Skip navigation

Power resilience for a net zero world

Contact Us

Case Studies

NHS Hospital in South Yorkshire





Battery Energy Storage System


Powerstar were engaged to replace a large hospital’s existing Uninterruptible Power Supply (UPS) system with a more efficient, intelligent Battery Energy Storage (BESS) alternative. As UPS systems are used to ensure critical care systems remain online in the case of a power disruption, it is vital that any proposed replacements are tested to the most rigorous standards and will operate exactly as intended.

Traditional UPS suffers from significant losses, typically around 10% of their total capacity. For a typical hospital installation, this equates to around £262,000 in additional energy costs annually, as well as adding around 210 tonnes of CO2e to their carbon footprint. Traditional UPS is also inflexible and unable to carry out other tasks, and there is no accurate way to determine the state of charge of a battery. This risks them failing in the event of a significant power disruption.


Powerstar proposed to replace the hospital’s existing UPS system with a BESS that also incorporated the rapid switching speed and reliability of a UPS. As well as providing the same instantaneous load support as a UPS, but with the ability to support an area and not just specific systems, BESS offers much lower losses at less than 1% of total capacity. In addition to this, a BESS can be used to engage with Grid Services and Demand Side Response to generate additional revenue and further reduce electricity costs, as well as being used to store renewable electricity generated on-site, such as that from rooftop solar, to further improve sustainability performance.

Powerstar’s BESS is protected by warranty for 15 years and has a typical system lifespan of around 25 years. This contrasts with traditional UPS, where batteries need replacing between every 7 and 10 years. Batteries are cycled daily, ensuring that they are functioning correctly and can meet NHS minimum requirements of 20 minutes load support in the event of power disruption. The BESS solution from Powerstar is the first HTM-06-01 compliant commercial BESS system with UPS capabilities and the ability to access Grid Services.


BESS offers savings through greater energy efficiency of around £225,000 annually, as well as eliminating around 190 tonnes of CO2e. Grid Services can also generate around £100,000 in additional revenue on top of that saving.

Annual savings of


and eliminated 190 tonnes of CO2e

South Yorkshire Hospital Power Disruption


For this NHS customer, the 500kW/500kWh Powerstar system was called upon two times in the same day in April 2022 to protect critical care at the hospital from power disruption.

The grid failed twice, and each time the BESS seamlessly supported the full load, first for a period of 15 seconds, and the second for a period of 23 seconds. Below is a graph showing one of these UPS events.

Contact us to discuss how we can support your organisation with its energy objectives

Get In Touch

You might also be interested in



The healthcare sector has by far the most critical requirement for a consistent, reliable electricity source.


Generating Revenue

Access grid contracts to generate additional revenue for your organisation.


This website uses cookies. You can read more information about why we do this, and what they are used for here.

Accept Decline