You could use an online ...

You could use an online calculator, such as from pump supplier Grundfos, or speak to them. I've included details below should you wish too determine / understand yourself.

As an example a 5Ml/d flowrate (208m3/hr), with a total lift of 100m and a typical total efficiency of 0.65, has a electrical input power of 87.2kW. Used 24/7/365 (8760 hours) at £0.1/kWh, would cost £76,370 per year.

The costs are proportional to flowrate, total lift, hours run and tariff cost. The costs will however increase ( and could double ) as efficiency reduces, which can easily happen if the pumpset is not well selected for the required flow / lift. A good engineer is required here, as a poor / simple design can also easily lead to pumpset failure.

Calculations Explained in detail:

Total Cost = Energy Cost £/kWh * Energy usage (kWh) per year.

You will need to know:

Energy usage (kWh) per year = hourly kW usage * hours of operation.

Hourly kW usage depends upon Flowrate, Pumping Lift and total efficiency...

Hourly kW usage (kW) = flowrate(m3/hr)*998.2/3600/1000*9.81*Total Lift(m)/System Efficiency(e.g. 0.65)

Total Pump Lift (m) (Pumping Water Level (measured from the discharge pressure gauge) + losses in motor cooling shroud+rising main losses + discharge pressure gauge reading (static lift to discharge point + losses in the discharge pipeline)

Total Efficiency (pump, motor, all other electrical efficiencies).

This covers most items.