this post was submitted on 03 Sep 2024
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I guess this is cool, but even though it's an efficient heat pump it's still a poor use of electricity. It would make more sense to use cogeneration, to use the incidental heat from a thermal power plant, for district heating.
It looks like this is what they currently do. I believe the goal is to retire some of these older district heating systems and just use renewables for electric generation. https://www.helen.fi/tietoa-meista/energia/energiantuotanto/voimalaitokset In the short term they can shut down some of the gas/coal/pellet thermal centers without needing to build a new generator.
And Helen is also pulling heat from waste water. The latest heat pump was just the next logical step.
Hanasaari shut down last year and Salmisaari is going to be closed by april next year, after that Helsinki will have no coal or pellet power plants left.
Electricity generation isn't the main problem, but that those plants were responsible for a huge majority of central heating in Helsinki (iirc they were designed on purpose to be so inefficient they generated 2/3rds of their output as heat for that use). That's why they are building wacky solutions like huge underground lakes and stuff
Helsinki is getting out of the "burning stuff to make electricity" business. It used to have coal power plants - last ones closed down in 2023 and 2024. There are some dedicated plants for district heating still, but also there's the trend to move away from burning stuff.
I suppose it depends on how you look at it. Take solar, for example. On the one hand, you could argue that if your primary goal is to generate heat, you might as well use a solar thermal plant with lots of focusing mirrors over photovoltaics. The conversion to electricity first would inevitably be far less efficient.
On the other hand, if you've got your PV plants for electricity already but they are overproducing at times, there is the question of what to do with the excess power, and using it to run heat pumps may actually be a pretty efficient application at the point?
What about when you don't have excess solar power? People need heat when they need heat, not just on sunny days. So, you'd need a massive battery for that, which has some undesirable implications. Instead, a thermal plant (be it solar, geothermal, or nuclear) can be designed to reliably satisfy heating and electricity demand with excess electricity going to hydrogen production for emissions-free steel, fertilizer, and vehicle fuel.
Helen runs your wastewater through a heat exchanger before this step. I guess the actual heat is from the water treatment when the solids are being nommed on in a big bubbly pool of bacteria that give off heat. But outgoing water is warmer than incoming by itself, too.
There's just not a whole lot of industry close enough to an urban center like Helsinki, but paper mills and burning sorted trash is usually the source for these networks.
Okay, district heating with a heat pump makes more sense to me if there are processes that require cooling and can act as the source, like lowering the temperature of treated wastewater before adding it back to a waterway. However, the heat supply for the water treatment plant should still probably come from cogeneration. District cooling with a central heat pump system also makes sense, especially if it eliminates noisy condensers on the sides of buildings.
That's already being done. This is the first time I'm hearing about this heat pump despite the fact that I live in Finland but I'm guessing it likely has something to do with the fact that we have a ton of wind turbines and more is being added each year, so at times there's a plenty of excess energy being produced so I guess it makes more sense to use it for something rather than to sell it abroad. This is why they're planning hydrogen producion plants and "green" steel mills here as well. Running those only makes sense when electricity is cheap.
Ok but then you'd be living right next to a coal/nuclear power station.
They're designing shipping container sized nuclear power plants in Finland, so living next to one will hopefully soon be a reality for a ton of Finns. These however are much simpler and only heat water, not create electricity.
lol
Nothing wrong with putting nuclear power plant next to where people live and work. They produce good steam for residential and industrial uses.