While energy efficiency has become the leitmotif of green builders, the road to eco habitats also involves the production of energy within buildings. A subject that is no longer limited to photovoltaics. Since January, the Parisian start-up Ennesys has been proposing to equip buildings and eco-neighborhoods with an unusual energy system. Its uniqueness? Power is provided by the cultivation of phytoplankton, microalgae whose growth is spurred by the wastewater of the building. “All methods of algae cultivation are based on the same principle. We take a body of water in which we inject fertilizer and CO2. Exposed to light, the algae grow by photosynthesis,” says Jean-Louis Kindler, CEO of Ennesys. “They reach maturity in 48 hours and then we can harvest them.” Fruits of that biomass harvest: biomass, vegetable oil (algolipide) and even hydrogen captured during photosynthesis. That’s three energy sources that can be combined to cover the needs of a building and / or sold as biofuels or fertilizer.
A demonstration by the end of the year
For the founders of Ennesys, it’s agreed: their innovation will change the landscape of green building and, even shock that of renewable energies. “In terms of investment and net area occupied, we propose an energy efficiency three times higher than solar. This performance is based on the diversity of items utilized,” said Pierre Tauzinat, President of Ennesys. That’s the theory. In practice, the calculation may be more complex. The system must be adapted to each locale. The modes of acquisition of CO2 and the nature of the wastewater will, for example, vary greatly depending on the sites as would the structures of photosynthesis. To expose their algae-water mixture to light, Ennesys will have to work with the architectural constraints of each building. Photobioreactors integrated within building facades are being considered in particular (see photos). The last uncertainty rests on the treatment of mature algae. “Biomass could be our biggest obstacle. A relatively large volume is difficult to handle. We will therefore focus on installations where the biomass can be processed directly on site (note: stimulation, fermentation …). We want to avoid having to pass a building each day with a truck,” says Kindler. The leader looks forward to building a demonstration installation before the end of 2011, to show the viability of their innovation.
Operating diagram (click to enlarge)
The French market is considered a priority
In terms of sales, the plan of attack is already mapped out. The start-up will primarily target the French market, for chauvinistic as well as opportunistic reasons. “We are currently working on eight projects, three are awaiting final approval,” says Tauzinat. “We arrive at a time when French players of the construction sector are looking for solutions like ours.” Another certainty, Ennesys only equips eco-neighborhoods or buildings with an area exceeding 12,000 m², and an average of 500 inhabitants. With this positioning, the start-up promises its prospects a return on investment in between three and five years, a pledge that’s difficult to assess because the cost of the system remains confidential for now. Beyond financials, Tauzinat also hopes that public developers and contractors will be sensitive to his final argument: the transformation of sewage water into “clarified” water, thus reusability. “This is a major selling point. This speaks to the elect. ” No wonder. According to the site Eaufrance.fr, a French person consumes an average of 150 liters of water per day.
Estimation of energy efficiency (source: Ennesys)
Photo credit: Thomas Ernstig
Ennesys in brief
- Headquarters: Paris
- Created: September 2010
- Launch of activies: January 2011
- Shareholders: OriginOil and PJC (capital increase pending)
- Employees: two
- Objectives: five contracts signed in late 2011, fifteen contracts signed in 2013
- Clients: public developers, developers, private investors
Related content: Biomass, Building, eco-neighborhood, Energy, hydrogen, microalgae, positive building, renewables, wastewater
