ارزیابی اثرات اجرای استانداردهای بهره وری انرژی عمرانی ساختمان سازی روی سیستم اقتصادی و محیطی چین

In this paper, in contrast to the usual rough estimation, we present a model to simulate and evaluate the direct, indirect economic and environmental impacts of the implementation of building energy efficiency standards on Chinese economic system and environment by 12 indicators in two scenarios. Four indicators are used to evaluate the direct economic impact degree, five indicators are used to evaluate the direct environmental impact degree, three indicators are used to evaluate the indirect economic impact degree of 34 sectors and the whole Chinese economic system. This research makes it possible to link developments in the implementation of building energy efficiency standards with environmental and economic structure change. The most important finding is that the implementation of building energy efficiency standards can reduce a large amount of pollutants emissions and increase the GDP at the same time.

China is facing a major challenge posed by increasing energy requirement and greenhouse gas emission. From 2000 to 2020, the national planning targets call for quadrupling the value of China's GDP with a concomitant doubling of energy consumption, implying an energy elasticity coefficient should be 0.5. However, in the last three years, the coefficient was estimated at more than 1.3, suggesting that future energy levels (absent any major conservation efforts or significant improvements in efficiency) will be far higher than those estimated by the current planning's forecast. Furthermore, China's development has entered into the heavy industry stage. According to the development experience in the rest of the world, the stage of rapid growth in energy requirement of China seems to be insurmountable [1]. According to preliminary estimations, over the period from 2001 until 2006 the energy consumed by residential buildings in urban areas accounted for 20–27% of the total annual energy consumption in China. In 2006, the total energy consumption of residential buildings in urban areas is 539.75 million tce, which accounted for 24.5% of the total energy consumption in China (Table 1). If the energy consumption in the building materials production and in construction is added, the total energy consumption of the construction industry accounts for about 46.7% of China's total energy consumption. Due to strong capital investment, the large population, urbanization, and heavy reliance on coal, Chinese GHG emissions are high. The IEA has estimated that China's GHG emissions for 2005 were 7527 MMTCO2e. Of these emissions, about 78% were CO2. By most estimates, China is now or soon will be the largest emitter of GHG globally [2]. The world bank, working with the Chinese government and other experts, in 2007 estimated that the cost of outdoor air and water pollution to China's economy totaled around US$100 billion annually, or 5.8% of China's GDP. Related to such findings, the Chinese government put environmental protection into its 11th-Five-Year-Plan (2006–2010) as a high priority. Chinese central government officials have over the past decade pursued a combination of measures to control air, water and soil pollution, and are struggling to build a recycling industrialized economy to ease environmental pressures. These efforts have met with mixed success. The greenhouse gas emission incurred by building energy consumption accounted for about 25% of the total greenhouse gas emission. Along with the population and economic growth, and the associated expansion of the building stock, if there have no major conservation efforts or significant improvements in energy efficiency, the overall energy use and the energy use in buildings and the greenhouse gas emission in China will be on an up-rising trend [3]. Energy used by air-conditioning and heating in buildings account for 65% of the total buildings energy consumption. Practice in China has proved that energy-efficient residential buildings can reduce the use of energy by air-conditioning in summer, can also reduce about half of the energy consumption in heating at the same heating effects in winter. By the end of 2002, there were only 230 million m2 existing floor spaces of residential energy-efficient buildings in China, which accounts for 0.86% of the Chinese total existing floor space of residential buildings [21] and [22]. With great efforts of Chinese government to promote the building energy efficiency, the ratio increased to nearly 5.3% until 2007 October. Obviously, improvements of building energy efficiency are urgently needed. As an effective way, the implementation of building energy efficiency standards can achieve the goal. However, studies reveal that the effort made to improve the efficiency and effectiveness of using energy in buildings remains limited [4] and [5]. In China, there are mainly 17 building energy efficiency standards, codes and technical specifications that had been enacted by the MOHURD (Ministry of Housing and Urban–Rural Development of the People's Republic of China) until 2007 [6]. JGJ26-95, JGJ134-2001, JGJ75-2003 and GB50189-2005 are the core of these standards. The other items play support and complementary roles to the above four. We call all 17 items in Table 2 as the building energy efficiency standards (BEES) commonly in the later analysis for their same aim to improve building energy efficiency. China is divided into three climate zones which are freezing and cold zone, hot summer and cold winter zone, and hot summer and warm winter zone (see Fig. 1). For each climate zone, there have a design standard of residential building JGJ26-95, JGJ75-2003, JGJ 134-2001. There is a design standard for energy efficiency of public buildings GB50189-2005 (see Table 2). In each standard, it gives the weather condition of the climate zone, the outdoor design temperature in summer, the cooling load of the building, etc. For example, COP of the chiller is 2.2 in hot summer and warm winter climate zone, and in hot summer and cold winter climate zone. COP of the electric heating is 1.0 in hot summer and warm winter climate zone, and in hot summer and