London Underground Northern Line Extension
Cygnus® 4 Delivers Silent Power During Build
London Underground’s Northern line extension from Kennington to Battersea is a significant project in the city, with the build of two new underground stations. TfL appointed the joint venture Ferrovial Agroman Laing O’Rourke (FLO) to design and build the Northern line extension. FLO mobilised a multi-disciplinary team of designers, engineers, tunnellers, construction experts, rail systems engineers and environmental managers.
Located in the urban city area, project work needed to take place immediately adjacent to surrounding buildings, both commercial and residential. 24/7 temporary power was required for the welfare cabins, security and lighting during the build. However, the site management team recognised that continuous noise from the generators was intrusive to local residents, especially at night. To address the noise problem, sound barriers and smaller diesel generators were introduced. Neither solution completely resolved the problem. Both transport for London and FLO, who are committed to reducing the impact of the construction on local people by considering issues such as noise, tasked Aggreko to find a solution.
Aggreko connected Cygnus® 4 to the two 100 kVA diesel generators on site to create a hybrid power system. The Cygnus® 4 provided silent power between 7pm and 7am (by automatically switching the diesel generator on and off), with the diesel generator running during the day. Whilst the diesel generator ran during the day, the Cygnus® 4 recharged.
By reducing the run-time of the two diesel generators to 12 hours per day during the week and six hours on the weekend, total diesel generator run-time was reduced by over 50%.As a result overnight noise was eliminated whilst delivering continuous overnight power for the welfare cabins and essential security systems. In addition, Cygnus® 4 also reduced fuel usage, CO2 and NOx emissions, particularly in this scenario, where the large 200 kVA diesel generator would have be running at idling speed to supply low overnight loads.
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