Using electricity to heat buildings should be one of the last steps to take, after almost everything else using energy is renewable. Electricity is a precious form of energy, while heat is primitive. Converting in both directions is not lossless, so you want to keep the precious form.
The author makes it seem like that the negative prices are constant, which is not the case. Germany also does not have 100% renewable energy. Once you have an electric heater at your home, you will be using electric energy generated by burning coal to heat your home.
It also does not solve the problem of the German electricity market, which is mostly that renewable energy is not steady. Power is not distributed evenly across space and time. So you need to store the energy and move it from North to South. But storage and transmission lines are lacking to say the least.
One intermediate strategy you could take, would be to convert abundant electric energy to hydrogen, which you can feed into the already existing natural gas pipes and burn inside the already existing gas heaters, the author is criticizing. This way you would solve both problems (missing network and missing storage) at the same time.
Electric heating via heat pump is ridiculously efficient and has a much bigger bang for your carbon-reducing buck than anything else a homeowner can do.
The issue with heat pumps is you may need far less heat at 15c when their very efficient than at -15c when their not. Couple that with the losses from heat to electricity at power plants and burning natural gas at home is about as efficient on average depending on your area.
So, it really does depend on how cold it gets where you are if it’s better to burn fuel at home or at a powerplant.
PS: Solar hot water heaters are generally the best overall option any place heat pumps are actually efficient.
"The issue with heat pumps is you may need far less heat at 15c when their very efficient than at -15c when their not."
My home is heated with a heat pump. I live in Canada, and just went through a period of -20C. It works great and is a fraction of the cost of heating with natural gas. It also operates as a fantastic AC in the summer.
It uses a closed loop of water to pipes in the ground, with the ground as the "sink". It is very efficient, and the ground is always 8-10C.
This conversation seems to be dominated, and moderated, by a lot of people who are in the dark, or misunderstand the fundamental physics behind how a heat pump works, or who gatekeep what "electric" means with heating (which is particularly bizarre).
The ground ends up close to the average temperature of the local environment which in your case is a long way from -15c. Excluding of course hot springs etc, but that’s a separate and very localized solution. Further, if you’re that far south a solar hot water heater system is still cheaper to build + operate and in terms of energy costs.
People dealing with permafrost both directly are stuck with lower temperatures and would need to dig much further as your dependent on water exchanging heat with a large thermal mass. That’s the tipping point I am talking about, not your balmy 8-10c average temperatures.
And people in the tropics have little need for heating.
My point is solar hot water heaters are generally the better solution, even if they don’t work in the very far north. But, if you’re that far north heat pumps also fail.
I'm not quite getting your point, and honestly it seems like you're digging deep to stick with what you originally stated.
The climate I live in is colder than the majority of humans. Maybe the vast majority. I have a very efficient heat pump (I've been using it for 8 years now -- it's well proven to me by now). Ergo, any notion that heat pumps only work in balmy conditions has no bearing on reality -- yes, those super cheap air exchange units you grab from Home Depot to take the chill off in Atlanta during January might have such limits, but that has no bearing on the market as a whole.
The article linked talks about how Germans don't heat with electricity -- even with very efficient heat pumps -- because a regressive tax on such use makes it uneconomical. I don't see what solar heaters (which seldom even pay for themselves in great conditions -- e.g. California -- as an aside) have to do with this conversation.
My point is solar hot water heaters are generally the better option for home heating as I have been saying. You may assume I am referring to a specific case but this is very general advice. Including arctic through tropical climate, sea level or extreme altitude, detached single family homes through skyscrapers, building on bead rock vs oceanfront silt.
In the tropics at high altitude you can use cheap systems for domestic hot water and minimal heating needs. Colder local temperatures require larger and more complex systems but also increase demand for heat. Meanwhile, heat pumps get steadily worse until ground source heating becomes viable though at significantly higher upfront costs and more limited locations. Salt water for example dramatically increases heat pump costs costs vs fresh water.
Large cities often shift things to heat pumps. Though neither system is that great for dense NYC skyscrapers or other large northern cities. And most cites skyscrapers have significant unused exposures where solar collectors are at least somewhat viable. Many short apartment buildings in China for example have solar collectors for the top few floors.
PS: That said, it’s generally not exactly a dramatic difference. However, unlike many things it’s both generally if not always cheaper and more environmentally friendly.
I assume there is zero chance of you reading this, but just felt the need to clarify something.
When the efficiency of a heat pump decreases it’s producing less heat for the same energy (when running) rather than the same heat using more energy. As you need more meat output as the temperature drops that quickly becomes a problem. This means you quickly need either a larger heat pump or a backup resistive heating element in the worst conditions. That’s rarely an issue for ground source heating, but is a huge issue than means a heat pump may theoretically be much more effect looking at a chart than what actually happens in practice.
