This is very different from the sort of geothermal being discussed for power generation.
Residential geothermal for home heating and cooling could make a ton of sense, but more likely based on the scale of a residential natural gas network.
Drilling a hole per home is super expensive. Replacing gas pipes with moderate thermal pipes would be about the same cost as gas infrastructure but allow the massive efficiency gains of larger scale. Heat pumps operating on pumped water through these sorts of pipes doesn't need very high or low delivered temperatures to be effective, as long as it's somewhat above the -20C of the extremes of winter.
Thermal storage quantity scales roughly with volume (x^3) and storage costs roughly scale with surface area (x^2). Though I'm not sure if storage plays much into the gas -> thermal plans that have been explored.
We have that in the Netherlands in plenty of cities called “stadsverwarming”. It is hot water pumped around in a closed loop and residences take heat out of it with heat pump. The source is the cooling off industries, power plants, or dedicated heaters.
They currently are efficient but still expensive because of a law that the pricing has to be similar to heating with would have been.
Actually the homes typically take heat out with a simple heat exchanger, not a heat pump. Projects previously could use the waste heat from electricity generation, but fewer of those sources are available with coal plants shutting down and gas plants only being run when there is no wind. Add to that the much higher cost of infrastructure compared to installing a heat pump in every home and it's not looking good for future projects. But inner cities that do not have room for that could still benefit.
Thanks for the extra context! Could you explain the law on pricing a bit more? What was the motivation, and what is the usual alternative heating source?
Natural gas, from the Slochteren gas field, was the cheapest way to heat a home for the past 60 years. It's probably not so anymore, considering the Slochteren field is mostly shut down.
The city heating network operator is a monopoly, that is why the price is capped.
Even though city heating networks utilize 'waste heat', the capital cost of the network is significant. The price cap and the capital costs (especially now with higher interest rates) led to many proposed projects being cancelled in recent years.
Residential geothermal for home heating and cooling could make a ton of sense, but more likely based on the scale of a residential natural gas network.
Drilling a hole per home is super expensive. Replacing gas pipes with moderate thermal pipes would be about the same cost as gas infrastructure but allow the massive efficiency gains of larger scale. Heat pumps operating on pumped water through these sorts of pipes doesn't need very high or low delivered temperatures to be effective, as long as it's somewhat above the -20C of the extremes of winter.
Thermal storage quantity scales roughly with volume (x^3) and storage costs roughly scale with surface area (x^2). Though I'm not sure if storage plays much into the gas -> thermal plans that have been explored.