二氧化碳減量共同技術成本比之建構--考量經濟發展及CO2排放之跨國技術比較

Abstract

本研究在同時考量經濟發展及CO2排放下，結合影子價格模型與共同邊界分析之概念，並以技術競爭力指標分數作為國家分群的依據，建構了共同技術成本比（meta-technology cost ratio，MTCR）指標，試圖以減碳成本的變化衡量各國生產技術差異，MTCR可直接反映技術水準進步所能帶來之成本改善幅度，並可對應得知在技術水準進步後，CO2邊際減量成本（marginal abatement cost，MAC）能夠降低的金額支出，決策者不僅能藉由MTCR評估促使其追求技術進步的誘因大小，亦能從MAC的差額得知該政策能為該國帶來的具體經濟利益。本研究亦使用共同技術比MTR（meta-technology ratio，MTR）分析各國以技術效率衡量之技術差異。 估計結果發現，在以技術競爭力指標為分群基礎下，隨著技術競爭力的發展，各國之技術效率表現會逐漸上升，減碳成本則會呈現先降後升的趨勢。藉由技術水準的提升，低技術競爭力國家可獲得最大的技術效率進步空間及減碳成本節省幅度，並可對應至最高的減碳成本節省金額，顯示其應該投注較多資源於技術進步的追求上；相較之下，雖然高技術競爭力國家具有與低技術競爭力國家相似的減碳成本節省金額，然而由於高技術競爭力國家的所得水準較高，藉由技術進步獲得之成本改善對其經濟的影響程度並不大，故促使高技術競爭力國家追求技術進步的誘因也就不高。 檢視各群組國家投入產出以及技術效率變動率可知，投入要素的累積對一國經濟發展的貢獻會隨著技術競爭力的發展逐漸式微。而在技術與產出水準變動的影響下，各國的邊際減碳成本會隨著時間推進而逐年增加，並會逐漸趨於往在不同產出水準所對應之最低減碳成本邁進。此外，減碳成本隨著人均所得、石化能源使用強度、人口密度，以及貿易開放程度等環境結構因子的上升而增加，技術效率的改善則有助於降低減碳成本，且不同技術競爭力國家所受影響程度亦有所差異。

The purpose of this paper is to construct a meta-technology cost ratio indicator by combining shadow price model and meta-frontier analysis under grouping different technological competitiveness index. The meta-technology cost ratio which can be used to measure the technical differences across countries under economic development and different emissions of carbon dioxide. The meta-technology cost ratio can not only reflect the improvement rate of carbon abatement cost by technological progress but also provide the exact amount of cost savings. Traditional meta-technology ratios are also computed for comparison. Estimates results find that the performance of technical efficiency of each country increases as the technological competitiveness reaches to higher level. At the same time, the abatement cost for emission reductions will be declined and then increased later on. Those countries with the lowest technological competitiveness level result in the most technical improvement and the highest cost saving for carbon emission reductions. It shows that more resources are required for these countries to pursuit the higher technology levels. On the contrary, although there is similar abatement cost for emission reductions for countries with the highest and the lowest technology levels. Such cost saving is insignificantly for countries with high income however similar amount for low income countries has critical impact. As such, there is low incentive for high income countries to pursue technological advances. Furthermore, simultaneously taking into account the technical efficiency and outputs levels, abatement cost for emission reductions will gradually increase over time and tend to approach the ideal abatement cost for emission reductions under different output levels. It is also found that income per capita, fossil energy use intensity, population density, and trade openness have positive impacts on the abatement cost of carbon emission reductions. The improvement of technical efficiency assistants the declining of the abatement cost of carbon reductions.