Although solar power has flourished in many parts of the UK, London has lagged behind for many years. Largely, this is due to the complexity of operating the technology in urban environments, and because of the prevalence of rented accommodation.
That London has the lowest uptake of solar power was confirmed in a report released last year by Green Party London Assembly member Jenny Jones. It found that only one in every 260 households was investing in solar installations. Compare that to one in 32 households doing the same in the south west of England.
But it's not all doom and gloom: efforts are being made to improve the use of energy from renewable sources in the city, and especially, it seems, in the form of railway stations. In January 2014 the world’s largest solar bridge was unveiled in London in the form of a canopy over Blackfriars railway station. 4,400 solar panels were mounted on the newly modernised platforms, estimated to be able to supply up to 50% of the station’s energy needs.
A year down the line, how have the panels performed and have they met expectations? Donna Mitchell from Network Rail says the panels generated 865 megawatt hours (MWh) of clean energy between September 2013-July 2014, which equated to 25% of the station’s energy needs. That said, on the days with most sunshine hours, the panels do indeed produce 50% of the station's electricity needs. And in all, those panels create the average yearly electricity usage of 207 UK homes (or, if you prefer, 80,000 cups of tea a day).
Blackfriars isn't the only Network Rail station to up its green ambitions. In 2012, King's Cross received a solar facelift. In this case, solar cells were integrated into 1,392 glass laminate roof units. This project generates 175 MWh per year — roughly a fifth of the energy generated by the Blackfriars project. These two railway infrastructure projects, both have shaved 100 and 500 tons, respectively, off London’s CO2 emissions.
It was in the City of London that the first large scale London solar project was born. In 2011, the Heron Tower, then the tallest building in the City of London, also integrated solar cells into laminated glass in window panels. Heron Tower currently produces 92.5 MWh of energy a year — just over half of what the King's Cross installation creates.
So perhaps solar cells integrated in windows could be a feature Londoners will enjoy more of in years to come? Scientists have already produced transparent solar cells barely noticeable to the naked eye, which are becoming increasingly commercially viable by the day. These could be installed in windows across the city and completely revolutionise how solar power is used.
While the residential solar revolution has struggled to take off in London, technological breakthroughs and ambitious projects could be starting to remove the city from the bottom of the UK’s solar league table.
By Anders Lorenzen