Wooden Skyscrapers? A New Market Rising In Eiffel’s Iron Shadow

France has long been an innovator in building materials, from the steel splendor of the Eiffel Tower to concrete to surprisingly resistant wood. Environmental factors hold sway.

The rise of wooden scryscrapers
The rise of wooden scryscrapers
Richard Hiault

PARIS â€" Canadian architect Michael Green thinks the sky's the limit for buildings made with wood. And it was in Paris, with a project called the Baobab Tower, that the "high priest" of wooden high-rises hoped to prove it.

Controversy surrounding the Tour Triangle (Triangle Tower), a conventional skyscraper planned for the French capital, ended up killing Green's 35-story (120-meter) project â€" at least for now. Paul Jarquin of the company REI France, which collaborated on the Baobab Tower plan along with an architecture firm called DVVD, insists the project has only been postponed.

Even if the Baobab blueprints don't, in the end, amount to anything, the idea behind them â€" that wood can be used instead of steel and concrete to construct multi-story structures â€" is making serious inroads around the world.

France is no exception. The best example to date is the Hyperion project, an 18-story (57-meter) housing tower slated for the southwestern city of Bordeaux. The structure, being developed by a firm called Euratlantique and scheduled for completion in 2020, will be roughly one-third concrete and two-thirds French wood.

On the other side of the country, in the southeastern city of Nice, architect Jean-Michel Wilmotte is working on an even taller wood-and-concrete structure. "The building consists of a concrete cylinder around which two wooden hemispheres are attached," he explains. "With a height of 115 meters for 35 stories, it should include a hotel, offices and apartments."

Wooden skyscrapers aren't only a French trend. All over the world â€" in Australia, Canada, Austria, Great Britain, even Norway â€" similar projects are popping up. "It’s a cultural revolution in which France is playing a part," says Stéphane Bouquet, the head of Ywood, a branch created in 2009 of the French real estate company Nexity. "We are among the pioneers. When we launched into wooden constructions, everyone was skeptical. But not anymore." Among their recent projects is a six-story wooden tower in the Mediterranean port city of Marseilles.

A comeback for CLT

Half-timbered houses from the Middle Ages are proof that using wood for buildings is hardly new. Until now, it was limited to individual houses or mountain chalets, a market that already represents 12% of all constructions. What's new is that builders are starting to think bigger (or taller, to be more precise) for wood-based projects.

Driving the design shift is the emergence of a "revolutionary" material called cross-laminated timber, or CLT. “It’s made up of several strips of wood, generally resinous, each of them crossed at 90 degrees," says Guillaume Poitrinal, head of Woodeum, the French distributor of the Austrian company Stora Enso. "The assembled result can be up to three meters wide. Its thickness can be adapted according to needs, and it can be as long as 16 meters. But most importantly, these boards have a resistance and load-bearing capacity that makes it possible to build towers higher than 15 stories.”

CLT has actually been around for quite some time. The ultra-solid wood was invented in France by Pierre Gauthier all the way back in 1947. But it sunk into oblivion, with builders favoring reinforced concrete and steel. “In France, concrete is almost something natural. Proud of our technological advance with this material, we took a conservative approach," says Poitrinal. "And so northern countries, the Germans and the Austrians, sort of took the product from us. But France can still react. The resource is there."

Wood use is also being encouraged by the risks of global warming, given the high-emissions associated with concrete production. Producing one cubic meter of concrete, according to the consultancy group Carbone 4, emits 471 kilograms of greenhouses gas. CLT has a far lower impact, so much so that if France could triple its wooden constructions by 2030, it would save 3.1 million tons of CO2 per year, or 25% of France’s gas emissions, Carbone 4 estimates.

"Nothing to be ashamed of"

Stakeholders in the construction industry are aware of these changes and are taking great interest in this market in the making. Bouygues Immobilier, for example, is working on an 11-story building in Strasbourg that will be made almost entirely of wood. "Only the ground floor will be made of concrete. Given its significant height, this project will rely heavily on CLT," says Florence Hauvette, the company's eastern regional manager.

