To become net-zero is an applaudable achievement, but an entire city in Germany has gone even farther by becoming net positive, generating 4x the amount of energy it needs. The self-sufficient Sonnenschiff solar city in Freiburg was able to begin producing such a substantial amount of energy by installing an incredible amount of photovoltaic panels to harness solar energy.
The Sonnenschiff (Solar Ship) and Solarsiedlung (Solar Village) were designed by Rolf Disch and started out as a vision for an eco-community. Disch wanted to create a space that balances size, accessibility, green space and solar exposure.
The Sun Ship is the service center for the Solar Settlement in Freiburg – and the first commercial PlusEnergy building. It extends itself over 125 meters along a main road and functions as a sound barrier for the housing community on its opposite side. The Sun Ship is three stories, with a northern front section that is five stories. Embedded in roof garden landscaping, nine exclusive three level penthouses were constructed. In two underground floors you will find storage rooms and a parking garage with 138 parking spaces.
All of the houses are wooden and built only with healthy building materials, all with large photovoltaic roofs as well. The color concept was developed by a Berlin artist, Erich Wiesner. The premises remain auto-free thanks to the parking garage underneath the Sun Ship and the well organized Car-Sharing system.
Now, 52 homes make up a neighborhood anchored to Sonnenschiff, which is a mixed-use residential and commercial building. As Inhabitat reports, advanced technologies such as phase-change materials and vacuum insulation have helped to boost the thermal performance of the building’s walls system.
The Solar Settlement is an ensemble of multistory townhomes and a commercial building, the Sun Ship. The 59 homes are divided among 11,000 m2, 9 of which are penthouses on the Sun Ship roof. The single homes range from 75 to 162 m2, all the homes together with over 7,850 m2 of floor space. All of them are PlusEnergy homes, which produce more energy than they consume and whose supplementary income heavily outweighs the low additional costs.
Each home in the community is designed to Passivhaus standard and has great access to passive solar heating and daylight. Additionally, a simple shed roof with deep overhangs is installed on every home, allowing winter sun in while shading the building from the summer sun. Disch made sure to incorporate a series of large rooftop solar arrays on each house when planning the community, as he knew they’d be essential for generating more energy than the collective needs.
The Sun Ship offers infrastructure for a city catchment area of about 25,000 people. To a considerable extent many of the businesses who settled in the building cater towards the sustainability industry, and thus it became an important ecological and economic pulse transmission for the region and beyond.
The Sun Ship with the penthouses in the background / image by Rolf Disch / source Rolf Disch
The Solar Settlement generates 420,000 kWh of solar energy from a total photovoltaic output of about 445 kW peak per year. If one calculates the energy savings from the optimal efficiency, here annually 200,000 liters of oil and 500 tons of CO2 are saved. For the first time worldwide, even until today, PlusEnergy was implemented as a community in Freiburg – receiving heavy worldwide response and exciting awards.
On top of the Sonnenschiff are penthouses, where residents have access to rooftop gardens and a plethora of solar resources. The rooftops also feature rainwater recycling systems that irrigate the gardens. Toilets are supplied with greywater. Even during Germany’s cold winters, residents have all the resources they need. Every building makes use of wood chip boilers for heat and this further decreases citizen’s environmental footprint.
Simultaneously an ethical-ecological financial investment / image by Rolf Disch / source Rolf Disch
For the undertaking, financing and marketing of this PlusEnergy pilot-project a building development company was founded. A portion of the marketing was completed through four ‚Freiburg Solar Funds, corporate real estate funds and simultaneously an ethical-ecological financial investment.
In the spring, one can mosey through the development and gaze up a colorful and dynamic facade. Gardens and paths link the inhabitants and offices and stores add to the practicality of the community.
Rolf Disch speaks about the Solar Settlement and necessity of PlusEnergy