Energy management: providing the key to a green and profitable future

The current increasing pressure on industry to clean up environmental performance is regarded by many as a direct conflict with one of industry’s primary goals - management of operational costs in order to increase profitability. Improving environmental performance is commonly believed to require expensive and largely unrecoverable costs. But this need not be the case.

Manufacturing processes have, for the most part, evolved over time as the easiest and cheapest way to fabricate a product. Yet a great many industrial processes have their roots in an age of cheap energy - a time when the energy efficiency of a production line might have been the least important factor in the process design. Today, as industry faces increasing energy costs, reducing energy usage can therefore fulfil the goals of both industry’s bottom line and environmental policy simultaneously.

Industry need not make the mistake of distancing itself from environmental performance as a lesser issue. The simple fact exists that reducing energy use will reduce a company’s environmental impact. Any investment which reduces energy usage will also reduce operating costs, and therefore will have an associated payback. If the capital investment produces a payback within a short timeframe - with ongoing operational savings to be enjoyed thereafter - then environmental responsibility begins to assume the patina of economic commonsense.

Drivers for change

Power and energy management’ (PEM) is an umbrella term that covers a range of initiatives designed to reduce industrial power consumption and the associated carbon footprint. The drivers for PEM initiatives are numerous; but at the current time, the principal driver for Australia and New Zealand is legislation, devised to meet global environmental concerns.

The principal energy conservation legislation in New Zealand is the New Zealand Energy Efficiency and Conservation Act 2000. From this, the New Zealand Energy Efficiency and Conservation Strategy 2006 has been developed to provide a framework for implementation of the Act. Although six years ahead of Australia, New Zealand’s legislation and strategies have resulted in fewer energy initiatives than in Australia to date - a situation commensurate with New Zealand’s greater reliance on renewable resources, and the fact that industrial users are not currently penalised for high energy usage. A proposed emissions trading scheme (ETS) is still under discussion in New Zealand.

Australia’s first legislation aimed at promoting energy efficiency was the Energy Efficiency Opportunities Program 2006. This required that all companies using in excess of 0.5 PJ of energy annually begin monitoring their energy consumption by July 2008. The National Greenhouse and Energy Reporting (NGER) Act 2007 tightens this threshold to oblige individual facilities using more than 0.1 PJ of energy (or corporations using more than 0.5 PJ collectively across all their sites) per year to begin reporting their usage by August 2009. This latter Act further introduces a supplementary focus relating to greenhouse gas emissions. Any facility producing more than 25 kT (or corporation producing more than 125 kT) of greenhouse gases per year similarly needs to begin reporting its emissions by August 2009.

This legislation is designed to get Australia’s industry monitoring and measuring energy usage and emissions in preparation for the proposed carbon trading scheme, scheduled for implementation in 2011. The message they deliver is clear: use too much energy, or produce too many emissions, and you will be penalised. As a driver for PEM implementations, legislation is crucial to help industry overcome its inherent ‘environmental inertia’ and take the first steps to energy reduction.

Site-specific drivers for implementing PEM programs centre on optimising the cost efficiency per unit of production. A prime focus is cost allocation. Many facilities know how much energy is coming into the plant, but they do not know how much energy each process or department is using. Measuring, monitoring and reporting, as required by legislation, help create awareness and thus enable the allocation of accountability for energy used by individual departments, processes and machines. Reducing the cost of collecting and interpreting this data also becomes an important driver in its own right towards the implementation of PEM initiatives.

Environmental considerations themselves are a direct - albeit lesser - driver for PEM, and tend to be interwoven with the social perception of a company held by its customers and trading partners. Traditional bottom-line accounting has now given way to the concept of ‘triple-bottom-line’ accounting, which gives equal weight to financial, environmental and social performance. Environmental performance is increasingly becoming a product differentiator strategy, and companies like to be seen to be ‘green’ in order not to alienate their customer base; the marketing power of the ‘green label’ should be ignored by industry at its peril.

You can’t control what you don’t monitor PEM implementations can be broken down into three steps: monitor, analyse and control. Monitoring energy use is the fundamental first step, as you can’t control what you don’t monitor. All energy streams into the plant - water, air, gas, electricity and steam - need to be monitored and, for most companies, electrical and gas energy are the most significant. As a minimum, the incoming feeder and the feeders to the main distribution boards must be monitored. From there, monitoring can be taken to whatever level is desired - even down to machine level for energy-hungry processes. Once monitoring has been enabled, the data needs to be captured into a database to facilitate analysis. This will allow the identification of potential energy efficiency improvement opportunities, and facilitate their implementation.

Figure 1: Power monitors should be used to monitor the incoming feeder and the feeders to the main distribution boards as a minimum, but can be used down to machine level for energy-hungry processes.

