Climate Special 18: Greener Blueprints

As we continue our series on climate change, today we talk about how that after more than a decade of Sino-US collaboration, a trend called “nearly zero-energy tech” is transforming China’s building sector into a green-energy model for climate progress. 

Transcript

Greener Blueprints  

As we continue our series on climate change, today we talk about how that after more than a decade of Sino-US collaboration, a trend called “nearly zero-energy tech” is transforming China’s building sector into a green-energy model for climate progress. 

On a brisk November afternoon, visitors toured a decade-old brick building in Beijing that still remains ahead of its time. 

Completed in 2014 by the State-owned China Academy of Building Research (CABR), the four-story office building stays cozy through winter and cool in summer, while slashing energy costs to a fraction of the norm.

As part of the China-US Clean Energy Research Center’s Building Energy Efficiency Demonstration Project, CABR’s office building serves as a model of energy conservation for the private and public sectors and academics alike.

The Academy’s building hosts an array of solar collectors, tubular daylighting systems and ground-source heat pumps for heating, cooling and lighting – qualifying it for nearly zero-energy status.

Nearly zero-energy buildings aim to reduce energy use for heating, ventilation, air conditioning (or HVAC) and lighting through passive design strategies that integrate renewable energy systems.

Zhao Qi, a public relations staffer with the Academy who guided the tour, credited the toasty temperature inside to 144 vacuum tube solar collectors and two sun-tracking solar reflectors.

In the fourth-floor conference room, a daylighting system harnesses natural light with a collection of long, reflective tubes from the roof. 

The building’s insulated outer walls reduce heating and cooling demands compared to ordinary public buildings in China. In addition, each vacuum double-glazed window has blinds installed in between the panes that open and close automatically to maximize sunlight in winter and shade in summer.

All this adds up to big savings. According to Dr. Lü Yanjie from the Academy, their building uses approximately 40 percent less energy per square meter compared to the average office space in Beijing. At just over 4,000 square meters, the Academy’s building can save up to around 140,000 yuan (or US$19,000) in energy costs annually.

Addressing Emissions

A March 2024 report by United Nations Environment Programme and the Global Alliance revealed that the building and construction sector accounted for 21 percent of global greenhouse gas emissions, 34 percent of global energy demand, and 37 percent of energy-related CO2 emissions in 2022.

In China, according to the Research Report on Carbon Emissions in China’s Urban and Rural Construction Sector (2024 Edition) jointly released by the China Building Energy Conservation Association and Chongqing University, in 2022, total energy consumption for building and construction nationwide was 2.42 billion tons of standard coal equivalent, accounting for 44.8 percent of total national energy consumption. The building and construction industry emitted 5.13 billion tons of CO2, which accounted for 48.3 percent of energy-related carbon emissions in China.

To combat this, the Intergovernmental Panel on Climate Change (IPCC) recognizes building energy standards as a critical climate policy, particularly in urbanizing nations like China. Ultra-low, nearly zero and zero-energy buildings are central to reducing energy consumption in this sector.

Globally, the push for energy-efficient buildings has gained momentum. Professor Zhang Shicong with the Academy noted that developed countries began zero-energy building demonstration projects in the early 2000s. The EU’s 2024 revision of the Energy Performance of Buildings Directive mandates zero-emission standards for all new buildings by 2028. The US, South Korea, Japan, Italy and Australia have also set ambitious energy-saving targets. The US government’s April 2024 National Blueprint for the Buildings Sector outlines plans to cut building greenhouse gas emissions by 65 percent by 2035 and 90 percent by 2050.

China’s building energy conservation efforts began in the 1980s with the release of its first National Standards for Building Energy Conservation in 1986, aiming to achieve 30 percent energy efficiency improvements every decade through upgrades by 2016. Early collaborations with other countries like Switzerland, the UK and Germany laid the groundwork for reducing building energy consumption.

Sino-US Collaboration

The China-US Clean Energy Research Center (or CERC), established on June 15, 2009 with US$150 million in joint funding, has been instrumental in advancing building energy efficiency. Its Building Energy Efficiency Consortium promotes ultra-low and zero-energy building technologies by integrating advanced building envelopes, renewable energy, HVAC systems, energy storage and intelligent controls.

