Blue and green

Water companies are generating ever more of their own power so they are not held hostage to price hikes from energy suppliers. Lee Jones report

Water companies are increasingly looking to reduce their reliance on the big six by generating their own renewable power. Some have plans to self-generate as much as a fifth of their electricity within two years.

“We currently produce enough renewable electricity to run a city the size of Oxford,” says Gerard Lyden, senior energy strategy and standards consultant at Thames Water, which generates 12.5 per cent of its energy using renewables. “We are investing hundreds of millions of pounds to help us achieve our target to renewably self-generate 20 per cent of our annual energy requirements by 2015.

“As well as being environmentally friendly, generating energy from waste [sewage] also reduces our running costs by protecting us from price fluctuations of mainstream markets, delivering savings that help to keep customers’ bills down.”

The company deploys a combination of renewable energy sources. Lyden says: “The bulk of our generation is tied to our core processes – generating power from waste – and as a multi-site organisation we also have opportunities for other renewables such as wind and photovoltaics wherever these can pay for themselves. We expect energy prices to continue to go up faster than inflation, so we are looking to develop further self-generation to protect us and our customers against this.”

Scottish Water is also using a mix of sources including wind, solar and hydro to increase its renewable energy generation across more than 2,000 treatment works and assets. Chris Toop, general manager for the company’s energy programme, says: “Scottish Water generates around 7 per cent of the energy it consumes, but through innovative use of our assets we are capable of significantly increasing this proportion.”

A landmark project is the installation of 10 small Evance R9000 wind turbines at a treatment works near Stornoway on the Isle of Lewis, which will generate around 500kWh of electricity a day to power the site. Toop says: “We have a number of other small or ­medium-scale wind schemes in development in the Highlands and Islands, such as at Stronsay on Orkney. We also host larger-scale projects on our land, such as at Whitelees in Ayrshire, and a consultation is under way on the potential of a windfarm up to 54MW on land at Backwater reservoir in Angus.”

Scottish Water has 10 hydro schemes in operation and another 41 sites in development, and a minimum of 25GWh additional self-generation is expected to be delivered through these schemes by 2015. The company has also installed the UK’s first “difgen” hydro-turbine, on a main near Denny. This captures the energy from pressure reduction and converts it to power.

Wessex Water has a specialist waste and renewable energy subsidiary, GENeco. By 2015 the company aims to deliver 51GWh a year from sewage sludge processing, around 20 per cent of its annual electricity use. “Over the past three years we averaged 44GWh of renewable generation, which equates to around 17 per cent of our total electricity use,” says a company spokesman. “Typically, around 6GWh of that power is exported. The rest we use ourselves.”

Anglian Water has cut its overall electricity usage for four consecutive years and also generates some of its own power. For instance, a single 100 metre high wind turbine at its March sewage treatment works reduces the company’s carbon emissions by approximately 2,300 tonnes annually.

Richard Peverell, Anglian Water’s estates manager, says: “Energy costs account for roughly 11 per cent of all our expenditure, and the costs of energy are constantly rising. We’re keen to explore any project that reduces our reliance on fossil fuels, and that can help us offset the impact of constantly rising energy costs on our customers’ bills.”

Our final example is United Utilities, whose Davyhulme wastewater treatment works is home to the largest advanced sludge digestion facility of its type in the world. By the end of the financial year, it will generate over 80GWh.

Steve Fraser, managing director of United Utilities, says: “Energy displacement saves the business in excess of £11 million every year, which in turn helps keep customer costs lower.”

Lee Jones is a freelance journalist

This article first appeared in Utility Week’s print edition of 19th July 2013.

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