Until control measures are implemented, there is little scope for payback. The cost of monitoring and analysis need not necessarily be prohibitive, however, as two different approaches can be employed: continuous monitoring or a ‘campaign policy’.

Continuous monitoring involves the permanent installation of monitoring devices in key areas and is the preferable approach, especially for larger processes or pieces of equipment. Once installed, these monitoring devices will provide continuous near-real-time data collection. A campaign policy, by contrast, involves the installation of temporary monitoring equipment. This can provide a useful initial strategy in order to determine which areas require continuous monitoring. It can also prove useful as a periodic check on smaller processes or equipment that does not warrant its own permanent sensor, and can be effectively employed in parallel with continuous monitoring.

Implementing efficiency improvements

With the data collected and analysed, target areas for improvement can be identified. The possible control measures that can be taken are numerous, but a certain hierarchy exists to the order in which they should be prioritised. Much of the choice of measurement comes down to a simple cost analysis of the expected payback.

It makes sense to begin with the simple, low-cost, commonsense measures, such as switching off equipment not being used, either manually or by more sophisticated automatic measures. Often, simple changes in operating procedures can result in impressive savings. For example, sensors can be used to detect if a conveyor is running empty and can be turned off, or with the use of variable speed drives slowed down to accommodate varying loading rates.

Power providers often promote demand-side management (DSM) for large industrial consumers, by using the incentive of different tariff bands. DSM helps smooth out a facility’s power demand, ironing out energy demand ‘spikes’ and rendering their power demands more predictable. While not reducing overall power consumption, such measures can still reduce costs by helping ensure the facility stays within a lower tariff band. More importantly, DSM better enables the power provider to more accurately anticipate the user’s requirements, improving the power quality experienced by the site, due to a more predictable match between electricity demand and supply. DSM will reduce the frequency of power outages and processes tripping out that otherwise result in costly machine downtime, equipment damage, time-consuming resetting of processes, loss of product and subsequent knock-on effects further down the production line.

From a user’s perspective, simple measures such as sequencing out plant start-ups, moving power-hungry processes to off-peak tariff periods and the use of soft-start motors can help keep a plant in a lower tariff band and reduce costs.

With motor systems accounting for 63% of industrial energy usage, replacing existing motors with high-efficiency units and upgrading to modern control systems will result in significant energy reductions. The capital cost of any motor is often a small proportion of the overall cost incurred during its lifetime, as they typically consume an energy cost equivalent to their purchase price within two years of operation. The additional capital cost of a high-efficiency motor can soon be offset by the three to five per!!0x00A0!!cent increases in energy efficiency during operation.

Moving one stage further, the greatest efficiencies can be realised through the implementation of integration and smart controls. Individual machines should not be seen as standalone entities, but rather more as an integral part of an entire process. By applying integrated control and information systems across a process, utilising energy-efficient equipment with soft starts and variable speed drives, huge improvements in efficiency can be made.

Modern plants have been moving progressively towards information-enabled systems. It is a short step to link in production control systems with integrated networks, and the next intuitive step is to link in energy use. By these means, physical energy costs can be directly equated to production rates, with improvements measurable per unit of output over time.

Preparing for 2011 and beyond

Implementing such measures in one particular steel plant, for example, resulted in energy savings of 41%, and production delay reductions of 78%. Overall energy savings of 15% across all industries is a realistic figure, with 30% savings attainable for most manufacturing plants.

These savings are not achievable overnight, however. Most plants will begin with a campaign policy to evaluate where they need continuous monitoring. Once this is established, they will analyse their findings and effect the necessary changes to the biggest energy users in their facility. Down the line, some of the less energy-hungry processes can be revisited and changes effected there too. As the cycle continues, more and more areas of the plant will be provided with continuous monitoring, and more incremental savings will be made from more of the equipment.

The process is not dissimilar to what the legislation is trying to achieve at a national level in Australia. The legislation in its current form is aiming to target the top 250 companies, which collectively account for 60% of the nation’s industrial energy use. The future of the legislation is not entirely clear, but it is obvious that the usage/emission thresholds will continue to be reduced in order to encompass more companies as time goes on. Whatever form carbon trading takes from 2011 onwards, all companies would be well advised to have a plan to reduce their consumption and emissions. This will not go away.

The interim period until carbon trading takes effect in 2011 is an ideal opportunity for companies to lay the foundations for energy-use reduction. A business that begins addressing these issues ahead of 2011 will be doing itself many favours. Implementing PEMS initiatives will not only reduce a company’s operational costs in the short term, but it will also be minimising the penalties it will face after 2011. This will give it enormous competitive advantages in the market once carbon trading takes effect.

Author Corrie F Jansen van Rensburg is Rockwell Automation Industry Solutions Business Manager, South Pacific Region.

Rockwell Automation
www.rockwellautomation.com.au