How can a geothermal resource lose output even though Earth keeps producing heat?

Although Earth continuously produces internal heat, a specific geothermal resource can lose output if the rate of heat extraction exceeds the rate of natural heat recharge.1

Geothermal energy relies on the concentration of heat in underground reservoirs of steam or hot water. While these resources are considered renewable, they are not inexhaustible if managed improperly. When fluids are extracted for power generation, the reservoir's thermal energy and pressure can decline over time, potentially making continued development uneconomical.21

However, this decline does not mean the resource is permanently lost. With proper management, such as drilling new wells or injecting wastewater to recharge the reservoir, capacity can be restored. Furthermore, if use is suspended for a period, the reservoir can recover as natural heat recharge replenishes the system. Sustainable utilization depends on balancing extraction with these recharge processes.1