Drawing No. EH–PG–008 // Power Generation & Grid
Worked Example: Datteln 4 Coal Power Station Water Usage
Reviewed August 2026
A real-world water-balance example for Datteln 4, the 1,052 MWe net hard-coal power station in North Rhine-Westphalia, Germany. Unlike the BWRX-300 worked example, this case is anchored to a published water permit: up to 2,300 m³/h and 15 million m³/year may be withdrawn from the Dortmund-Ems Canal for plant operating water.
Net electrical output reported by Uniper.
Maximum Dortmund-Ems Canal withdrawal.
Maximum permitted annual withdrawal.
Modern hard-coal unit; model starts at 45% net efficiency.
What the permit tells us directly
The 19 January 2017 water permit authorizes up to 639 L/s = 2,300 m³/h, 55,000 m³/day and 15,000,000 m³/year from the Dortmund-Ems Canal. It states that operating water is used mainly to replace cooling-tower evaporation, as cooling-tower and flue-gas-desulfurization process water, and to produce fully demineralized water for the steam/water cycles. The environmental assessment also notes that using collected precipitation can reduce operating-water withdrawal by up to 25%. Official withdrawal permit ↗
Cooling-tower assumptions
editable reconstructionDatteln 4 uses a large natural-draft wet cooling tower. The exact operating range, cycles and latent fraction are not quoted in the public permit and remain assumptions here.
Auxiliary-water assumptions
FGD + high-purity + serviceThe permit names FGD and fully demineralized water as plant water users, but does not expose their normal flow split. These starting values are transparent estimates.
Rainwater credit & annualization
permit sensitivityThe environmental assessment says precipitation use can reduce operating-water withdrawal by up to 25%. The 70% annual utilization is illustrative and is not a published Datteln 4 capacity factor.
Permit-constrained result
modeled full-load conditionCooling & process breakdown
model reconstruction| Estimated thermal input | — |
| Non-electric heat | — |
| Estimated heat to cooling tower | — |
| Cooling-water circulation | — |
| Tower evaporation | — |
| Drift | — |
| Blowdown | — |
| Gross tower makeup | — |
| FGD / process raw water | — |
| Demineralization raw feed | — |
| Other service/process water | — |
Detailed plant balance
estimated flow streams| Stream | m³/h | m³/day |
|---|
Published permit vs engineering reconstruction
keep facts separate from assumptions
| Parameter | Value | Status | Basis |
|---|---|---|---|
| Net electrical output | 1,052 MWe | Published | Uniper's 2025 sale announcement for Datteln 4. |
| Gross electrical output | 1,100 MWe | Published | Public plant descriptions and project material. |
| Net efficiency | >45% | Published | Public plant descriptions. Model uses 45.0% as an editable screening value. |
| Canal withdrawal permit | 2,300 m³/h; 55,000 m³/day; 15.0 Mm³/year | Published | 2017 Dortmund-Ems Canal water-withdrawal permit. |
| Fish-protection return | up to 35 m³/h to Dortmund-Ems Canal | Published | Separate permit item for Multidisc fish-return water; excluded from the process balance below. |
| Rainwater reduction potential | up to 25% | Published | Environmental assessment says supplemental precipitation use can reduce operating-water withdrawal by up to 25%. |
| Cooling range / cycles / evaporation split | editable | Estimate | Not exposed as normal operating values in the public withdrawal permit. |
| FGD, demin and service-water split | editable | Estimate | Permit names these uses but does not publish the normal flow allocation. |
Where the wastewater goes
separate process water from stormwater
Industrial plant wastewater → treatment plant → Lippe
The 2017 environmental decision refers to the approved indirect discharge of Datteln 4 process wastewater through the Dattelner Mühlenbach wastewater treatment plant and onward to the Lippe. The modeled liquid discharge on this page represents the plant-side flow before that downstream treatment.
Fish-return water → Dortmund-Ems Canal
The withdrawal permit separately allows up to 35 m³/h to be returned to the canal from operation of the Multidisc fish-protection system. This is not treated as FGD or cooling-tower wastewater in the worked balance.
Treated precipitation → Deinebach
A separate water permit allows treated precipitation from the Datteln 4 site to be discharged to the Deinebach, up to 180 m³/h. This is a stormwater-management stream and is excluded from normal operating process-water demand here.
Storm-event overflow → Dortmund-Ems Canal
A separate permit allows large precipitation-water discharge to the Dortmund-Ems Canal during heavy rainfall only. It explicitly does not authorize continuous discharge, so it is not part of the normal-operation water balance.
Calculation method
how the reconstruction is built
1. Heat balance
The model converts net electrical output and editable net efficiency into thermal input:
At 45% net efficiency, 1,052 MWe implies about 2,338 MW thermal input and roughly 1,286 MW not exported as electricity.
2. Cooling circulation
A selected share of non-electric heat is assigned to the cooling tower. Circulation follows:
The default 12 °C range gives an order-of-magnitude circulating flow of about 85,000 m³/h.
3. Evaporation and blowdown
Evaporation is tied to latent heat and blowdown is derived from cycles of concentration:
4. Permit check
Cooling makeup is added to estimated FGD/process, demineralization and service water. Any rainwater credit reduces the canal draw, not the underlying plant water demand.
5. Annual permit
The 15 million m³/year limit corresponds to only about 6,522 hours/year at the maximum 2,300 m³/h withdrawal—about 74.4% of a full calendar year. Actual annual withdrawal therefore depends strongly on dispatch and rainwater substitution.
6. Interpretation
This is a constrained engineering reconstruction, not a reproduction of Datteln 4 operating logs. Its value is showing whether a plausible heat- and solids-balance can fit within a real permitted water envelope.
References
official sources first
Reference status checked 21 August 2026. Published permit values are kept distinct from EngineerHub flow assumptions throughout the page.
Compare the water-balance examples
same framework, different evidence