- Resilient Hybrid Set-Up – A fully off-grid solution combining a battery and two 275 kVA generators to ensure continuous, reliable power for temporary classrooms in a critical education setting
- Smart Redundancy – Dual-generator system provides seamless backup in case of failure, with automatic switchover ensuring no interruption to lessons
- Noise Reduction in Sensitive Environments – Battery handles overnight and low-load periods, keeping noise and emissions to a minimum in a residential area
- Fast, Flexible Deployment – Rapid installation on a school site with no grid connection, meeting urgent needs without disrupting the academic schedule
TEMPORARY CLASSROOMS FOR SCHOOL AFFECTED BY RAAC
When a UK school was forced to close part of its main building due to concerns over Reinforced Autoclaved Aerated Concrete (RAAC), temporary classrooms were brought in to keep education going. Working with Power Electrics, Greener provided a reliable and low-emission power solution for the new units.
This is the second school project Greener has supported in response to the ongoing RAAC issue. The priority was to deliver a system that could be deployed quickly, run efficiently, and ensure resilience in a residential area.
THE CHALLENGE
The school needed continuous power for modular classrooms placed on the school grounds. As the site was no longer connected to the grid, a complete off-grid solution was required. Noise levels also had to be kept low to avoid disruption to lessons and to the surrounding neighbourhood.
High load peaks during the school day, combined with low demand overnight, called for a system that could manage fluctuating usage without compromising on reliability or efficiency.
THE SOLUTION
Greener designed and delivered a hybrid microgrid in partnership with Power Electrics, consisting of:
- A 318 kVA battery system
- A 275 kVA generator in island mode
- A 275 kVA fixed export generator connected to the load side of the battery
The battery is the main power asset and forms the microgrid at 400 volts/50 hz providing energy to the load. When the primary generator is started by the Greener EMS the frequency and voltage across the system synchronises, allowing the battery to perfom peak shaving whilst re-charging. The battery is then able to manage low or fluctuating loads, particularly overnight when silence is essential. During peak periods, the fixed generator steps in to assist or take over, adding resilience and preventing any disruption to the power supply.
This setup offers a high level of reliability. If one generator were to fail, or if the site load were to increase over the power output of the primary generator alone the system would detect the fault immediately, and the second generator would start and export energy to the load/battery to recharge or take over from the primary generator. This redundancy ensures uninterrupted operation at all times.
THE RESULT
The system provided reliable power to the temporary classrooms throughout the school year, with no unplanned outages. By combining a battery with two 275 kVA generators, we reduced generator runtime by more than 6,350 hours compared to a standard single-generator setup. This led to a saving of almost 60,000 litres of fuel and prevented over 190 tonnes of CO₂ and 930 kilograms of NOₓ from being emitted. The battery managed low loads and overnight demand, which helped keep the site quiet during sensitive hours and further reduced emissions. This was especially important in a residential setting.
This project shows what’s possible when smart technology is paired with practical design. It delivered dependable power, lowered environmental impact, and kept disruption to a minimum. It is a clear example of how we are helping organisations move toward cleaner, quieter, and more easily emission-free power without compromising on performance.
