CommentTimeFeb 25th 2019
It's a laudable goal at one level, but suffers from a lack of joined up thinking. As things stand, we're going to have difficulty keeping enough generating capacity on the grid to deal with current demands. Adding more demand by starting to convert the demand for heat to a further demand for electricity (plus electric cars etc) means we need an answer to the generation and storage problem before considering adding substantial additional demand.

Given it's from the Committee on Climate Change, I think they should have pointed out this major gotcha!

We're doomed, I tell you.

Thanks for the link though. It's an interesting subject.
- CommentAuthortony
- CommentTimeFeb 25th 2019
The long term fuel of the future will be electricity.

Gas will run out

A hydrogen economy is a possibility but it is unlikely to use pipes to transport it.

Reducing our energy demand is key to a sustainable future

We are not doomed
- CommentAuthorfostertom
- CommentTimeFeb 25th 2019 edited
Posted By: tonyReducing our energy demand is key to a sustainable future
Yes but not quite as previously advertised.

'Almost unlimited' supply of 'completely clean' energy is on the horizon, in the form of very cheap non-silicon PV, consumed as much (if not more) 'on the spot' where it's captured, as via the grid.

This will alter the balance of energy saving vs energy supply - total-saving systems like Passive House, while correct at present, won't need to go that far in future.

Of course such ubiquitous PV won't be here in time to fill the gap left by banning gas boilers - but solar continues to come in far faster than the most optimistic projections dare hope.
- CommentAuthorbhommels
- CommentTimeFeb 25th 2019
IF (big IF) an efficient, solar energy driven process for methane synthesis can be found, our existing gas infrastructure could go a long way with methane fuel cells producing the power for your heat pump. In addition, more distributed (micro)generation will lessen the demands on electricity grid infrastructure.

Long-term, a hydrogen based energy economy is the best. It sounds complicated, but the hardly is an alternative for storing and pushing around large amounts of energy in a clean and efficient manner.

The stone age did not end because of lack of stone
- CommentAuthordereke
- CommentTimeFeb 25th 2019
From the few scientists I have talked to a "hydrogen economy" is not going to happen. The losses involved in converting electricity to hydrogen are phenomenal. Far better to focus development into batteries.
Solar+Wind+Batteries is fairly "simple" well understood tech.
- CommentAuthorfostertom
- CommentTimeFeb 25th 2019 edited
Yes but hydrogen is 'portable power', may be indispensable for purposes like trucks and ships (payload dominated), trains, heavy equipment which are always going to be less viable on batteries than ever-lighter cars.

Cars will go all-electric but the above heavies will go hybrid, carrying high-density liquid fuel. Trains will draw/recharge from overhead wires (or sub-surface charging coils) but as we've seen such electrification is too costly for all but the main routes; for any chance of extended coverage, latest development is hydrogen/ hybrid trains.

Hydrogen conversion is a terrible idea if made with fossil-fuel electricity but is ideal to soak up peaks of wind/solar capture, and for the above purposes the inefficiency of conversion is 'worth it', esp if it's from effectively limitless PV.
- CommentAuthorbhommels
- CommentTimeFeb 25th 2019 edited
Posted By: derekeFrom the few scientists I have talked to a "hydrogen economy" is not going to happen. The losses involved in converting electricity to hydrogen are phenomenal. Far better to focus development into batteries.
Solar+Wind+Batteries is fairly "simple" well understood tech.

High-temperature electrolysis has an efficiency of 70-80%. Losses of 30% are hardly phenomenal in my opinion.

Hydrogen is an excellent energy vector, allowing enormous amounts of energy to be transported and stored with relatively low losses. Electrolysis can take place where there is solar energy in abundance, taking the efficiency of generation out of the equation. The number that hurts the most is the conversion efficiency of around 60%.

On the other hand, batteries are expensive, wear out, need to be carefully conditioned and do not have great energy density. A Tesla model 3 logs 600kg of batteries around, and weighs in at 1800kg. Another question is what the equivalent of a petrol station would look like when everybody has a battery powered electric car?

Toyota is selling hydrogen cars already, the Mirai, and is working on Hydrogen powered utility vehicles. I think the hydrogen economy is closer than many of us might think.

So no, we are not doomed if we don't want to be.
- CommentAuthordereke
- CommentTimeFeb 25th 2019
Hydrogen is not a high density fuel but I get your point. We would have to have quite a lot of excess renewable capacity to produce it at a reasonable cost though. I think we are a fair way off that yet ATM.

Regarding trains, there was a pilot project a couple of years ago where they had an electric train with battery in it. On parts of the line where there was no overheard wires they used the battery and where they had the wires they obviously charged it up. I think they got like 50miles of range out of it when I believe they were expecting about 15.

