Measures implemented by a Scottish galvanizing company to achieve the ISO 14001 environmental management standard have helped the company cutting its energy costs by several thousand pounds a year. Among the measures introduced by Elgin-based Highland Galvanizers was to replace an existing fixed-speed compressor with a ABB variable-speed drives.

As well as meeting the requirements of ISO 14001, the company was hoping to cut its energy use to help meet its Climate Change Levy (CCL) commitments and to counter the effects of escalating energy costs.

A survey of the site’s compressed air system revealed that the existing compressor spent a significant lot of time running off load. The compressor had been designed to perform continuously at maximum output capacity, but this capacity was only being used at peak times.

A local company recommended replacing the installation with a variable speed compressor. The new installation was data-logged and showed energy savings of around £6,000 a year.

“We implemented a number of measures that have resulted in electricity savings of over 197,000 kWh per annum – cost savings in the order of £12,200,” says Highland Galvanizer’s managing director, Geoff Crowley. “The new compressor alone has contributed some 50% to those savings and we saw a payback on our investment in just 19 months. The measures have also enabled us to maintain our CCL discount of £2,000 a year.”

The new speed-regulated compressor incorporates a variable-speed switched reluctance drive which matches power consumption to air demand. The compressor can maintain a set pressure accurately while responding instantly to changes in air demand. Maintaining the air system pressure at a pre-set level eliminates the need to operate within pressure bands, enhancing the energy performance and cutting electrical and mechanical loads.

A further advantage for Highland Galvanizers is the fact that the compressor starts without drawing a current above normal running levels. This reduces stress on the site’s power supply and eliminates peak current energy cost penalties.

The company has introduced a similar compressed air system at a new galvanising and powder coating plant in Cumbernauld.  “We formed a new company, Highland Colour Coaters,” explains Crowley. “Compressed air is critical to the operation of the plant and our experience at Elgin had already shown that by selecting a variable speed drive compressor we could ensure an energy-efficient operation from the outset.”

The same type of compressor has been installed at the Elgin site and data-logging has confirmed that it is saving more than £8,000 a year compared to a fixed-speed compressor.

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