Pumped Thermal Energy Storage Efficiency Calculator

Benchmark pumped thermal energy storage (PTES) projects by combining charge energy, discharge output, and optional parasitic losses to measure gross and net round-trip efficiency in one step.

Electrical energy consumed during the heat-pump charging cycle in megawatt-hours.
Gross electrical energy delivered back to the grid during discharge in megawatt-hours.
Defaults to 0. Enter pumping, control, or fan loads incurred across the full cycle in megawatt-hours.
Optional. Defaults to 0%. Represents percent of charge energy lost to thermal leakage before discharge.

Conceptual planning aid—validate with detailed thermodynamic simulations before financial commitments.

Examples

  • Charge 120 MWh, deliver 90 MWh, auxiliaries 6 MWh, 3% leakage ⇒ Gross efficiency 75.00%, net efficiency 67.00%, net delivered 80.40 MWh.
  • Charge 60 MWh, deliver 46 MWh with defaults ⇒ Gross efficiency 76.67%, net efficiency 76.67%, net delivered 46.00 MWh.

FAQ

How should I estimate auxiliary consumption?

Sum the electrical energy drawn by high-temperature and low-temperature pump skids, control systems, and fans across the full cycle. If you only have kilowatt data, multiply by hours active to convert to MWh.

Can I model standby periods longer than one cycle?

Yes. Increase the leakage percentage to represent additional storage duration. For example, a 2% per-day loss over three days equals roughly 6%.

Why does the tool flag outputs above the charge energy?

PTES systems cannot deliver more energy than they absorb. Large mismatches usually indicate inconsistent metering windows or missing auxiliary loads, so the calculator prompts you to revisit inputs.

Additional Information

  • Result unit: percentage efficiency referenced to the initial charge energy, with net energy returned in megawatt-hours.
  • Leakage defaults to 0% when omitted and caps at 100% to avoid non-physical values.
  • Auxiliary consumption defaults to 0 MWh; include combined pumping, compression, and control loads if measured separately.

Related calculators