I think with the mass of the train you get quite a lot of regen out of it so while it may be heavy it is still reasonably efficient. Similar effect with trucks - and they won't be hydrogen either. In fact Nikola motors recently announced that their hydrogen trucks (which you can't buy yet) are going to be available as... completely electric. It just doesn't make sense to pack all the fuel cell tech into trucks/trains and then build a distribution network and then deal with all the extra maintenance when there is good tech available for it already. Also.. if you go fuel cell + hydrogen you need all that tech + electric motor and batteries anyway.

I think you may have a point regarding ships though, at their scale I think the economics would change.
- CommentAuthordereke
- CommentTimeFeb 25th 2019 edited
Posted By: bhommels
High-temperature electrolysis has an efficiency of 70-80%. Losses of 30% are hardly phenomenal in my opinion.

...

The number that hurts the most is the conversion efficiency of around 60%.

So you waste energy when you store it and then again when you try and use it?

Posted By: bhommels
On the other hand, batteries are expensive, wear out, need to be carefully conditioned

They last for quite a long time to be fair. There are Teslas that have done 200,000 between battery swaps. Leafs that have done over 150,000 etc. And at this point they are still valuable for stationary storage. The conditioning is a solved problem.

Posted By: bhommels
Another question is what the equivalent of a petrol station would look like when everybody has a battery powered electric car?

Mostly like a socket in your driveway/garage. But on long trips like this https://www.youtube.com/watch?v=n-7iu6ZeGuE

not an EV owner yet, hoping to get one later in the year.
(first time quoting so hopefully I didn't screw up the tags)
- CommentAuthorfostertom
- CommentTimeFeb 25th 2019
https://theconversation.com/hydrogen-trains-are-coming-can-they-get-rid-of-diesel-for-good-110450
- CommentAuthorbhommels
- CommentTimeFeb 25th 2019 edited
So you waste energy when you store it and then again when you try and use it?

At generation, and at consumption, yes. Not during storage & transport. The round-trip efficiency is not great, admittedly. However a petrol car delivers only 12% of the input energy to the tyres!

They last for quite a long time to be fair. There are Teslas that have done 200,000 between battery swaps. Leafs that have done over 150,000 etc. And at this point they are still valuable for stationary storage. The conditioning is a solved problem.

My initial concern is how much you get out of your Tesla when running it in North Siberia. Or in the Gobi Desert.

Posted By: bhommels
Another question is what the equivalent of a petrol station would look like when everybody has a battery powered electric car?

The trouble with filling stations is that one minute there is nobody, the next there are 20 cars demanding to charge at 100-150kW each. This needs some kind of intermittent storage, and I think Hydrogen is better for this than another massive battery.

Don't get me wrong though, I think battery powered cars are a fantastic development, and eliminating ICEs from our streets can't go fast enough. Long term I think hydrogen has the best cards, and in the medium term there are likely to be all kinds of hydrogen/battery hybrid solutions depending on the application.

Driving your car does not help heating the house however.
- CommentAuthordereke
- CommentTimeFeb 25th 2019 edited
Posted By: fostertom
https://theconversation.com/hydrogen-trains-are-coming-can-they-get-rid-of-diesel-for-good-110450

A second alternative is to use a â€œthermochemicalâ€ production method that involves reacting water with sulphur and iodine in the presence of heat. The good news is that this method is set to become economical within the next ten years thanks to the development of generation IV nuclear power plants.

This is like saying nuclear fusion is just around the corner

Posted By: bhommels
The trouble with filling stations is that one minute there is nobody, the next there are 20 cars demanding to charge at 100-150kW each. This needs some kind of intermittent storage, and I think Hydrogen is better for this than another massive battery.

Why? A big battery does the trick and it can provide grid balancing services as well.

Posted By: bhommels
Driving your car does not help heating the house however.

If you are at home are using V2G and a heatpump it can certainly help though
- CommentAuthordereke
- CommentTimeFeb 25th 2019 edited
New research just out today:

https://www.carbonbrief.org/renewable-hydrogen-already-cost-competative-say-researchers

Hydrogen produced using renewable electricity is â€œalready cost competitiveâ€ in niche applications, a new paper says, adding that it is likely to match industrial-scale alternatives in about a decade

I am refining my position on hydrogen: industrial processes and shipping.
Still a decade away of course
- CommentAuthorfostertom
- CommentTimeFeb 25th 2019
Yes, this was a depressing bit of the article:

