Be they sceptic, activist, or just perplexed, people these days can scarcely avoid a discussion on climate change and its possible impacts. Part of the perplexity lies in knowing what and how to prioritize: how do we know what we need to concentrate on, if we are to truly combat global warming?
Urbanization is a key global megatrend presenting one of the biggest challenges to sustainable development. Understanding and learning to guide our shifting urban patterns of living has become the priority for many planners and decision-makers, something that can lead to solutions such as eco-cities. And since buildings account for 40 percent of energy usage worldwide, many believe that focusing on the design and energy efficiency of buildings themselves will make a significant contribution to reducing carbon emissions. Jan Klerks, research and communications manager at the Chicago-based Council on Tall Buildings and Urban Habitat (CTBUH), is one of a variety of experts working with the idea of efficient – while attractive – urban density as embodied in tall buildings.
Building green
Klerks thoroughly understands the complexity of sustainable solutions. “Sustainability sometimes feels like trying to nail a jellyfish onto the wall,” he concedes. “The moment you think you’ve thought through some sustainable policy, you might find yourself in a position in which unexpected counter effects offset the initial gains. It is a holistic, complicated and interactive system in which nothing moves independently.” What, then, is the role of the Council? “We consider it an important mission of the CTBUH to find and support ways in which the design, development, construction, management and usage of tall buildings can contribute to a more sustainable society as a whole.” Why the focus on tall buildings? “Densities allow for faster movement of goods, people and ideas. Tall buildings could play a substantial role in this.”
According to Klerks, sustainable building is an evolutionary process. “It involves many little insights, inventions, initiatives and policies that make buildings gradually more energy friendly, more durable, and so on. Solutions are aimed towards reducing the use of energy, transportation costs and creation costs; and increasingly towards the creation of energy, carbon neutral development, and the like.”
How do we know when we are making progress? Are certification systems like LEED® (Leadership in Energy and Environmental Design) Green Building Rating System and BREAAM (Building Research Establishment Environmental Assessment Method) useful tools? “Being visible objects in dense urban areas, tall buildings are ideal subjects for LEED and BREAAM certification, not only because of the size of development, but also for being able to become a present example of sustainable development. Especially for companies whose business is about intangible services (like financials), a sustainable policy is a good way to express their involvement and responsibility to the outside world.”
What can we do about the infrastructure we already have? Is it worth modernizing our current building stock? “Given that most buildings have already been built, retrofitting existing buildings could have a far bigger impact than making new developments sustainable. The retrofitting plans of the Willis Tower in Chicago and the Empire State Building in New York are two instances of this in practice.”
Balance and compromise
Aiming for energy efficiency and optimal density in building always means looking at both inputs and outputs. The design of the structure has to balance the performance of the building and the needs of the client with the demands of the location within the urban and geographical context, the need for low or no unfavorable ecological impacts and the financial considerations – not to mention aesthetic and functional attractiveness. Technological innovations and guidelines help, but the peculiarities of local conditions and the need for a holistic approach considering the urban infrastructure complicate the process. Klerks explains further: “Urban density can be an opportunity, but there’s also a danger in mixing the wrong ingredients. It takes a thorough process of urban planning to ensure typical urban functions don’t get in each other’s way and create unpleasant environments because of it.”
Learning from nature
And what about the future of sustainable building? What does a ‘zero net energy’ building look like? Many experts expect to see increasing use of biomimicry techniques in architecture to more closely reflect the local environment. Klerks explains that in this kind of design, certain ecological characteristics can be used to the building’s advantage, such as wind current and sun paths.
“This is part of an ecological design process, in which one tries to incorporate existing flows into the design of the building, so they become an integral part of it.”
Moreover, Klerks suggests that not only energy-efficiency and energy-saving developments will continue to evolve, but the actual creation and sharing of renewable energy by individual buildings themselves is one promising route. “Energy could be more of a network industry involving many suppliers,” offers Klerks. “This however requires quite a bit of technical development.”
This kind of zero net energy strategy for buildings could nearly halve the expected growth in electricity demand worldwide, according to a study by McKinsey. With such a positive gain, an energy-neutral approach seems less a compromise than a necessity.