[rvalue]

and suffer the fate of krypton?

sorry, I couldn't read the article without solving the question of energy cycle in my mind. renewable sources like solar, wind are kind of taking energy from outside, so in case of geo-thermal, if we keep using that, there is nothing thats balancing the equation.

[stareatgoats]

You are right, this tech would cause the core to lose temperature at a slightly higher rate than otherwise. At the moment the earths core is cooling at the rate of 0.1 °C per million years from the current temperature of about 5,100 °C, interspersed with periods where the temperature loss is stopped or reversed because of gravity forces [0]. But any conceivable number of deep geothermic wells would not affect that rate in any measurable way.

[0] https://en.wikipedia.org/wiki/Earth's_inner_core