Elfed Green Solar PV, Battery Storage & Ventilation Upgrades

Elfed Green was a solar PV, battery storage and ventilation upgrade programme delivered for Cardiff Council across a residential estate. Each property received 10 solar panels, a 5kW inverter and a 5.1kW battery, providing on-site renewable energy generation and storage.

Ventilation upgrades were delivered alongside the solar works, with mechanical fan installations carried out throughout each property. Garden walls were constructed to protect the inverter units from weather and damage, extending the operational life of the equipment. The Switch-E remote monitoring system was installed across all properties, giving Cardiff Council real-time visibility of ventilation performance from a single dashboard.

The main technical challenge came from the National Grid, which imposed a 2.5kW restriction on the inverters, well below the preferred specification. Resolving it took sustained technical engagement and persistent communication with the grid provider. We worked alongside the designer and the client throughout, advocating for the most appropriate technical solution and reaching a resolution that satisfied grid requirements while protecting the energy performance objectives of the scheme.

All works were delivered in occupied properties. Solar PV, battery installation, ventilation upgrades and garden wall construction ran concurrently across the estate, which required careful sequencing and close on-site coordination. Each trade worked around residents’ daily routines while maintaining quality and safety standards. One resident declined access during the programme. This was handled sensitively, the programme was adjusted around that property, and the position was communicated transparently to Cardiff Council with all documentation completed.

The result is a modern energy package in every property, combining renewable generation, battery storage, improved ventilation and smart monitoring. Residents benefit from clean on-site energy with storage that keeps power available when the sun is not shining. For Cardiff Council, the Switch-E system provides estate-wide post-completion visibility and the ability to respond quickly if any system underperforms, a lasting asset management benefit beyond the contractual deliverables.

To find out more about our retrofit and decarbonisation work, visit rmwgroup.co.uk