Presentation of the company

Rhonalu is an aluminium foundry specialized in gravity casting. This SME with 25 employees masters the entire supply chain from the production of foundry blanks to the delivery of finished parts (machining, finishing, heat treatment). The company has several types of furnaces (melting, temperature maintenance, heat treatment, etc.), machining equipment (band saws, robotic finishing cell) and related utilities (compressed air production, ventilation, etc.).

Context and issues

In foundries, energy is an important competitive issue. This is why the manager has taken the challenge of integrating energy management into the company's strategy. All decisions and investments made take into account energy efficiency.

Actions

For several years, the company has been acting on the control of its consumption through:

• Choosing the best technologies and energy sources for its equipment (new generation electric furnaces for heat treatment)
• The systematic installation of sub-meters on all new furnaces to monitor their consumption
• Membership of an energy purchasing group (30% savings compared to its previous energy contracts)

Thanks to the EE-METAL energy audit, new actions, complementary to those already carried out, have been implemented to optimise energy consumption and expenditure:

• Reduction of the CSPE tax (reduction of the energy bill): saving of 4,500 €/year (i.e. 15% of the annual electricity bill) with an immediate ROI
• Adjustment of the subscribed power (to avoid power overrun penalties): saving of 3,500 €/year (i.e. 11% of the annual electricity bill) with an immediate ROI
• Installation of a capacitor bank (to avoid reactive energy billing): savings of €1,000 per year (or 3% of the annual electricity bill) with a 3-year ROI
• Detection and suppression of leaks on the compressed air network (quarterly preventive maintenance): savings of 4,000 kWh/year or 0.5% of annual energy consumption) or 500 €/year (or 2% of annual electricity bill) with an immediate ROI
• Replacement of the compressor (variable speed motorization + heat recovery): saving 20,000 kWh/year (2% of annual energy consumption) or 3,400 €/year (11% of annual electricity bill) with a 7-year ROI (investment of 24 k€)
• Replacement of the workshop lighting (with LEDs) saving 9,400 kWh/year (1% of annual energy consumption) or 1,100 €/year (4% of annual electricity bill) with a 5-year ROI (investment of €5k).

Conclusion

Already ISO 9001 certified for quality and ISO 14001 certified for the environment, the company wanted to extend this continuous improvement approach to energy. Based on the results obtained in the EE-METAL energy audit, Rhonalu obtained ISO 50 001 certification based on an accompanying methodology specially developed for SMEs in the metallurgy sector as part of the EE-METAL programme.