What is the real story around heat pumps?

[nctnico]

What certainly does not make sense is to instead install 700 to 800 TWh of solar capacity plus the matching P2G plants in order to generate and store 500 TWh of methane for use in gas fired home heating systems during the winter.

Not methane but hydrogen. Plants to convert electricity to hydrogen are being build right now. First to turn 'useless' electricity into hydrogen for other purposes (including mixing with natural gas to reduce the amount of natural gas being use), but soon also to convert hydrogen back into electricity. Batteries just aren't going to cut it for seasonal storage. Not by a long shot.

[pcprogrammer]

I'm also looking in to the possibility to control the heat pump with my own system, and that seems to be a bit tricky due to proprietary interfaces and protocols.

Look at terms like "EVU" or "smart grid" or "SG" or "SG-ready", which is a simple two-bit digital on/off control, allowing increase/decrease of setpoint. If even that isn't supported, then you most likely still have a simple on/off logical control you can interface to, and possibly another to prevent usage of aux resistive heating.

No one actually interfaces the RS485/CAN buses of these heatpumps, even we doing this thing professionally have postponed such feature creep and still offer simple on/off control as the primary means and dedicated our efforts elsewhere (e.g. support gazillion of solar inverters instead of gazillion of heatpumps).

One option is to use relays to add resistors in series/parallel with the thermistor used to by the heatpump to measure reservoir tank temperature, this way you can cheat setpoint finetuning without having to figure out an interface to actually control the setpoint (or more specifically, curve parallel shift).

Be careful with your control, though - if you prevent heating for too long, creating large dip in temperature, then after releasing the control the heatpump's internal logic might decide that using resistive support heating is a great idea, ruining your COP.

Good options to look into. For De Dietrich I found that there is an opentherm to modbus converter option. Also found some French forum about it and might be able to get some more information when I register there. Downloads are restricted for me as is. 

[m k]

We have a small direct electricity radiator that is rattling.
It's close to both units of the air to air heatpump but it's also rattling when heatpump is off, I think.
Plus side is that it's easy to adjust, after successful adjustment it's still vibrating but silently, I can still clearly feel it.

It's a completely different ball game if geothermal pump is vibrating through the building.
One of those things where personal sanity may be questioned.

Our house has few resonating places but all are higher pitch and avoidable.
One is a corner, or near of it where upper part of a hearing band whine can be heard, or I can, moving a head about a head size and it's gone.
Generally I hear some kind of whining all the time, occasionally also short and probably universal tinnitus stylish things.
If I start listening I'm still hearing an old CRT TV, maybe it's in my head, at least all machines, that I know of, are long gone.
When that tinnitus thing happens, is mild or lower and turning head is giving it a direction I know that washing machine is ready.

It's also not unheard of that outdoor unit of a neighboring heatpump is generating ground noise, so good vibration absorbing is important.
We can faintly hear when neighbor is dropping logs to down stairs, most likely onto a stone floor of some sort and maybe 40m away.

Air to air heatpump control through self made remote controller was a thing here a decade or so ago, now there are more possibilities.
Air to water machine has much more settings.
So my opinion is that connecting it must be supported by the manufacturer.

[zilp]

What certainly does not make sense is to instead install 700 to 800 TWh of solar capacity plus the matching P2G plants in order to generate and store 500 TWh of methane for use in gas fired home heating systems during the winter.

Not methane but hydrogen. Plants to convert electricity to hydrogen are being build right now. First to turn 'useless' electricity into hydrogen for other purposes (including mixing with natural gas to reduce the amount of natural gas being use), but soon also to convert hydrogen back into electricity. Batteries just aren't going to cut it for seasonal storage. Not by a long shot.

That doesn't contradict what I wrote. Yes, electrolysis/P2G plants will be built and are being built right now here in Germany (which I already mentioned). But we will not add 700 TWh of solar generation capacity plus the same P2G capacity in order to generate sufficient methane or hydrogen to keep running gas fired heaters, for the reasons that I have explained at length.

