Core reading

The construction industry is one of the key industries for energy conservation and carbon reduction. By the end of 2020, the total green building area in China has exceeded 6.6 billion square meters, making outstanding contributions to reducing carbon emissions. To improve the level of building energy efficiency, we should accelerate the updating of standards for building energy conservation and municipal infrastructure, improve the requirements for energy conservation and carbon reduction, and release the potential for energy conservation and carbon reduction in the construction field.

To save energy and reduce carbon, we should focus on key industries. The action plan for carbon peak before 2030 (hereinafter referred to as the action plan) previously issued by the State Council proposes to accelerate the updating of building energy conservation, municipal infrastructure and other standards and improve the requirements for energy conservation and carbon reduction.

China's total construction volume is large. How is the current progress in improving energy-saving standards in the construction field? What should we focus on next? The reporter interviewed the heads of relevant departments and industry experts.

Green buildings achieve leapfrog growth

Colorful aluminum alloy grids cross obliquely, like falling snowflakes under the action of light and shadow at night... Wukesong ice sports center, the ice hockey training venue of Beijing Winter Olympic Games, not only has ultra-high 'appearance', but also realizes ultra-low energy consumption. 'The venue adopts carbon dioxide ice making, which can improve the efficiency by 40% compared with conventional refrigerants. After ice making waste heat is recovered, it can also be used for hot water supply. In addition, the 600 kW photovoltaic power generation panel installed on the roof can realize an annual power supply of about 700000 kWh.' Feng Yanjun, project manager of Wukesong ice sports center of China Construction First Bureau, who participated in the venue construction, said.

In recent years, China's building energy-saving standards have been steadily improved. Tian Guomin, director of the standard quota Department of the Ministry of housing and urban rural development, introduced that since the promulgation of the first edition of building energy efficiency design standards in 1986, China's building energy conservation has experienced 'three steps', that is, on the basis of ordinary residential heating energy consumption in the early 1980s, the proportion of building energy conservation has gradually reached 30%, 50% and 65%. For more than 30 years, China has promulgated standards and specifications for residential building energy conservation (five climate zones), public building energy conservation, rural building energy conservation and energy-saving products, forming a relatively systematic energy-saving technology system and standard system.

According to estimates, by the end of 2019, China's new and completed energy-saving buildings can achieve an annual energy-saving capacity of nearly 300 million tons of standard coal, reduce carbon dioxide emissions by 740 million tons, and effectively slow down the growth rate of total building energy consumption.

At the same time, China's green energy-saving buildings have achieved leapfrog growth. By the end of 2020, the proportion of new green buildings in cities and towns in China had reached 77%, and the accumulated green building area had exceeded 6.6 billion square meters; The total built energy-saving building area exceeds 23.8 billion square meters, and energy-saving buildings account for more than 63% of the urban civil building area. According to the action plan, by 2025, new buildings in cities and towns will fully implement the green building standard.

'Building energy conservation has made outstanding contributions to reducing carbon emissions. Especially after the goal of carbon peak and carbon neutralization is put forward, a systematic and perfect comprehensive evaluation and assessment system for carbon peak and carbon neutralization will be gradually established, which will help the concept of energy conservation and green development to be more effectively implemented in the whole field of construction.' Tian Guomin said.

Building energy conservation and carbon reduction face certain challenges

It is reported that with the acceleration of urbanization and the improvement of people's living standards, coupled with the adjustment of industrial structure and the rapid development of the tertiary industry, which mainly relies on buildings to provide service places, China's building energy consumption intensity and carbon emission intensity will increase significantly. In the future, the construction field will also release great potential for energy conservation and carbon reduction, and there will be no small challenge and pressure to achieve the goal of carbon peak and carbon neutralization.

For example, the rising cost of construction faces certain financial pressure. 'Improving energy-saving standards means reducing the heat transfer coefficient of windows and thickening thermal insulation materials, which will increase the cost. In addition, China has a large stock of existing residential buildings, and energy-saving transformation needs sufficient financial support.' Tian Guomin said that at present, the government still plays a major role in promoting building energy conservation, the market-oriented promotion mechanisms such as contract energy management, carbon trading and comprehensive energy efficiency services need to be improved, and green financial support is also being explored.

