How did the price and income elasticities of natural gas demand in China evolve from 1999 to 2015? The role of natural gas price reform

As a cleaner,high-efficiency,and low-carbon fuel,natural gas has been an important fuel resource for China.To achieve a substantial increase in natural gas demand,China has sought to reform its natural gas pricing mechanism.Employing a set of unbalanced panel data for China’s 30 provinces covering 1999-2015,this study aims to estimate the evolving price and income elasticities of natural gas demand and explore the effect of natural gas price reform in China.For this purpose,a series of econometric techniques allowing for cross-sectional dependence and slope homogeneity is utilized.The results suggest that although natural gas demand in China still lacks negative price elasticity,the phenomenon is improving.Moreover,the estimates suggest that natural gas demand in China is indeed becoming increasingly sensitive to income changes.Our estimates also provide strong evidence in favor of the effect of natural gas price reform on the change in price elasticity as the price elasticity decreases in five of the seven regions.In addition,the results indicate large variations in the change in price and income elasticities of natural gas demand across China’s regions.Natural gas demand is becoming more price inelastic in Southwest China and Northwest China,while such demand in North China and East China responds less sensitively to income changes.These findings offer several policy suggestions for the reform of China’s natural gas market at the national and regional levels.

中国出口能源的供给价格弹性大小的一个估计——基于CES生产函数的估计

基于CES生产函数形式,文章推导了出口商品供给价格弹性的表达式。根据中国1997年至2017年的能源数据,文章计算出中国出口能源的供给价格弹性值。文章计算结果显示,中国出口能源供给价格弹性值为0.868266。从出口能源品种上看,中国出口能源商品供给价格弹性值存在很大的差异性。文章计算结果显示,中国出口煤炭的供给价格弹性值为-1.328703,中国出口石油的供给价格弹性值为-3.148054,中国出口电力的供给价格弹性为0.335038。

考虑负荷时空均衡和弹性响应的电动汽车快充电价定价策略

为了引导电动汽车有序充电,提出了一种考虑负荷时空均衡和弹性响应的电动汽车快充电价定价策略。引入交通流理论描述交通路网,建立电动汽车快充负荷时空分布模型;考虑配电网调度和电动汽车快充负荷的弹性需求,构建源-荷互动下的快充电价定价架构,并基于潮流追踪法从时空双维度推导快充电价的计算方法;在此基础上,计及电动汽车负荷弹性响应特性,以提升配电网的负荷均衡性为目标,建立快充电价定价策略,并通过迭代算法求解该定价策略。算例仿真结果表明,所提定价策略能够有效引导电动汽车进行有序快充,激励电动汽车用户与配电网友好互动,提升负荷的时空分布均衡性。

简易续约规则对谈判药品价格和持续供应的影响:现象及可行性方案探究

目的:探索在2022年医保目录简易续约背景下是否存在一类特殊现象,即部分药品会不断触发连续降价条件以致最终退出医保目录。方法:本文通过构建需求价格弹性模型,结合医保目录谈判和续约规则进行数值模拟,对多轮简易续约情况进行讨论,以验证简易续约规则是否影响药品可持续供应。最后,本文对可行性方案的适用条件进行数理分析。结果:在2022年简易续约规则下,市场上确实存在一类药品,当其首次医保谈判药品降价幅度和其弧弹性满足一定条件时,会陷入无限降价的困境。该现象可能是由于企业错估药品需求或是进入医保目录后药品销量飙升,量价线性关系被打破。减少续约次数和重新谈判能够降低此类现象发生的可能性。结论:2023年简易续约规则一定程度上避免了此类现象的发生,后续政策可将阶梯型降价标准改为连续型。

Women’s empowerment and food consumption:Evidence from female-headed households in Tanzania

Despite the growing recognition of women’s increasing role in the household and corresponding empowerment programs in sub-Saharan Africa,intensive research on the relationship between women’s influence and household food consumption is minimal.Using the most recent(2017-2018)national household survey data from Tanzania,this study examined the influence of women’s empowerment on household food consumption.First,we compared the monthly consumption of eight food categories between female-headed households(FHHs)and male-headed households(MHHs)using both descriptive statistics and the propensity score matching(PSM)method.Furthermore,we adopted the two-stage Linear Expenditure System and Almost Ideal Demand System model(LES-AIDS)to estimate income and price elasticities for the two household types.The results show that FHHs consume bread and cereals,fish,oils and fats,vegetables,and confectionery(sugar,jam,honey,chocolate,etc.)more than MHHs.Moreover,FHHs have a significantly higher income elasticity of demand for all food groups than MHHs.They are also more price elastic than MHHs in meat,fish,oils,fats,sugar,jam,honey,chocolate,etc.