Also, hydrogen isn't all that useful for seasonal storage either because its energy density is way lower than that of methane. As I already mentioned, our current natural gas storage capacity already isn't sufficient to store what Germany currently uses through the winter. If we stored hydrogen instead, that number would be significantly lower still. Which is fine-ish if we switch to heat pumps and therefore massively reduce the required amount of primary energy and then use that storage to feed gas power plants to smoothe over gaps in renewable generation, but not for keeping gas fired heaters in any significant numbers.

Really, though, the primary use of hydrogen (and methane synthesised from it) will be for industrial processes that need hydrogen or methane as a chemical input, or for industrial processes that need temperatures that you can't reasonably reach without fire.

The idea that we'll mix renewable hydrogen into the natural gas supply also is largely nonsense. I mean, it's not that that might not happen, but it's certainly not a long-term solution, but likely more an option to make use of excess hydrogen, especially during the transformation, in case electrolysis plants get completed faster than industry switches over their processes from fossil inputs to hydrogen or P2G methane, or where separate hydrogen pipelines don't exist yet.

Because of the lower energy density of hydrogen, as you increase the fraction of hydrogen in the natural gas supply, the transport capacity of your distribution network decreases. If we add only 20% of hydrogen (a number often claimed as possible without modifications to the network), that decreases the network capacity by 14%. And at the same time, that only decreases natural gas demand (and therefore CO2 emissions) by ~ 7%. Which is better than nothing, granted--but obviously not really a solution.

Possibly, that could work out if we swap out 90% of gas fired heaters for heat pumps, thus massively reducing the demand on the network, so that we can then switch it to 100% hydrogen and still have sufficient transport capacity. But in addition to the probably relatively high price of green hydrogen, that would also mean that the newtork maintenance costs now would be distributed among a tenth of the customers we have now and thus would increase tenfold per customer. Which doesn't exactly make things more economical for the customer. Also, we'd probably have to swap out compressors and stuff, which makes for additional costs that that remaining customer base would have to pay for.

[JohanH]

Geothermal heatpumps with variable speed are very silent. I have a small Nibe F1255 (6 kW) and a 170 m borehole. It has a Mitsubishi BLDC motor that runs between 20 and 120 Hz. By default it's limited to max 102 Hz. I tried increasing the output and it becomes a bit noisy at 120 Hz. As it is now, it's more quiet than the old oil burner. The house is 145 m^2, with about a third in-floor heating and the rest radiators. I've changed to bigger radiators after installing the heatpump. The floor is shunted from the radiator system. This is of course not optimal. I haven't looked up recent numbers, but in 2021 the heatpump used 4700 kWh electrical energy that it turned into 13500 kWh heat energy and 4000 kWh warm water. In total 17500 kWh heat energy. This makes an SCOP of 3.7. This is not bad for a house from 1927 with some parts lacking good insulation. On really cold days, such as this winter with -30°C, the heatpump doesn't make enough power, so it's intermittently turning on the resistive heaters. It doesn't do this when warmer than -25°C. I could turn up the power, but it seems that the 170 m borehole is not deep enough. I don't dare running the hole colder. As of now, at prolonged max power, the hole gives -1°C in with -5°C out from the compressor (at lower power levels, incoming returns to plus degrees and delta is about 2°C). With increased power output, there is a risk for freezing around the hole, in worst case creating damage. In hindsight, a 190-200 m borehole might have been better and wouldn't have costed much more. Around here, 220 m boreholes are common.

[pcprogrammer]

For our situation the two boreholes are quoted at 85m deep to be sufficient. Have to wait and see what the other company suggests.

[tom66]

What really disappoints me is in the UK we are still building homes without heatpumps.  Gas boilers and gas networks continue to be installed.

A geothermal heat pump is difficult to install for an existing home because you need an expensive crane to come in to one home just to drill the borehole.  Depending on the ideal location of a borehole this may be impractical.  In any case, it's typically around £20,000 -after- a grant to have such a system installed, even though the borehole is likely to cost only a little more to drill.
This makes the payback time of such systems nearly infinite.

