With the power situation in New York City remaining acute, a man accused of pulling a gun in a petrol queue and investment banks still closed or running on back-up power supplies, it's worth sparing a thought for what would happen in London in the event of a widespread power shortage this side of the Atlantic.
London is built on a floodplain. Over the past decade much has been made of the threat to the city from rising sea levels. In March last year, the Environment Agency warned that London would be completely submerged if no flood defences were in place, with the flood map here clearly showing some degree of threat to both the City and Canary Wharf.
Sue Tapsell, head of the Middlesex University Flood Hazard Research Centre, says that although the Thames Barrier provides a lot of protection to London, there could always be, 'the big one.'
"If you had a huge tidal surge coinciding with high tides and a bad storm in the North Sea, that could come over the top of the London defences. It would be an extreme event, but we know that these things happen," Tapsell says.
As in the US, investment banks in London have substantial back-up power supplies of their own. The site specifications for Goldman Sachs' Peterborough Court offices clearly state that it has an emergency generator and the photograph below (taken from Google Earth) show the existence of six very large generators on the roof of the Merrill Lynch Financial Centre in the City. The specifications for Merrill's building mention that it has 'Six diesel-driven rotary UPS/generator sets' that will enable it to operate 'independently of the external power network.'
Back-up generators at Bank of America Merrill Lynch in London
Neither Goldman Sachs nor BAML responded to requests for information about their back-up power supplies in London. Barry Ferguson, hardware sales supervisor at RMD Power and Cooling, which provides uninterrupted power supplies for financial services firms says BAML appears to have the capacity to generate 6x1.8 MW of power on its roof. "That is a lot of power," says Ferguson. "This place is state of the art - it cannot fail - it would take a nuclear bomb to stop it working."
How many houses could BAML power in the event of a power failure? At least 1,000, says Ferguson. Maybe more: when the new BAML office was completed in 2002, there were suggestions that it could power a small city the size of Reading.
Ferguson says most organisations have a dual back up power supply: the first comprising a set of batteries, the second comprising a series of generators running on diesel. It's common to store enough diesel to power the generators for at least 9-10 hours, he says. Many banks will also have a bulk fuel tank.
Ferguson says he has received a request from a financial services organisation that wants 13 generators with fuel tanks buried below ground. At the other end of the scale, his database suggests that Citigroup's Canary Wharf building has a mere two 1.5 megawatt generators, although this has not been confirmed by the bank.
Outside London, Ferguson points to the Corning Glass Building on 5th Avenue (also, coincidentally occupied by Merrill Lynch) as having some particularly impressive back-up power provisions. This building has its own natural gas supply. Such things are very rare, and very expensive, says Ferguson. Diesel generators can run low on fuel (as appears to have happened at Knight Capital this week), but natural gas is usually piped-in, making gas-powered generators "unstoppable."
If the slight risk of London flooding were realised, it would most likely be residential areas that would be flooded. A London flood risk appraisal report prepared several years ago suggested that boroughs at confluences of Thames tributaries were at particular risk of inundation. These include - Havering, Barking & Dagenham, Newham, Tower Hamlets, Greenwich, Lewisham, Hounslow, Richmond, Kingston, and Wandsworth - the latter three being popular residential areas for financial services workers.