Positive energy at Lyon's Confluence site

Last week the great and the good of Greater Lyon unveiled plans for the latest stage in the development, and proudly boasted that their choice of architect was motivated by a desire to be as avante-garde in energy efficiency as possible. The winning team who will now go on to build the site are led by Japanese architect Kengo Kuma.

This is the north face of the winning design, which its designers say will produce more energy than it consumes and have a very low carbon footprint.  Photovolatic cells will be on the roof and parts of the the south-facing facade, and the building will have its own batteries to store energy and release it during prime time consumption hours. Alongside natural ventilation it will use absorption chillers to create a cooled environment in summer. In winter rapeseed oil grown within a radius of no more than 100km of Lyon will be used for heating and hot water. In theory the design will use 42kw/h per square metre per year, just half of the energy load set by French building standards. In terms of cost the developers expect the final bill to be about 15% more than if it had been built with less ambitious energy standards, a sum which should be offset by the lifecycle running costs.

We should be able to see for ourselves how that looks in reality by 2014.

For the moment La Confluence has plenty of other cool-looking designs for low-energy architecture fans to feast their eyes on. One of my favourites is the Eiffage building, not because it’s especially pretty, but because of the way thesolar panels are integrated into the facade, rather than resting just above it, and are perfectly angled towards the sun, creating a sun shade on the windows below.

The architects working on Confluence buildings have to follow a set of principles established by Herzog & de Meuron,  which was summed up by one of my energy consultant contacts like this: “Basically the buildings have to look square, and generate a high proportion of their own energy”. The result is a great mix of modern building materials  and textures, and a lot of biomass boilers and solar panels!

For a nice aerial view of the Confluence have a look at http://www.lyon-confluence.fr/, and in the meantime here are a few snaps showing some of the residential, leisure and office blocks populating the site.