Our work on energy efficiency

We are busy working on increasing the energy efficiency of our operations.

Our long-term goal is to be carbon neutral and we have a carbon management strategy to help us achieve this. A key part of this strategy is our energy efficiency programme.

Our energy team has been running a programme of energy efficiency projects to help reduce our energy use and relative emissions, as well as cut our energy costs by around £900k each year, following a one-off investment of £1m.

The team is aiming for:

• 5 gigawatt hour (GWh) savings by April 2011, having met the same target in April 2010
• a further 5GWh saving by April 2011
• year on year reduction in the long term.

How are we going to achieve these energy reductions?

The energy team maintains and updates a portfolio of energy saving initiatives. Its current programme has 150 current live projects, including:

• aeration optimisation
• ammonia monitoring
• pump optimisation
• ultraviolet plant optimisation
• advanced, real time process control measures.

Focused on our larger infrastructure, projects are identified from an on-going energy audit programme and leads given by operational staff.

During the last year the focus has been on a variety of different projects and at current prices, for every GWh saved, we are saving approximately £89,000 in electricity costs.

For example we have:

• extended ammonia control to 10 sites
• begun a thorough review of the operation of our biological aerated filter plants
• begun an advanced process control project at Holdenhurst STW, one of our largest STWs.

Reviewing the efficiency of a treatment works’ processes has had good results. Recent work on pumping, secondary and tertiary treatment at our Kingston Seymour site in Somerset has reduced power consumption to 2004 levels.