The two south-facing facades are covered in a shell of bioreactors, clear containers that create a controlled environment for an algae farm. Exposed to sunlight, the algae photosynthesise, absorbing CO2 as they grow. Nutrients and CO2 are circulated through the bioreactors to encourage growth. Periodically, the algae are collected and fermented in a nearby biomass plant, then burned to produce electricity.
The BIQ building, which contains 15 apartments, opened its doors in April. Its main source of energy is heat recovery, capturing energy not used in photosynthesis from the bioreactor solution. The façade also acts as a natural thermostat: thick algae growth in the summer keeps the sunlight out.
Energy production from algal photosynthesis isn’t new of course. But the project is the world’s first full-scale bioreactive façade.
The technology was created by SSC Strategic Science Consult, which developed the building in collaboration with Arup, a design, engineering and consultancy firm; Colt International, a project management company; and Otto Wulff, a Hamburg construction firm.
Subject to further tests, SSC claim a conversion efficiency (the amount of light hitting the façade converted to energy) of 10% for biogas and 38% for heat – almost 50% in total. That compares to a typical efficiency of about 15% for PV solar. The heat and power from the bioreactors are also supplemented by rooftop solar panels and an underground heat storage system. The building’s creators claim it can meet 100% of its energy needs.
The main barrier to further adoption of the technology is price. Of the €5 million invested in the project by the German government and IBA Hamburg, an international building exhibition, over €1.3 million financed the bioreactors. However, Martin Kerner, Managing Director of SSC, is confident the technology can become competitive. “We need standardisation of hardware production to reduce costs”, he says.
Demonstrating the efficiency of the algae building could not only prove a source of sustainable energy production, it could also shape future cities, according to Jan Wurm, Europe Research Leader for Arup. “If we can demonstrate microalgae facades, we can transform the urban environment [and provide] architects with a new source of inspiration.”