5 ms·

the article also doesnt mention france's gas consumption, which was mostly about electricity, while german uses the gas 50:50 (heat and electricity). basically

by merb 5y ago

the article also doesnt mention france's gas consumption, which was mostly about electricity, while german uses the gas 50:50 (heat and electricity). basically nuclear won't replaces gas and gas won't replace nuclear. if we want to discuss about electricity generation, coal is the thing that germany could reduce with nuclear, but not gas. it's always the same thing about these articles, blame germany for a mistake (shutting down nuclear too early) but than just blame it on the bad gas, which is basically needed for nuclear operations anyway... and no german citizens won't replace their gas heating because of the war, that will simply not happen (of course some people do reduce gas heating but a lot of people just can't).

fabian2k 5y ago
The sentence about simply replacing gas with heat pumps is almost delusional. You can't just switch out the main heating system for an entire country. Heat pumps require quite a lot of conditions that simply are not met by many older buildings. And even if that weren't an issue, there is still the sheer scale of the problem.
- diordiderot 5y ago
  > require quite a lot of conditions that simply are not met by many older buildings. Such as?
  - fabian2k 5y ago
    The temperature you achieve is lower than for older gas heating equipment, so your radiators are likely not dimensioned correctly if you switch. You really want floor heating for heat pumps, and very well insulated walls. The moment the heat pumps can't provide enough heating you have to heat with electricity, and that is incredibly expensive especially in Germany.
    - diordiderot 5y ago
      Modern heat pumps work well below freezing, in Chicago 2021 there were 4 days that gas heating would be more efficient. Maybe don't use a radiator? American heat pumps hear air directly.
      - rad_gruchalski 5y ago
        > Maybe don't use a radiator? And how do you do this in a building never designed for this king of system?
      - cycomanic 5y ago
        Heating the air is less efficient, by a significant margin (you need a high temperature for the same comfort level). Using US houses as an example is quite laughable, the energy consumptions of US households is much higher than German ones.
        hedora 5y ago
        I doubt heating air to a higher temperature with a heat pump is less efficient than natural gas heating. The heat pump will have a coefficient of performance over five for small temperature differentials. For huge differentials, the thermal loss of the building is linear in the differential, and dropping the thermostat a few degrees only drops a few percent of thermal loss. In those scenarios, the COP of the heat pump is still something like 1.5 or 2.
        scythe 5y ago
        >Using US houses as an example is quite laughable, the energy consumptions of US households is much higher than German ones. It's an extremely heterogeneous dataset, but a cursory analysis does not agree: Germany: 136 kWh/m^2 https://bpie.eu/wp-content/uploads/2018/01/iBROAD_CountryFactsheet_GERMANY-2018.pdf https://bpie.eu/wp-content/uploads/2018/01/iBROAD_CountryFac... US: 47000 Btu/ft^2 — because we like dumb units — 148 kWh/m^2 https://constructionphysics.substack.com/p/looking-at-energy-use-in-us-residential?s=r https://constructionphysics.substack.com/p/looking-at-energy... That's a slight win for Germany, but it's not by much. For the most part, US houses are simply larger than German ones, which is where that energy use comes from. (US temperatures are also harsher, in both directions.)
    - deleted 5y ago
      [deleted]
  - fmajid 5y ago
    The technology is improving by leaps and bounds: https://www.theguardian.com/environment/2022/jan/07/new-heat-pump-could-ease-uk-shift-to-low-carbon-homes-say-developers https://www.theguardian.com/environment/2022/jan/07/new-heat... My parents in France ditched their 40 year old gas furnace for a heat pump, more than 50% subsidized by the French government, and they couldn’t be happier.
    - rad_gruchalski 5y ago
      Where in France?
      - fmajid 5y ago
        Paris outskirts, halfway between Versailles and St Germain en Laye. They did have to install an external compressor/heat exchanger unit which would have been harder if they didn’t own a single-family detached home.
  - munk-a 5y ago
