Residential tower, London

Strata SE1 is a 148-metre-high, 43-storey residential tower that forms a dynamic new addition to the London skyline. The first building in the world with integral wind turbines, it sets a new benchmark in terms of environmental strategy. The tallest residential building in central London, Strata SE1 will deliver 408 high quality private and affordable residences to the area, and will be home to more than 1000 residents. Additionally, energy costs per apartment will be substantially less than the typical UK housing average, significantly reducing occupational costs for residents and tenants.

The client's brief challenged the design team to develop a high-rise residential concept that would embrace energy efficiency, targeting an EcoHomes assessment rating of 'excellent'. Located in one of the Mayor of London's Energy Action Areas, sustainability has been key to the evolution of Strata SE1 from the outset of initial design back in January 2005.

Sustainability has been integral to the evolution of Strata SE1. In the five years since inception, the professional team has developed and implemented a comprehensive sustainability strategy that details all of the processes undertaken from project concept, design, construction and post-occupation. All renewable energy technologies, practical to the site, were considered by Strata SE1's professional team during the initial planning period in early 2005 as potential solutions to the mandated 10% on-site renewable energy target set by the Mayor of London and the Greater London Authority (GLA).

Wind turbines, photovoltaic (PV) cells, ground source heat pumps and solar thermal heating were all tested for their suitability and effectiveness, with wind turbines finally being pursued as a result of their potential to achieve the best results given the height and shape of the proposed building. The opportunity to incorporate them into the architecture and deliver a highly visible commitment to sustainable design added further validation.

The wind turbines are located at the top of Strata SE1, installed within three nine-metre-diameter Venturi tubes, which form part of the facade design. A Venturi is a shaped tube that creates a pressure differential, which results in an acceleration of wind speed through the tube. Free-standing horizontal wind turbines generate their nominal power output at wind speeds around 12 m/s. The reason for Strata SE1 integrating Venturi into the facade is to capture lower wind speeds and accelerate them to greater velocity to increase the annual power output from the wind turbines. The three five-bladed wind turbines are rated at 19 kW each and are anticipated to produce 50 MWh of electricity per year. To put this into context, it is enough energy to meet the total annual demand from 30 two-bedroom apartments (based on current 2006 Building regulations) or 20 two-bedroom apartments (based on 2001 Building regulations); approximately 8% of Strata SE1's estimated total energy consumption.

The actual energy output of the wind turbines will only be accurately known after they are fully commissioned and two years of comprehensive wind data analysis has been completed. The optimum operating range for the turbines is at a wind speed of between eight and sixteen m/s from a southerly direction. It is envisaged that they will run 24 hours a day in order to maximize the potential to produce electricity. The electricity generated by the turbines will be used to supplement the landlord's supply for the common areas of Strata SE1.

Noise output has been considered at great detail throughout the design process and it is not anticipated that there will be any acoustic impact to the residents of Strata SE1 or the nearby Draper House from the operation of the turbines.