自由化電力市場的競合與風險控管(I)

Abstract

1980 年代以前，電力產業傳統上是垂直整合的，且獨佔於世界上的大多數區 域。然而，研究發現這些獨佔的電力事業體效率異常低落，並歸咎於獨佔市場的高操作 成本、高價格與缺發市場競爭及新市場投資。有鑑於此 世界各國於1980 年代末期開始 開放電力市場，希求以市場競爭來提升市場效益。 電力與一般有形體商品不同，開放市場中的電力價格可能高度的不穩定。其因 有三：（1）電力商品的難以儲存性；（2）電力供應的不穩定性；（3）電力需求的不穩定 性。美國加州於1990 年代中期開始開放電力市場。然而，加州電力價格的高度不穩定 卻造成開放電力市場的自由化政策失效，並進一步導致2000 年與2001 年著名的＂美國 加州電力系統崩潰事件＂。面對難以掌握的波動電價，加州電力供應商與電力批發商損 失了可觀的金額。而電力消費者也被迫接受極高的電力市場價格。此一雙輸的局面最後 造成了供電者無法承受價格風險而退出市場，最終整個加州供電系統崩潰。 一般商品市場上，參與者可以透過bilateral contracts 來鎖住於市場外交易 的價格，並藉此降低市場內價格波動的風險。Bilateral contract 是一種買賣雙方同意 的交易契約。此一契約包含了買賣雙方同意的交易限制，比如說交易數量、價格、交貨 時間等等。為了控制電力市場價格的波動性與樽節電力市場的獨佔力量，我們可以考慮 使用bilateral contracts 作為電力市場的風險控管工具。例如，政府可以於自由電力 市場中施行半強制式的＂市場限量＂與＂市場限價＂來做為價格波動性與風險的控管 工具。然而此一管控工具必須小心，不適當的＂市場限量＂與＂市場限價＂可能傷害市 場參與者的正常獲利，並阻礙新市場投資者的參與。此一結果可能最終傷害市場的競爭 性，並使市場失去效率。 台灣與新加坡國情類似,皆自1995 年開始開放電力市場。本研究的目的在於探 索一般與半強制的bilateral contracts 對電力市場的價格波動性所造成的影響。我們 的研究目標是bilateral contracts 對電力市場自由化與市場力量的效應，並提出合理 使用bilateral contract 以穩定自由化電力市場的方法。最終希望能以台灣或他國的 歷史電力交易資料，來驗證此一電力市場自由化的風控管工具。

Electricity industries were vertically integrated monopolies in most areas of the world before the 1980s. However, these monopolies were inefficient due to high operating costs, high prices and lack of new investment existed in such systems. As a result, many countries deregulated their electricity industries by the introduction of a market mechanism. Not like other tangible commodities, electricity prices in deregulated electricity markets can be highly unstable due to three reasons: high storage cost, unstable supply, and unstable demand. California deregulated its electricity markets in the mid-1990s. If electricity prices are stable, then the deregulated market works. In fact, electricity suppliers and retailers in California were asked to supply electricity at variable prices and lose considerable amounts of money. Simultaneously, electricity consumers were required to purchase electricity from the wholesale market at sky-high prices. As a result, the California electricity crisis of 2000 and 2001 demonstrated that electricity prices may be highly unstable and the deregulated market is risky. In general commodity market, participants may privately establish bilateral contracts to lock prices and trade commodities outside the wholesale market in order to reduce risks of unstable prices. A bilateral contract is an agreement between two parties to exchange commodities. The agreement contains a set of specified constraints, such as commodity amount, price, delivery time and duration. In order to control the volatility of electricity prices and mitigate the market power on the electricity market, bilateral contracts can also be introduced as a management tool. For example, these bilateral contracts can be regulator-mandated “hedge quantities” and “hedge prices” on the electricity supply. However, an improper hedge price and quantity may discourage new investors and may be detrimental to participants' profit, thereby discouraging new investment. As a result, the wholesale market may become less competitive and efficient. Taiwan and Singapore have similar situation. They began Their electricity industry reform from 1995. We are interested in exploring the impacts of private and regulator-mandated bilateral contracts on the volatility of electricity price. Our goal is to study the effects of regulator-mandated bilateral contracts on electricity prices and market power and finally to ensure a stable market environment.