Personally I think these new towers are broadly positive. Okay, as with everything it would be greenest if they were never built at all, but assuming that they must be constructed, how have they done?
One of the most high profile of the new towers is the 42-storey Strata in South London which comes complete with three building integrated 19 kW wind turbines – the world’s first. These are expected to produce around 8% of the building’s electricity, or 50 MWh. Critics have been quick to point out the poor record of urban wind, and condemn the turbines as a gimmick. This would certainly be the case if the developers had made no effort to improve efficiency, but actually things aren’t too bad on that front, with the flats as a whole expected to produce 13% less CO2 than the required standards. As to the efficiency of the turbines, the height of the building and the clean air around it should give them the best chance of generating meaningful energy.
Similarly, the new under-construction Heron tower in the financial district has over 200 kW of building integrated PV on the south side. As with the Strata, architectural opinionis mixed, but the building was recently awarded an ‘excellent’ by the BREEAM rating system. Aside from the PV, the building uses a multi-layered skin (like the Gherkin building) to minimise heat build up and reduce cooling loads.
Finally, just down the road from the Heron Tower is the just started Bishopsgate Tower. Again once complete this building will contain more than 200 kW of PV, as well as double layered skin to reduce heating and cooling costs. Interestingly the whole building will have only 6 parking places, for more than 8000 workers.
So what do we make of these developments? Personally, I am positive. Yes, there is far far more that needs to be done, but these buildings are positive in a number of ways. First they help to normalise renewables and green design, providing high profile examples of renewables in the city. The energy efficiency measures are the quiet side of this, hopefully ensuring the renewables are not purely cosmetic. Finally, they are a first step, and first steps matter.