Corporate Responsibility

Mitigating climate change.

Last reviewed:
We’re committed to reducing our contribution to climate change, and we aim to reduce our greenhouse gas emissions in support of the Climate Change Act 2008. Compared to 1990 levels of 845.8 kTCO2e, we’ve achieved a 27 per cent reduction in our gross emissions*. When the purchase of renewable grid electricity is taken into account, the net reduction in our greenhouse gas emissions emission was 67 per cent compared to 1990 levels*#. This reduction is against a backdrop of serving around 3 million more customers. 2017/18 was the first full year of using renewable grid electricity.

Thermal Hydrolysis Plant (THP) at Riverside sewage treatment works.
2016/17 2017/18
Gross emissions* 705.9kt CO2e 617.3kt CO2e
Net emissions *# 498.0kt CO2e 277.9kt CO2e

Different types of emissions. 

There are two distinct categories of greenhouse gas (GHG) emissions which affect our business the most:

  1. GHG emissions associated with the operation of our assets- these are under our control, so we’re taking action to reduce them by becoming more energy efficient, using less energy, enhancing our understanding of fugitive emissions and making our own renewable electricity.
  2. GHG emissions associated with the use of electricity taken from the national grid - we can directly affect the volume of electricity we consume, but overall de-carbonisation of grid electricity is achieved through government policy.

To sustain and improve on our 67 per cent reduction, we need to continue find ways to use less energy by being more efficient, making more of our own renewable energy, and continuing to invest in low carbon operational processes and assets.

Our renewable energy use.

Generating our own renewable energy helps mitigate against climate change and the amount of energy our operations need to use because of population growth and higher wastewater treatment standards.

In 2017/18, we produced 22.2 per cent (293GWh) of our own electricity needs from renewable sources including sludge treatment, wind and solar power. This reduces our greenhouse gas emissions and is the equivalent of £30 million a year in energy savings. We also produce and use renewable heat, which increased last year by 4 percent to 124.3GWh in 2017/18. When renewable heat is combined with our renewable electricity generation, we’re expecting our total generation of renewable energy to exceed 500 GWh by 2020.

We’re on track to deliver the 35 per cent reduction we’ve planned for our net amount of electricity we import from the grid by 2020. Despite this good progress, however, we don’t think we’ll reach our absolute target of 771 GWh, mainly due to starting from a higher level of usage at the beginning of this AMP than we expected.

When we’re not able to generate our own renewable electricity, we began sourcing renewable grid electricity# in October 2016. Last year 100 per cent of the grid electricity we consumed came from renewable sources. This contributed to significant reductions in greenhouse gases from both our water (69 per cent) and wastewater operations (33 per cent). When combined with our renewable self-generation, this means 100 per cent of the net electricity we consume is from renewable sources.


*Scope 1 emissions refer to greenhouse gas emissions associated with the operation of our assets. Scope 2 emissions are emissions associated with the use of grid electricity.

#From October 2016 our net operational emissions account for the grid electricity we imported being 100% REGO accredited renewable. We use the government’s REGO (renewable energy guarantee of origin) accreditation scheme to demonstrate that the electricity we consume is from a renewable source.