Working with aggregators, UK water utilities are flexing demand and optimising on-site generation, reducing energy operational expenditure.


Water utilities’ operations need lots of electricity, and so energy has become their biggest operational cost. The challenge has been how to tap into this demand, which is spread over networks comprising dozens of sites.

Both Anglian Water and United Utilities are meeting more of their electricity demand with onsite renewables, including combined heat and power (CHP), solar photovoltaics (PV) and hydropower. They are working with aggregators to increase their self-consumption of clean energy as well as better manage their electricity demand.


Severn Trent

Working Open Energi and its aggregation platform, Severn Trent wants to unlock over 20MW of flexible capacity from across its network by 2020. The company provides water to over four million customers across Wales and the Midlands. Open Energi’s technology enables pumps, motors and blowers to automatically adjust electricity use second-by-second.

Having deployed the technology at two sewage treatment works in the Midlands the water company provides transmission system operator National Grid with 1.2MW of real-time flexibility. Six more sites were enrolled earlier this year.


Credit: United Utilities

United Utilities

Since it trialled Open Energi’s aggregation technology in 2014 at sites include two wastewater treatment plants and a pumping station, in northern England, United Utilities has since installed it at more sites, including several of its larger activated sludge plants. The technology has become part of the sites’ daily operation, with no detrimental effect on the treatment or pumping process.

Open Energi’s commercial manager Sebastian Blake says: “United Utilities is pretty clued up and see them see themselves as being more of an energy market participant, so the way they deploy our technology is moving more towards licensing type of model. They want it to be deeply integrated within operations, and be very much in charge of it.”

The system is monitored by Open Energi on behalf of United Utilities, generating revenues and offsetting rising energy costs.

By 2020 United Utilities aims to provide National Grid with 50MW of flexible capacity from various demand side response solutions, enough to displace a peaking power station. The income generated will be reinvested into site assets to reduce operating costs.

When United Utilities first trialled the aggregation technology dynamic frequency response provided a key revenue stream. “It was lucrative then but now the value has roughly halved. We saw it coming and so have been pursuing wholesale and imbalance. To always extract the best value of megawatts your aggregation technology needs to be able to switch application, which ours is able to do,” Blake adds.

United Utilities now generates 21% of its electricity consumption through its own renewable fleet, from solar PV, biogas and hydroelectric, and plans to install a further 30MW by 2020.

The platform allows United Utilities to be flexible about when it uses power, shifting consumption away from expensive peak periods, while responding to fluctuations on the grid to help balance the power system.


Stacking revenues and savings

Over the next 12 months, pumps, motors and biogas CHP engines across eight more of United Utilities sites’ will be connected to Open Energi’s Dynamic Demand 2.0 platform, providing 8MW of flexibility to respond to earn revenues, as well as avoid charges, expected to cut electricity costs at the water company’s sites by 10% annually.

The stack comprises firm frequency response balancing services, peak-time network charge avoidance at transmission and distribution system level, as well as wholesale and imbalance prices, including working with United Utilities’ electricity supplier to deliver energy arbitrage opportunities within its existing supply contract and to access the imbalance market and local constraints.

Credit: RedT

Anglian Water, the largest electricity consumer in eastern England, is installing a 60kW/300kWh flow battery system alongside a 450kW solar PV system at one of its treatment works in Norfolk to store excess solar energy and use it at other times to reduce the site’s reliance on the grid. The flow battery will also provide balancing services and take advantage of wholesale energy price arbitrage. Solar plus storage will slash the site’s electricity costs by 50% annually by 2040.

Open Energi’s Dynamic Demand 2.0 software is being used with the battery to optimise energy consumption and stack several demand-side value streams.


Flexitricity helps water firm access additional revenue streams

Aggregator Flexitricity is working with a water utility to access revenues through access to the Balancing Mechanism (BM), an additional revenue stream to add to the stack that can only be accessed by energy companies with supply licenses.

Flexitricity’s chief strategy office Alistair Martin says: “Planning to turn off pumps weeks ahead or even days ahead for water companies is difficult. In an ad-hoc market, where, say an interconnector trips, you can take that demand off the grid by aggregated industrial load adjusting demand.

“If customer demand is low and tank levels are high then it is an ideal opportunity to turn off pumps at certain sites. If not and the utility is unwilling to take the next step then the grid operator simply moves onto the next one up the price stack.”