Sofitel London Heathrow

An innovative HV project delivery with a nine month payback.


When the Sofitel London Heathrow hotel explored options to migrate from the Airport’s privately owned and operated High Voltage (HV) electricity system to a new supplier, significant potential energy cost reductions were identified, but only if a series of complex engineering challenges could be overcome.

Although there was a connection point to a new HV network only 200m away, a conventional ‘excavation and reinstatement’ approach to lay the cable was rejected on economic grounds. So DragonIS provided a directional drilling solution, using topographical data mapped by ground penetrating radar. This meant negotiating a host of critical – and densely located - underground services, including fuel delivery pipes, hydrant mains, fibre optic cabling, 11 and 33kV electricity cables and a gas feed.  

At the hotel site, a new intake substation was installed, along with HV switchgear, to take the feed from the DNO (SSE).


As a result of DragonIS’s innovative design and programme of works, the hotel achieved project payback in just nine months, thanks to much reduced energy costs.  

With support from the team at DragonIS, we were able to explore the options and calculate the return on investment of each. While the directional drilling approach was clearly the most complex, given the density of critical services in the area, it also offered the best payback option. In fact, ROI was achieved in around nine months and now the hotel benefits from significantly reduced energy costs.

Mark Higgins, Director Arora Property