Abstract: A multi cycle geothermal power plant (5) has at least the following cycles: a primary cycle (10) configured for a geothermal reservoir fluid; a closed loop second cycle (20) having a vaporizer (7), spanning the primary cycle (10) and second cycle (20), for transferring thermal energy from the primary cycle (10) to the second cycle (20); and at least one further closed loop water/steam cycle (30) having a heat exchanger (8), spanning the primary cycle (10) and each further cycle (30), for transferring thermal energy from the primary cycle (10) to each further cycle (30). By providing indirect secondary cycles, the power plant (5) is capable of exploiting high impurity wells with high energy extraction efficiency.