If that was all done before the plots were even built then we'd save a lot of money on that alone whilst giving quite a practical heatpump infrastructure for many.  Since the ground (at least in the UK) is typically around 10-15C year round, geothermal heatpumps typically have higher CoP and less concern over cold weather performance (they work nearly as well at -10C as they do at +10C outdoor.)

[coppice]

How energy efficient would it be if we all move from north to south & vice versa twice a year in order not to need heating? 

There is a reason migration is a common trait in animals. The more mobile they are (e.g. birds) the more energy they seem to expend on migration for the benefits in brings in other ways.

[coppice]

What really disappoints me is in the UK we are still building homes without heatpumps.

That's not the core problem. The core problem is building land has become such a scarce resource that houses are built to get the maximum use of the space available. Also the building has to be constructed cheaply, so the final price, including the land, is somewhat affordable. This is incompatible with heavy insulation. In the 1930s land, in even suburban London, was so available even the cheapest houses could have huge gardens. Now luxury houses have tiny gardens. No space == no room for thick effective insulation. No space == no room to bore for geothermal heat. No space carries an energy burden.

[zilp]

Politics aside, are there heat pumps which use natural gas or oil, rather than electricity? It won't give the same COP but might be more economical. That might also suit me, although my energy usage is fairly low, so not worth it, until I need a new boiler.

Yep, there are. My understanding is that the Netherlands are betting on natural gas driven heat pumps quite a bit.

But of course that is only economical because the externalities of CO2 emission are subsidized by other people. Less so than with purely natural gas heating, of course. But it's a risk to consider, in that chances are that the subsidy will stop at some point and all the externalities will be internalized, at which point that will stop being economical. And that especially if you are the exceptional user of such a system and thus don't have the lobbying power to force other people to subsidize your CO2 emissions. And also, if everyone around you switches to electrically driven heat pumps, chances are that the fixed costs of a gas supply line will increase significantly as the few remaining users will have to pay for the keep-up of the whole distribution infrastructure.

[coppice]

Politics aside, are there heat pumps which use natural gas or oil, rather than electricity? It won't give the same COP but might be more economical. That might also suit me, although my energy usage is fairly low, so not worth it, until I need a new boiler.

Yep, there are. My understanding is that the Netherlands are betting on natural gas driven heat pumps quite a bit.

When I was at a grid conference and exhibition in Amsterdam about 10 years ago there were at least 2 vendors pushing gas powered heat pumps for domestic heating. They were claiming about 1/3 of the gas use compared to a conventional boiler in the Netherlands environment, which seemed optimistic. I can't remember what sort of water temperature they were basing their claims on.

[nctnico]

Politics aside, are there heat pumps which use natural gas or oil, rather than electricity? It won't give the same COP but might be more economical. That might also suit me, although my energy usage is fairly low, so not worth it, until I need a new boiler.

Yep, there are. My understanding is that the Netherlands are betting on natural gas driven heat pumps quite a bit.

No, these are hybrid boilers. If the heatpump can't provide enough heat, the gas burner is turned on. This leads to needing a much smaller heatpump because it doesn't need to cover the extreme cases. Still, the problem with heatpumps is the outdoor noise. Especially in densily populated areas. In the NL quite a few cities are installing or upgrading district heating systems. With such a system you can combine various heat sources and heat a large part of the homes in a large area.

[coppice]

Politics aside, are there heat pumps which use natural gas or oil, rather than electricity? It won't give the same COP but might be more economical. That might also suit me, although my energy usage is fairly low, so not worth it, until I need a new boiler.

Yep, there are. My understanding is that the Netherlands are betting on natural gas driven heat pumps quite a bit.

No, these are hybrid boilers. If the heatpump can't provide enough heat, the gas burner is turned on. This leads to needing a much smaller heatpump because it doesn't need to cover the extreme cases.

There are probably some of those, but the vendors I referred to above were really pushing gas powered heat pumps in the Netherlands. Maybe we could go back to the old steam engiine powered heat pumps of 19th century refrigeration.

