电价交叉补贴的多维视角:效率、公平、外部性与供给约束

A multi⁃objective look at electricity price cross⁃subsidies:efficiency,equity,externality,and supply constraint

中国电力行业长期实施工业高电价、居民低电价的交叉补贴价格政策,这与追求效率的拉姆齐定价法则似乎背道而驰。为解释这一西方经典理论跟中国实践之间的悖论,作者综合运用自然垄断部门定价模型和数值模拟等方法,从效率、公平、环保和供给约束多维视角探究中国电力消费的最优部门定价。研究发现:当电力部门只存在利润约束时,工业电价应低于居民电价,此时符合经典拉姆齐定价;当不仅有利润约束,还存在社会公平、外部性和供给受限等其他目标和约束时,最优的工业电价应高于最优的居民电价,此时反拉姆齐定价比拉姆齐定价更为合理和有效。因此,电力短缺和社会公平等背景下的工业高电价、居民低电价不应简单理解为许多人诟病的电价交叉补贴,而是一种可以促进电力供需平衡、保障社会公平以及环境保护等目标的电价政策安排。该研究试图澄清学界对电价交叉补贴的普遍误解,并对中国长期的反拉姆齐定价现象提出多种合理解释,这些研究结论为电价市场化改革提供了有益参考。在碳中和背景下,文章对电价改革提出几点建议:一是工业降电价要慎重,避免形成“降电价”与“碳减排”的两难困境;二是电力短缺时应灵活调整电价,而不是简单地拉闸限电;三是要有效连接电力市场与碳交易市场。

Electricity price cross-subsidies have long existed in the power sector of China,which seems to contradict the efforts of the ongoing price marketization reform in the sector.In theory,the classical Ramsey pricing model states that electricity price cross-subsi‑dies are almost equivalent to efficiency losses,which calls for an urgent need to explain why such a large discrepancy exists between economic theory and the Chinese government’s pricing practice.This article builds upon the classical Ramsey pricing model,further re‑fines it,and supplements it with simulation analyses,in order to explore the best pricing scheme for electricity consumption from a multi-objective perspective.We find that Ramsey pricing is only optimal when pursuing an efficiency goal under the profit constraint.However,when there are considerations such as equity,externality,and power supply constraints,reverse Ramsey pricing is more ap‑propriate than Ramsey pricing.As such,the high electricity prices in the industrial sector and low prices in the residential sector can be better attributed to electricity supply shortages or other reasons than to cross-subsidies from the industrial sector to the residential sec‑tor.Only when supply constraints are relaxed,or other policy objectives are discarded,could reserve Ramsey pricing shift to Ramsey pricing.Given that,the current policy practice of lowering industrial electricity prices is reasonable considering the overcapacity situa‑tion in the power sector.Thus,we provide multiple explanations from the reverse Ramsey pricing perspective to help better understand the phenomenon of electricity price cross-subsidies in China.In the context of carbon neutrality,the article has important policy impli‑cations for electricity price reform:first,the regulator should be cautious in the reduction of industrial electricity prices.The continuous reduction of industrial electricity prices will increase its demand,causing enormous challenges to carbon emission reduction.Second,the electricity prices should be flexibly adjusted when there is a power shortage,instead of simply shutting off the electricity for indus‑try.Third,the electricity market should be more effectively linked with the carbon trading market.