Urban energy use and carbon emissions from cities in China and policy implications

Urban areas contain 40% of the population and contribute 75% of the Chinese national economy. Thus, a better understanding of urban energy uses is necessary for Chinese decision-makers at various levels to address energy security, climate change mitigation, and local pollution abatement. Therefore, this paper addresses three key questions: What is the urban contribution to China's energy usage and CO₂ emissions? What is the contribution of large cities, and what alternate energy–economy pathways are they following? How have energy uses and CO₂ emissions transformed in the last two decades in key Chinese cities? This three-tier analysis illustrates the changes in urban energy uses and CO₂ emissions in China. The results show that the urban contributions make up 84% of China's commercial energy usage. The 35 largest cities in China, which contain 18% of the population, contribute 40% of China's energy uses and CO₂ emissions. In four provincial cities, the per capita energy usage and CO₂ emissions have increased several-fold. Rapid progress was made in reducing the carbon intensity of economic activities in cities throughout the 1990s, but alarmingly, such progress has either slowed down or been reversed in the last few years. These results have important policy implications.     

太阳能照明有望扮靓中国城市

2006年12月5-6日,中国太阳能照明应用技术论坛在德州召开,这标志着中国太阳能光电照明迈出了实质性的一步,未来,会有更多太阳能照明扮靓中国城市。     

我国能源依赖型城市的能源供应分析

随着我国经济的发展速度和城市化演进过程不断加快，能源消耗逐渐向城市集中，能源的可持续利用和城市的生态环境问题也随之而来，制定、实施科学的能源供应规划对于城市实施可持续发展具有重要意义。探讨了基于能源禀赋的城市能源类型划分，着重分析了我国主要能源依赖型城市的能源供应状况，并提出城市能源供应规划的建议。     

Sustainable cities – modelling urban energy supply and demand

A model of urban energy consumption has been developed using energy supply data and post-code information. The model simulates spatial and diurnal variations in energy demand, and also models the effect of energy-management measures and associated reductions in CO₂ emissions. A linear programming optimisation module is used to identify the most cost-effective measures to achieve specified CO₂ or energy reduction-targets. When combined with data from an associated attitudinal survey, the model can be used to assess the potential for CO₂ reduction in the urban environment.     

Structural change in energy use

Structural change in the economy, from agriculture to industry to services, causes similar sector shifts in final energy use. This paper illustrates such energy sector shifts for 11 world regions from 1971 through 1998 and discusses their impact on the decline in energy intensity.     

A comparative analysis of urban energy governance in four European cities

Cities are at the forefront of efforts to combat climate change and in this paper, we examine the influence of urban energy governance on these policy goals. An innovative framework for quantifying the combined governance of cities and energy systems is presented before focusing on a detailed study of London, Paris, Berlin and Copenhagen. By applying an optimization model to assess the lowest cost technology pathways to achieve emission reduction targets, the links between the governance of urban energy systems and the cost of achieving carbon targets are shown. Additionally a novel metric of scenario similarity is introduced in order to evaluate the difficulty of hypothesized energy system transitions. The results indicate that these tools can be valuable in identifying similar cities for the sharing of best practice, for performing comparative evaluations of energy transitions, and for reinforcing the need to complement quantitative assessments with a more holistic appreciation of local context.     

从城市热岛现象谈建筑节能

热岛现象，是指由于工业、人口、建筑以及污染等原因而造成一个城市或地区的环境温度显著高于周围地区的现象。近年来，随着我国城市化进程的加快，城市人口不断膨胀，新型建筑大量增加，运行车辆急剧增多，工业经济持续发展，生产规模日益扩大以及其它诸多因素的影响，城市热岛现象正呈现不断加剧的趋势。     

Typical weather data of main Turkish cities for energy applications

Energy consumption and performance investigations of environment‐dependent systems such as building HVAC and refrigeration systems, solar collectors, cooling towers, usually require weather information. This introduces a problem because there may be significant variances between the recurrent days or years. In this work, typical hourly weather data for the selected 23 provinces that represent demographic and climatic conditions of Turkey are obtained by using actual recordings. The results are stored as computer files ready to be used by simulation programs. By using these typical meteorological years, heating and cooling degree‐days, dry‐bulb temperature bins and winter and summer design dry‐bulb temperatures are calculated. Sample typical‐year simulations show for example that energy savings of about 11 and 16 per cent could be expected in Ankara by 3 and 5 K night‐setback, respectively. Copyright © 2000 John Wiley & Sons, Ltd.     

