High-rise energy horrors tackled| Catherine Triomphe 11 Jun 2019
It's a tall order indeed: How do you make aging, energy-hungry skyscrapers more efficient and less polluting?
The city of New York, the historic capital of the skyscraper, is determined to do so by requiring the enormous buildings to drastically curtail energy consumption.
Traditional skyscrapers are an energy-saver's nightmare, with vast glass facades, lighting everywhere, overly generous use of air-conditioning and heating, and elevators by the dozen. They almost seem designed to consume maximum energy while emitting copious quantities of greenhouse gases.
If a growing number of newer skyscrapers around the world are designed, from the start, to be energy-efficient - London's Shard and Shanghai Tower are two examples - the costs and effort involved in transforming an older building, built decades before the world became conscious of global warming, can be daunting.
And yet those are precisely the buildings targeted by the Climate Mobilization Act, passed in April by New York as part of its commitment to reduce emissions by 80 percent from now through 2050.
It requires buildings of more than 25,000 square feet to reduce emissions by 40 percent by 2030 from 2005 levels, affecting around 50,000 buildings that emit one third of the city's greenhouse gases.
In targeting the dense buildings that account for 70 percent of all city emissions, New York has adopted a landmark law, says Nilda Mesa, director of the urban sustainability program at Columbia University.
"The act is really pathbreaking," she adds. "It will have a number of positive effects. It will basically create a market and create demand for energy-efficient technologies" that can then be used by other cities.
Although the law provides long-term borrowing facilities to help property owners, it was vigorously opposed by the powerful real-estate sector, worried by estimates that the costs of renovation could run more than US$4 billion (HK$31.1 billion).
But some older buildings, like the Empire State Building, have already begun to address the problem, "showing other people how it can be done," Mesa says.
That legendary skyscraper, an Art Deco jewel dating from 1931, launched a vast renovation program in 2009 at a cost of US$550 million, allowing it to cut its energy consumption by more than 40 percent.
More than 6,500 windows, three million light bulbs and 67 elevators were replaced or renovated to improve insulation and cut energy consumption even as it was becoming much more densely occupied.
Engineers also installed an ultra-modern energy management system, constantly optimizing consumption according to the needs of the moment.
With those changes already made - and paid for in only four years - Anthony Malkin, chairman of building owner the Empire State Realty Trust, is feeling sanguine about the impact of the new law. "But we will have to improve for 2030," he says.
But experts point out reducing emissions is easier for an older tower like the Empire State Building than it will be for the glass-clad skyscrapers that seemed to start sprouting everywhere in the 1970s.
A prime example is the 58-story Trump Tower that Donald Trump built on Fifth Avenue in 1984. It is now one of the city's most energy-greedy buildings.
The tower could face fines of over US$500,000 a year under the new law.
But energy updates, even for glass towers, make economic sense when seen over the long term, says Jacob Corvidae, a building and energy expert.
The economic pain can be lessened, he says, by timing energy updates to coincide with the major renovation work that big buildings nearly always need every 35 to 40 years, making their cost "marginal."
Another tactic is to adopt a new type of "green lease" in which owners and tenants share energy savings - giving tenants an incentive to pare back on energy use.
Most owners in New York today build energy costs into rents so tenants have no idea of the true costs.
Despite the resistance of owners, Mesa is convinced the market will adjust.
"New York is a competitive place," she says. "Buildings want to have the bragging rights, and anybody can look it up how efficient buildings are."
In five to 10 years, she adds, resistance will fade and the new law will seem like old news.