The impact of transitioning to renewable energy-from-waste projects – problems for UK designers

The energy-from-waste (EfW) sector is a fast growing industry in the UK but still lags behind continental Europe. This is largely due to the UK’s dependence on landfill and the fact that many of the UK’s early incinerators were disposal-only plants, which simply burned waste to reduce its volume. However, the introduction of landfill diversion targets in the mid-1990’s helped drive a new generation of EfW plants, designed to meet new strict emissions standards and provide low carbon energy. Whilst EfW is only partially renewable due to the presence of fossil based carbon in the waste, the industry has developed sophisticated processes to recycle and recover energy from residual (non-recyclable) household waste which would previously have ended up in landfill sites.

Currently, the EfW sector contributes less than 10% of energy to the grid. However, predictions indicate that the number of EfW plants in the next decade will double which will significantly reduce the greenhouse gases (as a result of methane generation when waste is buried in landfill). As such, it is another valuable contribution to the circular economy.

Whilst we have seen around 50 EfW projects in the UK over the last decade, they remain challenging and high risk for civil engineering and building designers. Indeed, there have been a number of high profile delays, cost overruns, and disputes, with a number of well-known UK contractors exiting the sector altogether having reported hundreds of millions of pounds worth of losses on failed EfW projects.

The primary design issue for EfW facilities is the process plant design, manufacture and installation. The process plant is the mechanical equipment and the associated electrical and control equipment, which:

• Receives, mixes, transports and incinerates the domestic waste
• Generates electricity and provides heat as a by-product
• Deals with the incinerator ash which is left over after combustion.

Therefore, the building design and civil and structural engineering design are an important but secondary design consideration, and the technical requirements for the civil and structural engineering design depend to a large extent on the design and requirements of the mechanical plant and associated equipment. And that is where the problem often lies for the building designer whose design is dominated by the process plant design (commonly carried out by highly specialist manufacturing companies, often based overseas) and so outside of its control.

This can cause real problems, particularly for contractors who have entered into contractual arrangements and agreed construction programmes without fully appreciating that their ability to comply with contractual terms and deadlines is contingent on receiving accurate data about the process plant.

Without accurate information at an early stage, the designer (often through no real fault of its own) can be left second guessing aspects of the process plant, which critically impacts on the building layout and loading design. As EfW facilities are bespoke to the site and local area which they are servicing, second guessing these critical design elements is not always straightforward. This, in turn, can result in major changes and delays later on down the line when accurate information about the process plant is finally forthcoming.

In order to guard against these risks, contractors and designers should ensure that the process plant and building design are fully aligned and, ideally, the performance of their services should be linked to satisfactory and timely information about the process plant design. Contractors should try to maintain control over the process plant design, and they should approach pricing and procurement more realistically, with less reliance on information from previous projects and more emphasis on the specific project in hand.

There is evidence that recycling rates in the UK have slowed down over the last few years as a result of cuts to local authority budgets, and the absence of sufficient demand for recyclable materials at a price which makes is economic to collect and sort to the required standard. If this stagnated recycling trend continues then there will be more waste to deal with and an increased demand for incineration and EfW facilities in the UK.

EfW will play an important role in the future. Whilst this will present potentially lucrative opportunities to UK based construction companies, if professionals and/or design and construct contractors continue to underestimate the complexities involved in the building design, professional indemnity insurers may find themselves facing an increased number of significant claims in the EfW sector.

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Related item: EU Directive on renewable energy: new opportunities in the construction sector across Europe