[Siwastaja]

No, these are hybrid boilers. If the heatpump can't provide enough heat, the gas burner is turned on. This leads to needing a much smaller heatpump because it doesn't need to cover the extreme cases.

This is the sensible thing to do. Actual gas/oil driven heatpump only makes sense if electricity is always expensive and sparse. In reality most of the time there is no shortage of production and grid is pretty clean thanks to all the renewables, in almost any country. Actual percentage of "prefer electricity" varies per region being maybe 98% somewhere and just 80% somewhere else. By using the heatpump with relatively cheap and plentiful electricity 90% of the time, at high COP in modestly cold conditions, and burning oil/gas/wood/whatever for 10% the time in traditional simple burner, when it is too cold such that COP would plummet anyway, you get the energy consumption advantages of the heatpump, can use green energy produced by wind and solar power, and utilize the excellent storage capability of fuels.

This is also why I suggest the OP does not dismantle the operational wood burning system they have, even if currently planning not to use it. Even if just for one week per year, it could make a difference. I burn oil/wood for about 1-4 weeks per year depending on year.

[zilp]

Honestly your straw man arguing style is very exhausting to reply to.

Would you mind pointing out a straw man argument of mine?

A few things that make your plan unviable is the simple facts that during summer there will be so much excess electricity, thats not even funny.

How so? Like, how much are we talking about? How do you know it's "excess"?

Your own government is betting on power to gas, with short term plans for a 100 TWh  a year.

Yeah ... so?!

Just to be clear: Your original claim that I am responding to is this:

I really don't know why they cannot do back of the napkin calculations, to see that they should be working on P2G plants for sustainable energy. That way we don't have to replace the entire infrastructure of basically everything we own.

And 100 TWh would obviously be a joke if the plan were to keep gas fired heaters so "we don't have to replace the entire infrastructure of basically everything we own", given that gas fired heaters currently burn ~ 500 TWh in a year, and that that 100 TWh obviously is not exclusively for heating, which itself currently is only responsible for about a quarter of primary energy consumption, but rather also is intended to provide hydrogen and methane for the chemical and steel industry, for backup electricity generation through gas fired power plants for all elecricity supply (i.e., heating, EVs, industry, and other minor uses). So, the plan obviously is not to use P2G gas for heating in order to avoid switching to heat pumps, the plan is to use P2G to make the electricity supply reliable that then is supposed to feed heat pumps and EVs.

To achieve anything close to "not replacing the entire infrastructure" with P2G, we'd have to install 1 to 2 PWh of solar power and P2G plants, quadruple our gas storage volume, ... essentially: Put more resources into adding all of that additional infrastructure than would be needed to replace all the inefficient systems, just to avoid replacing those inefficient systems.

And banning fossil fuels and forcing people to install heatpumls is again the government forcing something on the people.

You do realize that that sounds incredibly dishonest, right?

For one, here in Germany, noone is forced to install a heat pump. The law simply says that you can't exceed a certain fraction of non-renewable energy for newly installed heating systems. You are completely free in how you meet that requirement. I have no idea what the exact rules are in the Netherlands, though.

But also, you are obviously just pretending as if you didn't know that the government is banning fossil fuels because you burning fossil fuels hurts other people. "Banning fossil fuels is the government focring something on the people" is about as sensible as "Banning putting cyanide in people's food is the government forcing something on the people" ... technically true, but also obviously intentionally playing ignorant as to the fact that this is done to protect other people's legitimate interests and not in order to harass you. If you feel harassed by the government banning you from hurting other people, maybe you should reflect on why that is.

But there has been enough research on the subject, so instead of typing here a wall of text like you, I'm just going to link those studies.

https://cris.vtt.fi/files/53434850/1_s2.0_S0306261921010643_main_1_.pdf

Would you mind at least giving a short summary as to what specific claim of yours you think that study supports and how you think it does so? At least from skimming through it, I don't get the impression that this study supports the idea that P2G will be the solution to just keep using the gas infrastructure as before.