基于时变价格弹性矩阵的深谷电价多目标定价策略

随着碳中和、碳达峰目标的提出,构建高比例新能源的新型电力系统已成为未来能源电力的发展形态,由此导致的高比例新能源渗透使系统净负荷曲线呈现剧烈的波动性和显著的深谷特征,对电力系统安全运行以及供需平衡提出了新挑战。为此,提出了一种基于时变价格弹性矩阵的需求侧深谷电价多目标定价模型。首先,确立基于模糊隶属度的深谷时段划分方法,并利用贝叶斯判别法对时段划分结果进行合理性评估。其次,针对用户需求响应的动态性,建立具有时变特征的价格弹性矩阵模型衡量用户的响应程度。最后,以用户满意度和系统峰谷差作为待优化的两个目标,建立多目标混合整数规划的深谷电价定价模型,并用非支配排序遗传算法求解模型并得到其Pareto最优解。为了检验所提模型的有效性,将其应用于中国华东地区某省的实际场景进行仿真分析。结果表明,上述模型可在高比例新能源渗透情景下降低峰谷差,促进用户用电行为向深谷时段转移,缓解电力系统在深谷时段的运行压力。

蓄热式电采暖参与消纳受阻风光的源荷协调滚动调度

蓄热式电采暖负荷具有时移性和连续可调性,可作为需求侧资源解决乡村地区新能源消纳困难与清洁供暖问题。当前实施的峰谷分时电价,不能根据源荷变化有效引导电采暖运行以消纳受阻风光。因此提出采用场景法描述风光荷的不确定性,根据源荷峰谷时段变化确定分时电价。并且考虑电采暖响应分时电价时出现用电同时率高问题,引入需求价格弹性系数,建立以蓄热式电采暖运行成本和系统负荷峰谷差期望最小的日前日内源荷协调优化模型,滚动调整每时段各灵活资源出力。最后,通过仿真验证模型的有效性。

基于弹性需求和动态定价的共享泊位分配

为解决共享车位管理中的车位分配与定价问题,考虑了价格变化对于用户不同停车时长选择的影响,分析在不同停车收费标准下用户停车时长选择的概率,并采用多项式拟合得到精细化的共享停车需求价格弹性函数。进而,为实现停车场价格的动态调整与车位分配,以平台收益最大与用户步行距离最小为目标,构建基于弹性需求和动态定价的泊位分配非线性混合整数规划模型,并设计了遗传算法。最后,设计了包含3个停车场共1000个泊位、共享平台运营时长为3 h的算例,对模型及算法加以验证,通过对比分析,基于弹性需求和动态定价的共享泊位分配方案相比于静态定价,实现平台收益增加19%且满足了大部分停车需求,说明动态定价下共享泊位分配模型及算法的有效性,为共享平台的车位管理提供了新思路。

基于多维价格弹性系数的分时电价对负荷特性影响机理

基于23个省级电力公司经营区各行业固定用户群负荷曲线,测算多维价格弹性系数评估分时电价调整对各地区各行业峰谷时段用电的影响,并分析峰谷段电力需求对多维价格指标的敏感性。利用多维价格弹性系数定量评估各地区各行业降低峰段电量、提升谷段电量、缩小负荷峰谷差率三维电力电量指标对提高高峰时段电价、降低低谷时段电价、拉大峰谷电价比三维价格指标的敏感性。根据多维价格弹性系数分析结果可针对不同地区、行业、时段提出分时电价优化调整策略。

