Are you in control?

The Climate Change Levy (CCL) came into force in April this year. The effect is that commercial energy bills have been substantially surcharged. Various industrial sectors have negotiated up to 80 per cent rebates, subject to stiff energy/ environmental targets being met in stages over the next 10 years. This has had a galvanising effect in some companies.

A recent survey was carried out by the Energy Efficiency Best Practice Programme (EEBPP) to find out what companies were doing to improve the control of their processes in response to the CCL. Answers ranged from, 'We didn't need the CCL to make us improve control, we're doing it anyway because it is very cost effective.' through, 'The CCL has made management take an interest in energy saving.' to 'What is the Climate Change Levy?'

Leaving aside the minority who had never heard of it, it is a concern that a substantial number of companies (a majority?) have needed the 'stick' of the CCL to make them take an interest in reducing energy costs by improving control. The 'carrot' of increased profit has always been available.

The EEBPP has identified process control as one of the three high priority measures for energy saving - and thus profit generating - technologies. The others are Combined Heat and Power (CHP) and Motors and Drives. Improved process control has the added advantage that it can often be implemented at little or no cost and it can usually be done while the plant is running so that production is not affected. Not possible with most large capital projects, even if the benefits are significant.

The major process industries have enthusiastically embraced process control improvement as a major driver to reduce energy costs to meet their CCL commitments, which also include reduced environmental effects. But the benefits are much greater. Better process control can increase yield and provide better, more consistent quality. All of this may be of even greater benefit to your profitability than energy saving alone.

Views from industry

Paul Oram, Process Control Assurance Manager, at the BP Hull Site confirms BP's commitment to improved control as a major profit generator. Oram says that BP is applying conventional and advanced control enhancements across the company. The object is not to save energy per se, but 'to make money'.

Nevertheless, the consequence has been to reduce energy costs per tonne (specific energy costs) by 5 - 6 per cent, coupled with production increases of around 10 per cent as a direct result of improved control methods. Paul agrees with the oft-quoted figure of 2 - 6 per cent of raw materials and energy costs being recovered by improved control.

So convinced is BP's higher management of the value of this work that over the last five years they have increased the number of control engineers specifically charged with seeking out profit opportunities and maintaining existing advanced systems from three to twelve.

The picture is similar on Teesside, where Huntsman now operates plant previously owned by ICI. Huntsman is pushing the plants hard and has turned previous loss-makers into high profit generators. Mike Oglesby, control engineering consultant with Huntsman, says that the secret is to maximise throughput and drive the plants hard against constraints. Control technology is key to this, he says - although it is not the only method being used to improve operations, it is virtually the only one where major improvements can be made between shutdowns.

Huntsman is applying model based control (MBC) and plant-wide economic optimisation where it is justified, but also ensuring the proper application of conventional control, such as making sure controllers are properly tuned. Diagnostics techniques are now standard on some plants using, for example, Gensym G2 systems and rule-based logic. As with the BP project, Oglesby says that improvements are saving 2 - 6 per cent on materials and energy, and again, extra control engineers are now working on the plant - ten, rather than the previous three.

Control improvements such as these provide a quick payback. EEBPP has found that around 80 per cent of projects pay for themselves in about a year, with about half breaking even after only six months. Some projects paid for themselves in days. One project saved over £250 000pa in energy for the per-day cost of a fitter making adjustments to existing installed instrumentation. Yet the plant had been operating that way for at least 5 years.

'Advanced' Control

Most control does not need to be 'advanced' or 'modern'. Probably 90 per cent of control can be adequately satisfied by conventional control techniques. All that is needed to see a major benefit is to make sure existing systems are working properly. Nevertheless, by using standard building blocks in modern DCS systems it is very easy to apply cleverer ideas. An example might be on a furnace where you want to push it as hard as possible, subject to stack analysis and tube skin temperatures, to maximise efficiency.

