Case Study – Capital replacement programme in a metal fabricator

Sector: Industrial Sector

Project: Capital replacement programme in a metal fabricator



Using the correct energy source to do the job is critical in ensuring that the least amount of energy is used for maximum return. Manufacturers typically use compressed air as a common form of energy. Over 80% of the energy consumed by compressors is lost to heat. This means that even if energy efficient air compressors are used to reduce energy consumption by up to 40%, there is still another 50% of waste energy going to heat. This inefficiency can be overcome by replacing air driven systems with direct electrical systems that are 85% to 95% efficient.




A small metal fabricator uses compressed air to drive air drills in the assembly area. These drills are used to screw the product together. On running an energy measurement project across their facility it showed that the compressors cost on average £32 a day to run.

When looking at the hourly energy costs it becomes apparent that the amount of work being performed has no relationship to the cost, as the cost is roughly similar. This is due to the compressors being fixed speed so they produce the same amount of air regardless of the load requirements.




By replacing the air drills, the compressors can be retired from the operation. The resulting cost for the compressors therefore becomes zero. At a cost of less than £1,000 for the drills it would remove £8,000 per annum from the operating costs even after the cost of charging the batteries was taken into consideration.

Using the right energy sources at the right time and the right place within a manufacturing process is key to being efficient and effective. Traditional air driven systems should be phased out wherever possible and replaced with direct electric driven systems.

The benefits are that the energy reduction can be as high as 95% to 98% compared to compressed air systems. Maintenance costs are also reduced as air lines do not have to be maintained.