Achieving zero air leakage
November 1st 2007

To help Anglian Water (AW) understand its compressed air energy consumption, the company has appointed Airchannel as its nominated compressed air partner. The partnership has already paid dividends, with savings being made in leakage detection and repair to the pipework network

Serving 2.6 million properties, Anglian Water is geographically the largest water company in England and Wales covering 27,500 square kilometres. It supplies over one billion litres of water every day through its network of 36,000 kilometres of water mains and treat wastewater at 1075 sewage treatment works.

Airchannel's Steve Holman says "We have been working very closely with the Energy Team at Anglian Water. We have surveyed approximately 15 sites for air leaks. An example of this is at the Grafham water reservoir in Cambridgeshire, where we have calculated that there will be a £21,312 benefit (worked out at 7.5kWh) thanks to leak detection, and over a further 15 sites we estimate the total benefit is £48,000".

Under the first phase of the work, which has recently finished, Airchannel was tasked with a leakage detection and repair programme to ensure a reliable sealed system, across the entire network of pipework. To do this efficiently Airchannel worked in association with Leekseek, who provided the pressure testing to help define the leakage.

For some companies it is the lack of verification that is the biggest obstacle in starting a leakage detection programme.

However, the two key factors for determining progress, air consumption and pressure are relatively easy to measure, before and after the survey.

The results can then be converted into kWh and into monetary terms. By doing this Airchannel was able to demonstrate a verified before/after scenario, showing that by opting to invest in a leakage detection and remedial programme, AW has significantly reduced energy consumption. Additionally, it has been able to verify what size compressor it will need in future processes.

There is no single determined cost for compressed air that applies to all companies. Energy represents approximately 50% of the compressed air cost. Other costs include capital, service, maintenance, ventilation, monitoring, spare parts, insurance, and management costs.

By reducing leakage level Anglian Water has contributed to reducing CO2 emissions. Anglian Water's energy targets support UK energy policy to implement the Kyoto protocol – to reduce carbon dioxide emissions by 12.5% and to raise the level of renewable energy used to 10% by 2010.

The energy used for compressed air production in the EU is equivalent to 7.5 nuclear power stations. If all companies in the EU could reduce their air consumption by 20% which is a perfectly achievable goal, that would be equivalent of 1.5 nuclear power stations.

Increased awareness of the impact of compressed air reductions on the environment has led Anglian Water to include compressed air management and leakage detection in their environmental policies. To its knowledge it is the first water company to undertake such an policy.

Airchannel is now working on a second phase, a compressor audit, logging all the compressors currently running at AW's sites across East Anglia. Categorising all the compressors and analysing their operating efficiency is critical to understanding how economically they are running. Depending on the results, Airchannel can recommend the optimum compressor for the requirements, with significant potential savings on running costs.

The review is also beneficial from other aspects. It will reveal how the compressors are utilised and controlled which can greatly affect the compressed air economy.

Work has meant metering the compressors. Their usage data is linked to asset databases, to work out how much energy individual appliances are consuming. This information is then linked to data on the age of the equipment, maintenance costs and potential upgrade costs, Airchannel can then start to build a dynamic picture of its network.

The next stage is to run benchmarking exercises comparing energy use and costs for different sites or processes and define principles for optimum energy and cost savings.

Value for money is the optimum combination of quality and whole life costs to meet users' requirements. Whole life costing allows Airchannel to determine if it is cost effective to invest in a more expensive product initially to reduce costs in the long run.

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