    I think the biggest ask the article is making in an unreasonable way is to somehow find millions of contractors who can actually go home by home and refit the heating systems in a timescale that'd actually be relevant for the war in ukraine. If Germany wanted to switch everyone over to a different kind of lightbulb they'd need to ensure the production capacity to make the new bulb exists and set up logistics to actually distribute it. You'd have a fair amount of non-compliance due to paranoia and other factors but I think you could probably get it done with a year or two of warning... Once you hand the household the lightbulbs they just go through and replace them all and dispose of the old bulbs... To change out a heating system you need to remove large appliances, install other large appliances, fiddle around with gas lines and the breaker panel (probably you'd need to replace a fair number of breaker panels in older houses to handle the higher throughput), deal with the wiring which might be unsafe for the power you'll be sending over them... then you'd need to actually install the radiators, that involves tearing up floors to do it right (floor radiation can be extremely efficient and generally creates a higher apparent heat than traditional radiators placed next to windows for fire hazard reasons), or else popping in some other more module style of radiator. Those radiators might use direct electric generation or you might opt for additional boiler capacity (much more sane for efficient stand-radiators) which comes with piping requirements along with a lot more wiring work. All of that is in addition to all the problems I mentioned around lightbulbs - you're still going to need to actually produce and distribute all the material needed to execute this change. If you, as a person, want to swap out the heating in your house it'll be a weeks (maybe if you're lucky) or months long renovation - imagine trying to do that on the scale of a country, the only way it'd be even plausible is if you essentially drafted large portions of the population and trained them up on trades - that might not be a terrible economic investment, but it certainly isn't going to happen fast.
    - diordiderot 5y ago
      This was a great answer and well thought out! Thanks for taking the time. My only rebuttal is heat pumps can heat the air directly. No need for a radiator or plumbing.
      - namibj 5y ago
  - scythe 5y ago
    A vapor-compression heat pump generates hot air. But many old buildings transmit heat using hot water. This only works if the water is quite a bit hotter than a heat pump usually gets, because the water heats by blackbody radiation, the radiation power is proportional to T^4, and the effective surface area of the existing radiators is calibrated to the old drive temperatures. Heat pumps are a drop-in replacement if you have forced-air heating, but if you have hot-water radiators, it's not so easy. In theory, you could add another stage, but now you're sacrificing a lot of COP. New buildings should always be built with heat pumps (and heat exchangers) but old buildings take a lot of work to fix.
    - ajmurmann 5y ago
      > But many old buildings transmit heat using hot water I thought hot water heating was still by far the norm in Germany for homes with new homes having water heated floors. Has this changed recently?
- LordDragonfang 5y ago
  Heat pumps have gotten very good in the past couple of decades, especially in the east Asian markets, and even older homes have fairly drop-in options available, assuming the market demand is there. https://www.youtube.com/watch?v=43XKfuptnik https://www.youtube.com/watch?v=43XKfuptnik Yes, it's a solution that requires a significant investment in (individual) infrastructure, but so does almost every other solution to anthropogenic climate change. If the solutions were totally easy, we'd have done them by now. Moving to heat pumps is on the easier end of the spectrum, though.
- postingawayonhn 5y ago
  This is pre-war thinking though. Germany needs to think of itself as being at war and mobilise as such. Less efficient portable heaters can be used as stopgap measures, qualified heat pump technicians can be brought in from other countries, people with transferable skills can works as installation assistants, local production of electric heating systems can be increased (convert other factories if needed). It's Spring in Germany right now. They've got about 6 months until next winter rolls around and should use that time wisely.
  - Xylakant 5y ago
    One could also ask for the US to replace their car centric mobility with bikes and trains to save oil. It’s spring right now, they’ve got 6 month until winter rolls around, time to be used wisely. Our apartment complex uses a small central gas power plant to produce electricity and use the waste heat for heating/water, supplying about 20 buildings with roughly 500 - 1000 units. Replacing that system is not something that’s planned and executed within a handful of months. I’m not convinced that air heatpumps of the required size even exist - drilling for a ground heat pump in a city will require even more planning. How well would it work if all of those unit just pulled another extra 5kw continuously from the grid for heating, not to speak of warm water? I’m not even convinced that the grid itself could sustain that - it’s never been planned for that kind of usage.
_ph_ 5y ago
So much this. While recently the energy production used a bit more gas (shifting from coal) due to less CO2 output, the main reason for gas in electricity generation is the ability to quickly switch power output to match quickly changing electricity consumption. You cannot replace that with nuclear or coal as both are rather slow switching.

