Sonnenschiff: Solar City Produces 4X the Energy It Consumes

Although net-zero projects have been creating a lot of buzz lately in the field of green building, the Sonnenschiff solar city in Freiburg, Germany is very much net positive. The self-sustaining city accomplishes this feat through smart solar design and lots and lots of photovoltaic panels pointed in the right direction. It seems like a simple strategy -- but designers often incorporate solar installations as an afterthought, or worse, as a label. Designed by Rolf Disch, the Sonnenschiff (Solar Ship) and Solarsiedlung (Solar Village) emphasize power production from the start by smartly incorporating a series of large rooftop solar arrays that double as sun shades. The buildings are also built to Passivhaus standards, which allows the project to produce four times the amount of energy it consumes!

The project started out as a vision for an entire community — the medium-density project balances size, accessibility, green space, and solar exposure. In all, 52 homes make up a neighborhood anchored to Sonnenschiff, a mixed-use residential and commercial building that emphasizes livability with a minimal footprint. Advanced technologies like phase-change materials and vacuum insulation significantly boost the thermal performance of the building’s wall system.

The homes are designed to the Passivhaus standard and have great access to passive solar heating and daylight. Each home features a very simple shed roof with deep overhangs that allows winter sun in while shading the building from the summer sun. The penthouses on top of the Sonnenschiff have access to rooftop gardens that make full use of the site’s solar resources. The rooftops feature rainwater recycling systems that irrigate the gardens and while supplying the toilets with greywater. The buildings also make use of wood chip boilers for heat in the winter, further decreasing their environmental footprint.

The project’s simple envelope design is brightened by a colorful and dynamic façade. Gardens and paths cross through the development as well, linking the inhabitants. Offices and stores expand the livability of the community while contributing a sense of communal purpose.