Metrics and targets

Adaptation – delivering an improved service despite climate change

We have a number of key metrics and targets that demonstrate our capability of adapting to climate change and increasing the resilience of our service. These metrics and targets are focused on the corporate risks identified in our adaptation report that are most adversely impacted by climate change.

140 l/day

per capita consumption


reduction in supply interruptions


sludge treatment compliance

Water sufficiency

In order to release headroom in our water supply demand balance we have set short and long-term targets against key performance commitments. Our targets for reducing per capita consumption (how much customers use) and leakage will reduce the demand for water in all climate scenarios.

Per capita consumption: Household consumption has increased slightly over the last five years with the average person currently using around 140 litres per day. Our plan is to work with customers and stakeholders to reduce that figure to around 135 litres by 2025 and to around 115 litres by 2045. We have developed an AMP7 water efficiency programme, primarily aimed at reducing household consumption, and working with the non-household sector to drive water efficiency across the board.

Leakage: We have achieved our regulatory leakage target every year for 14 years. From 2015 to 2020, we have delivered a stable level of leakage and, by 2025, we plan to reduce leakage by 15 per cent. In the longer term, to 2045, we plan to reduce leakage by just over 40 per cent. In the last 12 months, we have installed around 44,000 noise monitoring devices (100,000 by 2025) to locate hidden leaks in the most challenging parts of our water network and enable overall reductions in leakage.

Water network failure

We have assessed our ability to maintain water supply to our customers, even in extreme weather events, and we have set improving targets for supply interruptions.

We have reduced interruptions to supply by nearly 40 per cent since 2015. Supported by Systems Thinking and the use of machine learning and artificial intelligence, we are targeting a further 50 per cent reduction by 2025, from a 2020 baseline.

Failure of the wastewater network

To reduce the impact of variations from future storm intensity and frequency on the performance of our wastewater network we are targeting significant reductions in sewer flooding.

We have set ourselves a target to reduce it by 20 per cent by 2025 and 70 per cent by 2045.

Failure to treat sludge

Climate change puts an additional strain on the treatment and recycling of sludge particularly with the flooding of farmland which is the outlet for recycled sludge (biosolids). By taking a Systems Thinking approach and managing our assets as a regional system we can mitigate for loss of treatment capacity by transporting the sludge to other treatment centres or by using capacity in the market.

To measure the success of this approach we set stringent targets for 100 per cent sludge treatment compliance with regulatory requirements and we have achieved this for five consecutive years.

In addition, and new for AMP7, we are targeting 100 per cent conformity to best practice requirements set out by the national Biosolids Assurance Scheme.

Failure to treat wastewater (exceedance of permits)

The impact on climate change can affect the wastewater treatment process in a number of ways: prolonged dry periods can lead to septicity and rivers to run low; high rainfall intensity can cause high flows to be passed through to treatment facilities, outfalls to block and river banks to erode.

We have managed this risk through our treatment compliance metric which assesses our wastewater treatment compliance against environmental permits. Having delivered a stable level of service over AMP6 we are joint industry leaders in the Environment Agency's Environmental Performance Assessment across AMP6 and achieved 4 star status for three consecutive years.

We are striving to meet 100 per cent level of compliance for this measure in AMP7.

Failure of wastewater assets (serious pollution)

Pollution incidents can occur when the sewer system becomes overwhelmed and it overflows into the nearby watercourse.

Despite the upward pressure from climate change, since 2012 we have achieved 37 per cent reduction in the total number of pollution incidents (category 1, 2 and 3) and an industry-leading position for serious pollution incidents (category 1 and 2).

We have set targets to reduce the number of pollution incidents by a further 27 per cent by the end of AMP7.

