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The taller the building, the harder it is to deliver Paris Proof. | Credit: Adobe Stock

Building Paris Proof is already a challenge, but with high-rise buildings it is even more so. So how do we ensure that high-rise projects in the future also meet the agreements of the Paris Climate Agreement? Arcadis made calculations and simulations. "It is feasible, but only if we take it into account from the first sketch."

New buildings in the Netherlands must currently meet BENG (Nearly Energy Neutral Buildings) requirements. This means they are energy efficient, but not yet energy neutral. The dot on the horizon is a lot more ambitious than that. In the future, buildings must comply with the Paris Climate Agreement, i.e. Paris Proof, which means that new buildings must not contribute in any way to climate change.

CO2-neutral new construction

The Paris Climate Agreement contains all kinds of detailed guidelines. These set out exactly what different buildings must meet in order to comply with the agreement. For existing buildings, for example, Paris Proof means thoroughly improving energy performance. Martijn Goossens, sustainability specialist at consultancy and engineering firm Arcadis: "In principle, that is quite doable. We now know what to do to make existing buildings Paris Proof."

With new construction projects, it's a bit trickier because the requirements are a lot stricter. New buildings must soon no longer contribute to climate change in any way. In other words, they must be truly energy neutral (WENG). This is a challenge, but clients are increasingly asking for it. "In low-rise projects we are already getting that done. But many Arcadis projects are actually medium- and high-rise buildings," says Goossens. "Think ten, fifteen, twenty stories high. Then we quickly run into technical problems and limitations. That doesn't just apply to Arcadis, by the way; everyone struggles with this."

What does Paris Proof building mean?

A building is Paris Proof if its operational and embodied emissions meet the guidelines of the Paris Climate Agreement. The operational part is about the emissions a building emits during its lifetime. From building-related energy use, such as heating, cooling, ventilation and lighting, to use-related energy use, such as laptops and coffee makers. Embodied emissions are in the materials the building is made of.

The problem of high-rise buildings

What makes it so difficult to go to height with Paris Proof? And how do you get it done anyway? Arcadis researched it for the operational emissions of high-rise projects and wrote a paper about it. "The higher you build, the more people use the building. And the more people, the higher the energy consumption," Goossens outlines. "That's problematic, because you quickly need one solar panel per user to cover usage-related energy consumption alone in a sustainable way. But the roof area of a tall building is limited. And wind turbines are usually not an option either, because high-rise buildings are mostly found in urban areas."

"So a roof full of solar panels is far from sufficient to cover the energy consumption of, say, an office tower," he continued. "You therefore need other and more extreme measures to arrive at Paris Proof."

The key role of the architect

A Paris Proof high-rise project therefore begins at the drawing board. "Certain choices have to be made already at the first design sketches, otherwise Paris Proof building becomes a difficult story right away," says Goossens. In particular, an efficient building design is an absolute must. The prime example is a cube-shaped building. This is because a cube-shaped building has much less wall surface area (read: the walls, windows and roof of the building), from which energy can "leak" in the form of heat and cooling. For a similar building but with an L- or U-shape, the facade area rises sharply, allowing more energy to "escape," and thus the building's total energy use is much higher.

"For a building that has to meet BENG standards, we can correct that difference in energy loss with installation solutions," says Goossens. "But for a Paris Proof building, that's not an option. Then the building must have an efficient and compact form, otherwise it simply won't work."

Solar panels on the facade

But even with an efficient building form, all kinds of measures must still be taken to achieve Paris Proof. Funnily enough, better insulation is not one of them. "The insulation of new buildings, complete with solar control HR+++ glazing, is already very good these days, there is little room for improvement there," Goossens explains. "Improving insulation further might give you a percent improvement over BENG."

So what does make an impact? For starters, as many solar panels as possible on the east, west and south facades are essential. But that is easier said than done, says Goossens: "First of all, solar panels on the facade currently still have quite a price tag. So if a client is primarily looking for the cheapest possible building, it is quickly no longer an option." In addition, the available facade area is often limited. Here again, the architect plays an important role, Goossens argues. After all, the smaller the window area, the more room there is for solar panels.

Glass boxes are a thing of the past

Arcadis published a long list of other measures that together contribute to making high-rise buildings Paris Proof. For example, shading is normally not done in high-rise buildings, but for a Paris Proof building it is actually indispensable. "Otherwise, your energy consumption for cooling simply remains too high," Goossens said. In addition, the open/close ratio of buildings can be adjusted. "Glass boxes are a thing of the past in that respect," he continues. "If you reduce the glass area of buildings from 80 to 50 percent, that has a huge impact. Lower than 50 percent, on the other hand, is again inadvisable, because then not enough daylight enters and energy consumption for lighting skyrockets."

Curious about all the measures Arcadis recommends? containing all the recommendations .

It can be done, but...

Arcadis' whitepaper shows that Paris Proof high-rise buildings are possible, which is good news. But it's certainly not easy. "On paper it is now clear what needs to be done, but that is no guarantee for practice," said Goossens. "It involves many and far-reaching measures, which are not easy. It therefore requires a lot of commitment and courage from all parties involved. And it stands or falls with the choices made at the drawing board."

But if everyone is on the same page, it is possible. And that is a good thing, concludes Goossens: "Ultimately, the entire built environment must meet the guidelines of the Paris Climate Agreement. So high-rise buildings must also comply."

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