From Europe to North America, from the Middle East to Asia, the trend of net-zero buildings is sweeping the world as governments and enterprises make every effort to become carbon neutral by 2050. However, as major carbon emitters, existing buildings currently account for as much as 40% of global carbon emissions. The rapid increase of new buildings in the future will pose an even greater challenge to carbon reduction. International Energy Agency (IEA) estimates that with global population growth and accelerated urbanization, the gross floor area of buildings across the globe will double by 2060, while only 3% of the total investment amount of new buildings will be dedicated to green carbon reduction and energy efficiency. The UK government estimates that if the country is to reach its overall net-zero target by 2050, non-domestic buildings will need to reduce energy consumption by 59% and embodied carbon emissions by 82%.
What is a net-zero building? While its definition varies, the most important motivation is to reduce building emissions and energy consumption as much as possible to achieve zero carbon emissions or zero energy consumption during the entire life cycle of construction, use, and disposal. Depending on the extent of emissions reduction and energy saving, it can refer to Zero Emission Building, Zero Energy Building, Nearly Zero Energy Building (NZEB), Ultra-Low Energy Building, and so on. Developed countries such as Europe and the United States are among the first to pay attention to building carbon emissions and have currently set stricter ZEB (zero emission building/zero energy building) targets, while Asia and the Middle East started with NZEB and are steadily practicing building carbon reduction.
Net-zero building life cycle certification standards
For buildings to truly move toward net zero, a complete set of standards and certification systems is required. However, since carbon neutrality is a very new agenda, even the European Union, a pioneer in carbon reduction, is yet to develop a whole-life-cycle carbon emissions standard for net-zero buildings, especially in terms of "embodied carbon emissions" such as those for raw materials, transportation, construction, maintenance, and disposal. In contrast, the "operational carbon emissions" generated by buildings after they are put into use, such as water, electricity, and air conditioning have become the primary identified items (energy consumption and operational carbon emissions) for current net zero buildings because they are easier to calculate.
As the carbon emission of the whole life cycle of buildings is a problem that must be solved, it is imperative that a standard be formulated. Taking the lead in addressing the issue, the United Kingdom has recently launched a project, where the Royal Institute of British Architects (RIBA) invited the Carbon Trust to jointly set up the "UK Net Zero Carbon Buildings Standard" development group. The Carbon Trust has run a series of environmental standards for more than 20 years in the UK that certify measurement and reduction, together with building-related public associations, energy transition initiatives, and verification departments. The purpose of the new development group is to assist building owners and managers to clearly define the accounting, reporting, disclosure, and verification requirements for carbon emissions of an asset throughout the entire process at interim stages from design planning to building demolition. The project is taking shape, and the proposed future results are expected to become important reference indicators for net-zero buildings.
Buildings account for 40% of global carbon emissions; various countries adopt regulations on carbon reduction
To drive the public and private sectors onto an ambitious path to achieve a net-zero emissions buildings goal, various countries have adopted regulations and policies accordingly. The European Union and the United States require that all new construction projects will be net-zero emissions by 2020 and 2030, respectively. The White House recently announced “The Climate Smart Buildings Initiative” in early August, which will leverage public-private partnerships to modernize Federal buildings to better meet agencies’ missions of reducing emissions by 2.8 million tons by 2030. Through this initiative, the government hopes to take the lead in promoting private investment in net-zero buildings. In Singapore, the 2030 Green Plan stipulates that 80% of new buildings (by Gross Floor Area) must be SLE (Super Low Energy) buildings from 2030.
China is promoting the adoption of net-zero buildings through a series of regulations, including energy efficiency in new and existing buildings. For example, the "Technical Standards for Near-Zero Energy Buildings" regulates the relevant standards for near-zero energy consumption buildings, ultra-low energy consumption buildings, and zero energy consumption buildings for energy efficiency indicators and various environmental parameters of buildings. The updated General Specification for Energy Conservation and Renewable Energy Utilization, which took effect this April, stipulates that calculating the carbon emission of buildings is a mandatory requirement, and that the carbon emission intensity of new public and residential buildings must be reduced by 40% compared with the 2016 standard. On average, the carbon emission intensity per square meter must be reduced by more than 7 kilograms per year. From 1 April 2022, new buildings are required to install solar energy systems.
As early as in 2015, Japan established a net-zero building standard, requiring that by 2030, all new non-residential buildings and residential buildings must meet the zero energy building (ZEB) standard and the quasi-zero energy home (ZEH Ready) standard.
In 2019, New York City formulated the LL97 regulation, the most stringent building standard for cities in the world. Buildings above 25,000 square feet have carbon emission caps, which will take effect from 2024 and become more stringent every year. It is expected to reduce carbon emissions by 80% for New York City by 2050.
In Taiwan, in line with the 2050 net-zero path announced by the National Development and Development Council earlier this year, the Ministry of the Interior classifies buildings into seven levels based on energy efficiency starting from 2022. The goal is that by 2030, all public new buildings will reach level 1 (near zero), and by 2050, 100% of new buildings and 85% of existing buildings will be near zero buildings.
While the carbon reduction of new buildings is robustly regulated, we should not ignore the carbon reduction potential of existing buildings. Taking Europe as an example, 35% of existing buildings are over 50 years old, 97% of which are unable to meet future carbon reduction standards. They apparently require large-scale renovations that will employ software and hardware technology and automatic control systems to reduce carbon emissions. In fact, the 2022 Russia-Ukraine war detonated an energy crisis in Europe, which has indirectly become a driving force for building carbon reduction. To grow out of its dependence on Russia's natural gas, which is as high as 40%, Europe, is actively looking for alternative energy sources and resorting to energy efficiency. The European Commission announced the "REPowerEU" plan in May this year, which prioritizes renovating buildings to reduce energy consumption, accelerating the introduction of heat pumps, and installing more smart meters in the buildings. The European architectural think tank BPIE also specifically suggested a fast rollout of building renovation programs, such as rolling out energy management systems in large non-residential and public buildings and giving out grants to support serial renovations targeting multi-family homes.