Low-temperature geothermal energy use in Iceland

The results are given of a recent survey of the utilization of geothermal energy produced in low-temperature areas in Iceland. About 70% of Icelanders enjoyed geothermal district heating in 1979 and in the next 3–5 years this percentage should increase to about 80%. Most of the district heating systems receive hot water from low-temperature (reservoir temperature less than 150°C) geothermal areas. In late 1980 the thermal power above 15°C used for district heating amounted to 850 MW while the total low-temperature use was about 950 MW-thermal.     

Geothermal energy use in hydrogen liquefaction

We propose the use of geothermal energy for hydrogen liquefaction, and investigate three possible cases for accomplishing such a task including (1) using geothermal output work as the input for a liquefaction cycle; (2) using geothermal heat in an absorption refrigeration process to precool the gas before the gas is liquefied in a liquefaction cycle; and (3) using part of the geothermal heat for absorption refrigeration to precool the gas and part of the geothermal heat to produce work and use it in a liquefaction cycle (i.e., cogeneration). A binary geothermal power plant is considered for power production while the precooled Linde–Hampson cycle is considered for hydrogen liquefaction. A liquid geothermal resource is considered and both ideal (i.e., reversible) and non-ideal (e.g., irreversible) system operations are analyzed. A procedure for such an investigation is developed and appropriate performance parameters are defined. Also, the effects of geothermal water temperature and gas precooling temperature on system performance parameters are studied. The results show that there is a significant amount of energy savings potential in the liquefaction work requirement as a result of precooling the gas in a geothermal absorption cooling system. Using geothermal energy in a cogeneration scheme (power production and absorption cooling) also provides significant advantages over the use of geothermal energy for power production only.     

Residential energy use in Lithuania: the prospects for energy efficiency

The energy demand in Lithuania's residential sector is very high. While the potential for saving energy in this sector is large, significant barriers to energy efficiency remain. Removing or ameliorating these barriers will be difficult since these are systemic barriers that require societal change. This article analyzes the barriers and offers several recommendations for promoting energy efficiency in Lithuania. Also, a proposal for short- and medium-term strategies for implementing such policies is proposed.     

Renewable energy and coal use in Turkey

Turkey becomes more dependent on foreign countries for fulfilling its energy needs day by day. While 77% of the overall primary energy consumption in 1970 was met by the domestic energy sources, this percentage decreased to 28% in 2003. As for the electricity production, while 89% of the produced electricity was produced by using the domestic sources, this percentage decreased to 68% in 1970 and 44% in 2003. The percentage of dependence on foreign countries increased year by year and reached 56% in 2003. The energy sources of Turkey are renewable energy sources and coal. If both of these energy sources are used effectively, Turkey will have a capacity to produce its overall electricity production using its own sources. The incorrect policies applied in Turkey introduced oil as a primary energy source for electricity production in 1970s and Turkey defrayed the cost of this wrong application severely by oil crisis. After 2000, natural gas, which was completely imported, was introduced as an energy source and its share in electricity production reached 45%. It is vital for Turkey to question this situation in order to ensure a sustainable development using reliable energy sources.     

Review of wind energy use in Algeria

Most scientists now agree that human-induced global climate change poses a serious threat to both society and the Earth's ecosystems. Renewable energy holds the key to future prosperity and a healthy global environment and is considered as a promising way to solve the problem of environmental pollution such as major environmental accidents, water pollution, maritime pollution, land use and sitting impact, radiation and radioactivity, solid waste disposal, hazardous air pollutants, ambient air quality (CO, CO₂, SO_x, NO_x effluent gas emissions), acid rain, stratospheric ozone depletion, and global warming (GHG). Solar, wind and hydrogen power can be considered as potential renewable energy sources in Algeria. The share of renewable energy sources in Algeria primary energy supply is relatively low compared with European countries, though the trends of development are positive. One of the main strategic priorities of New Energy Algeria (NEAL) which is Algeria's renewable energy agency (government, Sonelgaz and Sonatrach), is striving to achieve a share of renewable energy sources in primary energy supply of 10–12% by 2010. IEA projects that the fastest growing sources of energy will be supplied by renewables. Much of this capacity will be installed in developing nations where solar and wind electric power is already competitive. Clearly, the nation that can capture a leadership position has potential for substantial economic returns. The article presents a review of the present wind energy situation and assessed potential of wind energy sources in Algeria in particular the southwest region of Algeria (Adrar, Timimoun and Tindouf).     

Some evidence concerning energy use in manufacturing

The dramatic increase in energy efficiency in the U.S. economy since the early 1970s has been the subject of much study and controversy. Among the factors responsible for improved energy efficiency are better housekeeping measures, technological innovations and a changing product mix. These factors are discussed for the manufacturing sector using published input-output data for the years 1963, 1967 and 1972, and data from the Annual Survey of Manufactures for the years 1975 and 1979. Data for the years 1972, 1975 and 1979 are the most revealing in terms of improved energy efficiency. For the purpose of this analysis, a real IO coefficient was calculated by dividing deflated energy input costs by the deflated value of sector output.     