[tszaboo]

Honestly your straw man arguing style is very exhausting to reply to.

Would you mind pointing out a straw man argument of mine?

A few things that make your plan unviable is the simple facts that during summer there will be so much excess electricity, thats not even funny.

How so? Like, how much are we talking about? How do you know it's "excess"?

Maybe breaking down my replies sentence by sentence just to find something to criticize. It's a strawman argument style, when you don't take a comment as a whole but you try to poke holes in sentences individually.  It's what you are doing right now.

For one, here in Germany, noone is forced to install a heat pump. The law simply says that you can't exceed a certain fraction of non-renewable energy for newly installed heating systems. You are completely free in how you meet that requirement. I have no idea what the exact rules are in the Netherlands, though.

But also, you are obviously just pretending as if you didn't know that the government is banning fossil fuels because you burning fossil fuels hurts other people.

In the Netherlands newbuilds cannot be connected to the gas network, and by 2026 if your heating craps out you are forced to install heatpump or go homeless. There are other countries.
That lefty bullshit about natural gas "hurting other people", please take that to your support group, nobody is interested in that on an engineering forum. You cannot just wish yourself into a better future.

To achieve anything close to "not replacing the entire infrastructure" with P2G, we'd have to install 1 to 2 PWh of solar power and P2G plants, quadruple our gas storage volume, ... essentially: Put more resources into adding all of that additional infrastructure than would be needed to replace all the inefficient systems, just to avoid replacing those inefficient systems.

Last comment it was 700 TWh, I guess two comments from now it's going to be 10 PWh of solar, and then 100 PWh.

Yet you still failed to make a few very simple calculation.
1) How much TW of electricity generation you need to power the heatpumps during the winter. You will find that it's ridiculous compared to any other plan.
2) Where do you get the approximately 2 trillion EUR to change 40 million households to use geothermal.
3) What do you do when you realize that the rest of the world doesn't care one little bit about your carbon neutral plan, they keep on using fossil fuels, and there is no way to convince them, because they either burn fuel, or their children will be left without food. Germany produces 2% of the global CO2 emissions, if it would sink to the bottom of the ocean tomorrow, it wouldn't make a dent.
You need to make cheap, storable, high concentration, renewable energy available for everyone if you want to change anything. And something that turns a profit. Which is exactly what P2G does, it turns rooftops, unused land and CO2 and so on into money.

[coppice]

In the Netherlands newbuilds cannot be connected to the gas network, and by 2026 if your heating craps out you are forced to install heatpump or go homeless.

How are their grid tributary upgrades going for all those streets where the underground cables were installed at a time of light consumer loads? Most places like to talk about grid backbone issues, but the last mile is going to be staggeringly expensive.

[tszaboo]

In the Netherlands newbuilds cannot be connected to the gas network, and by 2026 if your heating craps out you are forced to install heatpump or go homeless.

How are their grid tributary upgrades going for all those streets where the underground cables were installed at a time of light consumer loads? Most places like to talk about grid backbone issues, but the last mile is going to be staggeringly expensive.

I don't know, you should ask our excellent government who made the law. The only thing driving them was the extreme hatred of natural gas.
I also don't know what will happen with people in apartments, cities. I guess it will look like 90s socialist office buildings where every office had their own air-conditioning and you had dozens of airco units on the front of the building.

[coppice]

In the Netherlands newbuilds cannot be connected to the gas network, and by 2026 if your heating craps out you are forced to install heatpump or go homeless.

How are their grid tributary upgrades going for all those streets where the underground cables were installed at a time of light consumer loads? Most places like to talk about grid backbone issues, but the last mile is going to be staggeringly expensive.

I don't know, you should ask our excellent government who made the law. The only thing driving them was the extreme hatred of natural gas.
I also don't know what will happen with people in apartments, cities. I guess it will look like 90s socialist office buildings where every office had their own air-conditioning and you had dozens of airco units on the front of the building.