by merb 5y ago

fabian2k 5y ago

The sentence about simply replacing gas with heat pumps is almost delusional. You can't just switch out the main heating system for an entire country. Heat pumps require quite a lot of conditions that simply are not met by many older buildings. And even if that weren't an issue, there is still the sheer scale of the problem.

diordiderot 5y ago
> require quite a lot of conditions that simply are not met by many older buildings. Such as?
- fabian2k 5y ago
  The temperature you achieve is lower than for older gas heating equipment, so your radiators are likely not dimensioned correctly if you switch. You really want floor heating for heat pumps, and very well insulated walls. The moment the heat pumps can't provide enough heating you have to heat with electricity, and that is incredibly expensive especially in Germany.
  - diordiderot 5y ago
    Modern heat pumps work well below freezing, in Chicago 2021 there were 4 days that gas heating would be more efficient. Maybe don't use a radiator? American heat pumps hear air directly.
    - rad_gruchalski 5y ago
      > Maybe don't use a radiator? And how do you do this in a building never designed for this king of system?
    - cycomanic 5y ago
      Heating the air is less efficient, by a significant margin (you need a high temperature for the same comfort level). Using US houses as an example is quite laughable, the energy consumptions of US households is much higher than German ones.
      - hedora 5y ago
        I doubt heating air to a higher temperature with a heat pump is less efficient than natural gas heating. The heat pump will have a coefficient of performance over five for small temperature differentials. For huge differentials, the thermal loss of the building is linear in the differential, and dropping the thermostat a few degrees only drops a few percent of thermal loss. In those scenarios, the COP of the heat pump is still something like 1.5 or 2.
      - scythe 5y ago
        >Using US houses as an example is quite laughable, the energy consumptions of US households is much higher than German ones. It's an extremely heterogeneous dataset, but a cursory analysis does not agree: Germany: 136 kWh/m^2 https://bpie.eu/wp-content/uploads/2018/01/iBROAD_CountryFactsheet_GERMANY-2018.pdf https://bpie.eu/wp-content/uploads/2018/01/iBROAD_CountryFac... US: 47000 Btu/ft^2 — because we like dumb units — 148 kWh/m^2 https://constructionphysics.substack.com/p/looking-at-energy-use-in-us-residential?s=r https://constructionphysics.substack.com/p/looking-at-energy... That's a slight win for Germany, but it's not by much. For the most part, US houses are simply larger than German ones, which is where that energy use comes from. (US temperatures are also harsher, in both directions.)
  - deleted 5y ago
    [deleted]
- fmajid 5y ago
  The technology is improving by leaps and bounds: https://www.theguardian.com/environment/2022/jan/07/new-heat-pump-could-ease-uk-shift-to-low-carbon-homes-say-developers https://www.theguardian.com/environment/2022/jan/07/new-heat... My parents in France ditched their 40 year old gas furnace for a heat pump, more than 50% subsidized by the French government, and they couldn’t be happier.
  - rad_gruchalski 5y ago
    Where in France?
    - fmajid 5y ago
      Paris outskirts, halfway between Versailles and St Germain en Laye. They did have to install an external compressor/heat exchanger unit which would have been harder if they didn’t own a single-family detached home.
- munk-a 5y ago
  I think the biggest ask the article is making in an unreasonable way is to somehow find millions of contractors who can actually go home by home and refit the heating systems in a timescale that'd actually be relevant for the war in ukraine. If Germany wanted to switch everyone over to a different kind of lightbulb they'd need to ensure the production capacity to make the new bulb exists and set up logistics to actually distribute it. You'd have a fair amount of non-compliance due to paranoia and other factors but I think you could probably get it done with a year or two of warning... Once you hand the household the lightbulbs they just go through and replace them all and dispose of the old bulbs... To change out a heating system you need to remove large appliances, install other large appliances, fiddle around with gas lines and the breaker panel (probably you'd need to replace a fair number of breaker panels in older houses to handle the higher throughput), deal with the wiring which might be unsafe for the power you'll be sending over them... then you'd need to actually install the radiators, that