Finland Supreme Administrative Court Clarifies Real Estate Taxation for Underground Seasonal Heat Energy Storage Facilities

The Finnish Supreme Administrative Court March 12 posted online Decision No. KHO:2026:12, clarifying the real estate taxation for underground seasonal heat energy storage facilities. The taxpayer, an energy company, constructed underground tanks for storing high-temperature water and sought clarification on the application of real estate tax. The Tax Administration ruled that the tanks didn’t constitute taxable buildings or structures for real estate tax purposes. The Helsinki Administrative Court annulled the ruling, holding the tanks to be taxable components of the property. On appeal, the Supreme Administrative Court found that the tanks weren’t: 1) comparable to any building categories under the ...