Solarsiedlungen North Rhine Westphalia: Building with the sun

At the end of the 1990s the Energy Agency of North Rhine Westphalia (EA.NRW) launched the "Mit der Sonne Bauen" project. The aim of this project was to build 50 new housing estates "with the sun". In conjunction with the Federal state of North Rhine Westphalia  the workgroup "Bauen und Wohnen" (= Building and Living) of the EA.NRW drew up plans to develop 50 so-called Solarsiedlungen in the new millenium.

The aim of this initiative was to greatly reduce the energy requirements of housing by appropriating solar energy and also to provided the energy needs of the residents by using sustainable sources. Three requirements were defined. For a housing estate to be eligible for the title of "Solar energy housing estate" at least two of the three requirements had to be met. The specific requirements for a "Solar Estate" are:

·         Heat energy consumption: max. 15 kWh/m²a (passive house standard) or max. 35 kWh/m²a. Use of the suns energy, earth warmth en/or extra insulation to achieve an low-energy of passive house.

·         Production of hot water: The solar energy contribution is to be at least 60 % of the energy requirements for the production of hot water for heating and domestic daily use..

·         Electricity: The production of electricity by photovoltaic cells should be at least 1 kWh per housing unit. 

To make these example projects in sustainable housing development possible the State government of North Rhine Westphalia coordinated all the subsidies granted by several ministries to provide a lasting and dependable financial framework. This is one of the reasons why this initiative succeeded in Germany (here NRW) whilst so many in other countries fail or only see a small number actually realised, as the funding is redirected or not guaranteed for long enough.

The government of North Rhine Westphalia invited local councils to come up with projects for Solar Housing Estates. This makes this initiative an excellent example of true bottom-up planning. Most large cities provided proposals, but also quite a number of smaller communities. The proposals submitted included both new housing, but also the redevelopment of existing estates or the sustainable refurbishment of extant social housing.

Most developments are rather small in scale. They vary from 15 new houses to a few hundred apartments in several blocks being refurbished. Most new housing can be classified as infill or redevelopment of brown field sites. As such these developments also know a more sustainable planning regime. As infill developments most of these housing estates are comprised of 20 to 40 buildings with several housing units arranged along cul-de-sacs or car free streets. As part of the design there is often a focus on stimulating cycling and walking -in a way similar to Danish and Dutch examples.

All in all these Solarsiedlungen are rather incidental in character both in scale, situation and embedding in the urban context. As example projects they are very successful. The architecture of the housing is often an expression of the sustainable measures included in their construction, much like in EVA-Lanxmeer. This results in what can be best typified as eco-architecture with vegetation roofs, sun boilers, photovoltaic arrays on roofs and sheds, wooden panelling and loam render on the facades, rain chains hanging from overhanging roofs, water rills in the pavement, open pavements, sustainable urban drainage and so on.

The Solar Housing Estates have been built -and are being built- all over the state of North Rhine Westphalia. Image after project information sheet EnergieAgentur.NRW.

In 15 years time the planned 50 Solar Housing Estates with 4300 housing units have been either finished or are in the process of being being built. More will be developed using the same regulatory framework. This makes North Rhine Westphalia a forerunner in Europe when it comes to sustainable housing development. The lessons learnt should now be extrapolated to "normal" developments and be made mandatory for all (re)developments. I always say: "you don't just talk about sustainability in project, you simply do it - always and everywhere".