The challenge
The water industry currently accounts for five million tonnes of carbon dioxide emissions per year; that's almost one% of UK greenhouse gas emissions from 23 companies. In the face of the UK target to reduce greenhouse gases by 80% by 2050, the water sector has an important part to play in reducing carbon emissions.
However, the industry also needs to meet current environmental quality standards, and in some cases, higher water quality standards required by the EU Water Framework Directive (WFD). This presents a dual challenge, because increased water treatment is likely to result in increased carbon emissions.
Over 10 billion litres of sewage are produced every day in England and Wales. To treat this volume of sewage requires approximately 2,800 GWh of energy, equating to 1.7 million tonnes of greenhouse gas emissions. The electricity demand required to treat sewage is expected to increase in the future as the population grows, we adapt to climate change and continue to deliver environmental improvements.
Working with Water UK, Ofwat and Defra, we have led a research project to understand the challenges around water industry carbon reduction, develop the evidence and help inform future policy and regulation.
Findings
The 'Transforming wastewater treatment to reduce carbon emissions' report focused on strategies to reduce emissions from wastewater treatment. It explores:
- the emissions associated with current sewage treatment processes
- what impact WFD quality standards may have on these emissions
- the potential responses available to water companies and regulators
Without intervention, the Water Framework Directive (WFD) is likely to lead to more wastewater treatment in the UK, which could boost carbon dioxide emissions by over 110,000 tonnes a year. This is a small increase of 2.2%, compared to the water industry’s carbon footprint of five million tonnes a year. However, this increase will more than double emissions from some individual treatment plants that will need to carry out additional processes.
Options to offset this increase over the long–term do exist. Our report identifies five key strategies that the water industry and its partners could adopt to mitigate the carbon impact of the WFD.
We explored two of these five strategies in more detail, completing reports on the potential for increased renewable energy generation by the water industry, and the benefits of sustainable drainage systems (SuDS) in reducing the amount of storm water which needs treating at sewage works.
A final ‘think piece’ invited five academics to submit their vision for a low carbon water industry in 2050.
Related work
In July 2008 we published a review of the greenhouse gas implications of new water resource and demand management options, highlighting the five per cent contribution of domestic water use to the UK’s total annual carbon emissions. We followed up in 2009 with a more detailed study with the Energy Saving Trust showing the significant energy and carbon (and financial) savings achievable through water efficiency measures in new and existing homes.