cold winter zone. These standards in Table 2 were published. The detailed parameters can be checked from them. Especially, in GB 50189-2005, the parameter of ventilation for acceptable indoor air quality is referred to [7]. In GB50365-2005, the rate of hydraulic disorder and the rate of airflow disorder are referred to ASHRAE standards and made some adjustment according to the specific condition in China. The newly designed standards in China will treat [8] as minimum acceptable outdoor air supply rate, follow ASHRAE standard for thermal comfort. Most standards in Table 2 require civil buildings adopt the 50% kind of BEES. Some require civil buildings adopt the 65% kind of BEES. The meaning of the 50% kind of BEES can be explained as this. Regard buildings built in 1980s as baseline, overall heat transfer coefficient of building envelope, index of design load for heating of building and other parameters are set according to buildings at that time. Then calculate the energy consumed by the baseline when the indoor environment was kept the same as that set in the design standard for energy efficiency of buildings. Assumed the result as 100%, adjust the parameters of the baseline to the parameters that set in the 50% kind of standard, the energy consumption of the baseline will be 50% of the primal result. The meaning of the 65% kind of building energy efficiency standard is similar. We have the energy consumption data of the non-energy-efficient buildings, assumed all the parameters of the buildings are set according to the corresponding building energy efficiency standard, according to the meaning of the building energy efficiency standards, we can evaluate how much energy could be saved after the building energy efficiency standards are implemented. China has made more mandates on implementing BEES in the recent years. It was ordained that all the newly built residential buildings must be adopted the 50% kind of BEES strictly, those in large cities and developed districts should adopt the 65% kind of BEES [9]. The residential building energy efficiency task was set to save 110.4 million tce by the end of the 11th-Five-Year-Plan, in which the newly built residential energy-efficient buildings should save 75.2 million tce; the existing residential buildings should save 35.2 million tce by energy-efficient reconstruction [10]. Implementation of BEES would obviously have many important environmental and economic benefits both regionally and globally [11], [12], [13], [14], [15] and [16]. The aim of this study is to evaluate the direct and indirect economic and environmental impacts of the implementation of BEES, in contrast to the usual rough estimation. The data should pave the road to find solutions to relief energy requirement pressure and to reduce the environmental problems. LCA can be used both as a tool for assessments and a concept in discussions and evaluations [17]. As a tool, LCA makes it possible to study which raw materials and energy types are used in producing products or providing services; to identify which discharges arise from a specific source to air, water and soil; and to assess the environmental impact of the identified discharges. As a concept, it represents a way of thinking about and looking at products and materials from cradle to grave, to categories problems and assign priorities in finding a solution, and to foster consensus and international co-operation. As a topic in environmental management, the history of LCA dates back to the early 1970s [18]. Active development and application of LCA has only a relatively short history. However, LCA addresses only environmental impacts and not other consequences of human activities such as economic and social effects. Some domestic experts and scholars have made some research on the economic impact of building energy efficiency standards. Lin et al. [19] analyzed the social and economic benefits of energy-saving construction and architectural features of the energy-saving projects. Wang and Liu [20] demonstrated the importance of research on economic issues of energy-saving building, and put forward several specific questions of energy-saving buildings that need to be studied urgently. Tu and Wang [21] and [22], considered objectives and policies of building energy efficiency in 2010, 2020. Yin and Liu [37] analyzed the positive externalities of building energy efficiency behavior, established a market allocation model of non-energy-saving and energy-saving building construction and provided policies and measures to eliminate the negative externalities of building energy conservation. Zhang and Li [38] developed an economic analysis of the energy-saving investments and associated benefits, the investment payback period, and several indicators of energy-saving buildings. Kang [23] evaluated building energy-saving measures that would be needed to achieve the goal of the 11th-Five-Year-Plan. Sun and Fan [24] analyzed the influence of the degree of building energy-saving on cost of construction while Peng [25] analyzed the existing economic problems of building energy conservation; putting forward some reasonable proposals to resolve these problems. Finally, Wu [26] provided some economic incentive policy recommendations to encourage building energy conservation. These studies focus on the qualitative analysis and policy recommendations of economic impact of building energy efficiency, quantitative studies are just limited to the estimates of direct economic impact; however, there have been no analyses of the direct and indirect impact of building energy efficiency standards on all industry sectors in the Chinese economy. In contrast to the usual rough estimation, we present a model to simulate and evaluate the direct, indirect economic and environmental impacts of the implementation of building energy efficiency standards on Chinese economic system and environment by 12 indicators in two scenarios. Section 2 presents assumptions. Section 3 analyzes the economic and environment impacts of the implementation of BEES. Section 4 is the model. Section 5 concerns with data source and parameters estimation. Section 6 provides results and discussion.