Between 2011 and 2013, Chinese and American scientists conducted joint studies on the planning, energy system design and operation of nearly zero-energy buildings. This collaboration culminated in the 2014 demonstration project, which involved over 30 experts from both countries. Joining the Academy were US contributors such as the Lawrence Berkeley and Oak Ridge national laboratories. 

Professor Zhang, who spent four months as a visiting scholar at Lawrence Berkeley in 2013, emphasized the shared research focus: “Experts from both countries worked together on technical systems, building envelopes, energy systems and renewable energy sources like photovoltaics.”

Other universities, such as Tsinghua, Tongji in Shanghai, Tianjin and Chongqing, also participated in CERC projects. Zhang explained the collaborative model: “Domestic research institutions apply for funds from the Ministry of Science and Technology, while US counterparts seek support from the Department of Energy. These programs operate on a task-sharing and cost-sharing basis.” 

Proof of Concept

Home to around 180 employees, the Academy’s building is China’s first nearly zero-energy structure built in a cold climate zone. Solar collectors on the roof, along with various heat pump units and energy storage tanks, ensure stable operation and enhance efficiency.

During a guided tour for the reporter and five other visitors from the construction and academic sectors, Zhao Qi said that on cloudy days, an extensive ground-source heat pump system kicks into action. This pumps water through underground pipes to draw up and radiate natural heat in winter or cooling in summer.

Hot water tanks store energy to be used as weather fluctuates. “When the sun is out, we can produce ample amounts of hot water,” Lü Yanjie said. “But at night or on cloudy days, this stored hot water can be used to reduce load fluctuations caused by variations in weather. This effectively improves the overall stability of the entire system.”

Solar heat is also used in summer thanks to a 35-kW absorption chiller, which cools water that is then used for air conditioning. Cold water tanks also utilize off-peak electricity at night for daytime cooling, Lü said. The building employs energy-efficient LED and fluorescent lighting with intelligent controls tailored to each floor, Zhao added.

Guided by the principles of “passive building, proactive optimization, and being economical and practical,” the building incorporates 28 advanced technologies for energy conservation and environment control. It achieves ambitious targets, including zero fossil fuel use for winter heating, a 50 percent reduction in summer cooling energy and a 75 percent reduction in lighting energy, setting a high standard both domestically and internationally.

Due to its insulation and airtight qualities, annual energy consumption for heating, cooling and lighting is kept below 25 kWh per square meter – 75 percent lower than the national standard. A comprehensive energy monitoring system tracks electricity and heat usage, measuring system power consumption and HVAC parameters in real time and uploading the data to a central platform.

According to the 2019 paper Tracking Research on Operation Energy Consumption of CABR Nearly Zero-Energy Demonstration Building in China’s Construction Science and Technology journal, the structure maintained its energy targets from 2015 to 2018, even as office staff numbers increased, with indoor conditions consistently meeting comfort standards.

Professor Zhang Shicong emphasized the project’s significance: “The Academy’s demonstration building represents a cost-effective Chinese effort to achieve a nearly zero-energy building. The experience gained here has been invaluable for formulating China’s nearly zero-energy building standards and roadmap.” 

Building on this success, the Ministry of Housing and Urban-Rural Development of China tasked the Academy with drafting the Technical Guidance for Passive Ultra-Low-Energy Green Building in 2015 and the Technical Standard for Nearly Zero-Energy Building in China in 2019, laying a foundation for nationwide promotion.

Race to Zero

The Sino-US collaboration on green building has evolved over several phases. From 2011 to 2013, pilot studies explored core technologies and design methods, followed by continuous optimization. In November 2014, the two nations renewed their commitment to CERC, extending its mandate to 2020 and re-funding research areas such as building efficiency, clean vehicles and advanced coal technologies, but it was terminated in 2020.

