伴隨環保意識的高漲，人們了解環境污染與身體健康的重要關聯，也讓各產業在環境保護上的表現逐漸成為焦點，進而影響到廠商營運的效率衡量，而焚化廠為一典型同時有正向產出(發電)與負向產出(污染物)的產業，又隨著焚化廠屆齡問題來臨，使其污染排放與技術效率成為重要議題。本篇論文即以台灣21家大型焚化廠為研究對象，利用隨機邊界估計法配合方向性產出距離函數，將負向產出納入效率衡量模型中，找出各焚化廠之發電效率並計算污染物的影子價格，及正向產出與負向產出之間的替代彈性。 估計結果顯示，台灣焚化廠在發電效率上，總平均無效率值約為22.8%，顯示在既有的投入情況下，台灣焚化廠仍有22.8%的提升空間；體制間比較結果，民營體制普遍較公營體制效率為高，又民營體制中，北部地區之效率是較優於中部及南部地區。在影子價格估計部份本篇論文分別以單一負向產出及多重負向產出作計算，則在單一負向產出模型下，氮氧化物、硫氧化物及一氧化碳三種污染物間價格相近，與實際情形較符合；多重負向產出模型下，則以氮氧化物之影子價格最高。另外有顯著證明氮氧化物的排放量與排放密度與影子價格呈正相關；硫氧化物的排放密度與影子價格亦呈正相關，推斷焚化廠在減少氮氧化物與硫氧化物排放上無邊際成本遞減的情形；一氧化碳排放量則與其影子價格有顯著負相關，呈現邊際成本遞減的趨勢。 Due to the limitation of plant-life and the rising of environmental concern, the incinerator’s technical efficiency and pollutants abatement have become an essential issue of Taiwan. The purpose of this research is to estimate the electricity-generated efficiency of incinerators by the stochastic frontier analysis. Our research considers the individual incinerator’s efforts in increasing the production of electricity (good output) as well as the reducing of pollution emissions (bad output) under the given resources and technology constraints. The directional output distance function was used and the shadow prices of pollutants and elasticity of substitution between good and bad outputs were estimated. Our results indicate that the average value of electricity-generated inefficiency is about 0.228, which implies that Taiwan incinerators could increase production of electricity by 22.8% and decrease emissions of pollution by 22.8% simultaneously. Furthermore, we found that incinerators located in northern part of Taiwan show higher values of efficiency than those in the middle and southern part of Taiwan. However, the estimates of shadow prices of pollutants obtained by the single bad output analysis are found more realistic than those obtained from the multiple bad output model. The shadow price of Carbon monoxide is found to have a decreasing marginal cost of pollution abatement with respect to pollution reduction.
