Good morning,
I just received a steep price increase from my energy provider enercity, raising the cost to 15 cents per kWh starting in August. That’s really tough, and I think prices will rise even further.
It’s a strange feeling to be thrown back so quickly into an energy supply situation where you have to figure out how to keep the house warm. It seems to me that the government has given up on the goal of enabling everyone to adequately cover at least their basic needs.
Goodbye central supply structures; now the winner is whoever has solar panels and a heat pump in their new build, while the others are left out.
Welcome back, coal heating 😕
Frustrated regards,
I just received a steep price increase from my energy provider enercity, raising the cost to 15 cents per kWh starting in August. That’s really tough, and I think prices will rise even further.
It’s a strange feeling to be thrown back so quickly into an energy supply situation where you have to figure out how to keep the house warm. It seems to me that the government has given up on the goal of enabling everyone to adequately cover at least their basic needs.
Goodbye central supply structures; now the winner is whoever has solar panels and a heat pump in their new build, while the others are left out.
Welcome back, coal heating 😕
Frustrated regards,
andimann schrieb:
20% admixture This is the approximate level mainly "promoted" by grid operators to keep their product viable. However, especially at the distribution level, single-digit admixture rates will likely be the limit. If necessary, methanation may then come into play.
Hi,
It would be nice if the values were like that...
In reality more like:
Burning gas for heat: 105% efficiency (Yes, over 100%, due to condensing technology and the definition of the lower heating value)
Gas power plant (without CHP) 35–40% * electricity grid transmission efficiency 90–94% * heat pump "efficiency" 3.5–4, about 130%.
Yes, somewhat better than the boiler, but not by a factor of 2. And in winter, an air-to-water heat pump does not reach 3.5–4, but more likely 2.5–3, which results in about 95% efficiency, so actually slightly worse than the boiler.
Unfortunately, the world is not that simple. Although I agree that from a purely ecological perspective, a combination of renewable electricity generation, power-to-gas (electricity to hydrogen), storing that gas, then burning it in gas power plants and heating exclusively with heat pumps would be ideal. But you don’t want to pay for that...
Best regards,
Andreas
RotorMotor schrieb:
Here in numbers:
Burning gas for heat: 100% efficiency
Gas power plant + heat pump: 40% * 500% = 200%
It would be nice if the values were like that...
In reality more like:
Burning gas for heat: 105% efficiency (Yes, over 100%, due to condensing technology and the definition of the lower heating value)
Gas power plant (without CHP) 35–40% * electricity grid transmission efficiency 90–94% * heat pump "efficiency" 3.5–4, about 130%.
Yes, somewhat better than the boiler, but not by a factor of 2. And in winter, an air-to-water heat pump does not reach 3.5–4, but more likely 2.5–3, which results in about 95% efficiency, so actually slightly worse than the boiler.
Unfortunately, the world is not that simple. Although I agree that from a purely ecological perspective, a combination of renewable electricity generation, power-to-gas (electricity to hydrogen), storing that gas, then burning it in gas power plants and heating exclusively with heat pumps would be ideal. But you don’t want to pay for that...
Best regards,
Andreas
R
RotorMotor14 Sep 2022 17:26@andimann Oh, for electricity, we have a "transmission efficiency," but not for gas? And for gas, you calculate with the highest efficiency available for appliances, but for the heat pump, you use a rather low average? Interesting...
Hi,
Gas leaks are quite rare, so not much is lost. They make a big effort because there is always bad press when a building burns down somewhere.
Sure, the 105% figure is an absurd value, but it simply comes from the definition of the lower heating value and the higher heating value. A gas turbine has exhaust temperatures of several hundred degrees and is therefore far from that. Combined with a steam turbine, you reach about 60% efficiency. The current world record is still held by the Siemens H-class, which achieves 60.75% efficiency with an attached steam turbine. After that, fast controllability ends, since you can only regulate the steam cycle very slowly.
The efficiencies of heat pumps are a constant source of discussion. Online, I usually find values for the seasonal performance factor of 2.5–3.5 for air-to-water heat pumps and 4–4.5 for ground-source (or brine-to-water) heat pumps.
The value in my rough calculation above is therefore also rather at the upper end of these assumptions.
But it’s not about 5–10% better or worse efficiency at all. Personal usage behavior is much more important. I always find statements like "The heat pump is easily twice as efficient in the energy chain as a gas boiler" quite nonsensical. That’s simply not true. The differences are not that big, and you can make both options look good on paper.
That said, the heat pump is probably a bit better in reality, and that will probably be the future—rightly so. But only as long as you use a comparatively clean gas power plant as the electricity source. If you do the calculation with electricity from a lignite (brown coal) power station, your heat pump becomes quite a polluter...
Best regards,
Andreas
Gas leaks are quite rare, so not much is lost. They make a big effort because there is always bad press when a building burns down somewhere.
Sure, the 105% figure is an absurd value, but it simply comes from the definition of the lower heating value and the higher heating value. A gas turbine has exhaust temperatures of several hundred degrees and is therefore far from that. Combined with a steam turbine, you reach about 60% efficiency. The current world record is still held by the Siemens H-class, which achieves 60.75% efficiency with an attached steam turbine. After that, fast controllability ends, since you can only regulate the steam cycle very slowly.
The efficiencies of heat pumps are a constant source of discussion. Online, I usually find values for the seasonal performance factor of 2.5–3.5 for air-to-water heat pumps and 4–4.5 for ground-source (or brine-to-water) heat pumps.
The value in my rough calculation above is therefore also rather at the upper end of these assumptions.
But it’s not about 5–10% better or worse efficiency at all. Personal usage behavior is much more important. I always find statements like "The heat pump is easily twice as efficient in the energy chain as a gas boiler" quite nonsensical. That’s simply not true. The differences are not that big, and you can make both options look good on paper.
That said, the heat pump is probably a bit better in reality, and that will probably be the future—rightly so. But only as long as you use a comparatively clean gas power plant as the electricity source. If you do the calculation with electricity from a lignite (brown coal) power station, your heat pump becomes quite a polluter...
Best regards,
Andreas
andimann schrieb:
Gas LeaksI think @RotorMotor was trying to point out that gas transport doesn’t have 100% efficiency either; there are (significant) losses during transport due to pipe roughness, compression, and also expansion (Joule-Thomson effect). “Leaks” in the sense of pipes that are not fully sealed are actually quite rare. However, diffusion through PE(X) materials is indeed not negligible, especially since methane is known to be extremely harmful to the climate.Similar topics