The Carbon-Neutral Future of the Construction Industry: Zero-Carbon Buildings and Zero-Energy Buildings

Reducing carbon emissions from buildings is crucial for achieving the Paris climate goals and net-zero emissions by 2050. However, data shows that greenhouse gas emissions from buildings account for 39% of global total emissions, with 28% from building operations and 11% from building materials and construction.

 

Although the decarbonization of buildings still faces many challenges, it also presents enormous opportunities. As early as 2010, the World Expo Zero Carbon Pavilion, China's first zero-carbon public building, demonstrated China's efforts in zero-carbon buildings.

 

Although it only covers 2500 square meters and has no fanciful exterior design, it has powerful functions—using Huangpu River water and water source heat pumps as natural air conditioning for the building; leftover food after meals will be degraded into biomass energy for power generation.

 

All the design and construction themes here have only one goal: zero carbon dioxide emissions, building the future of zero-carbon buildings.

 

The World Expo Zero Carbon Pavilion uses solar energy to cultivate green plants

 

 

Zero-Carbon Buildings and Zero-Energy Buildings

 

A zero-carbon building is one that fully utilizes building energy-saving measures and renewable energy, so that the annual carbon reduction of renewable energy is greater than or equal to the total annual carbon dioxide emissions of the building.

 

In addition to adopting passive energy-saving technologies such as high-efficiency insulation and high-efficiency energy-saving windows in passive building design, zero-carbon buildings mainly improve the efficiency of energy equipment and systems through active technical measures, introduce more intelligent control technologies, fully utilize renewable energy such as photovoltaics, and focus on the recycling of materials and products to effectively reduce carbon emissions throughout the building's life cycle.

 

Diagram of Zero-Carbon Building Home Technology

 

Zero-carbon buildings and zero-energy buildings are very similar and often used interchangeably, but they are different.

 

Zero-energy buildings are buildings that do not consume conventional energy and rely entirely on solar energy or other renewable energy sources. Zero-carbon buildings, on the other hand, refer to buildings whose total carbon emissions are no greater than zero over their entire life cycle; near-zero carbon buildings are those that approach the level of zero-carbon buildings as much as possible.

 

Zero-energy focuses on energy saving during the building's use phase, while zero-carbon buildings focus on carbon emission control throughout the building's life cycle, including the five stages of material production, transportation, construction, building use, and demolition and recycling.

 

In March 2024, the "Work Plan to Accelerate Energy Efficiency and Carbon Reduction in the Construction Sector" proposed accelerating the research and development and promotion of advanced energy-saving and carbon-reduction technologies. It supports the research and development of new generation technologies for ultra-low energy consumption, near-zero energy consumption, low-carbon, and zero-carbon buildings. It is foreseeable that zero-energy and zero-carbon are important technological development directions for the construction industry to move towards carbon neutrality.

 

State Grid's Zero-Energy Building

 

 

Domestic and International Cases

 

Brazil ・ Petinelli Curitiba Headquarters

As the world's first LEED zero-energy explorer and the world's first building to receive LEED zero-water certification, This project maximizes the advantages of energy consumption data collection and on-site renewable energy.

 

All the energy used in the building is generated on-site, and the on-site energy intensity is only 25 kilowatt-hours per square meter per year. Just one 15-kilowatt photovoltaic array is enough to provide the energy needed for this 25-person office, and there's even some surplus.

 

Internal structure diagram of Petinelli Curitiba headquarters

 

Through the rooftop constructed wetland, this 14-story building can treat 100% of its wastewater on-site. By storing rainwater on the roof, rainwater collection pools cover the entire roof surface. A lift-up floor system makes it easy for people to walk outside. The top of the floor is covered with fine gravel, and large plants and aquatic plants grow together in or near the water.

 

In addition to zero water consumption, it is reported that the indoor air quality of this office is higher than that of ordinary buildings, and the content of carbon dioxide, volatile organic compounds, and radon are all below average. In addition, the building is designed and constructed with high energy efficiency and thermal comfort as the goal, so the mechanical system only needs to use a small amount of energy for heating or cooling, which can provide enhanced ventilation for all spaces.

