The Problem
Anglian Water Services (AWS) serves 4.3 million customers across East Anglia. Operating 138 water treatment works, the company supplies almost 1.2 billion litres of water every day, serving nearly two million households and over 125,000 businesses.
AWS wanted to investigate its use of energy at a number of sites over the company’s extensive operating area and determine how it could make savings. AWS approached ABB for help in improving the energy efficiency of its sites and reducing its carbon dioxide (CO2) footprint.
Sentridge Control was part of the ABB team delivering this programme.
Sentridge’s Solution
Action Plan
Using its network of ABB Drives Alliance members including Sentridge Control, ABB put together a four year plan of action based on its DrivesAdvantage programme, a comprehensive care and support package for users of ABB drives. As well as service and repair, it also ensures that customers are gaining the best possible efficiency from their drives.
The initial part of the plan involved training over 90 AWS personnel in programming low voltage AC drives and giving them an appreciation of how drives can be used to save energy. This enabled the AWS engineers to assist in finding energy saving opportunities.
The Full Story
AWS engineers were also trained how to use the flux optimisation feature within the ABB low voltage AC drive, which enabled them to commission a drive correctly for energy optimisation. Another part of the programme was identifying opportunities to replace existing drives with newer, more efficient versions.
Sentridge Drive UpGrade
The viability of energy savings could be proven by monitoring the existing system for a period of time, then installing one of ABB Drives Alliance’s hire drive fleet and monitoring again. This helped prove to AWS that the proposed upgrade would achieve the savings predicted. Once a particular project was approved, ABB Drives Alliance decommissioned the old drive and commissioned a new one, disposing of the old drive in accordance with the WEEE Directive.
£2.7 million saved
An example application was an aeration ditch at the company’s Bassingbourne Sewage Treatment Works. To control the level of dissolved oxygen (DO) in the ditch, a 30 kW ABB standard drive was installed. A minimum speed of around 30 Hz was set on the drive to ensure adequate mixing is maintained within the ditch. Linked to an existing DO meter, the drive gives a greater range of process control, a reduced risk of mechanical failure and significant energy savings. Power consumption is cut by over 48,000 kWh a year, representing an annual cost saving of over £4,000.
Over the lifetime of the project, AWS saved 33,765 MWh in energy, giving a cost saving of £2.73 million across 100 of its sites. This equates to 16,695 tonnes of CO2.
Challenge
- Save energy at a number of sites over the company’s extensive operating area
- Cut CO2 production Solution
Four year action plan to investigate energy use and potential savings
- Train AWS personnel to identify energy saving opportunities
- Optimize drives to ensure they are operating at peak efficiency
- Identify opportunities to replace existing drives with more modern, higher efficiency versions
Benefits
- £2.73 million saved across 100 sites
- Energy use reduced by 33,765 MWh
- CO2 production cut by 16,695 tonnes