Who owns (geothermal) heat?

'Geothermal heat has the potential to make a significant contribution to... the UK Climate Change Act.' 'Heat, although not a "substance" in the physical sense, behaves in many ways analogous to water.' Heat from the earth, or geothermal heat, arises from the heat dissipated from the centre of the earth and, at shallow depth, from heating by the sun. High-enthalpy (deep) geothermal heat is found within some granitic rocks due to slightly raised levels of the radiogenic isotopes of potassium, uranium and thorium