At the same time, technological breakthroughs still need to be continued. 'For example, the thickness of external wall insulation materials for building energy-saving transformation has reached 15 cm to 18 cm. If the energy-saving standard is further improved, the 'cotton padded jacket' on the wall may be thicker. In this way, the risk of falling off and flammability of the insulation layer will also increase. In the future, we will actively develop external insulation materials with the same insulation effect, but lighter, better fire resistance and longer service life 。” Tian Guomin told reporters. Moreover, energy-efficient doors and windows, high-performance concrete, high-strength steel and other building materials, and waterproof technology at the joints of prefabricated buildings all need stronger technical support to improve the energy efficiency of buildings.

In addition, there are still some bottlenecks in promoting building energy conservation: the society still does not pay much attention to building energy conservation; The extensive construction mode of 'massive construction, massive consumption and massive emission' in the field of urban and rural construction needs to be transformed; The development of building energy conservation and green buildings is unbalanced between cities and rural areas, between the eastern coastal areas and the central and western regions, and the policies, standards, technologies and systems to adapt to the characteristics of rural areas need to be improved. The action plan mentioned that accelerating urban and rural construction, green and low-carbon development, urban renewal and Rural Revitalization should implement green and low-carbon requirements.

Accelerate urban and rural construction and green and low-carbon development

410 steel structural members, 197 roof unit plates and 170 photovoltaic curtain wall units took only 7 days and nights, and the wall of the photovoltaic building integration center of the national energy group with a building area of 1063 square meters was assembled like 'building blocks'.

Compared with the traditional cast-in-place method, the prefabricated construction is not only fast, but also can effectively reduce the emission of construction waste in the construction process, and reduce the environmental pollution such as dust and noise. According to the data, in 2020, the newly constructed prefabricated buildings in 31 provinces (autonomous regions and cities) and Xinjiang production and Construction Corps reached 630 million square meters, an increase of 50% over 2019, accounting for about 20.5% of the new construction area.

In addition to promoting new construction methods and reducing material waste and energy consumption on the construction site, how will we further promote energy conservation and carbon reduction in the construction field?

The action plan proposes to promote urban cluster development, scientifically determine the construction scale and control the rapid growth of new construction land. Build high-quality green buildings, further improve the energy-saving level of new buildings, strengthen the energy-saving transformation of existing buildings, and strengthen the operation management of buildings. In terms of improving building energy efficiency standards, Xu Wei, professional chief engineer of China Academy of Building Sciences, suggested that the construction of 'zero carbon building technical standards' should be accelerated to promote building energy efficiency to gradually move towards 'double control' of energy consumption, total carbon emission and intensity.

In addition, the optimization of building energy consumption structure needs to be accelerated. For example, deepen the application of renewable energy in buildings, actively promote clean heating in cold and cold areas, and improve the electrification level of building terminals. The action plan proposes that by 2025, the replacement rate of renewable energy in urban buildings will reach 8%, and the roof photovoltaic coverage of new public institution buildings and new plants will strive to reach 50%.

Nowadays, many places have introduced corresponding policies to encourage building energy conservation: the special fund for high-quality development of key industries in Hebei gives preference to the manufacturers of ultra-low energy consumption building proprietary parts and components such as high-performance doors and windows and special materials; Heilongjiang proposed to introduce substantive preferential policies in land supply, industry management, taxes and fees, and guide the construction of affordable housing in all localities to adopt the assembly construction method; Guangdong has introduced financial support, plot ratio incentives, tax incentives and other incentives for the construction, purchase and operation of green buildings or the green transformation of existing civil buildings

Next, the Ministry of housing and urban rural development, together with relevant departments, will promote all localities to further consolidate the responsibility for green development of urban and rural construction, improve relevant working mechanisms, and gradually form a legal system and policy system for green development of urban and rural construction, so as to make a positive contribution to China's goal of carbon peak and carbon neutralization.