Professor Zhang outlined three stages of China’s nearly zero-energy building development. Initially, efforts focused on building envelopes and energy systems. Later, the emphasis shifted to integrating renewable energy and improving energy storage. The current phase targets scaling from single-building research to community-level applications, expanding its reach.

In 2022, the Ministry of Housing and Urban-Rural Development and the National Development and Reform Commission issued the Plan for Implementation of Carbon Peaking in Urban and Rural Construction, mandating ultra-low energy standards for all new buildings. By 2021, major demonstrations were incorporated into the 14th Five-Year Plan (from 2021 to 2025), solidifying ultra-low, nearly zero and zero-energy buildings as key strategies for energy efficiency over the next 30 years. Nearly zero-energy buildings reduce energy consumption by 60-75 percent compared to 2016 levels, while ultra-low energy buildings achieve a 50 percent reduction. Zero-energy buildings ensure renewable energy production meets or exceeds total annual demand.

“The energy-saving system evolves, but the focus remains on ultra-low, nearly zero and zero-energy consumption,” Zhang said. “Each Five-Year Plan marks progress. Earlier, passive design and envelope optimization reduced heating and cooling loads, allowing for smaller systems. Now, research emphasizes building-integrated photovoltaics.”

Over the past decade, photovoltaic system costs in China dropped by 93 percent. “As building energy needs decrease, photovoltaic systems are becoming primary energy sources,” Zhang said.

Current research includes building grid and vehicle-building interaction for flexible regulation, expanding the nearly zero-energy building ecosystem.

Zhang noted that the Academy’s building laid a critical foundation. Since 2014 onwards, approximately 50 million square meters of ultra-low energy buildings have been completed or are underway across China, with hotspots in Hebei, Shanghai and the Yangtze River Delta.

Future Prospects

Constructing ultra-low, nearly zero or zero-energy buildings is still not mandatory for local governments or enterprises. “Technical standards serve as guidelines, encouraging green, low-carbon development,” Zhang said. Some voluntary projects include the zero-carbon headquarters of China Energy Engineering Group in Shanghai and Ant Group’s zero-emissions global headquarters in Zhejiang Province.

Over the past decade, demonstration projects have expanded in scale and complexity. Building on these achievements, China is now advancing regional community-scale nearly zero-energy buildings.

A September 2024 article in Science China, titled Review on the Recent Progress of Nearly Zero-energy Building Frontiers in China, highlighted the country’s rapid progress, despite a late start. By 2020, nearly 10 million square meters of nearly zero-energy building projects were completed or under construction. In 2021, major demonstrations were included in the 14th Five-Year Plan. The article underscored a consensus on adopting ultra-low energy, nearly zero-energy, and zero-energy building strategies as the core of building energy efficiency for the next three decades. According to Zhang, the target milestones are for new buildings to achieve ultra-low energy consumption by 2030, nearly zero by 2040, and zero energy by 2050.

Local governments in cities like Beijing, Shanghai and Guangzhou have introduced supportive measures, offering subsidies and favorable policies for constructing low-carbon buildings. In August 2024, Beijing unveiled new policies providing subsidies for newly built ultralow, nearly zero and zero-energy-consumption buildings in the Beijing sub-center area in Tongzhou District, and owners are eligible to receive 200, 300, or 500 yuan, respectively, per square meter – that’s 27, 42, or 68 US dollars per square meter with a maximum of 3 million yuan (or US$414,000) for a single demonstration project.

Industry experts believe the current phase of large-scale promotion is laying the groundwork for mandatory implementation of ultra-low, nearly zero and zero-energy-consumption buildings. “Only by fully understanding the technologies during this promotion phase and ensuring our country has sufficient resources for all potential projects can mandatory implementation proceed,” Professor Zhang said.

He emphasized a gradual approach: “Given China’s size, we must advance this step by step, region by region.”

Well, that’s the end of our podcast. Our theme music is by the famous film score composer Roc Chen. We want to thank our writer Wang Yan, translator Du Guodong, and copy editor Pu Ren. And thank you for listening. We hope you enjoyed it, and if you did, please tell a friend so they, too, can understand The Context!