When I run the numbers, a solar water heater does not work out for me. In order for me to eliminate my electric heater I would need an active (somewhat more costly) solar heating system which run ~$4k the lower end if you include the cost of installation. At a rate of about $500 a year in water heating costs that's a 8 year payback timeframe for a device that has a 5 year warranty (more expensive models have longer warranties).
Can you do solar preheat as a retrofit to an existing electric (or natural gas) hot water heater? Coil some flexible water line in a plywood box, spray paint it all black, put a plexiglass lid on, caulk it up, and lay it out in the sun. Feed cold water through it before it hits your hot water heater.
It probably would not be as efficient as a commercial solution, but it would be very cheap.
Don't forget about water safety, backflow valves, or local plumbing and building codes. Or winter - would want a bypass valve for flushing and draining it.
I think you are right and there are gains to be had with a hybrid system. I’m handy with plumbing and I think it is something I could figure out but the problem is, as always for everyone, I have so many other things going on I that don’t have the time to figure out a DIY system.
The best time to do an install is when you’re looking at buying a water heater either way. Thus significantly reducing the price premium. Further, sizing a system to also handle home heating is generally where the real savings takes place.
As to warranty, they generally last well past that point. You may be replacing a part or to at ~10 years, but a 20+ year lifespan is common depending on the model and your water hardness.
The really nasty issue with heat pumps that I suspect is going to start biting countries which go for them in a big way is that a lot of the costs of supplying electricity depend on peak demand, not average demand, and because they're so much less efficient in cold weather when heating demand is at its highest they simply don't reduce peak demand in the same way that they do average.
> Electric heating via heat pump is ridiculously efficient
Strictly speaking that's "electrically assisted" heating. What most people refer to as electric heating is the conversion of electricity directly into heat, eg. by a resistive element.
It is a bit of gatekeeping that has little relation with reality.
When people say that their home is heated by natural gas, they mean that they have a supply of natural gas, and that is the consumable they use / pay for, not the specific chemical process when it is oxidized. Similarly, when people say they heat their home with electricity, whether it's a heat pump or electric radiators is just a secondary possibility. I heat my home with electricity and it's a ground-source heat pump. If someone has some weird hangup or ignorance about that, that's on them.
If someone said that they cooled their home in the winter with "electricity assistance" I think everyone would rightly laugh.
> You're claiming that when mostly people say "electric heating" they are specifically excluding heat pumps?
No, just pointing out the usual definition of electric heating. A heat pump doesn't necessarily even use electricity. The mechanical power for the compressor (assuming a refrigerant based heat pump) could come from anywhere.
Yes if you analyze it thermodynamically heating via natural gas is terrible. You're taking a high quality source of energy (a flame at 3500 degF) and turning it into the thermodynamic equivalent of garbage (hot air at 70 degF). All the work it could have done (say generating electricity) is tossed.
Which is where district heating comes in. Utilities, who unlike households are fully exposed to fluctuations of the electricity market, are increasingly switching their cogen pants to decoupled operation where large heat storage elements are added so that the plant can run as a peaker plant. It's not glamorous because they are still burning fossil fuel, but it's a huge improvement not only over separate burning for heat but also over synchronous cogen that would follow the heart demand. It's even a reasonable long term investment because a fully decarbonized economy would shave supply peaks with power-to-gas.
An example from Hamburg is the Energiebunker. I went on a tour a few years ago which I can recommend. One comment was they had trouble with the local landlords not wanting to take up the offer resulting in poor utilisation.
Yeah, in practice I think district heating is probably the only way to actually improve on the thermodynamic efficiency of just taking all that high-grade energy and converting it straight to low-grade heat. Running heat pumps off electricty from non-cogeneration gas plants can only roughly match the efficiency of gas heating, and smaller-scale CHP setups have efficiency losses that make them questionable.
There is so much natural gas in Sibiria, due to climate change warming the permafrost, it will just escape into the atmosphere, before we come close to burning it all.
I don't have anything against heat pumps. I just don't think that they would solve the problems the article is talking about. I would put heat pumps all over the place, once electric energy, transportation etc. are 100% renewable.
I don't know why you are downvoted because this is pretty correct. Electricity is the most valuable form of energy that currently should only be used for heating in exceptional cases if no alternatives are present.
In my experience renewable energy, electricity and nuclear are highly controversial topics on HN. Like with this post, I often get heavily up- and downvoted by different camps. It correlates with time of day, so I suspect I have a European perspective.
The author makes it seem like that the negative prices are constant, which is not the case. Germany also does not have 100% renewable energy. Once you have an electric heater at your home, you will be using electric energy generated by burning coal to heat your home.
It also does not solve the problem of the German electricity market, which is mostly that renewable energy is not steady. Power is not distributed evenly across space and time. So you need to store the energy and move it from North to South. But storage and transmission lines are lacking to say the least.
One intermediate strategy you could take, would be to convert abundant electric energy to hydrogen, which you can feed into the already existing natural gas pipes and burn inside the already existing gas heaters, the author is criticizing. This way you would solve both problems (missing network and missing storage) at the same time.