台灣電動公車之成本函數與營運特性分析

Abstract

近年來，無論是面對氣候變遷與節能減碳之挑戰，或是原油價格攀升等國際議題上，皆促使各國積極思考其他新式能源取代石化能源的可能性。在各國運輸部門所占能源消耗量多半僅次於其工業部門的情形下，公共運輸業順勢成為各國積極導入新能源車輛的領域。其中，又以電動公車的節能效果最具潛力，但其伴隨大量的初期購置成本及技術需求，也使得各國在其發展上格外困難。我國推動電動公車亦不遺餘力，但同樣面臨車體、電池及相關設備等成本昂貴的問題。此外，透過實際調查業者營運情形，發覺過去五年配合政策而正式商業營運之電動公車，其妥善率並不如預期，除造成營運成本提高，更擴大推動的障礙。 本研究係針對台灣過去五年推動的電動公車成本特性進行分析，首先透過業者間成本變異分析，釐清電動公車之成本結構，其次則建立電動公車Translog成本函數，設定產出為營運里程，輸入為資本、勞力及中間投入等三項價格要素，並以4家客運業者從2014年4月至11月的營運資料，進行模型參數之校估，以探討其成本特性以及成本與營運特性之關係。實證分析結果顯示，電動公車之行駛路線具規模經濟，而資本要素價格存在僵固性，即其價格難以隨需求而變動。各項價格對成本之彈性分析，則顯示中間投入要素對於總成本之影響程度最大，與電動公車具有低營運成本之優勢明顯不符，而透過中間投入要素價格與營運特性之相關性分析，可知妥善率不佳是導致營運成本增加的主因。此外，透過妥善率對成本的迴歸分析，可知電動公車的妥善率較差時，成本節省效率較佳。本研究結果亦顯示用電效率乃妥善率不佳之主因，電動公車之營運成本乃因妥善率而升高，以致失去營運優勢的問題，因而建議對於電動公車補貼政策方向，除了現有車體方面的補助，亦宜思考納入有助於妥善率提升方面的營運需求。

In recent year, various countries are thinking the feasibility of new energy to replace fossil fuel because of the critical challenges on climate change and energy saving with the trend of increasing fuel price. Since transport sector contributes the high proportion of the energy consumption, which is only less than industry sector in most of countries, the public land transport has been recognized with the advantage of applying the new energy vehicles, such as hybrid, fuel cell, and electric bus. Among them, the electric bus has comparative advantages of quiet, clean and cost effectiveness. However, the expensive capital costs of the electric bus is still one of the key factor for success of commercial operation. In addition, it is found that the availability of electric bus is also a crucial factor which may not only cause the additional operation costs but also become an obstacle for promotion of electric bus in Taiwan. The study aims to identify and analyze the cost structure and operating characteristics of the electric bus by developing Translog cost function of electric bus in Taiwan. The output of the function is set as mileage while the input variables consist of capital price, labor price and intermediate input price. The data used in the emprical analysis is obtained from the four operators with their operation data from April 2014 to November 2014. The results have indicated that the operating routes of electric bus have characteristics of scale economies. It is also shown that the capital cost of electric bus exists the stickiness. Besides, it is found that the intermediate input cost affect the total cost the most, which is caused by the comparatively poor availability of electric bus. Through the analysis of regression between the cost and the availability, it has also indicated that the cost saving efficiency is good when the availability is low. It is also concluded that the key factor affecting the availability is the electric efficiency.