Key energy and carbon metrics 2019/20


reduction from our 2005/06 baseline

191 GWh

renewable energy generated – equivalent to 23.8 per cent of our electricity consumption


electricity consumption from renewable sources – 760.5 GWh

159,243 tCO2e

total greenhouse gas emissions

115,424 tCO2e

science-based target baseline (scope 1 and 2 net GHG emissions)

Our contribution to mitigating climate change – carbon and energy

Careful operational energy management and increasing renewable energy generation means we have achieved a further reduction of 8,613 tCO2e this year.

Our total greenhouse gas emissions for the financial year 2019/20 were 159,243 tCO2e, 73 per cent below the 2005/06 baseline.

This performance means we have outperformed our target to reduce our operational greenhouse gas emissions by 50 per cent from the 2005/06 baseline and to achieve a 60 per cent reduction by 2035.

We are now committing to achieve new medium and long-term science-based targets, based on the Paris Agreement's highest level of ambition, to limit global temperature rise to 1.5°C above pre-industrial levels.

2019/20 scope 1 and 2 net emissions, which were 115,424 tCO2e, will form the baseline for our science-based targets.

Reporting and assurance

We measure and report the greenhouse gases that result from all United Utilities' activities. We have used the financial control approach so our energy and greenhouse gas emissions reports are aligned with the consolidated financial statements for United Utilities Group PLC. This includes its subsidiaries listed in section A8 in A8 Subsidiaries and other group undertakings.

Our measurement and reporting is aligned to the GHG Protocol Corporate Accounting and Reporting Standard (2015) and the recommendations of the TCFD. We report as required under the Companies Act 2006 (Strategic Report and Directors' Reports) Regulations following the 2019 UK Government Environmental Reporting Guidelines: Including streamlined energy and carbon reporting guidance and our reporting is compliant with the international carbon reporting standard (ISO 14064, Part 1) and assured by the Certified Emissions Measurement and Reduction Scheme (CEMARS).

How we measure our greenhouse gas emissions

A carbon footprint is calculated by converting all emissions of Kyoto Protocol gases into a carbon dioxide equivalent (tCO2e). Emissions are categorised as direct, indirect or avoided emissions.

Direct emissions (scope 1 emissions) are those from activities we own or control including those from our treatment processes, company vehicles, burning of fossil fuels for heating and incineration of sewage sludge.

Indirect emissions, known as scope 2 and 3 emissions, result from operational activities we do not own or control. These include emissions produced as a consequence of electricity we purchase to power our treatment plants (scope 2) and other indirect emissions such as travel on company business (scope 3).

Avoided emissions are reductions from the purchase, or export, of renewable energy.

Gross emissions are the sum of all three scopes. Net emissions are the gross emissions minus reductions from avoided emissions.

The GHG Protocol recommends using two methods to quantify emissions – the 'location-based' method which uses average grid electricity emissions factors and the 'market-based' method which is specific to the actual electricity purchased. We report results using both methods and use the gross 'market-based' figure to report our headline emissions.

Greenhouse gas emissions by scope

United Utilities' greenhouse gas emissions

Current yearPrevious yearsBaseline Year
Scope 1 Direct emissions
Direct emissions from burning of fossil fuels17,12916,80914,32417,638
Process emissions from our treatment plants – including refrigerants84,04888,13691,456125,032
Transport: company owned or leased vehicles15,73914,40911,8037,514
Total Scope 1 Direct emissions116,916119,354117,583150,183
Scope 2 Energy indirect emissions
Grid electricity purchased – generationMarket-based(1)

Total Scope 2 Energy indirect emissions11,78918,503230,167357,660
Scope 3 Other indirect emissions
Business travel (public transport and private vehicles)2,1232,2362,5042,374
Emissions from sludge and process waste disposal27,41026,18623,04842,712
Grid electricity purchased – transmission and distributionMarket-based(1)

Total Scope 3 Other indirect emissions30,53829,99947,07278,174
GROSS GHG EMISSIONS(2)159,243167,856394,822586,017
Avoided emissions from renewable electricity exported(3,979)(3,434)(2,303)(1,597)
Avoided emissions from biomethane exported(9,302)(8,446)(8,577)
Avoided emissions from renewable electricity purchasedLocation-based(173,876)
Total avoided emissions(13,281)(11,880)(184,756)(1,597)
NET GHG EMISSIONS(3)145,962155,976210,066584,420

(1)Market-based figures for electricity purchased on a standard tariff have been calculated using specific emissions factors from published generator fuel mix disclosures.

