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在香港推廣水冷式空調系統的初步顧問研究執行摘要《中英文版 》

機 電 工 程 署

Electrical & Mechanical Services Department

Agreement No. CE44/98

Preliminary Phase Consultancy Study on Wider Use of Water-cooled Air Conditioning Systems in Hong Kong

Executive Summary

July 1999

合約編號CE44/98
在香港推廣水泠式空調系統的初步顧問研究
執行摘要
Agreement No. CE 44/98
Preliminary Phase Consultancy Study on Wider Use of Water-cooled Air Conditioning Systems in Hong Kong
Executive Summary

介紹
目標與目的		INTRODUCTION
Aims & Objectives
進行研究的目的如下： The objective of the study is as follows:
本研究旨在考察在香港推廣水冷式空調系統(WACS)，使之用於非住宅項目的可行性。研究將提供充分的獨立調查結果和推薦意見，使香港特別行政區政府能夠看到整個地區使用水冷式空調系統在工程、環境和經濟方面的可行性，能夠體現經過驗証的世界技術和創新設計的可用節能工程方案，及研究和項目實施的主體階段所採用的中長期策略。 To examine the feasibility of promoting water-cooled air conditioning systems (WACS) for non-domestic development in Hong Kong. Provide independent findings and recommendations sufficient to enable the HKSAR Government to have insights into the engineering, environmental and economic viability of territory-wide WACS, the available energy efficient engineering solutions demonstrating the proven world-wide technologies and innovative designs, and the medium and long term strategy to be adopted for the main phases of the study and implementation of the project.

研究表明水冷式空調系統是技術上可行的，並且有一些水冷式空調系統方案無論在經濟上和財務皆是可行的。The study has shown that WACS are technically feasible and that there are a number of types of WACS schemes that are economically and financially viable.

