不完全競爭市場結構下原油價格衝擊傳遞效果之一般均衡分析

The Transmissions of Oil Price Shocks in a Small Open Economy with Scale Economies and Imperfect Competition

王欣怡(Hsin-Yi Wang)

指導教授 ： 林師模

中原大學/商學院/國際貿易研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500420

摘要

自古以來，能源一直是人類賴以維生的要素之一，也是國家發展經濟的重要動力之一，而在所有的能源供給中，「原油」更是佔有舉足輕重的地位。我國因受限於地理環境之故，必須高度仰賴原油的大量進口，因此國際原油價格的變動對於我國而言，絕對是不容小覷的問題。近年來國際油價不斷飆漲上揚，對於我國總體經濟及各產業部門所造成的衝擊與影響，應是相當重要的探討議題。另一方面，政府為了落實經濟自由化、國際化以及民營化之政策方針，在積極規劃開放油品市場下，使得過去僅由國營的中油公司一家獨大的獨占市場，逐漸轉變為目前「寡頭雙占」（duopoly）的局面，因此在衡量國際油價衝擊的同時，油品市場結構亦是考量重點之一。

本研究透過建立一個納入規模經濟與市場結構設定的可計算一般均衡（computable general equilibrium，簡稱CGE）模型，並將定價方式區分為三種模型，包含完全競爭市場（PC）模型，以及分別從出口品與進口品相對於國產品價格角度所切入的兩種不完全競爭市場（IC-C和IC-A）模型，以針對近幾年急速上漲的國際原油價格，可能對我國整體經濟及各產業部門的影響加以評估。除進行議題模擬並比較模型結果差異以外，本研究亦就相關的轉換及替代彈性進行敏感度分析。

研究結果發現，國際油價上漲對國內生產毛額及國內總產出皆呈現負向影響，且在不完全競爭市場模型中，其總體經濟變數受衝擊的影響幅度會比過去傳統的完全競爭模型更大，表示在越接近完全競爭市場的結構下，經濟體系面對外在衝擊時所能因應調整的面向及彈性也越廣闊，亦即政府對於油品市場的自由化政策應是受到肯定的。而在產業部門的模擬結果方面，多數產業為因應油價衝擊而上揚的生產成本，呈現產出減量的情況，僅原油部門因進口量的減少而增加產量以維持國內的供給。由於部門調整產出導致勞動就業量出現流動的變化，且產業亦提高產出價格以反映成本的高漲。在敏感度分析結果上發現，在分別以不同的彈性值進行模型求解時，IC-C模型對於出口轉換彈性較為敏感，而IC-A模型則對進口替代彈性之敏感程度較不明顯。唯獨電力部門相關的細部敏感度分析結果顯示，在估計此部門的轉換及替代彈性時，由於電力與其進出口品間幾乎無替代關係之故，應採用較低的彈性數值才能符合我國實際的經濟現況。此外台灣僅為小型開放經濟體系，石油煉製業對於國際市場影響有限，故在考量本研究所建構的不完全競爭市場模型之適用性上，應以面對國內消費者為主所建立的IC-A模型，較能符合我國實際的現況。

關鍵字

可計算一般均衡 ； 油品市場 ； 規模經濟 ； 不完全競爭 ； 原油衝擊

並列摘要

Energy has been one of the key elements that the mankind has depended on and the important essential factor to countries for a long time. Constrained by the geographical and natural environment, Taiwan depends highly on the import in a large amount of crude oil. In recent years, the world crude oil price keeps rising constantly. Therefore the fluctuation of the world crude oil price is definitely an important issue to the macro-economy and industries in Taiwan. On the other hand, over the past several years the government has planed to open the oil market wider in order to implement the policies of economic liberalization, internationalization and privatization. The structure of oil market has thus changed from monopolistic market into the duopoly market. Consequently, the market structure has become an essential factor to consider while measuring the effects of oil price shock.

This study constructs a computable general equilibrium (CGE) model with scale economies and imperfect competition for Taiwan. It consists of three kinds of pricing model which include perfect competitive model (PC) and two imperfect competitive models (IC-C and IC-A) that describe the relationship between the export, import and domestic commodities separately. Our simulations have been focused on the effects of oil price shocks. Sensitivity analyses on the relevant elasticity parameters have also been carried out.

The simulation results reveal that when world crude oil price rises, GDP and domestic total output will be affected negatively. The change range of macro-economic variables in IC-C and IC-A model are larger than that in PC model. It represents that the economic system can adjust more widely in perfect competitive market when the shock happens. In order to reflect the rise of production cost, most of industries decrease their outputs. Only the crude oil sector increases its output to maintain the domestic supply. The labor market also changes accordingly with the changes in output and the domestic product price rise to reflect the cost, too. The sensitivity analysis results reveal that IC-C model is relatively more sensitive to transformation elasticity than IC-A model is to the import substitution elasticity. Detailed sensitivity analysis also shows that the elasticity value for electric industry should be smaller to reflect the real economic situation in Taiwan. Being a small open economy, the petroleum industry in Taiwan has very limited power in the global market. As such, IC-A model which focuses on the domestic consumers seems to fit in more with the actual situations in Taiwan.

並列關鍵字

Oil price shocks ； Imperfect competition ； Scale economies ； Oil market ； Computable general equilibrium

參考文獻

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