How to Get to Zero-Carbon Buildings

October 13, 2019 – In 2050 the United Nations forecasts world population distribution will largely be urban-centered. They project 68% of humanity will live in cities. In these cities, the vast majority of construction will have been built prior to the development of any green or net-zero building standards. In fact, the estimate at that time will be that 65% of all buildings will pre-date the beginning of zero-carbon initiatives. It is much easier to implement net-zero carbon in new construction, much harder in legacy buildings.

Here are some of the challenges:

• energy-efficiency will need to be implemented into all building codes in cities around the world.
• cities will have to create rewards and penalties and milestones to ensure builders comply with the new building codes.
• energy usage in buildings will need to be cut by 50 to 85% addressing heating, cooling, hot water, and lighting, the primary loads that in the United States account for 75% of the energy consumed in the sector, and between 40 to 50% of total energy demand worldwide.

To deal with these challenges do new builds and rehabs need as of yet uninvented technologies?

No. There are a number of buildings already incorporating materials and technologies that make zero-carbon a reality.

• Light-emitting adjustable panels and blinds can minimize the need for interior lighting.
• Smart windows exist that both allow heat to escape in the height of summer while filtering outside air to refreshen interiors.
• Green walls of living plants can offset carbon emissions and improve interior air quality.
• Solar windows can generate the energy a building uses for lighting, heating, and air conditioning.
• Storage systems can capture the surplus energy generated by renewable sources to provide 24-hour power.
• Gray water systems can purify and recirculate to minimize external freshwater use.

It is estimated that in 2030 more than 50% of all buildings in cities will have been built before green building standards for net-zero emissions were conceived. How, then can these buildings be retrofitted to be low-carbon. Remember, the goal here is to achieve carbon reductions. Here are some of the ways:

• Changing the energy source being used to provide heating and cooling.
• Low-rise buildings with flat roofs can become solar energy producers.
• Retrofits using heavier insulation, high-performance windows, and ventilation heat recovery systems can reduce energy requirements by up to 90%.

The above plus many of the solutions that are being applied to new builds are all feasible for older construction.

The World Green Building Council defines green buildings to include:

• intelligent approaches to energy throughout the building’s life cycle.
• integrating renewable and low-carbon technologies.
• safeguarding freshwater resources.
• minimizing waste and maximizing reuse and recycling.
• promoting interiors that provide for health and wellbeing through better indoor air quality and ambient temperature, avoiding the use of materials and chemicals considered harmful, incorporating natural light, improving acoustics and sound insulation.
• creating green spaces both within and around buildings.
• designing for resilience against flooding, fire, earthquakes and climate change.
• creating dynamic buildings designed not to become obsolete.
• minimizing the necessity for personal transportation by building mass transit infrastructure, and making sure buildings incorporate communities and amenities to create a positive economic and social environment.

For more information on achieving net-zero results visit the Canada Green Building Council.