DEEP IN THE heart of Brussels’ EU quarter sits an apparently ordinary- looking nineteenth-century townhouse which, at first glance, appears no different from most of the office buildings in this corner of Europe’s capital. But this unassuming building at 63–65 rue d’Arlon is in fact one of the most environmentally friendly offices in the world, and its creation has all the hallmarks of a fairy tale.

Once upon a time (not so long ago), a group of European renewable energy associations decided they wanted to share an energy-efficient office. As time passed, their original premises grew too small, but as chance would have it, a modern-day Prince Charming was on hand to help them out. Committed environmentalist Prince Laurent of Belgium offered to rent the group a building he owned in the heart of Euroland, and allow them to transform it into the office of their dreams.

The task was huge. The building was 120 years old, and because it was listed, its structure had to be preserved, meaning that any new technology had to be highly adaptable. Its position posed other problems: the team wanted to install a solar thermal system, but first had to figure out how this could be managed in a building surrounded by towering offices, where every corner of the roof remained at least partially in the shade.

But seven months later the group had managed the unthinkable: an energy-leaky building had been transformed into a state-of-the-art eco-house whose energy supplies are 100% renewable. Heating and cooling comes from biomass, wood pellets, geothermal and solar sources, while electricity is produced using the latest photovoltaic technologies; any extra power that is needed is bought from renewable installations.

The house also benefits from ventilation with a high level of heat recovery, a fully insulated façade and roof,

double-glazed windows placed in front of the original single-glazed windows, and high-efficiency fluorescent lamps. Together, this means that the building’s annual energy consumption is half that of a similar office.

Installing this kind of technology did not come cheap, at around €300,000, but this was a mere 15% of the total renovation costs of €2 million.

Eleven associations employing forty-five people work from the Renewable Energy House, which is open to anybody who wishes to visit. Christine Lins, Secretary-General of the European Renewable Energy Council (EREC), one the organisations living under the house’s roof, likens it to a “renewable energy supermarket” with a full range of energy-efficient technologies on its shelves. However, she is keen to emphasise that the office “is not a museum, but a functional business”. This means that the technology is not just there for show, but it must work efficiently as well. “If, for example, the biomass providing heat did not work, people would be cold and unhappy,” says Lins. But this is far from being the case, and according to her the house is a pleasant place in which to work, giving employees the best of both worlds – “new technology integrated with an old building”.

The house is in the heart of Brussels and was a truly European project, employing the skills of fifty people from fifteen countries. The lack of a common language made life more interesting, and the biggest communication problems were with the Belgian authorities, who were initially reluctant to support the project. They were particularly worried about plans to use geothermal technology, which involved digging four 115-metre-deep vertical borehole heat exchangers. “They were also at first very opposed to solar as they were concerned that the installation of the panels would damage the building,” says Lins. However, their fears proved groundless, and in the end the city authorities are “amazed” by the results, and have even expressed an interest in being involved in similar projects elsewhere in the EU capital.

And other projects there are likely to be. Since the building opened in January 2006, it has received over 4,000 visitors from around the world, and the Prince Laurent Foundation has had applications to fund similar projects in several other countries, including the UK. The owners of the original Brussels house have also just acquired the building next door, which will likewise be kitted out with state-of-the-art technology and will open in January 2008. But the current tenants are unlikely to be disturbed by the renovation work since, as Lins explains, the building is a constant work in progress. “If something new appears on the market then [the house] will be brought up to date,” she says.

Philippa Jones is a Brussels-based journalist specialising in agricultural and environmental issues.