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Pumped Storage Efficiency Calculator

Work out pumped storage efficiency instantly with clear inputs, formula shown and shareable results.

About Pumped Storage Efficiency Calculator

Round-trip efficiency is energy generated divided by energy consumed pumping, typically 70-80% for modern pumped storage. Because energy is lost, the peak-to-off-peak price ratio must exceed the reciprocal of efficiency — around 1.3 at 78% — before arbitrage is profitable at all.

Formulas

Round-trip efficiency

Efficiency = energy out / energy in

Arbitrage break-even

Minimum peak / off-peak price ratio = 1 / round-trip efficiency

Worked example

With the default values below, Pumped Storage Efficiency Calculator returns Round-Trip Efficiency of 75.000%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Energy Used Pumpingminimum 0 MWh
1,400 MWh
Energy Generatedminimum 0 MWh
1,050 MWh
Off-Peak Power Priceminimum 0 per kWh
2.5 per kWh
Peak Power Priceminimum 0 per kWh
6 per kWh

Results

Round-Trip Efficiency
75.000%
Margin Per Cycle
$2,800,000.00
Energy Lost In The Cycle
350.00
Minimum Peak To Off-Peak Price Ratio
1.3333

Step by step

  1. 1Values used
  2. 2Round-trip efficiency
  3. 3Arbitrage break-even
  4. 4Round-Trip Efficiency= 75.000
  5. 5Margin Per Cycle= 2,800,000.00
  6. 6Energy Lost In The Cycle= 350.00
  7. 7Minimum Peak To Off-Peak Price Ratio= 1.3333

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.

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

Frequently Asked Questions

Where do the losses go?

Pump and turbine hydraulic losses, penstock friction, generator and motor losses, and evaporation from the reservoirs. Variable-speed machines have narrowed the gap by operating efficiently across a wider range.

Is arbitrage the only revenue?

No. Frequency response, reserve capacity, black start capability and inertia provision are often worth more than energy arbitrage in modern markets.

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