The U.K. water industry leads the way to net zero

The race to global net zero emissions is on. The world must drastically reduce its greenhouse gas emissions and balance the unavoidable ones by carbon sequestration.

The United Kingdom has committed to international climate agreements and has gone the extra mile and made net-zero emissions by 2050 legally binding, holding the government fully accountable for reaching this target in the 27 years that remain.

But many argue that the U.K. (and in fact, most of the rest of the world) is falling behind, with many industries infamously finding obfuscated ways of resisting change, with some exceptions.

The U.K. water industry is one of them, having boldly committed to achieving net zero emissions by 2030, a full twenty years earlier than required.

In this article, we take a closer look at the water industry’s emissions and how two of the U.K.’s largest water companies are taking on this mammoth task in innovative ways.

Emissions in the water industry

There are two main sources of emissions for providing nationwide water services.

Treating wastewater

Sewage treatment plants rely on bacteria to break down the biological material. Using bacteria to effectively eat human feces is efficient, but it does emit three gasses that are global warming contributors:

• Carbon dioxide (CO₂)
• Methane (which has 23x global warming potential of CO₂)
• Nitrous oxide (which has 296x the global warming potential of CO₂)

Pumping water

The British water industry has one of the most elaborate water distribution networks in the world, covering nearly 400,000 miles and connecting over 50 million properties.

The water inside these pipes must be pressurized to 30-60 psi to give it the potential energy it needs to get to homes and flow out of taps.

In mountainous or hilly terrain, pressuring hundreds of thousands of miles of pipes can be done with gravity alone — but, in the largely flat lands of the U.K., energy-consuming pumping stations are required.

3% of the UK's electricity consumption goes into powering this low-key infrastructure, which is a significant source of emissions since gas-powered stations will still be operational for another decade or so.

Relatively small emissions, but pervasive

However, the water industry’s emissions pale in comparison to transportation and energy.

The 0.6% share of national emissions is still equivalent to the contributions of a typical 1GW gas-fired power station, such as Spalding and Peterhead, so net-zero emissions in the water industry is equivalent to removing one of these.

Another thing to bear in mind is that water use is pervasive, and consumer and business water habits largely affect the amount of water that needs pumping and treating. Reducing the emissions of clean water decreases everyone’s individual footprint.

The water industry’s road to net zero emissions

The water industry is the only large-scale industry in the country with an ambitious, coordinated net zero goal, and will be the first major sector to achieve its climate aims early on.

Being a recently privatized sector, this coordinated goal is a chance for water companies to regain some of their reputation that was recently tarnished with sewage and water scarcity scandals during the summer droughts of 2022.

To illustrate this transformation of the water industry, this article will look at what is being done by two of the major water providers: Severn Trent Water and Thames Water.

Severn Trent Water

As one of the largest water companies in the U.K., Severn Trent Water is one of the proponents of the 2030 net-zero plan.

The company has come up with a master plan that includes installing greywater systems, powering water treatment with renewables, and leveraging smart meter technology and big data analytics to improve water management at all levels.

Greywater Systems

The lack of differentiation of wastewater is an Achilles heel in the industry. Treatment for toilets’ wastewater is very different from that of rainwater runoff or the wastewater from washing machines, yet much of this unique treatment is not applied in practice.

Severn Trent water plans to reduce non-household demand for fully processed mains water by 4 million liters per day simply by facilitating gray water usage in homes and businesses, and by building graywater-specific infrastructure.

Next-generation treatment plants

Water treatment methods have been improving dramatically over the last couple of decades.

Improvements in ceramic membranes, alternative disinfection technologies, active media filtration and wetland pre-treatment — which should increase the amount of carbon locked in by the ecosystem — have experienced massive cost reductions.

Severn Trent Water wants to upgrade their existing works with all of these technologies to reduce the emissions of the 65 million liters of water per day that could be processed by the refurbished facilities.

Smart water management

The country’s now ubiquitous smart meter devices can track water usage. Machine learning algorithms can use this data to detect anomalies such as leakages just by analyzing the water usage data.

At present, leaks may go unnoticed for months if not years, causing more water to be delivered than is necessary and leading to extra costs and emissions. This is particularly true for slow yet persistent leakage.

Together with the U.K. government, the company has been incentivizing smart meters for households and businesses, as well as offering cost-effective water-saving devices that can reduce water usage, and therefore emissions.

Thames Water

Thames Water is another mammoth of the U.K.water industry that is looking to aggressively decarbonize. The company has a significant local monopoly and provides water to more than 15 million people in England.

Since 1990, the company has reduced its emissions by one-third, despite dramatically increasing its user base during this time.

And, despite playing exactly the same role as Severn Trent, their decarbonization efforts have a different focus: floating solar and biogas production.

Floating solar energy

Thames Water was the first company in the U.K. to pioneer floating solar farms on one of its London reservoirs to produce renewable energy to power its water treatment plants.

The company took advantage of solar power tariffs available from the U.K. government to install 23,000 panels that are producing clean energy for its facilities since 2016, with any excess energy being sold back to the grid, bringing another source of income.

The government tariffs have since been axed, yet the decrease in the cost of solar panels means more solar panels will be installed at six new reservoirs, increasing renewable power output by 50%.

Biogas recycling

Sewage sludge is full of carbon-rich material, locked in a liquid/solid form.

Through its exposure to bacteria, sludge naturally decomposes into methane — a powerful greenhouse gas — through the process of anaerobic decomposition.

Preventing sewage from rotting is a difficult task and frankly impossible to completely avoid, so instead of fighting against avoiding it, Thames Water has chosen to extract the methane for usage instead of letting it seep into the atmosphere unused.

Methane is similar to natural gas and can be used to power its own sewage processing facilities in a circular fashion, and any excess can be used to heat 2,000 homes adjacent to the area.

Conclusion

Water businesses in the U.K. are certainly putting their money where their mouth is, and the wheels of change have been turning for many years now.

The industry’s spearheading of decarbonization has significant consequences for the carbon inventories of the whole nation, and will put all businesses in the U.K. in a better position when it comes to offsetting their own emissions.

No one can be sure of how stringent carbon accounting will become in the future, but net-zero water is strategically a smart thing to do, especially considering the carbon squeeze that is expected this decade.