(2)Operational emissions for 2005/06 and 2017/18 use the location-based method, 2018/19 and the current year use the market-based method.

(3)Emissions from our regulated business have been estimated using the Water Industry Carbon Accounting Workbook V13 2020 v3 which encompasses the UK Government GHG Conversion Factors for Company reporting 2019.

United Utilities' greenhouse gas emissions intensity

As in previous years we state our emissions as tonnes CO2e per £million revenue. We also report the metric tonnes CO2e per megalitre (using the location-based method) broken down by clean water and wastewater, as these are common metrics for our industry.

Current year
Gross emissions per £m revenuetCO2e85.792.3225.6
Net emissions per £m revenuetCO2e78.585.7121.0
Regulated emissions per megalitre of treated water
Regulated emissions per megalitre of sewage treated
Kg CO2e/Ml
Kg CO2e/Ml

Energy use, generation and export

Energy use
Other fuels(1)


Total energy use984.0975.8
Electricity purchased
Renewable Tariff
0g CO2e/kWh
Supplier Standard Tariff
289g CO2e/kWh




Total electricity purchased643.7661.2
Renewable energy generated


Total renewable energy generated190.8172.9
Renewable energy exported


Total renewable energy exported32.326.2

(1)Energy use for other fuels includes fuel used in processing and transport plus business mileage in private vehicles converted to GWh using UK Government GHG Conversion Factors for Company Reporting.

(2)Renewable energy from hydro includes Oswestry which was not incorporated into the emission reporting pending review of ROC.

(3)Biomethane generated and exported to grid is expressed as an electricity equivalent.

Emissions and energy use

This year we consumed 984 GWh of energy including electricity, gas and other fuels purchased for use on-site and for transport. We increased generation across all our renewable sources of hydro, solar photovoltaics, wind, biomethane and energy recovery using sewage sludge to power combined heat and power (CHP) generators. We generated the equivalent of 191 GWh of renewable electricity, an increase of 18 GWh on last year and though we exported 6.1 GWh more we reduced our electricity purchased by 17.5 GWh.

Having largely addressed emissions from electricity, it is mostly methane and nitrous oxide emissions arising from wastewater treatment that remain. Understanding and reducing these emissions forms a long-term challenge for the industry as a whole.

Energy efficiency action taken

Our energy management strategy aims to achieve an appropriate balance between managing energy consumption, use of renewables and self-generation and being smart about how we operate our assets to get best value while maintaining security of supply.

We have continued to develop our Energy Management Programme which brings together processes, asset optimisation and data analytics. We have implemented a wide range of projects to reduce consumption and drive more dynamic control of our assets to reduce energy costs. To improve data capabilities we have rolled out an innovative sub-metering solution installing over 1,200 meters. Two major solar installations were completed with a combined capacity of 11.5 MW.

Renewable energy generation by technology

Energy recovery from bioresources

Biomethane (gas to grid)




In the past year we completed our Energy Saving Opportunities Scheme (ESOS) submission to the Environment Agency which includes potential opportunities for efficiency and generation improvements. We were shortlisted for the Energy Institute Energy Management Award in November 2019.

Breakdown of our 2019/20 emissions by activity and greenhouse gas

Carbon dioxide


Nitrous oxide

HFC refrigerant

Summary: good progress – ambitious, deliverable plans

We've been focused on climate change for over 20 years and have made good progress. We have committed to playing our part in limiting climate change to 1.5°C, we aim to maintain and improve services whether the climate change is 1.5°C, 2°C or 4°C, and we have the appropriate governance, strategy, risk management and metrics to make sure this happens.