Presentation of the company

STPL is active in fine sheet metal working and metal treatment and coating. It includes a paint shop and related utilities (boiler, compressor and air dryer, suction systems).

Background information

In this company of about forty employees, energy is a major expense. Indeed, the metal coating activity is particularly energy-intensive. Energy represents 12% of sales.

With variable and sometimes very high power requirements, the challenges of the EE-METAL audit were twofold: to reduce energy consumption and to better control peak consumption.

Actions

The audit made it possible to propose and implement various areas for improvement:

• Installation of a buffer storage tank on the compressed air network (to avoid peak loads on the compressed air network): savings of 20,400 kWh/year (2% of annual energy consumption) or 3,000 €/year (8% of annual electricity bill) with a ROI of 1 year (investment of €2k)
• Installation of a capacitor bank (at the top of the plant's electrical outlets, to avoid reactive energy billing): savings of €10,000 per year (25% of the annual electricity bill) with a ROI of 1 year (investment of 10 k€)

Conclusion

Other actions relating to process optimization are still under study: the more precise adjustment of the extraction rates of the paint line or the more complete closure of the drying tunnel. In addition, more substantial reflections could be carried out to review the organization of work and deploy production in 2 shifts rather than 10 hours a day. This will reduce the heating times and the maintenance of ventilation after the heater has been switched off.