With just 16 weeks to complete the project, the Ferrovial Agroman & Laing O’Rourke Joint Venture, on behalf or Transport for London, needed 24 hour power to supply works underground. A large air compressor, power tools and equipment and lighting all needing power as well as the administration and site services.
With no room underground, all the equipment needed to be installed at street level which meant being located immediately outside peoples’ bedroom windows. The prospect of having to re-house all of the local residents and the cost and problems associated with that meant this was highly undesirable.
The incumbent generator supplier was approached to come up with a solution but was unable to offer anything that was acceptable.
Running out of both options and time, the project team approached PE Generators, who partner with OGE for hybrid power systems, to find an answer. Together a solution was devised that required a system more powerful than the standard range of products, partly because of the high-inrush characteristics of a large air compressor plant. The two businesses were able to specify and build the system in a matter of four weeks and just in time for the beginning of the project.
A 300kVA diesel generator supplied by PE Generators was coupled to a custom built gridtogo™ system with output of 195kVA and 350kWh battery system. The management of the system was such that the generator would only be used during daytime hours so as to minimise any nuisance from noise and exhaust emissions.
The most important outcome was that there were no complaints from local residents and on all occasions when visited by the local authority, the site passed inspection with flying colours. No-one had their sleep disturbed by the sound of a large diesel generator in the dead of night and the impact of diesel emissions on local air quality was kept to an absolute minimum.
Whilst it was not the key driver, substantial cost savings were also enjoyed through significant savings in fuel and maintenance due to lower generator running hours. Some 160tCO2e were saved over the 16 weeks compared to what would her been the case had a generator run for the duration of the project.
Project Sustainability Manager:
“The Off-Grid hybrid unit provided a great solution to our challenge of providing 24/7 power in a residential area
where no mains connections were available. We were able to set the unit to run solely from the battery during the
night, which meant the noise levels were significantly lower. Without this it is likely that we would have had to rehouse
a number of residents for the 16 week period, which would have been highly disruptive for them and also very costly.
The hybrid unit also gave us significant fuel savings over the 16 week period of around 66,000 litres, which equates to
a carbon emission saving of approx. 160 TCO2e. The unit worked exactly as we hoped and was a great success.”