Mattei news

Small first steps can make a big difference

ESOS assessments carried out in the manufacturing sector have highlighted that energy efficiency can often be improved across industrial compressed air. Andy Jones, managing director of Mattei, talks through some practical first steps.

Insight from the ESOS assessments carried out among manufacturing businesses suggests that compressed air is often an area where energy efficiency can be improved*. This should come as no surprise, considering that compressed air is regarded as industry’s fourth utility and compressors account for around 10 per cent of the total electricity consumed in the industrial sector. 

Currently, businesses are under no obligation to action any of the recommendations identified during the ESOS assessment process. But if manufacturers do want to take ESOS fully on board and start making savings in compressed air, where’s the best place to start?

It will be difficult for a business to make savings if they don’t know how much compressed air they use, and how much it costs them besides initial air compressor price. Unfortunately, many manufacturers across the UK are operating compressed air systems without this essential information. 

The most straightforward way to evaluate compressed air needs and the efficiency of the system is through data logging. This involves recording and measuring air consumption profiles over a seven-day period, and some discussions to identify unusual patterns or planned process changes.

Data logging can also identify whether a manufacturer’s production processes require a fixed speed or a variable speed electric air compressor, and whether the output is correct. We found that one company running a 75kW compressor could actually fulfil its compressed air requirements with a 45kW machine, with estimated savings being in the region of £10,000 a year. 

Investing in a more detailed energy audit, carried out in accordance with the international standard ISO 11011:2013, Compressed air – Energy efficiency – Assessment, can paint an even more realistic picture about compressor efficiencies. Flow monitoring is also a very useful tool for understanding how much air is used in total and which areas are the greatest users, especially when combined with data logging.

Flow monitoring also helps identify air leakage more accurately than other methods. And, indeed, assessing leaks in the system is another important first step towards saving energy. In many companies, 30 per cent of the air generated is wasted through leaks, which can prove costly over time. According to the Carbon Trust, even a small leak (just 3mm) could cost more than £700 a year in wasted energy – and we often see compressed air systems with around 150 to 300 leaks. 

Our advice is to check for leaks frequently and carry out an annual leak detection survey. The pipework design should also be assessed, as excessive lengths and bends lower system efficiency.

Data logging, energy audits, flow monitoring and leak detection services are available from compressor manufacturers, and are well worth the investment. As an example, the average cost of a Mattei leak detection survey is less than 10 per cent of the overall leakage costs. We recommend that end users work only with compressor companies that are members of BCAS (British Compressed Air Society), as this demonstrates professionalism and competence, and a commitment to health and safety and best practice.

Changing employee behaviour can also improve energy efficiency (as is often the case in other areas, such as heating and lighting) and it doesn’t cost anything. Implementing a company training programme and an official compressed air policy – outlining when and how it should be used – will help staff save energy, while also improving safety. 

Compressed air should be used appropriately and as intended; for example, using it to remove dust and debris from machinery, workbenches or clothes wastes energy, and causes a safety hazard. And for some tasks, such as moving goods from A to B, there may be no need to compress air at all. A good example is the transportation of bulk materials in the food, construction and synthetics industries, where a blower might be a more efficient solution.

Employees should also be provided with guidelines about when the machinery should be turned off, which is ideally during breaks and definitely when the factory is closed – according to Carbon Trust figures, an idling compressor uses around 40 per cent of its full load power, although some compressors consume less than this. 

It’s also important for employees to fully understand the costs involved in producing compressed air. There is a misconception that this utility is free once a business has invested in the equipment, but this couldn’t be further from the truth. The initial purchase makes up a very small part of the total lifetime costs of a compressor; the main cost will always be the energy required to produce the compressed air. In fact, the electricity consumed during operation over a five-year period accounts for around 75 per cent of the total cost of ownership, including the initial capital outlay for the compressor.

Taking these first initial steps should result in energy savings, but investment in new equipment (but only if genuinely required) can also pay dividends. We have many examples we can cite where manufacturers have achieved substantial savings through updating the compressors in their factories and processing plants. One of our customers, a leading food manufacturer, is expected to save around £150,000 over five years as a result of replacing large reciprocating compressors (which had been in operation for nearly 40 years) with three Maxima 75 high efficiency low speed compressors. For another customer, replacing a 12-year-old 90kW compressor with a Maxima 75 resulted in energy savings approaching £20,000 per annum.

When choosing a new compressor, whether that’s a large model or a portable air compressor, it’s important to compare specific energy efficiencies. Higher efficiency machines often cost more, but money will be saved in the long run because of reduced energy costs. Indeed, a slightly higher-priced compressor could pay for itself in just a matter of months. Fortunately, we are starting to see end users placing more emphasis on the total cost of ownership of compressed air systems, rather than just the capital cost of equipment.

It’s been said that ESOS has already been successful in that it’s made businesses think about energy efficiency and their energy use – but there’s a golden opportunity for business owners and managers to take the findings of their ESOS assessments fully on board. Where compressed air systems are concerned, even some small first steps, such as data logging, leak detection and changing employee behaviour, can make a big difference. 

Back to news