New York (AFP) – How to make skyscrapers less energy-consuming and less polluting? New York City, historic capital of skyscrapers, intends to remain a pioneer by forcing them to drastically reduce their energy consumption.
Who says skyscrapers often says glass facades scintillating in the sun, lights in abundance, air conditioning or generous heating, elevators by the dozen… Enough to consume a maximum of energy and emit a quantity of greenhouse gases.
While examples of new towers designed to save energy have multiplied across the world, such as the Shard in London or the Shanghai Tower in China, transforming a building imagined at a time when no one was talking about global warming often requires important and costly work.
It is these buildings that are targeted by the “Climate Mobilization Act”, endorsed at the end of April by the largest American metropolis as part of its global commitment to reduce its emissions by 80% by 2050.
In particular, it obliges buildings over 2,300 m2, or some 50,000 buildings representing one third of New York’s emissions, to reduce their emissions by 40% by 2030 compared to their 2005 level.
By attacking its very dense housing stock, New York has adopted a “revolutionary” law, said Nilda Mesa, director of the sustainable development program at Columbia University.
“It will have many positive effects, such as creating a market and demand for energy efficiency technologies,” which can be used in other American and European cities with comparable climates, she says.
Empire State Building precursor
Although it provides for long-term loan facilities guaranteed by the town hall, the text has been opposed by the powerful real estate sector, frightened by the more than $ 4 billion in renovations it could entail, according to some. estimates.
However, some buildings have already made efforts, such as the Empire State Building, which has “helped show others that we can do it,” says Ms. Mesa.
The legendary New York skyscraper, a jewel of art deco completed in 1931, launched in 2009 a vast renovation program of 550 million dollars, which enabled it to reduce its energy consumption by more than 40% , explains to AFP Anthony Malkin, president of the Empire State Realty Trust, owner of the building.
More than 6,500 windows, three million light bulbs, 67 elevators have been replaced or renovated to improve thermal insulation and reduce the building’s electricity consumption, even as its occupancy density increased sharply.
The skyscraper is also equipped with an ultra-modern energy management system, constantly optimizing consumption as needed.
These renovations, amortized in a record time of four years, make Mr. Malkin serene in front of the new law, even if he admits having “improvements to be made” to reach the objectives of 2030.
Experts agree, however, that reducing emissions is easier in a high-rise like the Empire State than in the glass-fronted skyscrapers that have mushroomed in New York and elsewhere since the 1970s.
The Trump Tower, a 58-story tower erected by Donald Trump on 5th Avenue in 1984, is one example. It is now one of the most energy-intensive buildings in the city, according to New York-based environmental association Align.
Democratic Mayor Bill de Blasio, a 2020 presidential candidate and highly anti-Trump, has threatened her with more than $ 500,000 in annual fines when the law goes into effect.
It is not known whether the Trump Organization has already planned work, the holding company of the American president not having responded to AFP’s requests on this point.
“The market will adapt”
But even for these glass towers, an energy transformation is economically profitable in the long term, assures Jacob Corvidae, an expert in energy consumption of buildings for the environmental organization Rocky Mountain Institute.
One of the ways to cushion the shock, he explains, is to take advantage of a major renovation, essential after 35-40 years, to do work improving the energy balance, making the cost of the latter relatively ” marginal ”.
Another key is to promote a new type of “green lease”, where owners and tenants share the energy savings achieved. Today, most New York homeowners factor the cost of energy into the price of rent, depriving their tenants of visibility into actual spending.
Despite resistance from owners, Ms Mesa is convinced that the market will adapt to the new text.
“Competition is strong in New York, buildings want to be able to boast” of being well managed, she said. “We are still at the beginning, there are a lot of fears. But in 5-10 years, all this will become commonplace ”.