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Cranfield University

Driven by a goal to decarbonise their site, Cranfield University wished to introduce battery energy storage to capture and store their solar generation.

  • Industry:  University
  • System no:  3
  • Power:  900kW
  • Capacity:  1080kWh
  • Application:  Site optimisation
  • Functionality :  Maximising solar, overcoming export constraints and managing load demands

Background

Cranfield University is a postgraduate research university specialising in science, engineering, design, technology, and management.

The University was investigating ways to decarbonise their high energy use at their Bedfordshire campus.

Drive by a goal to decarbonise their site – and with a £5 million grant received from the Public Sector Decarbonisation SchemeCranfield University wished to introduce battery energy storage to capture and store their solar generation.

This was a multi-faceted and highly specialised project which saw three E-STOR systems installed across the campus site. The systems are being used to smooth out energy interactions between a solar farm, air source heat pump, and the gas CHP, and to maximise renewable generation.

The Brief

The project was borne out of the University’s decarbonisation agenda with a number of assets installed on-site to support this goal.

The University introduced a solar farm on site in 2018 with the goal of generating 5% of the campus’s annual usage and this was due for expansion. They also wished to reduce reliance on their gas-combined heat and power system by replacing it with a new air-source heat pump installed on the district heating network.

They, therefore, decided to install battery energy storage on-site to maximise the use of solar power; support the power demands of the air source heat pump and create the site’s own building energy management system.

The project presented some unique challenges that the installed systems would have to deal with. Firstly, the University had a challenging export capacity which meant that their excess solar was going to waste. They wanted to store as much as possible to be used by the campus overnight. Secondly, because of its role as a commercial testing facility, the site load could vary significantly, and with little notice.

Sophisticated energy management was required by the project, and we worked closely with the energy team to create a bespoke control system that could respond to their changing needs.

This is the start of completely reimagining how we balance our energy onsite. We will be using the batteries in a number of different ways to help us smooth out the energy interactions between the solar farm, the air source heat pump, the gas CHP, and the import of energy.

Gareth Ellis, Energy and Environment Manager, Cranfield University

The Solution

After reviewing the site and understanding Cranfield’s objectives – to maximise their solar generation on-site and to minimise the increase in electrical demand from the air source heat pump, with an additional, overarching aim of decarbonising their energy usage – it was decided to install three battery energy storage systems, spread across the large site.

The systems work together to allow the site to balance its energy across its own private network, and help the University to overcome grid constraints caused by import limits.

Three 300kW battery storage systems were installed at three separate locations. Working independently, but linked through our back office software to work as a team. The systems work on a schedule that was set at the start of the project. They allow the storage systems to take an excess solar generation at key times of the day and then deliver that power back to the campus when generation stops.

Two of the systems connect directly to the site’s 40 electricity transformers to provide power to energy-intensive equipment.

Therefore, the three E-STOR systems fit the brief, helping to harness their generated renewable energy, use it flexibly as it suited them to manage power-intensive equipment, and finally, supported them on their decarbonisation journey.

What was particularly important to Cranfield University and to other organisations with challenging Climate Strategy and Action Plan targets, is that a Connected Energy system is made from used car batteries.

In Cranfield University’s original system, there are 24 used Renault Kangoo vehicle batteries. While operationally identical to units made from brand-new batteries, these second life storage units provide a positive carbon benefit of 450tCO2e for every 1MWh installed compared with a first life energy storage unit.

Next Steps

As the site grows, we continue to support the University to adapt our control system and ensure that it continues to match their goals.

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