Severn Trent

Sector: Corporate

Employees:

> Approximately 5200 for Severn Trent Water in the UK, and 2500 for Severn Trent Services in 90 office locations worldwide.

Carbon Footprint:

> Severn Trent Plc’s average annual net UK emissions for the four years from April 2000 to March 2004 were 583,000 tonnes CO₂e

TARGETS

> In 2004, Severn Trent Plc undertook a Carbon Management Programme, which produced a scenario projecting the group’s net UK greenhouse gas emissions to 2020. In recent months Severn Trent has completed the third phase of this project, undertaking a long term greenhouse gas and energy cost analysis of different technology choices for wastewater treatment. In analysing long-term investment choices in the context of GHG emissions, Severn Trent Plc is responding to the climate change challenge at the very heart of its business.
> The Carbon Management Programme has identified a number of opportunities for Severn Trent including the expansion of its Site Energy Management Plans to promote energy efficiency and increasing its renewable energy generation through existing and expanding CHP and hydro installations.

Achievements

> In 2005/06 Severn Trent reduced net normalised GHG emissions by 16% to 849 tCO₂e / UK£M turnover. The decrease was largely due to reducing methane emissions from Biffa’s landfill sites through improved landfill gas capture. N.B. Biffa demerged from the Severn Trent group at the end of 2006.
> Energy efficiency programmes have enabled Severn Trent to improve water treatment standards whilst maintaining emissions at the same level over the last six years.
> In 2004/05 Severn Trent Water expanded its generation capacity by 26% to 27MW, capturing approximately 56% of the sewage sludge that flows through the business for renewables generation. During 2005/06 the company produced over 43% of the UK’s sewage-derived renewable energy.
> Ranked Utility Sector leader in the Dow Jones World Sustainability Index 2002 – 05.

Benefits

> The Carbon Management Programme has enabled Severn Trent to quantify increasing emissions due to environmental legislation over the coming years and also to examine opportunities to adapt its processes to mitigate the effects of climate change on its business.

Low Carbon Solutions

Background

Severn Trent Plc’s core businesses are Severn Trent Water, Water Technologies and Services, and Retail and Utility Services. Severn Trent Water (81.1% of group turnover) provides water and sewerage services to around 3.7 million household and business customers in England and Wales. Severn Trent Services provides water and wastewater solutions in 90 locations throughout the world, and Severn Trent Retail and Utility Services provides homes and businesses in the UK with services such a gas and electricity, insurance and property searches. Biffa, one of the UK’s leading integrated waste management companies, demerged from the Severn Trent group in October 2006.
The nature of Severn Trent’s operations means that climate change will have a significant impact on its business, and therefore its strategy on climate change involves a twin-track approach of measuring, monitoring and mitigating greenhouse gas (GHG) emissions; and adaptation to ensure operations are able to cope with the effects of climate change.

> Site Energy Management Plans are being carried out at Severn Trent Water sites. These work by understanding site consumption, challenging current practice, and identifying opportunities for reduction.
> The water company is carrying out a detailed programme of pump monitoring and replacement, working closely with suppliers to ensure that pumps selected are exactly suited for their workload.

> In November 1999 Severn Trent Plc gained ISO 14001 certification for its environmental management system.
> In 2004, the company undertook a Carbon Management Project, with the support of the Carbon Trust, which produced a scenario projecting the group’s net UK GHG emissions to 2020. In recent months Severn Trent has completed the third phase of this project, undertaking a long term GHG and energy cost analysis of different technology choices for wastewater treatment.

> Severn Trent Water converts the methane from the digestion of sewage sludge into electricity, using combined heat and power (CHP) units. Total installed generating capacity using CHP units was 32MW at end-March 2006. During 2005/06 the company produced over 43% of the UK’s sewage-derived renewable energy.
> In addition to its 30 CHP sites, there are hydro power installations at two sites - Clywedog and Vyrnwy - with combined electricity generating capacity of approximately 820KW.

The Carbon Management Report emissions scenarios include projected carbon savings by Severn Trent Water through improving process efficiencies. For example:
> Water supply: the projected increase in energy consumption for treatment is 13% by 2010/11, which is partially offset by a projected 5% improvement in pumping efficiency in the water distribution network;
> Wastewater: a projected increase in energy consumption of 10% by 2014/15, which is offset by an improvement in the energy efficiency of sewage treatment processes;
> Sludge: a decrease of -14 ktCO2e/yr by 2019/2020 due to an increase in the percentage of methane that is captured and utilised from the current baseline of 98% to 99% by 2009/10; and an increase in the percentage of methane utilised in CHP plants to generate electricity from the current baseline of 89% to 95% by 2005/06.

> In 2005/06 the introduction of a new system for cleaning digesters allowed the liquid sludge to be recycled through the standard sludge treatment, the grit to be recycled to agriculture and the remaining rag to be taken to landfill. Trials are now underway to identify recycling options for the remaining rag. This would reduce the amount of waste from digesters going to landfill to zero.