Balance of power

Overheads, once a notional, barely significant addition to total product cost, these days command almost parity with materials and labour. In less than a decade, energy costs have almost trebled – this through the toughest period of economic trading in modern history. What's more, with the scaling back of ageing coal and oil power stations, the widely anticipated shortfall of energy resources in 2014-15, could well see some form of restrictions placed on industrial users. Of course, the clock is also ticking on mandatory energy audits which will apply to larger UK enterprises from 2015, driven by European Directive 2012/27/EU on energy efficiency. The upshot: most if not all manufacturers have already begun addressing the tricky issue of energy consumption in one form or another. For some, this entails little more than a programme of workforce education. A shift in culture whereby lights are turned off when areas are unused, the thermostat is clicked down and air conditioning is reserved solely for unseasonably hot conditions. An employee or indeed a team might even be assigned the role of driving and refereeing such initiatives. The Pencoed facility of Sony UK Technology Centre – highly commended in the Energy & Environment category at the 2012 Best Factory Awards, and a 2013 finalist – is a case in point. This manufacturer of broadcast and professional camera systems has established a working group to target energy reduction and waste in its processes. The aim is to inject sustainability into the manufacturing culture without compromising competitive advantage, while the result of this investment in time and resources has led to a year-on-year energy reduction trend as well as impressive improvements in waste recycling rates. The company is even pushing towards zero CO2 emissions in the near future. Pressed to invest Beyond good working practice and common sense comes investment in technologies designed to ensure energy consumption is minimised. From the perspective of specific machinery, the latest equipment will invariably offer enhanced energy savings. Able to testify this fact is Allied Bakeries, Britain's second largest baker, following its latest round of investment which represents the largest capital expenditure programme in UK bakery. "We're investing in many of our bakeries, including Stevenage, Stockport, West Bromwich, Glasgow and Walthamstow," says operations director Nick Law. "New equipment, from new bread or rolls machinery, to silos, ovens, loading bays, coolers and provers, is being rolled out to improve functionality and deliver products at a consistently high quality. The new kit also provides energy savings, reducing our impact on the environment." By way of example, 36 new ovens installed across the five sites mentioned (which will accommodate 30% of bakery product throughput), use less gas, reduce heat loss and cut carbon emissions by up to 30%. Additional benefits include a 50% reduction in cool-down time to perform maintenance tasks. On a component level, one of the biggest industry trends is the continued uptake of variable speed drive (VSD) technology, particularly in plant applications such as compressors, pumps, fans and conveyors, where big improvements in energy efficiency can be delivered by driving motors at just the right speed to match the process. "The latest VSDs can give more detailed and understandable information, for example, showing on the drive's screen exactly how much energy is being used," explains John Guthrie, energy efficiency manager at ABB. "These measurements can help ensure that a plant or process is working to its optimum performance, while avoiding the extra cost of external energy measuring equipment." Yet, when first developed, VSDs were mainly valued for their ability to improve process performance and this remains a large part of their appeal today. For instance, improved quality was certainly on the menu for one of the UK's leading biscuit manufacturers when it investigated the potential of using VSDs in its processes. According to ABB, Fox's Biscuits of Batley, West Yorkshire, initially looked at VSDs for their energy-saving qualities but quickly saw how they could also improve product quality and potentially reduce waste. One of the major benefits for Fox's Biscuits is the flexibility to run at a wider range of speeds. The company uses a lot of additional ingredients in its biscuits, such as fruit. Previously, the mixers might over-mix, leading to staining where the fruit becomes a mush rather than remaining whole. Good speed control helps maintain a high quality product. The ability of the drive to change the speed of the mixer also allows the company to be more innovative. It can experiment by using different speeds throughout the mix, from as low as 2 rpm, to 50 or 60 rpm, depending on the recipe. ABB says that VSDs also have a role to play in reducing the maintenance effort, as vehicle component manufacturer GKN Wheels of Telford discovered. The company is saving around £25,000 in costs following the installation of a VSD on one of its production lines. One part of the line involves a walking beam that uses a system of reciprocating parallel bars to pass rolled and welded wheel rims from an oil dip to a flare press. As the beam reaches top dead centre, the larger wheel rims can cause the beam to over-speed and the momentum carries them too quickly towards the press. This can result in system jamming. This type of stoppage can take an average of two hours to remedy, resulting in lost production time and associated costs. To maintain