On November 29th, French biotech startup Ennesys will launch its first demonstrator system for “truly green” buildings in the Nanterre district of La Defense near Paris. It’s a simple idea: to turn buildings into energy production units by using green algae.
The concept, says Ennesys CEO Pierre Tauzinat, is “to produce energy while purifying the wastewater of buildings, and without using cropland”. Tauzinat will present this unique technology to developers and American architects at this year’s Greenbuild International Conferences and Expo, held at the Moscone Center in San Francisco.
Ennesys is a pioneer in the brand-new “urban algae” sector, which deploys algae on walls and roofs of buildings to help achieve a positive energy balance and uniquely, purify water in the process.
Coursing through “photobioreactors” made of polycarbonate or glass, and using only light, wastewater and CO2, the algae can be harvested every 24 to 48 hours. At the end of the growth cycle, the algae is harvested using Los Angeles-based OriginOil’s Algae Appliance™ and then processed into a bio-feedstock that has nearly the same energy value as coal.
Because the harvesting process uses no chemicals, the water used to grow the algae can be recycled into the growth system. Alternatively, once the algae has absorbed the nitrates, the water can then be used as “grey water” in building plumbing systems.
As a bonus, the bioreactors on outside walls are a heat shield that moderates building temperatures, making for a cost-effective insulation system.
Under optimum conditions, one hectare (about 2.5 acres) of photobioreactors can produce up to 150 tons of algae per year and is thought to reduce water consumption and primary energy needs by up to 80%; savings which can amount to six figures per year for large office towers.