"... electrolysis plants are unlikely to be economic unless they run for a high proportion of the day. This would mean that when there wasnâ€™t excess wind to power them, they would need regular electricity from the grid ... alternative is to use a â€œthermochemicalâ€ production method that involves reacting water with sulphur and iodine in the presence of heat ... set to become economical ... thanks to the development of generation IV nuclear power plants"

What can the latter mean - using waste heat? we can't have hydrogen tied to nuclear thank you.
Must hydrolysis plant be huge-scale? Maybe this would be a use for industrial-estate process waste heat, which is hard to use for e.g. district heating.
What would be the chemical precursors and byproduct of sulphur/iodine?
- CommentAuthordjh
- CommentTimeFeb 25th 2019
Posted By: derekeI am refining my position on hydrogen: industrial processes and shipping.
Still a decade away of course

The cost competitiveness they're talking about is against conventional hydrogen supplies, of course, not against natural gas especially in vast quantities.

The point is the housing paper implies we should start massively increasing the demand for electricity in 6 years. There are no plans to do any such thing, nor any feasible way to do it in a carbon neutral way that I'm aware of.
- CommentAuthorMike1
- CommentTimeFeb 26th 2019 edited
Posted By: djhThe point is the housing paper implies we should start massively increasing the demand for electricity in 6 years. There are no plans to do any such thing, nor any feasible way to do it in a carbon neutral way that I'm aware of.

Certainly, as implied by the title of last year's report from the Committee on Climate Change (An independent assessment of the UKâ€™s Clean Growth Strategy: From ambition to action), the Government have ambitions, but significant strategy & implementation issues.

Options mentioned include doubling UK electricity generation capacity by 2050 (if electricity is to become the dominant energy source); re-purposing the gas grid to deliver hydrogen (to power vehicles, as well as supplying over half of all heating needs and a third of industrial energy demand); and continuing to use high-carbon fuels alongside removal of CO2 from the atmosphere using bioenergy & carbon capture. Or a mixture. Decisions clearly need to be taken.
- CommentAuthorbhommels
- CommentTimeFeb 26th 2019 edited
Posted By: dereke

This is like saying nuclear fusion is just around the cornerhttp:///newforum/extensions/Vanillacons/smilies/standard/bigsmile.gif" alt="" title="" >

Posted By: bhommels
The trouble with filling stations is that one minute there is nobody, the next there are 20 cars demanding to charge at 100-150kW each. This needs some kind of intermittent storage, and I think Hydrogen is better for this than another massive battery.

Why? A big battery does the trick and it can provide grid balancing services as well.

Because of cost. The battery would have to be sized for worst-case peak demand, making it prohibitively expensive. Grid balancing services using batteries are only cost justified in rare cases, see the Tesla project in Oz for example. If it was really economically viable all of us on the forum here would have a battery storage at home by now.
- CommentAuthordereke
- CommentTimeFeb 26th 2019
It is precisely the Oz project that I am even mentioning using the batteries as grid storage :-)

You are right though, it might not be viable right now but as more renewables come online and more people get into EVs and battery costs reduce further it will solve two problems.
- CommentAuthortony
- CommentTimeFeb 26th 2019
Battery storage as i keep saying is inherently inefficient. better use the energy and save the fossil fuel that would have been used to generate it
- CommentAuthordjh
- CommentTimeFeb 26th 2019
Any storage is inherently inefficient, but the point is to be able to match generation capacity with instantaneous demand at all times.
- CommentAuthorfostertom
- CommentTimeFeb 26th 2019 edited
'inefficiency' will matter much less than we've obsessed about for so long, once the energy supply is potentially limitless, cheap and harmless. We can afford to use it a bit 'wastefully' as long as the supply is plentiful, cheap and harmless.

Well nothing is quite 'harmless' - the penalty of such happy profligacy is the release of man made lo-grade waste heat into the biosphere, which dissipates by radiating away into space. Sure, the biosphere would have to warm up a little, to cause such extra radiation to happen.

But that warming would be not a fraction of the biosphere warming that is presently having to happen in order to dissipate both natural and man-made waste heat through the increasing thermal resistance of a greenhouse-gas laden atmosphere.

While energy supply is inexorably linked with greenhouse-gas emission, the imperative to minimise the latter is what drives the present, rightful obsession with maximised efficiency, in generation, transmission/storage, and use - to get more useful use out less energy hence less greenhouse-gas emissions.

Once that link is broken, between energy generation and greenhouse-gas emissions (and other kinds of pollution too, actually), then the need for efficiency drops sharply, may still be pursued, but for other reasons.
- CommentAuthordereke
- CommentTimeFeb 28th 2019
Well this was unexpected :-)

https://nieuws.kuleuven.be/en/content/2019/belgian-scientists-crack-the-code-for-affordable-eco-friendly-hydrogen-gas

The summary is that it is a 15% efficient solar panel that produces 250L of hydrogen gas per day (average over a year) - 20 panels are apparently enough to electrify and heat a home for a year - obviously quite a few unknowns in that statement!

