Energy savings across the operating profile

Enter up to eight operating points on the pump curve, specifying the flow rate, head, current and improved pump efficiency of a single pump, motor efficiency and annual operating hours for each point. The operating hours distribute the year across eight points on the same pump curve. At each point, the current and improved conditions are compared at the same flow rate and head.

1. General assumptions

Electricity price (€/kWh)

Evaluation period (years)

CO₂ emission factor (kg CO₂/kWh)

Fluid density (kg/m³)

Variable frequency drive efficiency (%)

The drive efficiency applies to both scenarios and all operating points. Enter motor efficiency separately for each operating point. Use 100% if no drive is installed. The prefilled values are examples; adjust them to match the installation.

2. Pump curve operating points

One pump, eight operating points. For each point, enter the current and improved pump efficiency (excluding motor and drive). Also enter motor efficiency for each point; this applies to both scenarios at that point. The difference in pump efficiency in percentage points is calculated automatically. Points with 0 operating hours are excluded. The example points are illustrative and do not represent a validated pump curve.

Point	Flow rate Q (m³/h)	Head H (m)	Current Pump η (%)	Improved Pump η (%)	Motor η (%)	Operating hours (hours/year)	Difference (percentage points)	Current (kWh/year)	Improved (kWh/year)	Savings (kWh/year)
Total						—	—	—	—	—

3. Results across all operating points

Annual cost savings

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Savings over evaluation period

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Annual energy savings

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Relative energy savings

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Annual CO₂ reduction

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CO₂ reduction over evaluation period

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4. Annual electricity consumption

Current pump scenario—

Improved scenario for the same pump—

5. Savings per operating point

Annual savings in kWh; negative values indicate additional consumption.

Calculation method: for each operating point, P_electrical (kW) = ρ × g × (Q/3600) × H / (1000 × η), where η = pump efficiency × motor efficiency × drive efficiency (all as fractions). Annual energy = electrical power × operating hours. Annual savings are the sum of (current annual energy − improved annual energy) across all entered points. An efficiency difference of 5 percentage points is not the same as 5% less energy consumption. The points are discrete operating conditions with specified hours, not an automatic interpolation of the pump curve. Compare the same hydraulic operating conditions and hours for the current and improved scenarios of the same pump. Keep total hours realistic (maximum 8,760 hours per year for one continuously available pump). The evaluation-period calculation assumes identical annual operating profiles, a fixed electricity price and emission factor; capital costs, maintenance, discounting and degradation are excluded. The default CO₂ factor of 0.483 kg/kWh is illustrative only and is not an official current Dutch emission factor. For external CO₂ reporting, use an applicable documented factor and methodology.

Rodelta · Indicative technical and economic comparison · Runs entirely locally without internet access. No data is transmitted. Use “Download with my inputs” to save or email your completed version. Negative savings indicate additional consumption, costs or emissions.