Strasbourg's wooden project â€" Source: KOZ ARCHITECTE/Bouygues DD

Much of the CLT used here is imported â€" despite the fact that France has the third largest forest area in Europe. But again, things are changing. The wood sector is one of 10 focus areas in the government's "New Industrial France" project. The industry also celebrated the launch, two years ago, of ADIVbois, an association for the development of wooden housing buildings. "In June, we will start consulting with cities and developers to find five to 10 locations ready to receive 15-story wooden buildings," says Franck Mathis, the association head. "We're also looking into the possibility of 30-story (wooden) buildings."

Talking about a revolution?

The wood construction industry also wants to address what it sees as common misconceptions about the material, namely that it's dangerous, because it burns easily. REI France's Paul Jarquin insists that wood is in fact more fire-resistant than steel or concrete. "In 2001, immediately after the 9/11 attacks, didn’t the two World Trade Center towers collapse? Concrete caves in. Steel melts. But not wooden buildings. And the combustion time of CLT is even longer. I challenge you to set one on fire ," he says.

There are also concerns about deforestation to address. But Cyril Le Picard, head of France Bois Forêt center, has worked out that "only 60% of the natural regeneration of French forests is harvested. In addition to this, our forests are managed on a sustainable basis. When a tree is cut down, another is planted.”

Le Picard sees the construction of wooden high-rise buildings as a chance to revitalize the French wood industry. "At the end of the 19th century, Gustave Eiffel and his famous Parisian tower launched the steel revolution in construction," he says. "The ADIVbois project looks to trigger a new revolution: making wood the preferred material of the 21st century."

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In Argentina, A Visit To World's Highest Solar Energy Park

With loans and solar panels from China, the massive solar park has been opened a year and is already powering the surrounding areas. Now the Chinese supplier is pushing for an expansion.

960,000 solar panels have been installed at the Cauchari park

Silvia Naishtat

CAUCHARI — Driving across the border with Chile into the northwest Argentine department of Susques, you may spot what looks like a black mass in the distance. Arriving at a 4,000-meter altitude in the municipality of Cauchari, what comes into view instead is an assembly of 960,000 solar panels. It is the world's highest photovoltaic (PV) park, which is also the second biggest solar energy facility in Latin America, after Mexico's Aguascalientes plant.

Spread over 800 hectares in an arid landscape, the Cauchari park has been operating for a year, and has so far turned sunshine into 315 megawatts of electricity, enough to power the local provincial capital of Jujuy through the national grid.

It has also generated some $50 million for the province, which Governor Gerardo Morales has allocated to building 239 schools.

Abundant sunshine, low temperatures

The physicist Martín Albornoz says Cauchari, which means "link to the sun," is exposed to the best solar radiation anywhere. The area has 260 days of sunshine, with no smog and relatively low temperatures, which helps keep the panels in optimal conditions.

Its construction began with a loan of more than $331 million from China's Eximbank, which allowed the purchase of panels made in Shanghai. They arrived in Buenos Aires in 2,500 containers and were later trucked a considerable distance to the site in Cauchari . This was a titanic project that required 1,200 builders and 10-ton cranes, but will save some 780,000 tons of CO2 emissions a year.

It is now run by 60 technicians. Its panels, with a 25-year guarantee, follow the sun's path and are cleaned twice a year. The plant is expected to have a service life of 40 years. Its choice of location was based on power lines traced in the 1990s to export power to Chile, now fed by the park.

Chinese engineers working in an office at the Cauchari park


Chinese want to expand

The plant belongs to the public-sector firm Jemse (Jujuy Energía y Minería), created in 2011 by the province's then governor Eduardo Fellner. Jemse's president, Felipe Albornoz, says that once Chinese credits are repaid in 20 years, Cauchari will earn the province $600 million.

The Argentine Energy ministry must now decide on the park's proposed expansion. The Chinese would pay in $200 million, which will help install 400,000 additional panels and generate enough power for the entire province of Jujuy.

The park's CEO, Guillermo Hoerth, observes that state policies are key to turning Jujuy into a green province. "We must change the production model. The world is rapidly cutting fossil fuel emissions. This is a great opportunity," Hoerth says.

The province's energy chief, Mario Pizarro, says in turn that Susques and three other provincial districts are already self-sufficient with clean energy, and three other districts would soon follow.

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