 

United States ・ Unisphere

Located in Silver Spring, Maryland, the Unisphere building of UnitedHealth Group is one of the largest net-zero energy projects in the United States. It was also named the "Best Green Project" of 2019 by ENR magazine and has achieved LEED Platinum certification.

 

To meet net-zero requirements, the building combines geothermal heat pumps, on-site solar energy, and an integrated control system, including windows that automatically darken when the outside temperature rises; the concrete structure 12 feet below the building can be used as a passive heating and cooling system.

 

Interior of the Unisphere building (Source: Better Buildings)

 

However, there is still much room for improvement in the energy-saving capacity of the Unisphere building. For example, the 3,000 solar photovoltaic panels installed in the building have a short operating time and have not yet reached optimal efficiency. Later, to solve this problem, the building installed a SolarEdge or Enphase intelligent monitoring platform to track the power generation data of each panel in real time and identify anomalies; using a FLIR thermal imager to locate hot spots and faulty panels, improving their power generation capacity.

 

By following the path of net-zero energy consumption, the overall energy consumption of Unisphere can be improved, and 15% of renewable energy can be exported.

 

Norway ・ Powerhouse Brattørkaia

Located in Trondheim, Norway, the Brattørkaia Energy Building aims to establish a new standard for future buildings—producing more energy than it consumes over the entire life cycle of the building, including construction and demolition.

 

Located at 63 degrees north latitude, the amount of sunlight varies greatly throughout the year, creating a unique exploration opportunity for solar energy production and storage. The architects placed 3,000 square meters of solar panels on the sloping pentagonal roof and the upper half of the facade to maximize solar energy production.

 

It is estimated that this energy building will produce approximately 500,000 kilowatt-hours of clean, renewable energy per year. This makes the building a small power plant in the middle of the city, and the spacious battery room located at the foot of the building can solve the climate limitations of extreme daylight hours in summer and winter.

 

Exterior view of the Brattørkaia Energy Building (Source: ArchDaily)

 

To further reduce energy consumption for building lighting, the architects also adopted a design concept called "liquid light," which means that the building's artificial lighting system can gently adjust its brightness according to the differences in the activities of the people inside. In this way, the energy consumed by the lighting in this energy building is about half of that consumed by commercial buildings of the same size.

 

At the same time, the architects also used a series of other technological means to reduce the energy consumed by the daily operation of the building, making it an extremely energy-efficient building. These measures include: maximizing the building's thermal insulation efficiency, installing intelligent air circulation devices to reduce heating needs, developing strategies for heat recovery from ventilation and graywater (all wastewater except for toilets), using seawater for cooling and heating, and large-scale use of energy-efficient appliances.

 

Sino-Singapore Tianjin Eco-city Public Housing Exhibition Center

The Sino-Singapore Tianjin Eco-city is a major cooperation project between the governments of China and Singapore. It is the world's first eco-city jointly developed by two countries and has always focused on low-carbon, environmentally friendly, and green concepts since its construction.

 

In 2024, the State Council approved the "upgraded version" of the Sino-Singapore Tianjin Eco-city's construction of a national green development demonstration zone, which will create a "Chinese model" for the green and low-carbon development of global cities.

 

The center adopts 13 energy-saving and environmentally friendly technologies, including rooftop photovoltaic panels, soil source heat pumps, external maintenance structures, solar heat preservation and insulation, etc. It emphasizes the passive energy-saving design of the building enclosure structure, shifting the building's energy needs to renewable resources such as solar energy, wind energy, shallow geothermal energy, and biomass energy, seeking the best solution for the harmonious coexistence of humans, buildings, and the environment.

 

Based on Tianjin's local sunshine hours and intensity, fully considering the issue of photovoltaic panel solar absorption time, the Public Housing Exhibition Center chose a direction 15° east of south. The solar photovoltaic panel area of the Public Housing Exhibition Center reaches 2600 square meters, which can generate 240,000 kilowatt-hours of electricity per year, while the annual electricity consumption of the Public Housing Exhibition Center is only about 210,000 kilowatt-hours.

 

Overview of the Sino-Singapore Tianjin Eco-city Public Housing Exhibition Center (Source: Sino-Singapore Tianjin Eco-city Investment and Development Co., Ltd.)