Another good example of excellent savings made with a short payback period was seen at the Michelin Tyre Company. The company used statistical process control to determine the operational characteristics of its boiler water treatment processes. This, along with a Nalco Trasar water treatment system, led to significant savings in energy, water and the consumption of chemicals, and reduced the cost of effluent treatment. The payback on investment was less than 9 months.

Improved Control

Managers often perceive control improvements to be expensive and risky. This is usually because the benefits that have to offset the all-too-obvious costs have not been adequately estimated. There are well-proven ways to quantify the benefits before any capital is committed. It is not 'rocket science', simply a logical approach to assessing the value of improvements, usually based on experience of operating the particular plant or similar ones. Benefits analysis is a technique that allows you to estimate the value of an investment before making the commitment to spend the money.

Essentially, there are five stages to recover the money.

1. Establish a team to investigate the process. The team must contain expertise in plant operation and knowledge of what improved control can do. It is absolutely critical to have a 'Champion' (who need not be on the team) who has senior management backing to drive the investigation forward in the face of other priorities.

2. Establish a 'base case' - how the plant was operating to enable later 'before and after' comparisons to be made.

3. Prepare an opportunities list from findings. Collect 'wish lists'. Discuss your ideas with operators as well as management. Look for the 'low hanging fruit' - the easy to obtain benefits to establish your credibility. Don't worry at this stage about how you are going to solve the problem. There is always a way.

4. Quantify the benefits. Look at recent representative period of operation. Look at the frequency distribution of key variables. Some simple statistical ideas can help quantify the likely benefits. Draw on your own and operators' experiences.

5. Identify potential projects. Make the case for funding.

Once you have convinced yourself of the benefits of improved control, you will need to convince your management. This is unlikely to be easy in the face of competing priorities and projects. And you should expect management to give those proposing projects a hard time to test their conviction. Once management accepts the case, however, work should go forward speedily. The EEBPP can help you with making the business case.

Process Diagnostics

Many of the benefits we see on complex plant have been due to the development of advanced control methods, which capitalise on the power of modern distributed control systems (DCS). Without these advanced control techniques, DCS could only contribute a fraction of the total potential.

Until recently there has been no parallel development of advanced diagnostic tools able to extract information and knowledge from the massive amounts of data routinely collected in industry. Indeed, modern control systems very effectively compensate for disturbances and changes in the process - it's what they are designed to do. However, this can hide from operating personnel progressive changes in the plant or the product, masking problems which could be corrected by timely action before product quality is affected or the plant breaks down.

Recent developments in multivariate techniques, such as principal components analysis and multivariate statistical process control (MSPC), are beginning to redress the balance. These 'parallel developments' of techniques effectively use the same plant data and are totally complementary. Each can provide immense benefit in operations and understanding the process. Indeed, the information gained from one approach can highlight the need to make changes using the other. Whether diagnostics will ever provide 'wisdom' must be a moot point but certainly information about and knowledge of the process is becoming available.

David Stockill, who used to be control and computing manager at Shell's Stanlow refinery in Cheshire, now manages the Statistics and Risk Consultancy with Shell Global Solutions. He believes that, although good process control is of critical importance, process diagnostics can also reduce energy consumption and help maximise profit. He thinks that the benefits are of the same magnitude to, and are additional to, what can be achieved by good control.

How to get help

Despite excellent evidence on the cost-effectiveness of investing in better control, there remains considerable scope for improvement throughout industry. A random survey of 100 large industrial sites covering a range of manufacturing, found that just five had a level of monitoring and control which could be classed as adequate for today's competitive environment.

The potential to do better is enormous.

Free advice and guidance on how to improve control are available from the Environment and Energy Helpline, telephone on 0800 585794 or visit the website at www.energy-efficiency.gov.uk. In addition, you can get further help and evidence of the successful application of improved control from the Energy Efficiency Best Practice Programme (EEBPP) literature.

These high-quality publications include good practice guides and case studies that cover a wide range of the process industries from food production, through energy generation, to heavy chemical manufacturing. They also contain practical advice and ideas to help sped you up the learning curve, so that you start to reap the benefits of control improvements quickly and cost-effectively.