The UK and the Netherlands both got a lot out of North Sea gas. The UK squandered this bonus, as it did later with oil, propping up a failing economy. We used to see quite a lot of coverage about how the Netherlands was doing well from their gas bonus, although a lot of it seemed to be going into unsustainable social programs that would lack funding when the gas ran out. Are they just sore that the good days are over?

[Zero999]

No, these are hybrid boilers. If the heatpump can't provide enough heat, the gas burner is turned on. This leads to needing a much smaller heatpump because it doesn't need to cover the extreme cases.

This is the sensible thing to do. Actual gas/oil driven heatpump only makes sense if electricity is always expensive and sparse. In reality most of the time there is no shortage of production and grid is pretty clean thanks to all the renewables, in almost any country.

That certainly isn't the case where I live. Electricity is nearly four times as expensive as gas.


Renewables are often unavailable, when lots of power is required for heating, which is normally on cold, calm winter's days in much of Northern Europe, when a good proportion of the electricity will be generated with coal oil and gas.

A gas powered heat pump would certainly be the cheapest way to heat my home, in terms of running costs. An electric heat pump would cost more to run, than my gas powered condensing boiler!

[m k]

In the Netherlands newbuilds cannot be connected to the gas network, and by 2026 if your heating craps out you are forced to install heatpump or go homeless.

How are their grid tributary upgrades going for all those streets where the underground cables were installed at a time of light consumer loads? Most places like to talk about grid backbone issues, but the last mile is going to be staggeringly expensive.

Here bedrock is visible here and there.
People are also around and part of a year is cold.

Water distribution.
It used to be so that first bedrock is exploded away and later put on the pipes.
Maybe there still is no other way but everything is practically ready.

Luckily electricity can stand some coldness.
Yes, but here lines below tree tops to last transformer must be away from storms.

Many times company policy used to be like dig your own ditch.
Maybe they can figure out a deal this time, in case some of old ditches are too small.

Jan-24 electricity bill has arrived, the month was cold, partially -30C, then almost two decades old air to air pump can't help, so direct electricity and wood.
(the pump has most likely lost some liquid since it can't do much when temp goes near -15, it used to be fine a bit under -20)
Bill is 400€, energy part being a bit over half and 1567 kWh, other parts are transfer and taxes.
Now it's few degrees below freezing and the pump is chilling and keeping up using a bit over 400W.
Ventilation is doing its part but stove is not even warm, not cold either.

E,
temp, indoor temp went somewhere, it's 21C.

[nctnico]

As a sidenote: I have free wall-heating in my office. The neighbours next door have sound-proofed their attic which I appreciate. But -according to them- (*) they put the heating radiator partly behind the sound proofing so they have to run it at full blast. It heats my side of the wall to about 30 degrees at the warmest point. Oh, and the wall actually isn't a single wall but a decoupled one. It is 9 cm of concrete, a 9cm air gap and then another 9cm of concrete. I do not want to know how high their heating bill is...  I have to open a window to cool my office down in the winter.

* It took me a while to figure out the neighbours where causing my wall to get warm. My computer is under the desk at roughly the warmest spot so initially I thought that it was my computer heating the wall but it just didn't make sense to me from an energy standpoint. After using the thermal camera which showed the hot spot is way above the computer it started to dawn to me it had to be the neighbours.

[zilp]

Honestly your straw man arguing style is very exhausting to reply to.

Would you mind pointing out a straw man argument of mine?

A few things that make your plan unviable is the simple facts that during summer there will be so much excess electricity, thats not even funny.

How so? Like, how much are we talking about? How do you know it's "excess"?

Maybe breaking down my replies sentence by sentence just to find something to criticize. It's a strawman argument style, when you don't take a comment as a whole but you try to poke holes in sentences individually.  It's what you are doing right now.

You do understand that a strawman argument is when you misrepresent the other party's position, right?

You did notice that in this answer, you did not point out any instance of where I misrepresented your position, right?

Poking holes into sentences individually is not a straw man argument.

So, do you have anything to back up your accusation, or do you not?

