History of the solar tower
The CIS tower has been dominating the city's skyline for over 40 years. Built in 1962 to provide new premises for CIS Ltd, the Miller Street building was then one of the tallest buildings in Europe, and remains the UK's tallest office building outside London.
The architect was Gordon Tait, of Sir John Burnet, Tait and Partners, who was brought in to collaborate with the Chief Architect of the Co-op in Manchester, G S Hay. Tait used millions of mosaic tiles to clad the windowless service tower.
They were inspired by the steel buildings of the Chicago skyline. In recognition of its unique design the tower was grade II listed in the mid-1990s.
Tait used the mosaic tiles in the hope that they would create a shimmering, sparkling column on the Manchester skyline. Sadly pollution and repeated repairs meant the tower eventually appeared more dull grey than shimmering silver. Further problems developed as mosaic tiles began to fall off, exposing the concrete structure to weather damage. An urgent long-term repair was needed.
Retiling the Tower with traditional rainscreen cladding was one technical solution, however, this would have had a highly negative ecological impact. So it was decided that the CIS tower would go solar.
Work commenced in 2004 on an ambitious £5.5m project, which was supported by a £885,000 grant from the Northwest Regional Development Agency (NWDA) and a £175,000 grant from the Department of Trade & Industry. The groundbreaking initiative was pioneered by Solar Century, the UK's leading solar photovoltaics (PV) company. Repairs were made to the concrete structure and the mosaic elevations were enclosed behind a steel mesh before the re-cladding began. 7,244 solar photovoltaic panels, designed to convert daylight into electricity, were manufactured by Sharp Electronics in Japan. The panels were assembled into cladding cassettes, each housing seven panels. The electronics were then tested prior to installation.
The first solar panel was installed to the East elevation on 15th July 2005. New signage for the upper tower, and a nesting box for peregrine falcons were also integrated within the cladding. The then Prime Minister, Tony Blair, switched on the panels on the South side of the building for the first time in October 2005. This was the first time that electricity was fed into the national grid.
The project was finally completed in May 2006.
In a year, the solar tower provides enough electricity to light an average 3 bed house for 300 years.
How solar/photovoltaic cells work
- The word photovoltaic is a marriage of the words 'photo', which means light, and 'voltaic', which refers to the production of electricity. Photovoltaic technology generates electricity from light.
- Electricity is the existence (either static or flowing) of negatively charged particles called electrons. Certain materials, called semi-conductors, can be adapted to release electrons when they are exposed to light. One of the most common of these materials is silicon (an element found in, amongst other things, sand), which is the main material in 98% of solar PV cells made today.
- All PV cells have at least two layers of such semiconductors: one that is positively charged and one that is negatively charged. When light shines on the semi-conductor, the electric field across the junction between these two layers causes electricity to flow - the greater the intensity of the light, the greater the flow of electricity.