Why are energy-from-waste (EfW) schemes so troublesome?

With contractors getting their fingers burnt on energy-from-waste projects, Roddy Wilkie, Partner and Head of Energy at HKA, explains why the UK, uniquely, is having such trouble, and urges the construction supply chain to learn the lessons, because the sector will only grow.

It is now (almost) universally accepted that our warming world needs alternatives both to burning fossil fuels and burying waste. Turning waste into energy may seem an ideal solution, but it’s not necessarily that simple.

Problems can occur on any construction project, large or small. As a string of widely reported delays, cost overruns, contractual disputes and even failed projects in the UK and elsewhere show, the waste-to-energy sector seems to suffer more than its fair share.

Energy can be recovered from various wastes and in a variety of ways. In anaerobic digestors, bacteria break down organic matter in the absence of oxygen, generating gas to be used as fuel for heat and power. Waste wood and chip can also be burnt as fuel. Both domestic waste (solid municipal waste) and trade waste can be processed to form a solid fuel burned in cement kilns as well as other industrial plants, again producing heat and power.

These feedstocks are relatively homogenous and consistent, unlike the raw waste stream from refuse collections. It is the energy-from-waste (EfW) plants burning the residual waste left after recyclables have been removed that pose the greater technical challenges for the waste management sector, and it seems, engineering and construction.

Profits up in smoke

The generation of electricity in EfW plants is well established across Europe and, within the last decade, the number of EfW plants in the UK has mushroomed to around 50. That pattern of experience partly explains the heavy losses racked up by some major British contractors and withdrawals from the sector after getting fingers burnt.

While continental contractors are well versed in the intricacies of EfW projects, some of their UK counterparts approached them like any other major construction scheme – a ‘kit in a shed’, as at least one complacent contractor has told a client. The reality is that a modern integrated waste management plant is essentially a process plant, or mini power station. Unlike other process plants, however, it has to deal with a feedstock that varies hugely in composition and calorific value.

Local authorities, as clients, require that plants accept all kinds of material delivered by their waste collection services within quite broad parameters. By contrast, emission control limits under the EU Industrial Emissions Directive make energy-from-waste one of the most tightly regulated industrial processes in Europe. This places significant risk on the shoulders of those who design, build and operate EfW facilities.

Under a design and build contract, the contractor will usually be liable contractually and commercially for the technical and operational risks. It is not uncommon for design phases to overrun, leading to extra design cost and often impacting the programme’s critical path, with knock-on effects on procurement, civils and M&E works. Additional costs, from design work and preliminaries to subcontractors, are unlikely to be recovered.

Naive novices

Main contractors have underestimated the complexity of waste projects, which require multiple subcontractors for major elements, from the boiler to turbine, piping to cabling and insulation. A rigorous procurement process is essential to assemble a team of proficient specialist contractors.

On some more recent projects, new players in the EfW sector have suffered from a lack of specialist expertise in-house.

Reliance on a workforce without the necessary skills, know-how or commitment can compromise outcomes from design through construction. And commercial teams themselves are often transient, which can undermine the quality of record-keeping and severely weaken any prospect of commercial recovery in a dispute.

The moving-grate technology used in the vast majority of many EfW plants has proven reasonably effective, subject to acceptable tolerances in design and installation. However, some waste plants are complicated, perhaps overly so, by local authority clients. Incorporating other technologies – such as composting, gas production and refuse-derived fuel – makes these multi-faceted facilities more politically marketable to communities, at the cost of even more complexity.

Alternative technologies such as gasification and pyrolysis are still described as ‘emerging’ despite the completion of a series of different designs across the UK and Europe in recent years. Gasification involves thermal treatment of waste in an environment with little or no oxygen to produce ‘syngas’, which can be burnt as fuel. So far, the nearest success stories for gasification are in Japan, where the technology is reported to be working well.

While continental contractors are well versed in the intricacies of EfW projects, some of their UK counterparts approached them like any other major construction scheme – a ‘kit in a shed’, as one complacent contractor told a client.”
Roddy Wilkie, Partner, HKA
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