Will algae provide energy to buildings?

Nanterre (France) - Parisian office tower buildings covered with algae, which are a source of heating and electricity? A few steps from the Paris business district of La Défense, the French company Ennesys is preparing a new recipe for constructing "green" buildings, writes the AFP agency.
What is its concept? "To produce energy while cleaning polluted water. And to achieve this without using land areas," explains Pierre Tauzinat, president of this young company that relocated to Nanterre in the Paris area two years ago.
In a photobioreactor, a plastic aquarium filled with beautifully green liquid, a strange cocktail circulates hermetically sealed: a mixture of unappetizing waste (toilet water or the "juice" from garbage dumps), which is consumed by tiny algae reproducing at a rapid pace through photosynthesis thanks to light.
Ennesys assures that covering large buildings with these panels can reduce their primary energy consumption by at least 80 percent and 80 percent of water consumption. Office tower buildings could thus save hundreds of thousands of euros each year, if not more.
"Algae have almost the same energy value as coal," explains the company's scientific director Jean-Louis Kindler. He refers to himself as the "chef" of algae at Ennesys. "Moreover, a large part of the oil we discover today is formed from fossil algae," he says.
Ten thousand square meters of Ennesys panels can produce around 150 tons of algae annually. From that, 70 tons of oil can be obtained, a biofuel that can be used, for example, in a generator; the dry waste can be used for heating or electricity production.
As for the water that is 99.9 percent pure obtained through this process, it can be very well used for flushing toilets, which represent the largest water consumption in a building.
Ennesys will build such a structure on the walls of its own offices by September to attract potential interested parties. Its American partner OriginOil will supply equipment to separate algae from water.
The potential market consists of new buildings. From 2020, all newly built buildings will be required to produce more primary energy than they consume.
"For builders, this is a puzzle, and given the multi-year construction timelines, they have to deal with it today to meet the standards; otherwise, they will never be able to sell the buildings," explains development director Christine Grimault.
In addition to the energy produced by the algae, the Ennesys panels will provide a "thermal umbrella" that will prevent excessive heat in the summer and excessive cold in the winter.
The small company has four contracts in the works, the most advanced of which is with a large construction company regarding the construction of a tower building west of Paris. The contract amount is around three million euros (approximately 75 million CZK).
Besides buildings, another area of activity for Ennesys seems promising. It concerns landfills that produce huge amounts of leachate, "garbage juice." Algae love to recycle the "coffee" from highly toxic waste with a repulsive odor and feed on carbon dioxide, allowing them to reproduce.
Regarding vandalism, Jean-Louis Kindler assures that the panels can withstand heavy objects. The only problem that still needs to be solved is protection against the beaks of crows that threaten the facades.