Closed-loop technology applies thousands of meters long horizontal wellbores in the target thermal reservoir that are connected by two vertical wells, one inlet well, and one production well (Fig. 2). A low temperature working fluid is injected from the inlet, heated mostly through the horizontal interval in a geothermal reservoir with proper thermal properties, and the heat energy is harvested at the outlet for heating and power generation purposes.
That's reasonable enough. It's an underground heat exchanger. How hard is that to drill? Can you get the horizontal and vertical wells to meet up?
Output temperatures shown on the graph are in the 30C-50C range, so this is for heating buildings, not power generation.