Winning the power struggle

Nothing can be managed until it has first been measured. This basic rule of good management applies as much to energy as to any other manufacturing function. It really is a no-brainer, so why isn't it standard practice when it comes to factory energy? Chris Evans, director – marketing and operations group at Mitsubishi Electric, has this answer: "Many customers tell us that one of their biggest business costs is energy, so it would seem obvious that tackling and improving the problem would be the natural thing to do. "However, this ignores the pressure of producing product and satisfying customer demands, which all manufacturers face on a daily basis. An argument often heard is that the energy bill is seen as a 'sunk cost' or that it is the necessary evil endemic in the production process and 'it is what it is'." It pays to analyse your energy usage So the first battle for companies like Mitsubishi Electric is to convince hard-pressed manufacturers that there are opportunities for big efficiency improvements by paying more attention to their energy usage. But where to start? The answer is with energy monitoring and targeting (M&T), a disciplined approach to energy management which ensures that energy – whether in the form of electricity, gas, oil or steam – is used to the maximum economic advantage. Evans believes there is one compelling reason for factories to take M&T seriously: "In a nutshell, it will save them money." Indeed, depending on the process and how energy intensive the business is, he reckons you could easily slice 30% off your energy bill. But the benefits of M&T don't end with cost cutting. It also allows you to make better informed commercial decisions. Implemented well, the technique will reveal the energy cost for each process or product, allowing you to assess, for example, the fuel cost penalty involved in meeting the tight deadlines of a rush job. Making managers visibly accountable Beyond this, it makes line managers visibly accountable for their energy usage. M&T can also reveal things that are worth investigating further, such as differences between shifts. It gives you a method of checking the effectiveness of your capital investment decisions and it helps protect the environment – and therefore your corporate image – by reducing carbon emissions and greenhouse gases. So energy M&T makes obvious sense. The next question is how is it best implemented? For Evans, it starts with an audit: "Most plant is running inefficiently from an energy point of view. We can perform a feasibility study – go and look at the plant, do an audit of what they've got and then recommend areas where they could make some improvements, or put in some monitoring equipment." If you are unwilling to pay a lot of money upfront for M&T, there is the option of adopting a staged approach to identify easy wins. "This," says Evans, "is often nothing to do with adding control. For example, if an operator leaves a production line conveyor system running at full speed all day and goes off for a break, that is wasting energy. "The decision is whether keeping it running is more energy efficient than turning it off. That will depend on time. Using no energy is free, but there is a start-up overhead. So there is a balance, but you can identify something like that quickly." It is impossible to be prescriptive about energy M&T; how you go about it depends on the complexity of your particular factory and its processes. However, there are three general principles that always apply: - Gather information: monitoring energy consumption tells you where you are and enables you to set targets for improvement. - Quantify energy use: this relates energy usage to a variable such as shift hours, production tonnage or degree days (a measure of the difference between inside and outside temperatures) and provides a baseline against which improvements can be judged. - Set a target: finally, you need to define an achievable improvement in performance. It can either be a percentage reduction on standard performance or can result from more sophisticated analysis. A hotch-potch of control systems One problem facing typical manufacturing plants is the disparate control systems they often have. Evans explains: "They may standardise on one automation platform, but it may be that they've got machines that are controlled by a variety of different PLCs, for example; there isn't a common automation platform across the plant. That gives them some challenges." But, he adds, they may also not have networked all their production lines together so gathering information is more difficult. "All the production line machines will have the capacity to deliver information. If, for instance, there is a PLC controlling a machine, then it could offer you a lot of data. It may not have been programmed to do this because that wasn't the requirement at the time it went in, but it has the potential to." For example, it can offer information about hours run and it may have equipment it that can extract energy data. Evans again: "But if it is sitting there as a sort of island, and is not currently gathering that type of information, and even if it is it's not got anywhere to pass it to because there is no network, then that can cause problems. Extracting the data is going to involve some engineering as well as extra equipment in order to pull the data out." However, says Evans, this is worth investing in. Information is, he says, power – it pays to build an energy management strategy with M&T as the foundation upon which you can build an effective energy-saving (and therefore profit-generating) policy. Steps to better energy control Energy monitoring and targeting (M&T) is simply a technique where actual energy use is compared with the standard or expected consumption and the information is presented to those responsible for using it. Targets are then set for performance improvement. In most cases, M&T techniques and supporting systems can be easily implemented. However, M&T is only one of a series of steps you can take to improve your factory's energy usage. Good housekeeping measures can reduce your bill by 10% at little or no cost. Achieving a similar return from increased sales would require significant investment. So: - Perform a simple survey to detect obvious signs of energy wastage around the factory. - Ensure that existing controls such as valves, steam traps and thermostats are operating properly and are adjusted to suit your needs. - Employ tariff analysis to monitor maximum power demand to reduce electrical costs. - Learn to switch off (and on) at times which will minimise energy consumption. Use tamper-proof time locks. - Insulate your factory. You will find the payback period is dramatic, often two years or less. - Maintain energy-consuming plant regularly. - If you can afford it, install a plant-wide energy management system.