Analysis of residential energy use

The structure, inputs, validation and operation of a residential energy use model are examined with the intention of providing an analytical tool for evaluation of energy conservation option for effects on energy use and related costs.     

A review on compressed-air energy use and energy savings

Compressed-air systems account for about 10% of total industrial-energy use for few selected countries as found in literatures. Compressed air is typically one of the most expensive utilities in an industrial facility. This paper describes a comprehensive literature review about compressed air energy use, savings, and payback period of energy efficient strategies. This paper compiles latest literatures in terms of thesis (MS and PhD), journal articles, conference proceedings, web materials, reports, books, handbooks on compressed air energy use, efficiency, energy savings strategies. Computer tools for compressed air analysis have been reviewed and presented in this paper. Various energy-saving measures, such as use of highly efficient motors, VSD, leak prevention, use of outside intake air, reducing pressure drop, recovering waste heat, use of efficient nozzle, and use of variable displacement compressor to save compressed-air energy have been reviewed. Based on review results, it has been found that for an electric motor used in a compressed-air system, a sizeable amount of electric energy and utility bill can be saved using high efficient motors and applying VSDs in matching speed requirements. Also, significant amounts of energy and emission are reducible through various energy-saving strategies. Payback periods for different energy savings measures have been identified and found to be economically viable in most cases.     

基于层次分析法的关中盆地主要城市浅层地热能适宜性分区特征研究

浅层地热能是一种可用于建筑节能的新型能源,它具有无污染、可再生、分布广、能量大以及可就近利用等诸多优势,开发利用前景广阔。根据关中盆地主要城市的工程地质、水文地质、环境地质条件等因素,分别建立了每个城市地下水热泵和地埋管热泵系统的适宜分区评价体系,运用层次分析法对关中盆地主要城市的浅层地热能适宜性分区进行综合评价。将各个城市地下水热泵和地埋管热泵适宜性分区划分为适宜区、较适宜区及不适宜区,综合分区在两者的基础上进行,并优先选择地下水热泵。旨在有效地丰富浅层地温能勘察评价与开发利用的理论、奠定浅层地温能可利用资源量的计算基础,为构建我国环境友好型社会服务。     

Overall and zonal energy end use in an energy conscious office building

An office building of unusual design has been monitored for more than three years. Numerous submeters allow tracking of energy end use. The building was designed to make significant use of daylighting, with some passive solar heating, and an emphasis on night ventilation cooling of thermal mass. The overall building end usages are compared to those of three zones of varying orientation, spatial character, size, and population. Insights about daylight-sensing controls of indirect electric lighting, “task heating,” and night ventilation of mass and air quality are presented.     

Final energy use in IEA countries: The role of energy efficiency

Improved energy efficiency is a key policy goal of all International Energy Agency (IEA) member countries, but tracking energy efficiency gains is not straightforward. As part of its contribution to the G8 Gleneagles Plan of Action, the IEA has been developing in-depth indicators—tools that provide data and analysis of energy use and efficiency trends. This paper gives an overview of the IEA indicator methodology and presents examples of how disaggregated indicators can be used to identify the factors that drive and restrain energy demand at the end-use level. A decomposition approach is also used to separate efficiency effects from the impacts of structure and activity. The results clearly show the important role that energy efficiency has played in shaping trends in final energy use in IEA countries for more than 30 years. However, the analysis also reveals that recent gains in energy efficiency have been much lower than in earlier decades. Accelerating energy efficiency improvements is therefore a crucial challenge for IEA governments and indicators have an important role to play in helping to develop and evaluate the policies that will be required.     

Structural-behavioral determinants of residential energy use: Summer electricity use in Davis

Engineering models of the physical processes of energy use in individual houses are quite complex. We investigate simple statistical models of summer electricity use and compare them to engineering models. Our data include interviews, energy audits, and utility billings for a random sample of residences in Davis, California. We predict summer kWh using appliance and cooling-load models. The appliance model is based on manufacturers' or published data on average annual kWh used by major appliances; refinements for appliance location, seasonality and frequency of use have mixed success. The cooling-load model includes the major variables used in the DOE 2.1A simulation; coefficients estimated by a multiple regression model closely resemble interpolation parameters derived from DOE 2.1A. The appliance and cooling-load models explain over 50% of the variation in summer kWh in single-family detached houses. Using the appliance model and only two variables from the cooling-load model, house area and self-reported frequency of air-conditioner use, we explain nearly 60% of summer kWh in houses. The simple interview question on frequency of air-conditioner use captures most of the effects of structural features such as insulation and glazing. Finally, the appliance and cooling-load models are applied successfully to other house types (common-wall houses and apartments).