 

In 2024, the Sino-Singapore Tianjin Eco-city Public Housing Exhibition Center completed the dual certification of China's Three-Star Green Building and Singapore's Green Mark Platinum, and also opened for public reservations, setting up a VR interactive exhibition area to demonstrate the principles of zero-carbon technology.

 

As a core node of the Eco-city's "zero-carbon tourism route," it is expected to receive 100,000 visitors annually in 2025, with data shared to global building carbon emission databases (such as CaGBC) to promote the formulation of international standards.

 

World Expo Zero Carbon Pavilion

The World Expo Zero Carbon Pavilion mentioned at the beginning of the article takes its prototype from the world's first zero-carbon dioxide community, the Beddington Zero Carbon Community. The World Expo Zero Carbon Pavilion consists of two zero-carbon emission buildings connected front and rear, with four floors, including a zero-carbon report hall, a zero-carbon restaurant, a zero-carbon exhibition hall, and six zero-carbon model houses. It is the first zero-carbon dioxide public building built in China, showcasing the latest achievements in building energy conservation and emission reduction in China and the world from multiple perspectives and levels to Expo visitors.

 

The electricity required by the Zero Carbon Pavilion is generated by solar panels attached to the building and biomass energy cogeneration. Using cogeneration, this heat energy can be effectively utilized. More noteworthy is that the biomass energy cogeneration mixes food waste and organic matter from the restaurant and other biological waste generated in our daily lives, and degrades it through the anaerobic biological process to generate electricity and heat to achieve the release of biomass energy. The products processed by this system can be used for returning to the field as bio-fertilizers, achieving the transformation of waste into treasure.

 

The utilization of sunlight and water is also fully reflected in the Zero Carbon Pavilion. The solar panels on the roof can convert solar energy into electricity; the back of the building cultivates green roof vegetation through diffused sunlight, while the north-facing diffused light provides corresponding natural lighting for the interior; rainwater is collected from the roof and used to flush toilets or irrigate plants, reducing the Zero Carbon Pavilion's demand for tap water.

 

Zero Carbon Pavilion

 

At the same time, the Zero Carbon Pavilion adopts an overall external insulation strategy. The walls are constructed of insulation materials, reducing outdoor heat penetration, absorbing excess indoor heat, and stabilizing indoor temperature fluctuations. Through these designs of the Zero Carbon Pavilion, visitors can experience a future life that is both environmentally friendly and comfortable.

 

The Pavilion integrates various high-tech energy-saving and environmentally friendly materials throughout the venue, using green recycling technologies such as energy utilization and recycling, building materials and design, water resource recycling, and carbon dioxide absorption by the floor. This not only reduces greenhouse gas emissions but also promotes technological innovation and industrial transformation, improving the living environment and health.

 

 

Challenges and Opportunities

 

Although zero-carbon and zero-energy buildings represent an important direction for the building industry's transition to green and low-carbon development, these new building models still face many challenges, such as the large upfront investment usually required for energy-efficient technology upgrades, which deters many building owners from undertaking such projects; each structure may require a unique building decarbonization approach; a lack of standardized policies and unclear regulations, etc.

 

To address these challenges, various methods such as renewable energy integration and the construction of building energy management systems have been proposed. In the future, zero-carbon buildings can be deeply integrated with intelligent technologies. Through the application of technologies such as the Internet of Things, big data, and artificial intelligence, buildings will achieve more precise energy management and more intelligent environmental regulation, thus providing users with a more efficient, convenient, and comfortable living experience.

 

 

Zero-carbon and zero-energy buildings represent the future of sustainable buildings and are an important step in mitigating climate change and achieving carbon neutrality. By using renewable energy, high-efficiency energy systems, and sustainable materials, they not only reduce carbon emissions but also provide a healthier and more economical lifestyle. It can also be extended to more building types. In addition to the more common residential and office buildings, zero-carbon or zero-energy technologies can also be tried in the future in the fields of commercial complexes, schools, and hospitals. This diversified development will not only expand the market size but also promote innovation and improvement of related technologies.

 

Carbon neutrality in the building industry is an indispensable part of the national goal of achieving carbon neutrality. Promoting energy conservation and carbon reduction in the building sector is crucial, and zero-carbon and zero-energy buildings will become important technological means in this process, making significant contributions to achieving the "dual carbon" goals.

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