Peterborough energy from waste facility: Why 'traditional' works

Written by: RWW | Published:

There is a view, and to some extent misconception, that the development of small scale energy from waste schemes, say 120,000 tonnes per annum and below, can only be done using advanced thermal treatment technologies, instead of what is termed ‘traditional’ energy from waste technology. Simon Allin at Babcock & Wilcox reports.

This article considers three key aspects when it comes to considering the merits of using traditional energy from waste technologies in small scale EfW schemes. These are as follows:

- The delivery of a viable small scale energy from waste facility in Peterborough based on ‘traditional’ technology

- The future of small scale energy from waste schemes in the UK

- Whether traditional energy from waste technology can be considered ATT.

Firstly, below are key facts about Peterborough's energy from waste facility:

- Capacity 85,000 tonnes per annum

- Procured by Peterborough City through the competitive dialogue process

- Electricity only but CHP being developed

- Being delivered under an EPC/Turnkey contract for Viridor - Peterborough City Council’s waste partner for next 30 years

- R1 value of 0.77 and therefore classed as recovery

- Currently under construction.

Why is the Peterborough scheme viable?

This is down to two key factors. 

Firstly, Peterborough City Council is a forward looking and commercially minded authority, and secondly, robust, proven, and bankable technology was selected. 

In addition, it is also worth noting that the project has no reliance on the ever changing renewable energy subsidy regime.

Considering each of the key factors in turn, Peterborough City Council took an active role in the project from day one. This comprises:

Funding route: The council used prudential borrowing to fund the project. This has been successfully used on other procurement projects and avoids direct interface with banks.

Secured planning: Before the procurement process started, the authority secured planning for the facility. This is a very positive step, since a number of other long term waste treatment projects have been delayed due to issues in securing planning e.g. Gloucestershire and Derbyshire.

Ownership of electricity: Peterborough City Council has taken ownership of the electricity produced by the plant. 

This is a very commercial approach at a time when councils have to be a lot more commercial in their thinking due to on-going spending cuts. It also allowed robust pricing of the electricity going forward. 

Part of the local green energy mix: Peterborough City Council have their own energy company, Blue Sky Peterborough Ltd, and, as such, the EfW facility was seen as part of their energy portfolio, and the local green energy mix, which includes wind and solar projects.

Linked to the above, was the selection of a robust, proven, and bankable technology, as supplied by Babcock & Wilcox Volund. 

‘Robust, proven and bankable’ are well worn terms, but absolutely relevant to treating residual waste, when there have been a number of failures when ‘emerging’ and unproven technologies have been used. 

What the technology gave

The benefits from on-going research and development: There is a perception that tried and tested energy from waste technology has stood still. In fact nothing could be further from the truth. Companies like Babcock and Wilcox Volund have a dedicated programme to continuously improve their technology and associated outputs. 

Therefore, through the bespoke design developed specifically for the Peterborough scheme, high performance will be achieved underpinned by warranties and guaranties. 

For example, the plant will operate at a high gross and net electrical efficiency, being  >29% and 27% respectively, alongside greater availability, lower emissions, longer time between major stops (at least 18 months), reduced operation and maintenance costs, etc.

Fuel flexibility: Noting the long term nature of energy from waste projects, the ever changing characteristics of the waste stream, and the potential need to ‘play the market’ to secure sufficient waste for a facility, fuel flexibility is a critical element of any project. 

This was achieved at Peterborough through the use of a patented, advanced grate design, developed through the ongoing development of the technology, which has the following advantages:

It can handle a wide range of CV values: secures the future

No need to pre-treat waste with associated cost savings

It is robust in its design to handle a range of waste streams, including residual waste which is very abrasive and corrosive. In other words a difficult fuel.

The future of ‘small scale’ waste to energy schemes in the UK

There is a general view that as the large scale local authority procurement projects are coming to an end - North London notwithstanding - the way forward for EfW will be to develop smaller scale local energy from waste schemes. This will be driven by a number of factors as follows:

Development of PFI infrastructure: Once the construction programme has been completed, there will be gaps in the infrastructure to cater for residual waste, especially industrial and commercial waste, noting we still send circa 30 million tonnes per annum to landfill.

Refuse derived fuel going abroad: In 2013, the UK exported over 1.5m tonnes per annum of RDF to countries like Holland and Germany. 

There is an on-going debate as to how long this can last, but logic dictates that this is not sustainable, and it is expected that the existing spare capacity will come under pressure from other countries in Europe, especially Eastern Europe, as they seek alternatives to landfill. 

Furthermore, noting the on-going discussion in the UK about the circular economy, surely we should be supporting meeting our own energy needs here?

Residual commercial and industrial waste: How much actually exists? A good question. 

Interestingly in Scandinavia, when EfW schemes are developed, typically 30-50% of the capacity will be taken up by commercial and industrial waste. 

In the UK, when schemes have been developed under the private finance initiative (PFI) regime, the approach has often been to minimise the amount of merchant capacity as far as possible. Therefore, there will be a need to develop facilities to service this waste stream, noting the amount of waste we are still sending to landfill. 

Furthermore, recycling and resource management is a challenging proposition, especially when we have a limited number of processing facilities in the UK, and we are operating in a global market when selling materials. 

As a consequence, a number of companies are now considering that the development of a small scale EfW scheme, can give closed loop in-house treatment and more revenue and profit certainty going forward, and avoids the roller coaster ride of playing the recyclate market. 

Local authorities with smaller tonnages: Although the large scale procurement projects are coming to an end, there are still a number of authorities with smaller tonnages, who are looking for a waste treatment solution. 

As such, they need to look no further than the Peterborough model.

Combined heat and power and heat plans: In addition to the above factors, the on-going interest in developing CHP schemes for new developments, and by existing industrial sites, the latter being driven by factors such as energy security, making savings, and managing their own waste streams, will continue to be a growing development area. 

Furthermore, there is a significant amount of work being done to develop heat plans in a number of our major conurbations.

Fuel strategy: This is absolutely critical especially to funders. As such, there are a number of examples of renewable energy schemes in the UK that have failed because their fuel strategy has not stood up to scrutiny. 

The ability to secure the fuel and hence supply contracts will depend on key elements such as having flexibility within the plant to mix waste streams and to have as wide a fuel market as possible. Indeed, small scale is the way forward as plants will have to be sized accordingly to be able to ‘play the market’.

When considering what ‘advanced’ is, it is not simply a matter of electrical or thermal efficiency, but also wider considerations such as availability (proven and robust). As such, the answer to the question is, of course, it can.

Over the last 8-10 years, significant advances have been made, hence the performance of the facilities. For example, Babcock & Wilcox Volund are now designing renewable energy facilities with in excess of 30% gross electrical efficiency (27.5% net). This compares very favourably with gasification, and the current ETI demonstrator program, the aim being to investigate the development of small-scale energy schemes with a net efficiency of at least 25%. 

 

 


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