involves tearing up floors to do it right (floor radiation can be extremely efficient and generally creates a higher apparent heat than traditional radiators placed next to windows for fire hazard reasons), or else popping in some other more module style of radiator. Those radiators might use direct electric generation or you might opt for additional boiler capacity (much more sane for efficient stand-radiators) which comes with piping requirements along with a lot more wiring work. All of that is in addition to all the problems I mentioned around lightbulbs - you're still going to need to actually produce and distribute all the material needed to execute this change. If you, as a person, want to swap out the heating in your house it'll be a weeks (maybe if you're lucky) or months long renovation - imagine trying to do that on the scale of a country, the only way it'd be even plausible is if you essentially drafted large portions of the population and trained them up on trades - that might not be a terrible economic investment, but it certainly isn't going to happen fast.
  - diordiderot 5y ago
    This was a great answer and well thought out! Thanks for taking the time. My only rebuttal is heat pumps can heat the air directly. No need for a radiator or plumbing.
    - namibj 5y ago
- scythe 5y ago
  A vapor-compression heat pump generates hot air. But many old buildings transmit heat using hot water. This only works if the water is quite a bit hotter than a heat pump usually gets, because the water heats by blackbody radiation, the radiation power is proportional to T^4, and the effective surface area of the existing radiators is calibrated to the old drive temperatures. Heat pumps are a drop-in replacement if you have forced-air heating, but if you have hot-water radiators, it's not so easy. In theory, you could add another stage, but now you're sacrificing a lot of COP. New buildings should always be built with heat pumps (and heat exchangers) but old buildings take a lot of work to fix.
  - ajmurmann 5y ago
    > But many old buildings transmit heat using hot water I thought hot water heating was still by far the norm in Germany for homes with new homes having water heated floors. Has this changed recently?
LordDragonfang 5y ago
Heat pumps have gotten very good in the past couple of decades, especially in the east Asian markets, and even older homes have fairly drop-in options available, assuming the market demand is there. https://www.youtube.com/watch?v=43XKfuptnik https://www.youtube.com/watch?v=43XKfuptnik Yes, it's a solution that requires a significant investment in (individual) infrastructure, but so does almost every other solution to anthropogenic climate change. If the solutions were totally easy, we'd have done them by now. Moving to heat pumps is on the easier end of the spectrum, though.
postingawayonhn 5y ago
This is pre-war thinking though. Germany needs to think of itself as being at war and mobilise as such. Less efficient portable heaters can be used as stopgap measures, qualified heat pump technicians can be brought in from other countries, people with transferable skills can works as installation assistants, local production of electric heating systems can be increased (convert other factories if needed). It's Spring in Germany right now. They've got about 6 months until next winter rolls around and should use that time wisely.
- Xylakant 5y ago
  One could also ask for the US to replace their car centric mobility with bikes and trains to save oil. It’s spring right now, they’ve got 6 month until winter rolls around, time to be used wisely. Our apartment complex uses a small central gas power plant to produce electricity and use the waste heat for heating/water, supplying about 20 buildings with roughly 500 - 1000 units. Replacing that system is not something that’s planned and executed within a handful of months. I’m not convinced that air heatpumps of the required size even exist - drilling for a ground heat pump in a city will require even more planning. How well would it work if all of those unit just pulled another extra 5kw continuously from the grid for heating, not to speak of warm water? I’m not even convinced that the grid itself could sustain that - it’s never been planned for that kind of usage.

_ph_ 5y ago

So much this. While recently the energy production used a bit more gas (shifting from coal) due to less CO2 output, the main reason for gas in electricity generation is the ability to quickly switch power output to match quickly changing electricity consumption. You cannot replace that with nuclear or coal as both are rather slow switching.