Utility Week

36 | OCTOBER 2021 | UTILITY WEEK Analysis Burning through Covid waste Stuart Stone hears from Veolia about how its energy recovery facilities are helping to dispose of the glut of healthcare waste generated by the pandemic – at a minimal carbon cost. A ccording to its latest figures, Veolia's ten energy recovery facilities (ERFs) take around 2.3 million tonnes of non- recyclable waste and convert it into electric- ity for more than 400,000 homes. These facilities are said to generate around 1.4TWh of electricity a year and have helped dispose of pandemic medical waste — such as used test kits and PPE — by han- dling a 15 per cent increase in orange-bagged clinical and infectious material. Veolia's chief operating officer – treat- ment, Donald Macphail, describes producing secure energy from such items as a "win-win situation" — generating greener electricity and heat, reducing landfill, and striving for greater sustainability. "As more baseload generators such as nuclear, coal and CCGTs retire, ERFs are set to play an increasingly important role in keeping the lights on during winter evenings and during days where wind generation is low," he says. "Future development will increase this importance and we are already advancing trials of the latest carbon capture technology, and taking another step towards a zero car- bon future." How do Veolia's ERFs work? During a recent demonstration, Veolia's ERFs delivered nearly 25 per cent more energy than wind power — at one stage produc- ing 111MWe versus total wind generation of 58MWe. According to Macphail, once recyclables have been removed, waste delivered to these plants is burnt in what he describes as "care- fully controlled conditions". "The heat from the combustion process is used to turn water into steam," he says. "The steam then pow- ers turbines to generate electricity for export to the national grid. "Hot water is recovered from the generat- ing process and can be used by connected district heating networks. The water used in the process is recycled." Macphail says ash from the process, known as incinerator bottom ash, contains gravel-like glass, brick, stone, concrete and ceramic remnants, and can be recycled into construction aggregate — replacing quarried material in asphalt and cement production. "The gases from the boiler are exten- sively cleaned including neutralising any acid gases, removing pollutants with 'acti- vated carbon' and capturing fine particles with a fabric filter," he continues. "The gas treatment residues are kept in enclosed stor- age on site and then disposed of safely at a licensed facility." Lowering healthcare's carbon footprint Expanding on the broader implications of Veolia's ERF demonstration versus wind power in July, Macphail says that creating more baseload electricity for the UK power network complements existing generation assets. "ERFs operate 24 hours a day and repre- sent a continuously available and resilient low carbon baseload energy source," he says. "Wind and solar power are good renew- able energy sources but their intermittent availability and varying output means there is a generating gap. "Electricity powers the modern world and daily life, from the Internet of Things to electric vehicles. With the decarbonisa- tion of heat in homes, a resilient electricity supply that has 24-hour consistent availa- bility is essential. The ability to export heat from ERFs also means that district heating schemes become more viable." Macphail adds that the pandemic has

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