Clever to bypass the normal method of using electricity to power electrolysis. It will be interesting to get some more information about how it works.

My village is looking into the possibility of installing a low/no carbon district heating - if this is economical it might be a nice additional heat source.
- CommentAuthorfostertom
- CommentTimeFeb 28th 2019 edited
Posted By: fostertom... alternative is to use a â€œthermochemicalâ€ production method that involves reacting water with sulphur and iodine in the presence of heat ... set to become economical ... thanks to the development of generation IV nuclear power plants"

What can the latter mean - using waste heat? we can't have hydrogen tied to nuclear thank you.
Must hydrolysis plant be huge-scale? Maybe this would be a use for industrial-estate process waste heat, which is hard to use for e.g. district heating.
What would be the chemical precursors and byproduct of sulphur/iodine?

Any informed comment on this?

If large supply of lo-grade heat is key to this process, it sounds like a breakthrough.
Till now, the only ways to produce electricity direct from a thermal gradient, has been extremely inefficient, via thermocouple. Fine for a glimmer of light from your camping-gaz stove but not more.
If this process can produce hydrogen, thence electricity, from waste heat, of which there's vast unuseable quantities, with hopefully not too much chemical as catalyst, then ...

Any comment?
- CommentAuthorbarney
- CommentTimeFeb 28th 2019
It isn't necessarily waste heat - you need a heat source of around 1000C to accomplish the water splitting to derive the hydrogen in a SI reaction - the only credible one would be a small high temperature gas cooled reactor

It most certainly isn't a lo grade heat process by any means

Regards

Barney
- CommentAuthorWillInAberdeen
- CommentTimeFeb 28th 2019 edited
Tom, unfortunately the 2nd law of Thermodynamics applies to this, like it does to everything, and states that:

"You can't never ever get somethin' for nothin' "!

The point about low grade heat is precisely that it is low grade, so the work ( hi grade energy) that can be extracted when 1GJ of it flows to ambient temperature is only a small fraction of 1GJ, which is why it was dumped by its previous owner...

The sulphur/iodine thing seems to require 850degC, so it converts very high grade heat into hydrogen and low grade heat.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://en.m.wikipedia.org/wiki/Sulfur%25E2%2580%2593iodine_cycle

Edit: crossed with Barney's post. Had to fix dodgy wiki link.
- CommentAuthorfostertom
- CommentTimeFeb 28th 2019
Scuse ignorance but does the 2nd Law specify what 'the small fraction' is depending on the differential? I thought it was more general.
Unlike Carnot, which specifies it exactly, for the case of thermal to mechanical conversion.

What is the source temp of diffuse (cloudy day) solar-originated radiation? temp of the clouds, surely, which makes it lo-grade, but still decent conversion to electricity.
- CommentAuthorWillInAberdeen
- CommentTimeFeb 28th 2019
Having said that - this thread is supposed to be about heating houses to about 20degC, which is very low grade heat.

There's a disconnect somewhere that we all tend to assume (me included) that a very high grade energy carrier such as electricity/gas/hydrogen/battery is the best way to deliver this heat to each individual house. This may be historical because we grew up with our heating arriving through a gas pipe or a wire.

If there was a way to "pipe" low grade heat into each house maybe that would make more sense. District heating, maybe on a much more local scale? Or much less?

How about if each street had a shared GSHP loop buried under the street with branches into each house or flat, delivering heat at 10degC? Each house has a heat pump to boost this to 20degC. If there was a supermarket with freezers, it could sell their extracted heat into the ground loop. Ditto if there was an office with Aircon. Etc

Just wondering out loud..
- CommentAuthorWillInAberdeen
- CommentTimeFeb 28th 2019
Tom, source temp of solar radiation is given by its wavelength, so v high temp for sunlight, even when reflected off clouds. Hence you can't run a pv panel on low temperature radiation from the same clouds when in night sky.

Carnot efficiency is another way of stating the 2nd Law, so applies to all heat source (electricity) generators, not just mechanical ones.
- CommentAuthorbarney
- CommentTimeFeb 28th 2019
The "small fraction" is just a function of source and sink temperatures - for your hydrogen production using sulphur and iodine, you need many hundreds of degrees of heat capability - which isn't "lo grade"

If you are thinking of PV, then its the photons (in the "light") that deliver the energy, not the temperature of the radiation

Regards

Barney

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General: UK housing: Fit for the future?