Good practice

Tweaking fan speeds in cooling towers saves power in chemical sector

Tweaking fan speeds in cooling towers saves power in chemical sector
© ieang, image #125176108, source:
Chemical and process engineering
High cost
Annual saving:
Payback time:
1.5 Year(s)
Associated cost savings: Energy:
Payback time:
The exact payback time for this measure was 18 months
Co2 emission reduction:
15 tonnes of CO2 per year
Premises and operation areas:
Production building, Production processes
Size of company:
Medium (less than 250)
Advancement in applying resource efficiency measures:
One off investment:

Cool measure saves loads

  • Company rationalises fan operation
  • Saves € 24 000 per year
  • Reduces CO2 emissions by 15 tonnes per year

Yara is an international company operating in the chemical industry, specialisating in nitrogen and nitrate production. The plant in Montoir-de-Bretagne, the Loire-Atlantique region, supplies nitric acid, nitrates, CO2 and NPK fertilisers all over France. Customers use these chemical for industrial applications and in agriculture.

Cooling towers at Montoir-de-Bretagne accounted for a third of total electricity consumption. Four fans were in continuous operation at 100 % capacity, regardless of dissipated thermal load or the outside temperature.

Yara tackled this problem by installing four frequency inverters, which regulate the rotation speed of the fans in line with the cooling water network flow temperature. The cost of the installation came to € 35 000.

Key benefits

This investment is expected to pay for itself within 18 months, thanks to savings of an estimated € 24 000 per year. The environment is also a winner with 15 tonnes less CO2 being emitted into the atmosphere annually due to Yara's actions.


"Our cooling towers [used] 15 GWh a year or 30 % of the total consumption of the site. It was therefore important to ... [apply] the simplest lever by optimising ... the cooling tower fans which, whatever the outside temperature, were running at 100 %." - Katell Doucet, Environmental Technician, Yara


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