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Government legislation and pressure on local-authority waste management strategies have, in recent years, led to the growth of the energy-from-waste industry, according to Siemens Industry Automation.

Simon Ellam from Siemens looks at some of the market drivers and issues facing plant controllers and operators.

He claims that only an integrated approach to control systems at the initial design stage can deliver real operational efficiency and drive shareholder value from plants that will be in use for 25 years.

A major emerging industry in the UK over the last five years has been the energy-from-waste market.

This form of renewable-energy generation has been driven by the government’s Renewables Obligation (RO), which has been imposed on the UK electricity industry and requires that up to 15.4 per cent of the electricity that energy suppliers generate must be from renewable sources by 2015.

Adding to this, industry growth has also been fuelled by the issue of local-authority waste management obligations and how they best tackle their legislative commitments.

The incineration of waste to generate power is becoming more commonplace across the country as local authorities try to fulfil their side of the Landfill Directive, which involves diverting waste away from straightforward landfill disposal.

At a time of financial pressures on local governments everywhere, avoiding hefty fines in this area is of paramount concern.

‘Energy from waste’ is a broad title covering a number of different and diverse process technologies, such as gasification, pyrolysis, anaerobic digestion and a number of other emerging technologies, which are generally at the heart of a number of package plant deliverables such as material handling and treatment infrastructure.

This modular approach can often pose a challenge for contractors, EPCs and the energy-from-waste plant operators who are looking to engineer a coherent control system that will allow the consistent and efficient running of the complete plant.

The challenge of coordinating how package plant is controlled and bringing a degree of standardisation across the different deliverables falls mainly to the EPC or main contractor involved.

Increasingly, however, the end customer or plant operator involved is not prepared to accept a disparate control strategy as they typically have to live with this for the 25-year-plus asset life of the plant.

The answer lies in the provision of a standardised approach to technologies that incorporates open standards and protocols.

This solution underpins the task of engineering and connecting ‘islands of automation’ together.

The hardware aspect is the most obvious, but only the first benefit of having a standardised approach to engineering.

Process automation comprises a number of control-system solutions, including distributed control systems (DCSs), programmable logic controllers (PLCs) and fieldbus networking along with all the peripheral equipment, such as motor control and instrumentation that allow these control systems to provide the optimal control of a customer’s assets.

The key aspect of such a broad portfolio of potential solutions for energy from waste is the ability to offer sound engineering advice that fits the many and varied technical and organisational models that have emerged within this market over recent years.

A good example of this is the growth in ‘PFI’-style contracts as local councils seek to outsource the design, manufacture and operation of a plant on their behalf for 25 years.

This type of project is typically contracted to a consortium or an alliance of suppliers with the combination of requisite skills from initial design to decommissioning.

In this type of contract, there is an increasing focus on efficiently integrating the various elements of ‘packaged plant’ while combining this with a longer-term view of optimising operational costs over the ownership period.

This can be crucial in determining the difference between a long-term contract being profitable or not.

With this in mind, the second and most important phase of standardising the process solution in an energy-from-waste plant is to achieve the same look and feel of application or operational display that the operator uses to monitor and control the plant.

This allows operators to gain a quick and intuitive understanding of how to control the plant and if a co-ordinated approach has been achieved in the design and build phase the operator will not need to manage different skill sets to operate different areas of plant.

This standardised approach brings operational savings and allows the flexibility of operators and shifts to be applied to different roles without upheaval.

For the enterprises that will go on to operate these plants, the importance of the control system to influence shareholder value should not be underestimated.

The major factors that will have an impact on business value at a simplistic level are labour costs, consumable/energy costs, asset utilisation and environmental/regulatory constraints.

A poorly conceived plant control system will create complexity, leading to increased labour requirements and dependence on higher-skilled labour, reduced plant control and flexibility leading to higher consumable/energy costs and poor asset utilisation.

Generally, the contractual relationship between the owner/operator of these plants and their end customer is tied into their ability to serve (waste that cannot be processed is likely to go to landfill at a heavy cost) and to comply environmentally (heavy fines will be levied for non-compliance).

This requires the site control system to offer a high level of availability and the ability to constantly monitor and adjust/optimise the process to give the lowest running costs, while achieving environmental compliance targets.

There is no doubt that the energy-from-waste market is proving to be more sophisticated in its ability to drive for profitable operation.

Capital procurement processes have traditionally associated lower importance with automation and control equipment as this forms a small proportion of the overall costs of capital equipment and construction work.

However, most contractors taking on design, build and operate contracts, such as those found in the energy-from-waste market, are now attaching much higher importance to this category of supply.

This approach can mean the difference between a long-term success and a long-term sentence, according to Ellam.

Siemens Automation and Drives

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