Net-zero feels like the ultimate green goal for our buildings to reduce their collective impact on the environment. Currently responsible for 39% of global carbon emissions, the decarbonization of the buildings sector has long been seen as one of the most effective ways to mitigate the worst effects of climate change. The reality, however, is that net-zero is not that easy to achieve and very few buildings can truly claim to be fully net-zero over their entire lifecycle. The solution may be technical in practice, but can only be brought about by a significant shift in governmental policy towards buildings and the environment.
“Climate change is undoubtedly the greatest challenge of our times. We need to take urgent action to almost halve global emissions by 2030 and eliminate them completely by the middle of the century,” says Julie Hirigoyen, Chief Executive at UKGBC. “It is in this context that the term ‘net-zero carbon’ has started to enter the mainstream. Businesses, government, and civil society are all grappling with what net-zero carbon will mean for them and how it can be achieved in practice.”
Net-zero, in practice, can be achieved by implementing a range of green approaches throughout the building lifecycle. A good start is construction, where carbon emissions should be driven down for the selection and production of building materials, as well as their transportation and installation. However, design lays the foundation for construction, so in order to set the stage for net-zero construction, we must design with these environmentally responsible intentions in mind. Building design also has fundamental implications for operational energy efficiency, so to truly bring about net-zero as a standard in buildings, construction and operation must be better unified with design.
“The first step in reducing energy demand is to undertake a dynamic assessment of the building form and orientation in relation to its site, surroundings, and functional requirements,” says Dmitri Korolenko, lead building physics and sustainability engineer at S.I. Sealy. “A thoughtfully massed and oriented building utilizes the site’s features to provide balanced levels of daylight, natural ventilation, and opportunities for renewable energy generation. Considering the annual movement of the sun around the building can also serve to reduce annual heating and cooling loads and prevent summertime overheating risk.”
Operational systems efficiency, which involves reducing the amount of energy the building consumes by using intelligent engineering solutions and energy-efficient equipment, is paramount. Smart energy management systems must be implemented and managed with regular energy audits and continuous optimization, in line with occupant needs. On- and off-site renewable energy generation can further reduce the carbon cost of buildings, while carbon offsetting strategies, where building buy certified carbon credits from organizations that invest carbon capture and storage, can be another effective approach to achieving net-zero goals.
“Achieving net-zero is no small feat. The construction and operational assessments are often at odds with each other as efficient fabric, systems and renewable generation technologies often involve materials with high embodied carbon content. The net-zero carbon target needs to be set as early as possible to enable all relevant modeling and design work to focus on that goal,” says Korolenko. “Ultimately achieving net zero carbon will rely heavily on the building’s site and function. On some projects, the only way to reach net-zero carbon may be carbon offsetting and the purchase of renewable energy. In most cases, however, net-zero carbon is achievable, if the client’s commitment, an experienced design team, and an appropriate budget are all in place.”
While the technical side of the net-zero mission is gradually becoming feasible, the development of green building technology alone is not enough to bring about the change needed in the buildings industry. In fact, it would be fair to say that none of these tactics will become mainstream in the world’s key polluting regions without much stronger policy-based incentives driving them forward.
In Europe, buildings are the single largest energy consumer, responsible for approximately 40% of EU energy consumption and 36% of the greenhouse gas emissions, according to official EU statistics. Following the introduction of a variety of energy performance rules in national building codes, modern European buildings consume only half as much as typical buildings from the 1980s. However, about 35% of the EU's buildings are over 50 years old and only about 1% of the building stock is renovated each year, meaning almost 75% of the EU’s building stock is still currently considered “energy inefficient.”
In response, the European Commission and the European Committee of the Regions have launched a new program to improve energy efficiency in buildings across the bloc. The Renovation Wave program targets three key measures identified as vital to accelerate energy efficiency and the decarbonization of Europe’s building stock. First, a revision of state aid schemes and more flexible budget rules, which are intended to maximize investments and renovations. Second, an implementation of subnational targets for the renovation of buildings will be put in place and finally, the bloc will take significant actions to drive integration of renewable energy sources to the inefficient building stock.
“Making our buildings energy efficient will save money, reduce emissions, and tackle energy poverty which affects 34 million people in Europe. We need to ensure that local and regional governments are aware of, and have access to, the unprecedented EU budget and recovery and resilience funds available,” said Apostolos Tzitzikostas, President of the European Committee of the Regions. “I am therefore delighted to launch our cooperation between the European Commission and our Committee to support the Renovation Wave in all our territories.”
In the US, climate change is back on the agenda in 2021. After they officially rejoined the Paris Climate Agreement, eyes turned from the environmental commitments abandoned by President Trump to the new commitments President Biden is expected to make under the Nationally Determined Contributions program. Biden's climate plan includes a strong increase in green building, with 4 million buildings in the United States expected to be upgraded, and a further 2 million weatherized in the next 4 years. While Biden’s administration has certainly put the US back on the environmental track, not all policies are receiving green praise.
The International Code Council (ICC), an organization that manages building codes across the country, this month removed the rights of local governments to vote on future energy efficiency building regulations. The ICC’s new system gives the construction and gas industries more control over energy codes by replacing localities' voting power with a new "standards process" that will still factor local-level input but allows industry groups to wield more influence. The move could have major implications for environmentally progressive cities seeking to reduce greenhouse gas emissions within their building sectors, according to industry experts.
“States are likely to adopt the ICC’s most recent standards for building codes, and that can constrain cities’ ability to address energy efficiency in their building sectors, as most cities cannot be more ambitious than their state’s building codes,” said Kelly Shultz, a program lead for sustainable cities at Bloomberg Philanthropies. “Our mayors cannot hit the climate targets that they’ve set without dramatically decarbonizing their building, and working on energy efficiency. These codes are critically important.”
The bottom line is that Europe and the US, like many other regions of the world, are far behind their climate commitments, and those commitments are not nearly strong enough to meet the targets that science deems enough to tackle climate change. As a major source of energy consumption and emissions, renovation of the current building stock is key and the buildings industry has become fundamental to this global battle to avoid a future climate catastrophe, but without stronger policy, there won’t be significant change.