The brief
The original conversation at Arriva's Canton depot in Cardiff was about replacing ageing metal-halide high bays in their maintenance and carriage sheds, but quickly turned to a more pressing concern: the light fittings within their inspection pits. The fluorescent fittings were energy-hungry and required ever-increasing levels of maintenance and replacement. Any new fittings would also need to be durable enough to withstand cleaning with pressure washers, leading the client to assume that fully replacing each existing recessed metal and glass fitting would be prohibitively expensive.
What we did
Morgan Hope designed a bespoke LED gear-tray to retro-fit within Arriva's existing recessed carcasses, replacing the fluorescent tubes and control gear without the need to replace the whole fitting — substantially reducing both material and installation cost. The gear-tray was redesigned with two separate circuits of LED diodes, each with its own driver: one for full-output illumination and a second 5W 'background' circuit that keeps the pit safely lit when unoccupied. A microwave occupancy sensor on each fitting switches the main circuit on automatically when an engineer enters the area. After a positive trial, 318 retro-fit LedLite gear-trays were installed across the depot, 51 of which also supplied required emergency lighting.
Outcome
Annual energy consumption fell from 446,549.76 kWh (£34,880) to an estimated 69,080.63 kWh (£5,277) — a reduction of over 84% and savings of more than £29,600 per year. Carbon emissions fell by 207 tonnes a year. Including new gear-trays, bespoke brackets and £50-per-fitting installation costs, the payback period was just 26 months — and that's before factoring in the substantial reduction in ongoing maintenance costs.