Did you know that constructing a 2-bed cottage has a carbon footprint of 80 tonnes? Yikes! The estimate of 80 tonnes given above is for the construction of a brand-new cottage with two bedrooms upstairs and two reception rooms and kitchen downstairs. Building homes and skyscrapers with thousands of pounds of concrete, steel, and other materials is a major contributor to pollution and energy use.

Today, buildings are responsible for more than 40 per cent of global energy used and one-third of global greenhouse gas emissions, both in developed and developing countries. This makes construction and residences the top 5 causes of environmental pollution.

Why does a building cause so much pollution?

Constructing a building is much more than assembling raw materials. The manufacturing and transport of materials such as wood, steel and concrete account for another eight per cent of energy use.  Not only in terms of energy but the amount of water and electricity used in constructing a building is enormous. For about every 1 sqm of wall construction, an average of 350 litres of water gets consumed and about 30 per cent of the electricity buildings use is generated from coal-burning power plants, which release greenhouse gases, causing climate change. Our homes and office buildings’ lighting, heating and cooling, poor insulation, and integration into the surrounding environment have a lasting impact on energy use and costs.

To reduce that problem, we need some innovations around how we build our houses, offices, and skyscrapers. This is where net-zero and green buildings come in. These constructions are designed and built to create positive impacts on the environment and climate.

They can combine energy efficiency and renewable energy to reduce power consumption, benefit the environment, and improve the quality of life for the people that live or work in those buildings. The concept of green building has been scaling from small houses to big offices and skyscrapers around the globe. Some international certifications have been developed to provide clear guidelines on how to do it.

What can buildings do to become greener?

The U.S. Green Building Council (USGBC) developed the Leadership in Energy and Environmental Design (known as LEED) to rate green buildings and provide owners with a framework of cost-saving, high-efficiency, and health for design, construction, operations, and maintenance. Another popular certification is the Building Research Establishment Environmental Assessment. This is a method from the U.K. Also known as BREEAM.

Zero-energy buildings have on-site renewable power sources like solar panels to try and produce as much clean energy as it consumes. You can’t always do 100%, but the goal is to get as much as you can. The power generated during the daytime is consumed by the facility, and if there’s an energy surplus, the building delivers it to the grid to try and compensate for grid energy consumption at night. However, to improve efficiency, energy consumption needs to be reduced, so heating, cooling, and lighting need to be minimised. To achieve that it’s recommended to integrate things like green roofs, energy-efficient windows with triple-pane glass and a low-emissivity coating, as well as good insulation.

Net-zero buildings are also considered “green” if they’re constructed with non-toxic, eco-friendly, and sustainable materials. They should also use less water and have good air quality, so it becomes more sustainable. Some of the simplest solutions you may have already seen where you work. A good start to making a building more efficient is using high-efficiency LED and smart lighting. Another option could be occupancy sensors that are connected to the air conditioning or fan systems. All of those can contribute considerably to reducing energy consumption.

But taking things to the next level, engineers and architects can perform advanced analysis through 3D building energy simulation tools to achieve higher efficiencies. Some software like Green Building Studio®, Energy Plus, and IES Energy Modeling enables engineers and architects to improve a green building’s design to increase its sustainability. They can perform a climate analysis and HVAC simulations, to optimize what materials to use, and how to orient the building for best efficiency. They can see exactly how the building will fare throughout the year before it’s even built. Examples of green and net-zero buildings have been spreading worldwide over the past decade.

What are some examples of green buildings around the world?

In London, for example, Siemens has built The Crystal, one of the greenest buildings in the world. This highly sustainable building is also a unique events venue. It establishes the benchmark for sustainable building design, achieving the Platinum LEED and Outstanding BREEAM accreditation – the most rigorous standards for sustainable design.

The Crystal is 70% illuminated by natural light due to its triple-glazed windows, and the solar panels produce 20% of the electricity the building uses. Rainwater is collected from the roof and stored in an underground tank for use in the building. 100% of the water used in the toilets is taken from non-potable sources like that. This building cost about £30 million in 2012, but it saves a lot of money with electricity. Peter Daw, Cities Projects Developer at Siemens, said “In terms of CO2 savings, we are saving about 71% compared to an equivalent building. In terms of energy costs, we are saving about £500,000 a year.”

In Seattle, the Bullitt Center is considered one of the greenest commercial buildings in the world. Its structure is mostly composed of heavy timber and the materials were kept to their natural state to avoid the toxins in today’s finishes. And the wood was sourced locally. The triple-glazed curtain wall system, which creates an airtight seal, along with the orientation, provides heat control and improved daytime lighting, so the lights are basically off most of the year. In addition, a closed-loop geothermal system meets the heating and cooling load in the office, and an air-to-air heat exchanger provides incoming fresh air from outside. The Bullitt stores rainwater in a 56,000-gallon cistern in the basement, which is treated and used for non-potable and potable uses, which means they can use it for drinking water.

All of that is well and good for building new buildings, but what about existing buildings? One Embankment Place was built in the early 1990s in London for PriceWaterhouseCoopers, and it’s a great example of zero-energy retrofitting, and today it’s one of the greenest buildings in the world. With new buildings and retrofitting old buildings getting greener…

What’s the forecast for net-zero adoption?

According to one report, the global net-zero energy buildings market share was valued at $896.6 million in 2018 and is expected to reach $2.1 billion by 2024. That’s some serious growth that’s being spurred on by not only policy but the value it drives for building owners. Besides reducing utility bills and zeroing out energy use, it can increase the building’s valuation and isolate owners from future energy price variations.

Then there’s the World Green Building Council — a group of 70 Green Building Councils from around the world — who have, among other initiatives, the Net Zero Carbon Buildings Commitment. This challenges organisation, business, cities, states and regions to make all assets under their direct control operates at zero carbon by 2030. By sharing knowledge and lessons learned, the initiative aims to remove barriers to net-zero implementation and inspire others to take action. Oh, and they also have the little goal of making every building in the world decarbonised by 2050.

In addition to green policies, another approach to reduce cost and improve the efficiency of net zero buildings are newer technologies and techniques currently being researched.

What about walls made of plant materials?

This is still at the experimental stage, but buildings use mycelium, a kind of fungal spore that can be used to fill a form with an agricultural product, and the final result is a solid brick or plate. This composite has no toxic chemicals and doesn’t take a lot of energy to make. This material could be used as insulation between non-biodegradable materials to avoid breaking apart since it is biodegradable. A project using this material was developed by The Living Studio in New York in cooperation with Ecovative Design.

The Hy-Fi Project was a tower about 12 meters high, composed of 10,000 bricks made of mushroom mycelium and shredded corn stalks. When the event ended after three months, the structure was dismantled and the bricks decomposed to compost, exploiting their natural biodegradability. While it’s not primarily for net-zero reasons, using mycelium to build structures is being studied by NASA to grow habitats on the Moon and Mars. It has higher bend strength than reinforced concrete, is a great insulator, and can regrow and repair itself. If it’s good enough for Martians, why not us?

Conclusion

As you can see there are a lot of different options and techniques out there for improving how we build our buildings and use energy to keep them comfortable. Even though the costs are still not universally affordable for all office and skyscraper owners, the development of new materials, technologies, design improvements, and government incentives can help the growth of this market worldwide. It’s pretty easy to imagine high-rise buildings and office parks with green roofs and zero energy popping up in more and more cities in the next few decades.

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