双碳背景下中国天然气需求影响机制与趋势预测

文章分析天然气市场运行现状,深入探讨中国天然气需求特点,采用工具变量法和时间序列模型对其需求收入弹性与价格弹性进行估计,采用SARIMA模型预测未来中国天然气需求。需求弹性分析结果显示,天然气的收入弹性高于1,表明随着经济增长天然气的需求将呈现相应上升趋势。然而,天然气需求相对缺乏价格弹性,且受到煤炭替代效应的影响。在天然气价格上涨的情况下,市场消费者可能通过减少需求或选择煤炭替代能源以缓解能源成本压力。模型预测结果显示,未来天然气需求将持续增加。综合分析结果表明,天然气市场在未来将受到经济增长的推动,但需要谨慎应对价格上涨可能带来的替代效应。

考虑不同需求弹性的爬坡辅助服务市场出清模型

在新型电力系统建设背景下,高比例新能源出力间歇性和波动性给电网稳定和安全运行带来新的挑战,而提高电力系统灵活爬坡能力是应对新能源挑战的重要手段。为此,基于不同弹性的爬坡需求曲线,构建爬坡辅助服务市场出清模型,通过爬坡辅助服务市场激励灵活性爬坡资源建设,提升电力系统灵活爬坡能力。考虑不同区间的爬坡容量对电力系统的价值有所不同,建立不同需求弹性的爬坡需求曲线计算模型。在此基础上,设计了3种考虑不同爬坡需求弹性的爬坡与电能量市场联合出清模型,分析了这3种模型的爬坡影子价格定价方式及出清结果。构建算例展示弹性需求曲线计算方法及流程,基于IEEE 39节点系统对3种爬坡市场出清模型进行仿真分析。结果表明,增加爬坡需求弹性可提高系统整体运行的经济性。

基于需求价格弹性矩阵的大工业分时电价激励策略研究

分时电价机制是基于价格的需求侧响应机制中最有效的方式之一,执行峰谷分时电价能够有效抑制配电网负荷曲线波动,从而提高配电网运行可靠性。提出基于需求电价弹性矩阵的用户响应模型,以安徽省某市高新区大工业用户真实日负荷曲线为基础,以负荷曲线“削峰填谷”效果最好为优化目标,建立能更加充分反映城市电网大工业用户负荷变化的峰谷分时电价优化模型,建立面向用户需求侧响应的峰谷分时电价体系,利用粒子群算法求解分时电价的决策模型。通过算例验证所提方法的真实性和有效性,为实现配电网可靠运行和大工业用户节约用电成本提供理论和技术支撑。

一种基于回归方程的峰谷分时电价模型

峰谷分时电价是在不同时间段实施不同价格,由此达到削峰填谷、平衡负荷的目的。鉴于表示用户对电价响应的方法较少,而传统负荷电价弹性矩阵存在获取困难的问题以及缺少指标验证其精确性,创新性地提出建立含高次项与交互项的多元回归模型来反映用户对电价的响应,并分别从供给侧和需求侧考虑,建立了基于回归方程的峰谷分时电价优化模型。根据新加坡能源市场公司提供的负荷与电价数据,分别对基于负荷电价弹性矩阵和基于回归方程的多目标优化问题进行算例分析,对比两种模型并验证了基于回归方程模型的可行性和有效性。

基于阶段分时电价响应的电动汽车充电负荷优化策略

针对电动汽车的充电负荷优化问题,提出一种基于阶段分时电价响应的电动汽车充电负荷优化策略。该策略在考虑电动汽车负荷因素的前提下,建立电动汽车充电负荷模型,并通过蒙特卡洛算法模拟电动汽车无序充电的负荷变化。在峰、谷、平段电价弹性矩阵的基础上,细分不同的等分时间段建立阶段分时电价模型,构建以用户充电总费用和系统总负荷均方差最小为优化目标的电动汽车分时电价优化模型,采用改进的混沌多目标遗传算法对模型进行求解优化。实验对比结果验证了该策略的有效性和经济性,在给定数据条件下用户充电总费用和系统总负荷均方差较传统分时电价方案分别降低了0.4091万元和37.151 MW。

基于分时电价的电动汽车需求侧响应充电策略研究

分时电价策略是当前电力系统需求侧管理的有效方式之一,执行分时电价能够有效抑制配电网负荷曲线波动,从而提高配电网运行的可靠性。提出基于电价弹性矩阵的用户响应模型,以合肥市春、夏、秋、冬4个典型日的真实日负荷数据为基础,以负荷曲线“削峰填谷”效果最好为优化目标,建立能更加充分反映城市电网负荷变化的分时电价优化模型,制定面向用户需求侧响应的日前分时电价体系。结合区域电力市场最优分时电价对电动汽车用户的激励效果,提出基于需求侧市场机制的区域电网电动汽车充电策略,为电动汽车大规模有序接入和实现配电网的可靠运行提供参考。

