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AlphaESS STORION TB125 battery and static transfer switch installed in a Quest Power enclosure
AlphaESS STORION TB125 battery and static transfer switch installed in a Quest Power enclosure

03. Powering Healthcare Beyond the Grid with Off-Grid Battery Storage

How Quest Power, Immersa and AlphaESS UK are using battery storage to support mobile diagnostic services, providing dependable off-grid power for CT and MRI facilities while reducing reliance on continuously running diesel generators.

Battery storage is increasingly being used to cut energy costs, integrate renewables and reduce pressure on the grid. But some applications demand far more from the technology.

A collaboration between Quest Power, Immersa and AlphaESS UK is demonstrating how battery energy storage can also provide dependable off-grid power for mobile CT and MRI diagnostic facilities operating across the UK.

These facilities help bring vital imaging services closer to patients, but the equipment inside them requires an exceptionally stable electricity supply. To meet that challenge, the three companies developed a bespoke battery solution designed specifically around the demands of mobile healthcare.

Following extensive engineering, testing and commissioning, Quest Power committed to an initial deployment of 18 AlphaESS TB125 systems, delivering a combined 2.25MW of power and 4.698MWh of battery capacity.

18

AlphaESS TB125 systems

2.25MW

Combined power

4.698MWh

Battery capacity

Nominated
Renewable Energy Project of the Year
edie Energy & Tech Awards 2026
PROJECT GALLERY
AlphaESS STORION TB125 batteries and static transfer switch on a Quest Power mobile trailer
AlphaESS STORION TB125 battery cabinet deployed for Quest Power
Engineer commissioning AlphaESS TB125 battery enclosures for Quest Power

    A Different Kind of Energy Challenge

    CT and MRI scanners place unusual demands on an electrical system. Power demand can change rapidly during operation, while continuity and power quality are critical. An interruption can mean more than simply downtime, it can disrupt diagnostic services and patient appointments.

    Historically, diesel generators have provided the resilience required for this kind of off-grid application. Quest Power wanted to maintain that reliability while significantly reducing the amount of time generators needed to run.

    Rather than supplying a standard battery product, Immersa worked alongside Quest Power and AlphaESS UK to engineer and validate a system specifically for the application.

    IMMERSA’S ROLE

    Battery integration

    Commissioning

    Software and energy management development support

    Training for Quest Power’s engineering team

    Engineer with two AlphaESS STORION TB125 batteries and a generator on a Quest Power trailer

    Putting the Battery at the Centre

    BatteryAlphaESS STORION TB125
    125kW / 261kWh
    Switching300kVA Static Transfer Switch
    Peak outputUp to 110% of rated output
    Delivered temporarily during sudden demand

    The key difference is how the battery and generator work together. Instead of the diesel generator operating continuously as the main source of power, the AlphaESS battery powers the diagnostic equipment during normal operation.

    The TB125 can also temporarily deliver 110% of its rated output, helping it respond to the sudden power demands that can occur during diagnostic scans.

    HOW THE SYSTEM WORKS

    Battery first, generator only when needed

    1

    The AlphaESS battery powers the diagnostic equipment during normal operation

    2

    The battery reaches a predetermined state of charge

    3

    The generator starts automatically and recharges the battery

    4

    The generator shuts down again and the battery resumes supplying the load

    This approach reduces generator operating hours, fuel consumption and associated emissions, while retaining the additional resilience of diesel generation when required.

    Quest Power mobile power trailer carrying AlphaESS STORION TB125 batteries alongside a backup generator

    Beyond a Standard Battery Project

    2020

    Working together in the UK since

    50MW+

    C&I BESS projects supported

    AlphaESS UK and Immersa have worked together in the UK since 2020, supporting more than 50MW of commercial and industrial BESS projects. For Quest Power, that experience has helped create a repeatable platform that can be deployed across its growing mobile diagnostic fleet.

    The project also points to a wider role for battery storage. Beyond reducing energy costs or maximising renewables, BESS can support critical infrastructure where resilience is essential. In this case, helping mobile diagnostic services operate with less reliance on continuously running diesel generators.

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