The projected Brenner Base Tunnel (BBT), with an expected stabilized tunnel water outflow rate at the south portal of 745 liters per second and a temperature of 22 C to 26 C, exhibits a substantial geothermal capability of 68 MW to 81 MW year-round. This master thesis analyzes the usable geothermal potential of the BBT?s tunnel water and its utilization possibilities in two planned and existing district heating systems of different sizes near the southern tunnel portal. Whereas the tunnel water heat utilization by heat pumps for the relatively small planned district heating system of Franzensfeste (4,195 MWh/ year) is not feasible economically, a heat pump system for the district heating of Brixen/ Vahrn (over 100,000 MWh/ year) is reasonable and competitive with alternative energy sources. The two identified key factors for profitability of tunnel water heat utilization by district heating systems are: the amount of heat demand; the electricity price for driving the heat pumps. Assuming the lowest expected geothermal output of the BBT?s tunnel water and its utilization by the three district heat systems near the tunnel south portal (Franzensfeste, Schabs, Brixen/ Vahrn), the heat surplus referring to the required cooling of the tunnel water for surface water discharge, is still over 100,000 MWh per year.