A NORTH-EAST architectural firm has worked with Cambridge University to develop a system that could allow more historic buildings to meet carbon reduction legislation.

Sadler Brown Architecture designed “solar trees” after planning regulations meant Cambridge University Library’s grade II-listed archive stores had to offset ten per cent of the energy requirements for a new extension by renewable means.

Because of the historic nature of the library building, designed by Sir Giles Gilbert Scott, whose other work included Britain’s traditional red phone box, putting solar panels on the roof was not an option.

As a result, Sadler Brown, working with photovoltaics firm EvoEnergy, developed the idea of streetlight-height solar trees. It is believed that the system could be used in other listed or unusual buildings to meet carbon reduction targets.

Sadler Brown director Christine Howe said: “Finding a renewable energy source for a listed building can be challenging. We knew we would have to think outside of the box to develop a solution that was in keeping with the traditional design of the library while also generating enough energy to satisfy building standards.”

Inspiration for the design of the solar trees was taken from the windows of the library building, which are reminiscent of red phone boxes.

Ms Howe said: “Sir Giles Gilbert Scott’s influence is clear to see in the windows of the library, which are made up of clusters of small squares.

“Using square glass sheets with photovoltaic panels to create the ‘leaves’ of the solar trees allowed us to establish synergies between the traditional building and the modern additions.”

Dr Kevin Hard, managing director of EvoEnergy, said: “This project has really demonstrated how we can integrate new technology that is sympathetic to the requirements of listed buildings and our increasing need for clean energy. Cambridge University and Cambridge City planning department were incredibly accommodating and allowed us to push the boundaries to develop an innovative, attractive and vandalism-resistant solution.”

The four trees, which went from design to installation in only ten months, generate enough energy to power a large family home each year.

They are part of the final stage in a £40m extension to the library, which holds at least one copy of every book published in the UK and Ireland.

Sadler Brown Architecture, in Newcastle, was formed this year following a merger between Hopper Howe Sadler and Reid Jubb Brown.