It may need a little energy to run a pump, but this can be taken from the energy being generated. The big problem is that there are not many places where you can build a geothermal power station. You need hot rocks of a suitable type, at a depth where we can drill down to them. The type of rock above is also important, it must be of a type that we can easily drill through. Hazardous gases and minerals may come up from underground, and can be difficult to safely dispose of.
Geothermal energy is renewable .