CASE27 · Water & wastewater · Water-supply pumps
Integrating pump efficiency, reservoir levels and peak-demand control
Seasonal ten-minute data across intake, treated-water transmission and booster systems support efficient pump selection, demand-based staging and reservoir scheduling.
01 · CASE ANALYSIS
Operating challenge
Large pumps were distributed across several water-supply systems. Some individual flow and power values were unavailable directly, requiring calculated power and system-level information.
Reservoir levels, required head and peak electricity demand had to be reviewed together while maintaining reliable water service.
02 · CASE ANALYSIS
Diagnostic method
Nine major pump systems were compared using seasonal power, flow, pressure, load ratio and actual versus required active-unit counts.
The source defines pump UPI as delivered volume divided by electricity, in m³/kWh. Higher values are favorable. This is the reciprocal of the energy-per-output convention used in many other cases.
| Indicator | Definition or use |
|---|---|
| Pump UPI | Delivered volume (m³) / electricity (kWh) |
| Load ratio versus UPI | Identify efficient operating regions |
| Power versus flow | Review operating points and abnormal behavior |
| Operating margin | Actual active units − required units |
| Reservoir scheduling | Storage ↔ pumping head ↔ peak demand |
03 · CASE ANALYSIS
Operating strategy
Prioritize pumps with better measured efficiency at the applicable operating point. Check the demand-based number of running pumps against actual dispatch.
The proposed reservoir strategy combines lower night-time levels to reduce head with sufficient stored water before peak periods. Storage may allow temporary pump shutdown during the electrical peak, subject to service constraints.
04 · CASE ANALYSIS
Proposed savings and project scope
The 35-pump portfolio used approximately 27,155 MWh/year and KRW 1.97 billion/year in electricity. The reported total expected benefit was KRW 62 million/year, approximately 3%.
A nine-month project was proposed: six months of construction and three months of optimization, with an estimated investment of KRW 248 million.
| Measure | Annual expected benefit |
|---|---|
| Efficient pump priority | KRW 20 million |
| Reservoir-level optimization | KRW 17 million |
| Peak-demand reduction | KRW 25 million |
| Combined | KRW 62 million; approximately 3% |
05 · CASE ANALYSIS
M&V and engineering lesson
Separate consumption savings from demand-charge savings. Adjust comparisons for flow, head, reservoir level, tariffs and demand conditions.
Reservoir scheduling is a constrained service decision: apparent electrical savings must preserve water availability and required pressure.
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