Is burning rubbish a sustainable landfill alternative?

By District Energy posted 08-12-2020 14:52

  

Institution of Mechanical Engineers

Summary

Perhaps unsurprisingly, the country has one of the cleanest records in the world when it comes to this particular metric. The UK and France, by comparison, send a respective 28% and 22% of their collected refuse to landfill sites, where it releases methane and pollutes groundwater as it breaks down. 

However, Sweden doesn’t strictly recycle the remaining 99% of its rubbish. It incinerates about half of it to generate heat and power across its 34 waste-to-energy (WtE) plants. 

Once the combustion process is complete, all that remains is ash, flue gas and heat – which is made into steam that drives a turbine to create electricity. The energy efficiency of modern incinerators varies widely, with most estimates falling somewhere between 15% and 30%. These figures improve drastically when the residual heat in exhaust steam is captured and distributed to households via district heating networks. More than one million Swedish homes are kept warm thanks to the country’s comprehensive rubbish incineration and heat recovery schemes.   

In an era when public concern about pollution – especially the plastic variety – has reached an all-time high, incinerators appear to provide a practical alternative to landfill disposal. But critics point out that the facilities are no panacea when it comes to the separate, albeit related, fight against climate change. The level of carbon dioxide emitted through the combustion of one tonne of waste depends on what the waste is made up of. If plastics (themselves made from fossil fuels) dominate, then the CO2 emissions from incinerators can be higher than from traditional gas-fired power stations. 

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