schedules and keep its customers supplied, the plant needed to run overtime. A system was developed that employs a 1.5 kW VSD. At the beginning of the walking beam's cycle, the drive is started and the internal timer runs the drive for one second at full speed. After this time, the drive is switched to two-thirds speed and is decelerated gradually. The beam, carrying the wheel rim, is slowed as it approaches the press. Upon reaching the press, the beam triggers a limit switch that stops the drive to finish the cycle. Stoppages have been eliminated, cutting the extra maintenance costs and adding nicely to the energy savings accrued. For manufacturing plants sceptical of the energy savings available from specific technologies, many suppliers, such as motor specialist WEG, now offer free assessments that review equipment and outline a number of steps which can be taken to reduce energy use. In these instances, experts will assess existing plant equipment and can install drives on-site to monitor and demonstrate existing energy usage. Subsequently, a VSD can be fitted, energy savings can be proven and potential savings relating to project payback, ongoing operational savings and total cost of ownership can be calculated. Tackled at source Rather than address individual production processes or lines, some manufacturers are considering a more holistic approach using voltage optimisation. However, the hard sell of this technology using guaranteed savings as the driver means many plants end up with equipment that is inappropriate for their needs, at least according to Craig Needham, managing director at E-fficient Energy Systems. "In many instances, the result is that the products supplied fail to provide the savings promised," he says. "To make a more informed decision about product selection, find out whether the transformer has a single tapped point or multiple taps." Why so? Well, a single tapped point on a transformer – also called a fixed ratio or step-down transformer – will only deliver a preset amount of voltage reduction with no real voltage management. These are normally set to reduce the incoming voltage by a fixed ratio, say 8%. Simple in design, they offer fixed savings but little more. In contrast, more advanced voltage management systems incorporate multiple tapped points on the transformer, thus permitting the output voltage to be controlled more closely as the mains voltage fluctuates. This is known as voltage regulation. The higher the quantity of tap settings, the more control the voltage management system has over providing an optimised and regulated voltage. This enhanced control boosts the potential to reduce electricity consumption. Most UK systems use a variation of this principle to reduce the over-voltage being supplied by the National Grid. But the UK also endures under-voltage, and true voltage regulation is only achieved when the mains voltage is controlled in both scenarios. This is called 'buck and boost' voltage regulation. To identify the transformers which can provide the greatest energy saving, plants need to know how many transformers exist per phase and the amount of tapped points per transformer for real voltage management. "This type of technology sits in-line with the mains incoming power supply and, in our experience, offers customers energy savings in the region of 7-17%," says Needham. "The savings are quantified up front via a week-long site survey that entails activities such as mains analysis, data logging and asset registering. Furthermore, the installation process needs downtime of only 4-8 hours, and the work can be done overnight or at weekends to suit requirements." Associated benefits With energy initiatives becoming all the more intensive at manufacturing plants across the country, a new free-to-join organisation for people whose job role includes energy saving has been established. The UK Association of Energy Engineers (www.ukaee.org) offers benefits such as an 'ask the expert' section on its website and finding speakers for evening talks at regional centres. Vilnis Vesma has been appointed secretary of the UKAEE. A former energy manager who worked for many years as an independent consultant and provider of training in energy management, Vesma's particular expertise is energy monitoring and targeting, a topic in which he has lectured internationally. To support his work, he has developed a number of spreadsheet-based tools, notably implementing CUSUM (cumulative sum) analysis. Free white paper Industrial product supplier Eriks has released a new white paper on energy efficiency designed to help tackle the challenge of driving change in the workplace and beyond. The white paper presents two viewpoints: one provided by an expert commentator from within Eriks and a second from an independent academic observer. The publication looks not only at everyday questions of energy efficiency in industry, but also at the bigger picture. "The problem lies not just with machines, but with people," the paper begins. "When a message is repeated there's a danger that we no longer hear it anymore. There's also a danger that we don't go far enough to maximise energy efficiency because we believe we've already done all we can." The white paper sets out to challenge these assumptions and refresh the energy efficiency message. It also explains how Eriks can help environmental managers drive change from the roots to achieve a comprehensive, company-wide effect, and alter the attitudes of the workforce in all aspects of their lives. Download the white paper at www.eriks.co.uk/Energy-Efficiency/3877.