In addition to sand batteries, Finnish utilities are also building the world's largest #CavernThermalEnergyStorage in Vantaa (1,1 million m³)
www.vantaanenergia.fi/en/about-us/...
and the world's largest #PitThermalEnergyStorage in Hyvinkää (380.000 m³)
hlv.fi/lampovarastohanke/
#SectorCoupling

Example of solar #DistrictHeating cooperative in Germany
#SolarwärmeBracht.
12.000 m² #solarThermal collectors
20.000 m³ #pitThermalEnergyStorage 🇩🇰 style
Solar fraction 70%
#heatPump +Biomass boiler
130 households, total 2.7 GWh/a
Price 60€/month + 16 ct/kWh
www.solarwaerme-bracht.de/faq/

The technology of #Varanto, the 90 GWh #CavernThermalEnergyStorage project in Vantaa, Finland, was't investigated, obviously due to different geology in Nuremberg.
The #PitThermalEnergyStorage option could store 160 GWh but require twice the volume, 2 million m3
www.vantaanenergia.fi/en/about-us/...

There's another #SeasonalStorage project in Finland breaking records, the Hyvinkää #PitThermalEnergyStorage:

Pit Volume 380.000 m3
Area 225 x 165 m
Depth 20 m
Water temperature 40 - 90 °C
Capacity 18.000 MWh
Discharge max 60 MW
Cost 33 mil. €
In operation: Fall 2027
hlv.fi/lampovarasto...

The study covers several #ThermalEnergyStorage technologies:
#PitThermalEnergyStorage
#BoreholeThermalEnergyStorage
#AquifierThermalEnergyStorage
#PackedBedThermalEnergyStorage
(= #SandBattery)
and others like latent, multilayer, sorption, Ruths and methanisation

www.evt.tf.fau.de/files/2025/0...