The engineering firm behind Veolia and Covanta’s plans for an energy from waste plant in Bedfordshire has told the Environment Agency that the technology proposed is better on climate change and efficiency grounds than gasification processes.
Favouring a traditional moving grate furnace approach to the facility, the engineers have explained why this has been preferred rather than alternatives such as gasification. The explanation is contained within the documents for an environment permit application to the Agency for the project.
An artist’s impression of the proposed Rookery Pit plant
The current consultation is over the request for an environmental permit for a 585,000 tonnes EfW plant planned for the Rookery South Pit site in the Central Bedfordshire council area. The development was originally proposed by American firm Covanta which has now joined forces with Veolia to develop the facility under a “Project Development Agreement”.
The consultation started earlier this month and closes on 18 April 2017 and will help the Agency to decide whether or not the facility should be granted an environmental permit. Rookery South has already had planning support from government.
Few details have been disclosed by Veolia as to where the municipal and commercial and industrial waste for the plant will come from. However, the permit application says: “The waste will be delivered from the local area in Refuse Collection Vehicles (RCVs) and by Bulk Transfer Vehicles (BTVs).”
Combustion
Explaining the rationale behind the decision to use a traditional combustion technology approach, in supporting information for the permit, the engineers for the plant, Fichtner Consulting Engineers of Stockport, reflected on the different types of technology which could have been used.
They noted that “Various suppliers are developing pyrolysis and gasification systems for the disposal of municipal waste”. And, they explain that the systems can “theoretically” use gas engines or turbines which are more efficient that a standard steam turbine cycle. But, Fichtner warns that “the losses associated with making the syngas and the additional electricity consumption of the site mean that the overall efficiency is no higher than for a combustion facility and is generally lower”.
And, the engineers then add: “This means that a combustion facility will have a more beneficial effect on climate change.”
Small scale
Fichtner also point out that gasification systems are modular in approach “and are only available for small-scale facilities. The Rookery South ERF would require at least 11 modules in order to achieve the required capacity.”
Gasification projects remain a subject of discussion within the UK waste sector. The UK’s first waste gasification project on the Isle of Wight suffered a number of difficulties and the giant Tees Valley 700,000 tonnes project started by Air Products was halted last year.
More recently, Viridor has been wrestling with some problems at its 200,000 tonnes per annum gasification project at Polmadie in Glasgow although these are thought to be close to being overcome. The delays prompted its contractor Interserve to leave the energy from waste market.
Attention will remain focused on other gasification projects although the companies involved are understood to be confident that lessons learnt from earlier gasification projects and modern technological development of the process will lead to success.
Projects reaching operational stage soon include a 55,000 tonne p.a. gasification facility by Suez for Surrey county council in Shepperton while Amey is developing a 93,000 tonnes p.a. plant in Milton Keynes which is due to be operational this spring.
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Source: letsrecycle.com Waste Managment
