English enlightenment.

Innovatively exploiting site characteristics, renewable energy sources and low energy construction, this project for new council offices aims to generate a model for sustainable practice.

In the last 40 years, emissions of carbon dioxide have increased by 200 per cent, with a consequent deleterious effect on the global climate. Currently, buildings account for about half of total man-made carbon dioxide emissions. This competition-winning project for local government offices in Hyndburn, Lancashire, by Jestico + Whiles innovatively exploits natural site characteristics, renewable energy sources and energy conscious construction, to minimize carbon dioxide emissions and reduce running costs. Its architects describe it as the first public 'zero-energy' building in the UK, heated and powered entirely from renewable sources. Moreover, as a major civic building, it also aims to generate a model for environmentally sustainable practice that could be adopted by other agencies.

The site, a former colliery and railway line, lies on the southern edge of Hyndburn. It is surrounded by rising hills and the remnants of Victorian industry; old cotton mills and the stanchions of the Manchester railway line are still evident. To one side lies a 'lodge' or reservoir, originally built to provide water power for cotton production. The town's local authority offices and public facilities are presently housed in a variety of ageing and costly buildings. The aim is to amalgamate them into a new building, to decrease operational costs and provide improved public services.

The new building is on the south edge of the site, next to the reservoir. The remainder of the site will be transformed into a public park. Rather than being an aloof municipal object, some attempt is made to integrate the building both physically and conceptually with the town and its inhabitants. A new path winds from the town through the park, animated by sculptures and information points outlining the wider issues addressed by the building, its operational systems and the ecology of the site. A new cycle path also passes next to the building, linked to the national cycle route by means of a lightweight bridge structure cantilevered from the old railway bridge supports.

The four-storey building is divided into two wings, variously housing council offices, meeting and consultation rooms, wrapped around a distorted ovoid containing the council chamber and a pivotal atrium. Using high levels of insulation, well in excess of current British standards, the building envelope is intended to minimize heat loss. Reinterpreting the thermally massive construction of local cotton mills, the gently curved north elevation (which forms the building's civic aspect) is constructed from reclaimed stone. The south elevation overlooks the reservoir, and is predominantly glazed to maximize daylighting and benefit from passive, low-level winter solar gain. Daylighting is further enhanced by means of a linear lightwell through the length of the building which, in turn, acts as a thermal stack to help draw ventilating air through the building. Air is introduced by means of a raised floor, controlling draughts and enabling the structure to be cooled during summer nights and prevent overheating. Excess solar gain is controlled by prismatic glazing and shading.

Energy will be supplied from a combination of photovoltaic, wind and water power to sustain a projected requirement of around 180 000 kWh per annum. Initial on-site monitoring indicates that the roof-mounted photovoltaic installation will generate around 35 000 kWh, with the remainder provided by a single wind turbine located in parkland to the south of the site. Exploiting the existing site provision, an air-to-water heat pump will generate thermal energy for winter heating, using the reservoir as a source. Jestico + Whiles have clearly been fortunate in having a client body with an enlightened concern for energy use and the environment, and it will be fascinating to see if the building lives up to the high expectations of its architects, clients and users.