Aktiv-Stadthaus, a net zero residential building in Frankfurt, Germany of 11,700 m2, built in 2015.

It’s World Green Building Week, with Green Building Councils from across the world campaigning for all buildings to be “net zero” by 2050.

The intention is to promote the aspirations published in its report earlier this year, From Thousands to Billions – Coordinated Action towards 100% Net Zero Carbon Buildings By 2050, which calls for a dramatic and ambitious transformation towards a completely zero carbon built environment.

The plan is for all new buildings to be operating at net zero carbon from 2030. It advocates that net zero carbon buildings must become standard business practice as soon as possible, to avoid the need for future major retrofits and prevent the lock-in of carbon emitting systems for decades to come.

It wants to see not just an acceleration of current renovation rates, but these renovations to be completed to a net zero carbon standard so that all buildings are net zero carbon in operation by 2050.

The route to net zero

Ten national GBCs are already working with stakeholders in their markets to create or adopt voluntary net zero carbon building rating systems and support training. These include Australia, Brazil, Canada, Germany, India, Netherlands, South Africa, and Sweden, and UK.

Each national council is developing a program suitable for their markets, and each will respect the following principles:

  1. to use carbon as the key metric
  2. to promote deep energy efficiency
  3. to establish a hierarchical preference for onsite renewable energy, off-site renewable energy, and then offsets
  4. to transparently disclose how each building achieves a carbon balance and promote continuous improvement of the building sector

Achieving the targets would help to ensure that the worst impacts of climate change are avoided, and bring about a number of other political and economic benefits, says the WGBC. These include future-proofing investments, resilience against energy prices, education, technology development and innovation, and new jobs.

The report goes on to describe several net zero buildings in existence today, and suggests that businesses can help by committing to invest in, build or occupy only properties that will achieve net zero carbon.

NGOs have a part to play here. They can help to develop certification programs for net zero carbon buildings for businesses to adopt and support governments to create roadmaps, incentives and tracking systems.

Governments can help by committing, perhaps as part of their work to meet the goals of the Paris Agreement on climate change, to develop national and/or sub-national regulations for new and existing buildings to achieve net zero carbon standards, as well as themselves occupying only certified net zero carbon buildings before 2030.

One thing governments or NGOs could also do is to keep track of the rates of “deep energy renovation” of buildings in their country.

To achieve the 100 per cent net zero carbon by 2050 goal, this global average rate of renovation must reach three per cent a year if we start in 2017, or higher if we start later.

The current market

But that is currently a distant dream. The best estimates from building inventory studies are that there are approximately just 500 net zero energy commercial buildings and 2000 net zero energy housing units worldwide.

The Global Alliance for Buildings and Construction reports that current average renovation rates around the world are just one per cent or less of the existing building stock each year.

The European Union has the highest number of net zero buildings, due to government-sponsored retrofit programs and a history of progressive policies and market interest.

North America is estimated to have the second-largest concentration of net zero buildings. These include many smaller commercial buildings and single-family homes, especially in the western and northeast states.

Residential buildings comprise the highest number and type of net zero projects built to date, but many are single-family homes built as demonstration projects. Office blocks come second by type.

Some public-sector projects built to net zero standards in India, South Africa and the US have floor areas of over 30,000 square metres, but most buildings are under 900 square metres.


There’s an urgent need to identify and overcome the barriers preventing more net zero carbon buildings from being built.

There’s still widespread ignorance that such buildings are possible and, even if a client may have heard of them, a perception that they are either technically difficult, risky or expensive.

This is coupled with uncertainty about which technologies should be deployed and whether energy efficiency or renewable energy should be prioritised.

As a result, client demand is still low and technical know-how rare. Most of the research and evidence has focused on net zero energy buildings – which is much harder and likely more expensive to achieve than net zero carbon buildings.

For example, a 2013 report by International Living Future Institute, New Buildings Institute and Skanska stated that the average cost premium for three net zero energy buildings in Columbia, US was between 5-12 higher.

In practice, investor and owner return on investment in a net zero building can vary greatly, depending on they building type and where it is built, taking into account energy costs, incentive programs and climate policies, such as a tax on carbon.

The need for certification schemes

The WGBC believes that only by introducing voluntary net zero certification can the necessary market transformation occur.

For example, in Australia green building certification schemes promote holistic approaches to sustainable development beyond energy performance (such as water, waste, ecology, materials), and increase global awareness.

The green building market has grown over the past 15 years, including through the introduction of rating tools. Green Star has provided a common language for the property and construction industry to use when describing best practice.

Now, 30 per cent of Australia’s CBD office space has Green Star certification, up from 23 per cent at the end of 2014 and, on average, certified buildings produce 62 per cent less greenhouse gas emissions than average Australian buildings.

The benefits to investors are that as the real estate investment market responds to the call to combat climate change, net zero carbon assets will have the lowest operating costs and be the most de-risked and, therefore, highest-quality assets.

 David Thorpe is the author of  Energy Management in Building and Sustainable Home Refurbishment.

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