How have you worked out the Project’s carbon impact?

The net carbon impact of the Energy Recovery Facility (ERF) is expected to be 28,000 tonnes of carbon dioxide equivalents each year under current assessments. This calculation has been developed using the scientific standards set by the Intergovernmental Panel on Climate Change (IPCC) (Guidelines for National Greenhouse Gas Inventories – 2006) and the UK’s Department for Environment, Food and Rural Affairs (Energy Recovery for Residual Waste – A carbon-based modelling approach – February 2014).

In 2019, a Carbon Impact Screening report was produced for the North London Waste Authority (NLWA) by Ramboll, a world leading thermal engineering company, to compare the carbon impact of the new Energy Recovery Facility (ERF) to the alternative of sending non-recyclable waste to landfill. It was prepared in line with the standards set by the IPCC, in which guidance states that biogenic waste (like food, paper and wood) should not be included in national emission inventories for greenhouse gasses. This is because plants sequester carbon when they grow, taking the carbon in and storing it. 

IPCC guidance states that biogenic waste (like food, paper and wood) should not be included in greenhouse gas emission calculations because plants sequester, absorb and retain, carbon as they grow. The carbon impact screening can be viewed here.

In line with this guidance, the report divides household waste into fossil content (e.g. plastics) and biogenic content. It is expected that around 55% of the waste treated by the new ERF will be biogenic and 45% fossil.

Following IPCC standards, only the fossil content is included when calculating greenhouse gas emissions. The report shows that the fossil content from north London’s residual waste is expected to have an impact equivalent to 308,560 tonnes of carbon dioxide each year.

To establish the effective realistic carbon impact of the NLHPP, it is vital to consider the displacement of heat and power generated by other energy sources. The report follows the standard set by DEFRA for carbon intensity modelling, which is clear that a combined cycle gas turbine power plant is the appropriate counterfactual for assessing energy generated by an ERF.

In addition to displacing power plants that use virgin fossil fuels, the ERF will recover metals from residual waste for recycling. This will avoid the carbon-intensive process of extracting virgin metals from the ground.

Following this scientific methodology, the net CO2 emissions from the new ERF are predicted to be equivalent to 28,000 tonnes of carbon dioxide every year as a greenhouse gas emission under current assessments.

Sending the same amount of waste to landfill would generate 215,000 additional tonnes of carbon dioxide equivalents every year. That is the same carbon impact as putting 110,000 extra cars on the road. Though not intended to be a lifetime assessment for the facility, this methodology finds the carbon impact as the facility becomes operational. 

Landfill produces significantly more greenhouse gasses than energy recovery because a) methane is an extremely potent greenhouse gas, and b) thousands of additional lorry movements would be required to transport the waste outside of north London.

The new ERF is therefore part of the solution for tackling the Climate Emergency and minimising the carbon impact of north London’s waste.