Geothermal Heat Output Calculator

Work out geothermal heat output instantly with clear inputs, formula shown and shareable results.

About Geothermal Heat Output Calculator

Geothermal thermal power is mass flow times specific heat times the temperature drop between production and reinjection. Conversion efficiency is low because the resource temperature is low: a 150 C binary plant achieves 10-13% against a Carnot limit near 28%, so most of the heat is reinjected.

Formulas

Thermal power

Q (kW) = mass flow (kg/s) x cp (kJ/kg.K) x (T_production - T_reinjection)

Carnot limit

Carnot efficiency = 1 - T_ambient / T_source, in kelvin

Worked example

With the default values below, Geothermal Heat Output Calculator returns Electrical Power Output of 2.9568. Change any input above and every figure here is recalculated in your browser.

Inputs used

Geothermal Fluid Flowminimum 0 kg/s: 80 kg/s
Production Temperatureminimum -50 degrees C: 150 degrees C
Reinjection Temperatureminimum -50 degrees C: 70 degrees C
Power Cycle Efficiencyaccepts 0.1–40 %: 11 %

Results

Electrical Power Output: 2.9568
Thermal Power Extracted: 26.8800
Temperature Drop: 80.00
Carnot Efficiency Limit: 28.359%

Step by step

1Values used
2Thermal power
3Carnot limit
4Electrical Power Output= 2.9568
5Thermal Power Extracted= 26.8800
6Temperature Drop= 80.00
7Carnot Efficiency Limit= 28.359

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Geothermal development involves induced seismicity, subsidence and groundwater risks and requires regulatory assessment and monitoring.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Geothermal development involves induced seismicity, subsidence and groundwater risks and requires regulatory assessment and monitoring.

Frequently Asked Questions

Why must the fluid be reinjected?

To maintain reservoir pressure and to dispose of dissolved minerals and gases safely. Reinjection temperature is limited by silica scaling, which sets a floor on how much heat can be extracted.

What is a binary cycle?

An organic Rankine cycle using a low-boiling working fluid heated by the geothermal brine through a heat exchanger. It allows generation from resources too cool for direct steam flashing, from about 100 C upwards.