我國導入PFI模式時其適用性評估中折現率訂定基準之研究

A Study to Develop the Instructions for Setting Discount Rate in VfM Assessment of PFI Projects in Taiwan

楊淑雅(Yang-Shu Ya)

指導教授 ： 周慧瑜

朝陽科技大學/理工學院/營建工程系/碩士(2012年)

摘要

公共建設的投資具有提升公共服務水準並帶動國家經濟發展之效果，也往往是各國政府重要的施政工作之一。在我國現行之促參模式下，必須要有一定的自償率才得以施行，由過去歷年之促參案簽約件數及民間投資金額看來，已有日漸下滑之趨勢，對於未來面對許多具有高公益性卻低自償率之公共建設與服務時，我國現行之促參法所適用範圍實在有限。
　　目前世界各國在公共建設與服務上所推行之民間參與模式中，主要可分為「特許權(concession)」與「PFI模式(Private Finance Initiative)」兩種，其本文著重的PFI模式已廣泛應用於30多個國家，尤其用在推動公益性較高但自償率較低之公共服務項目中，推行至今普遍獲得之評價。本研究所針對之研究主體「折現率」，便是基於我國未來擬導入PFI模式時，政府主辦機關在面對傳統政府自辦模式、促參模式與PFI模式等，這三種機制與資金結構截然不同的採購形式下，必須決定各項投資計應採用何種模式時，便有可能發生因折現率設定不當，而影響了評估與評選結果正確性的問題。且我國目前對於折現率設定方面，尚未有明確之計算準則或設定依據。
　　綜合以上所述，本研究參酌澳洲政府所使用之資本資產定價模型(The Capital Asset Pricing Model ,CAPM)理論架構，並以行政院公共工程委員會「公共工程標案管理系統」之歷史資料，針對建築工程、道路工程、鐵路工程、港灣工程、捷運系統工程、下水道工程等六大工程類型之歷史案例作為試算之基礎資料，從中評估出各種工程類型之風險程度，再據以設定CAPM模式所需之風險係數β值，進而求得折現率。經上述實證研究顯示，在六大類型之公共工程中，就標案實際執行結果與原預定計畫之差異程度而言，以鐵路工程之風險度最高，其市場風險係數β值為0.9，計畫評估時所採用之折現率建議值則為7.15%；而捷運系統工程之風險度最低，其β值為0.3，折現率建議值為3.55%。希望藉由此研究結果，可作為未來導入PFI模式時折現率訂定基準之決策參考。

關鍵字

折現率 ； 民間參與公共建設 ； PFI模式 ； 資本資產定價模式

並列摘要

Governments around the world generally make many efforts to invest in infrastructures for improving public services and pushing forward the national economic development. With the promulgation of the Law for Promotion of Private Participation in Infrastructure Projects, the concession model has been used in Taiwan to bring private finance into public infrastructure projects with self-financing ability. However, the amount of contracted concession projects has been decreasing year by year. This downward trend shows that the existing concession model has its limits, especially for those social welfare facilities without self-financing ability.
　　The private participation model implemented in infrastructure and public service projects can be divided into two major systems: “concession model” and “PFI (Private Finance Initiative) model“. PFI model, the subject discussed in this research, has been introduced in more than 30 countries all over the world. It has not been applicable in Taiwan yet, but it is broadly regarded as positive to rapidly push ahead with the investment on infrastructure and public services, especially those with high public interests but low self-liquidity. Therefore, it is an important issue for Taiwan government to investigate how to introduce PFI model into domestic private participation system for social capital investment. Depending on different capital structures under various procurement models, the infrastructure or public service projects should be analyzed by different principles, for example, the discount rate. The influence of the discount rate over the results of project evaluation can be significant even to change the conclusion. However, there exists no standard for the calculation or setting of the discount rate, which means there is a lack of fair and consistent comparable basis among different projects or different proposals from bidders.
　　This research put the focus on how the discount rate should be set if PFI model was launched in Taiwan. The process and parameters of discount rate setting now used by Australia government were introduced here, which has a theoretical framework based on CAPM (The Capital Asset Pricing Model). Besides, “Public Construction Management Information System” developed by Public Construction Commission was used to collect historical data of six category of public construction projects, including building, road, railway, harbour, rapid transit system, and sewerage construction. The historical data were put into evaluation to measure the risk level and the beta coefficient (β) of each construction category. Thereafter the discount rate for each construction category of PFI project was suggested. The results gave the railway construction the highest β value 0.9 for its relatively highest risk level, and suggested its discount rate 7.15%. On the other hand, the rapid transit system was given the lowest β value 0.3 for its relatively lowest risk level, and its discount rate was suggested 3.55%. The results of this research are expected to be helpful for the authorities responsible for setting discount rates for PFI projects in the near future.

並列關鍵字

Private Participation in Infrastructure Projects ； Discount Rate ； Capital Asset Pricing Model (CAPM) ； Private Finance Initiative (PFI)

參考文獻

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