The evaluation results of the direct economic and environmental impacts of the implementation of BEES in scenario k can be seen in Fig. 2. There have nine indicators, in which CDE, SDE, NOE, SER, QSW are indicators about direct environmental impact, other indicators are about direct economic impact. Fig. 3 shows that seven indicators have negative impact degrees, in which CEE has the biggest absolute direct impact degree. This reveals that the implementation of BEES in scenario k can reduce large amount of expenditure on the buildings energy consumption, which could bring benefits for residents and government directly. There are two indicators CIU and CII that have positive impact degrees. It shows the implementation of BEES will promote the development of construction industry and construction material industry directly. CII is derived from the increased sales income of newly built urban energy-efficient residential buildings. In scenario k = 1, the floor area of the newly built urban energy-efficient residential buildings is bigger than that in scenario k = 2, so the CII in scenario k = 1 is bigger than that in scenario k = 2. The graphs of CDE, SDE, NOE, SER, QSW in Fig. 3 show the implementation of BEES has remarkable effect on main pollutants emissions reduction and water saving for energy saving. The key reasons are as follows. In china about 78% of electricity is thermal power2 that uses coal as primal fuel, which lead to a large amount of pollutant emissions. In 2005, 51% sulfur dioxide emission was from thermal power production in China [36]. To produce thermal power is also water consumed. To save 1 kW-h electricity equals to save 4 l of water on average3. The building energy consumption for heating in cold and freezing climate zone accounts for about 34% of the total building energy consumption per year [35]. Most of the fuel used for heating is also the coal. In scenario k = 2, more energy is saved therefore its environmental effects are more remarkable than those in scenario k = 1. We can see the indirect economic impacts of the implementation of BEES on total output of sector 17 (coal, oil and natural gas, electricity, heat, water production and supply) and on sector 8 (petroleum processing, coking and nuclear fuel processing) are negative, while its indirect economic impacts on total output and value added of other sectors are positive (Fig. 4). It has been shown by CEE that the implementation of BEES will lead to a significant reduction in building energy consumption directly, sector 17 and sector 8 are energy production and supply sectors and their total output will surely be reduced. On the other hand, through the interaction and mutual influence among various industries in the national economic system, the direct economic impacts will promote the development of other industries and make their total output increase. In Fig. 4, the changed degree of total output of sector 27 (tourism) is the largest followed by sector 28 (scientific research), sector 20 (post and telecommunications), sector 14 (instruments, meters, cultural and office machinery) and sector 33 (culture and arts, sports, entertainment), etc. In scenario k = 2, more floor area was adopted BEES than in scenario k = 1 therefore the absolute changed degrees of 34 sectors’ total outputs for the implementation of BEES in scenario k = 2 are bigger than those in scenario k = 1. The total economic impacts of the implementation of BEES on total output and total value added are positive (Fig. 5). These impacts are likely to continue to the future and increase as a higher proportion of buildings adopted the new energy efficiency standards. Although figures of CTO and CVA are small (Fig. 5), considering the implementation of BEES has remarkable effect on pollutants emission reduction, this is particularly interesting result which points out a practical way to save energy and reduce pollutants emission. The method in this paper can also be used in other countries. For example, it has been applied in Brazil after it was introduced and discussed on a seminar at Illinois University.