基于价格弹性的蔬菜类商品自动定价与补货决策

对于生鲜商超,在尽量满足市场需求的前提下,实现商超收益最大的补货量和定价策略尤为重要.本文探究了蔬菜销量与成本加成定价的关系,选取需求价格弹性的经济学指标,构建双对数需求模型对价格弹性进行估计,基于此建立价格弹性修正函数,对LSTM模型预测出的销量与定价进行修正.为确定各蔬菜品类未来一周的日补货总量与定价策略,建立了收益最大化模型,并通过GBest-PSO算法求解.为确定满足特定需求下各蔬菜单品单日的补货总量与定价策略,根据过去一周的可售品种,采用VIKOR评价方法量化蔬菜单品的需求,建立需求与收益最大化的双目标优化决策模型,通过NSGA-Ⅱ非支配排序遗传算法求解,并在Pareto前沿解中确定了最优方案.

Effect of Increase in Price of Oil on Behavior of Private Car Owners in Beijing

In order to understand the short-term response of private car owners to changes in the price of oil,a survey was conducted in Beijing after the gasoline price in China rose in June 2008.It showed that private car drivers in Beijing reduced their trips in the one month period following the price adjustment.Certain trip characteristics and drivers' demographics significantly influenced price elasticity in the short term,including the purpose of the trip,the distance covered and the income of the car driver.

The Impact of Price on Chemical Fertilizer Demand in China

Since 1998,the national policies on chemical fertilizer in China have been concentrated in limiting price plus subsidizing,abolishing agricultural tax,giving direct subsidies to farmers,and other aspects.In order to analyze the impact of national policies on the consumption of chemical fertilizer,this article selects the consumption of chemical fertilizer per unit,chemical fertilizer price index and farmers'net income in different provinces during the period 1998-2007 as variables,to conduct regression analysis of chemical fertilizer expenditure function,and calculate the price elasticity and income elasticity of chemical fertilizer demand in different provinces over the decade based on the regression results.The results show that at present the basic consumption of chemical fertilizer for agricultural development in China is 0.35 t/hm 2 ,and the consumption of chemical fertilizer is excessive in some provinces;the chemical fertilizer market has not been really established,and the price has little impact on demand.This indicates that the chemical fertilizer is essential for agricultural economic development,and it increases along with the increase of farmers'income; the intervention of the national policy in chemical fertilizer price is a fundamental reason for the rising demand for chemical fertilizer.This also to some extent indicates that the policy effect of merely using environmental taxes to change farmers'consumption of chemical fertilizer is limited;there is a need to transform the existing policies purely promoting agricultural economic development,toward giving different subsidies in accordance with whether the farmers'fertilization pattern is beneficial to the environment.

Price Discrimination of Film Products and Building of Hierarchical Market under the Background of “Internet Plus”

Price Discrimination of film products is theoretically feasible and logically inevitable, and it has been used for a long time in film industry as well. However, there are practical paradoxes in the new environment due to market factors like popularization of Internet environment and Online to Offline(O2O) retailers between hierarchical markets. Compared with high-level markets, low-level markets are lack of conditions for differentiated lower price like cinema infrastructure, and environment for film consumption market, so that the consumption potential for market has not been motivated yet. Therefore, it is quite important to pay close attention to how to expand the market by clearer gradient pricing structures and Internet platform.

Price Discrimination in the Steel Industry:Evidence from Egypt

This paper studies and enlightens mainly price discrimination;which is simply selling products for differentiated prices.First,a literature framework is detailed with all the theories and types of price discrimination throughout the years.It is a strategy that is used worldwide by so many companies and firms,but this paper studies specifically the activity of the major player in the Egyptian steel industry;Ezz steel.The research resulted in;that there is no price discrimination,activities are implied in the industry currently by the companies due to the interference of the government.However,before that,the company applied some strategies that are illustrated in the paper in detail.