That lefty bullshit about natural gas "hurting other people", please take that to your support group, nobody is interested in that on an engineering forum.

Oh, now we are at the "insult the other person instead of arguing my position" stage of this discussion?

Am I now supposed to call you a Nazi, or how does this work? I am sorry, I normally argue on the subject of the discussion instead of throwing insults at pople, so you will have to help me out a bit here.

I take it that you aren't interested in actually supporting your position with any non-fallacious arguments?

You cannot just wish yourself into a better future.

OK?! I mean, sounds reasonable, but no idea why you are throwing that in here?!

To achieve anything close to "not replacing the entire infrastructure" with P2G, we'd have to install 1 to 2 PWh of solar power and P2G plants, quadruple our gas storage volume, ... essentially: Put more resources into adding all of that additional infrastructure than would be needed to replace all the inefficient systems, just to avoid replacing those inefficient systems.

Last comment it was 700 TWh, I guess two comments from now it's going to be 10 PWh of solar, and then 100 PWh.

No, it wasn't, you just aren't paying attention. The previous 700 TWh was for heating purposes only, because that was the topic of the discussion. This was for the total energy demand.

Yet you still failed to make a few very simple calculation.
1) How much TW of electricity generation you need to power the heatpumps during the winter. You will find that it's ridiculous compared to any other plan.

Compared to what other plan?

2) Where do you get the approximately 2 trillion EUR to change 40 million households to use geothermal.

Do you have a source for that number, and why that would be needed?

3) What do you do when you realize that the rest of the world doesn't care one little bit about your carbon neutral plan, they keep on using fossil fuels, and there is no way to convince them, because they either burn fuel, or their children will be left without food.

Why would this hypothetical scenario be something that I should concern myself with?

Germany produces 2% of the global CO2 emissions, if it would sink to the bottom of the ocean tomorrow, it wouldn't make a dent.

OK ... so? Like, I mean, that statement sounds reasonably correct ... but how is that relevant?

You need to make cheap, storable, high concentration, renewable energy available for everyone if you want to change anything. And something that turns a profit.

OK?! Here is a question for you: And what if you can't? You saying "You need to" is not exactly something that reality has to obey, is it?

Like, you do see how that is a completely useless statement, right? It's one thing to say "if we had X, then that would solve the problem". But what is the point of saying "we need to have X"? If we can't have X, it's completely useless to say that we need it ... in particular when that in itself is actually a completely unsubstantiated claim. If there is no profitable way to solve climate change, that doesn't make climate change not a thing, right? So, if there is no profitable way, then demanding that the solution must be profitable is just going to doom us all, right?

Which is exactly what P2G does, it turns rooftops, unused land and CO2 and so on into money.

... OK?! I mean, you still haven't addressed all the reasons that I have given as to why I have my doubts about that, but OK, let's assume that you are right: So, how does that mesh with your call for the government to do something about that? If that is profitable business, then why would the government have to do anything about that?! Is there anything that the government is doing that is preventing investors from building these plants that supposedly would be so profitable?!

[Marco]

In the NL quite a few cities are installing or upgrading district heating systems. With such a system you can combine various heat sources and heat a large part of the homes in a large area.

It's all done with huge main-road excavation though ... that really limits the reach and the contractors who can do the work.

It was a huge missed opportunity to not combine fiber rollout with district heating AND EV charging (just access points, don't have to put chargers in immediately). 10's of billion Euro mistake. Now the fiber is in, the sidewalks are far less suited to new infrastructure.

[Someone]

Heat pumps are viable where electricity is cheap, such as near a hydroelectric or nuclear power station. Areas where electricity is expensive need more investment in nuclear power, then people will choose heat pumps for economic reasons.

Politics aside...

Except your idea of "cheap" is already biased by politics. Gas in the UK is being sold to consumers at a suspiciously low rate compared to electricity. Trigeneration or running your own micro gen should be the answer in those conditions. The unusual situation where gas is much cheaper per unit energy than the open market has settled on.