研究結果摘要Summary of Findings
研究顯示，採用水冷式空調系統有益於節約能源，可使本土地區範圍內減少溫室氣體排放(GHG)，減少發電站所用的進口礦物燃料，減緩發電站的建設和降低對環境的影響。 The study has demonstrated that there are benefits in adopting WACS in terms of energy savings which territory-wide can lead to a reduction in greenhouse gas emissions (GHG), a reduction in imported fossil fuels for power generation, deferred power station provision and reduced environmental impacts.
然而，要實施更廣泛的採用水冷式空調系統也有一些限制的條件，儘管這不是不能克服的，因此建議特區政府在計劃進一步時需配合另外一些行動。 However, there are a number of constraints to the implementation of the wider adoption of WACS and although not insurmountable, further actions on the part of the HKSAR Government are recommended in order to proceed.
水冷式空調系統的背景 
在香港目前的總用電量中，有超過60%是消耗在商業建築物上，而其中又有約40%消耗在空調系統上(即是總用電量的25%左右)。 More than 60% of the total electricity currently used in Hong Kong is consumed in commercial buildings, of this some 40% is taken up by the air conditioning system (i.e. around 25% of the total electricity use).
目前，大部分在港裝有空調的建築物皆配備了將熱量從建築內部傳送出來，再散發到大氣中的空調系統。這些系統通常被稱作氣冷式空調系統(AACS)。 The present situation is that the majority of the air-conditioned buildings in Hong Kong are constructed with air-conditioning systems that transfer the heat from the inside of the building and dissipate it to the atmosphere. These systems are commonly referred to as air-cooled air-conditioning systems (AACS).
氣冷式空調系統在香港佔主導的地位，很大程度上歸因於目前水務署對使用政府喉管供水用於空間舒適調節設備的蒸發式冷郤用途所實施的限制。這些用水限制從六十年代開始在港實施，是由於香港地區水源匱乏，而從廣東省提供可靠和持續的食水供應之前，這些限制已生效了。 The pre-dominance of AACS in Hong Kong may be largely attributed to the current restrictions imposed by the Water Supplies Department (WSD) on the use of the mains water supplies in evaporative cooling processes for comfort air-conditioning. These water use restrictions were imposed during the 1960’s as a consequence of the limited availability of water resources within Hong Kong and prior to the implementation of a reliable and continuous piped supply system of raw water from Guangdong Province.
此外，在近幾年中，通過“非循環”海水供應去消散建築物空調系統產生的熱量，已被接受為一個節能的建築物冷卻系統方案，特別是採用於那些靠近海岸線的建築物上。這就促進了一定數量的公共和私人海水引入泵房和水管系統的發展，並遍佈整個地區，直接為大型建築物空調冷卻的散熱裝置供應海水。現在有大約一百個這樣的系統為政府建築物，醫院，綜合性開發項目和大型交通項目的空調系統散熱提供海水。 Notwithstanding this, over recent years the use of “once-through” seawater supply for the dissipation of heat from building air-conditioning systems has been accepted as an energy-efficient solution to the cooling of some buildings in Hong Kong, particularly those close to the seafront. This has developed into a number of public and private sector seawater intakes pumphouses and pipeline systems, being constructed throughout the Territory for the direct supply of seawater for the air-conditioning chiller installations of large buildings. Today there are approx. one hundred once-through systems serving government buildings, hospitals, mixed-use developments and mass transportation developments - providing seawater supplies for air-conditioning system heat rejection.
水冷式空調系統的優點和缺點
水冷式空調系統方案的類型		BENEFITS AND DISBENEFITS OF WACS
Types of WACS Schemes
作為研究的一部分，本研究對三種不同類型的水冷式空調系統方案進行了評估，這三個是所有方案中比較具吸引力，且有潛力在香港被廣泛採用的。集中式管道供應冷凝器冷卻水系統。 Three different types of WACS schemes have been evaluated as part of the study and found to be attractive and having the potential for wider adoption in Hong Kong. These are:
集中式管道供應冷凝器冷卻水系統(CPSSCC)Centralized Piped Supply System for Condenser Cooling (CPSSCC)
此類型系統是由一個海水引入裝置和泵水站組成，通過管網或配送環路(見圖0201)向幾個建築提供大量的海水。海水被泵入每個建築物機房的水冷式冷凍水機中，用於消散從冷凍水機組排出的熱量。變熱後的水通過另一個包含增壓管網和海洋排水口的獨立系統排放到海洋中。排出的熱水也可再被作為建築物沖洗水途。 This type of system consists of a seawater intake and pumping station supplying a large quantity of seawater to a number of buildings via a pipe network or distribution loop (ref. Figure 0201). The seawater is pumped to the water-cooled chillers located within each building plant room and is used to dissipate heat rejected from the chiller plant. The discharge of warmed water is returned to the sea via a separate discharge system with pressurised pipe network and sea outfall. The discharged warmed water also has the potential to be reused for building flushing water purposes.
研究表明，與AACS方案相比，使用CPSSCC方案可以節約12%到24%的能量。 The study has evaluated that energy savings of between 12% to 24% can be achieved for CPSSCC schemes when compared to AACS systems.
集中式管道供應冷卻塔用水系途(CPSSCT)Centralized Piped Supply System for Cooling Towers (CPSSCT)
此系統與CPSSCC系統有類似的基本構造裝置，然而，這種系統是通過管道網絡或分配送環路，向幾個建築供應相對較少量的海水或淡水(見圖0701或0801)。海水或淡水被用做冷卻塔的補給水送往那些通常位於每一座建築屋頂的冷卻塔。這種冷卻水代替了會因蒸發、流失和飄走而失去的循環水流。從冷卻塔產生的流失或廢水是斷斷續續排放出來的，可即場進行處理後，排入附近的雨水管道。另外，如果公共污水管有足夠的富餘量，也可將其排入公共污水管道。為了驗證此等排放之可行性，將需進行一個排污或排水影響評估。 The CPSSCT system is a similar infrastructure arrangement to the CPSSCC system, however, this type of system involves the supply of a much lower quantity of either seawater or freshwater to a number of buildings via a pipe network or distribution loop (ref. Figures 0701 and 0801). The seawater or freshwater is supplied to each building for use as “make-up” water for cooling towers normally located on the roof of each building. This “make-up” water replaces the circulating water flow that is lost due to evaporation, ‘bleed-off’ and drift. The bleed-off or waste water from the cooling towers is intermittently discharged and can be treated on-site and discharged to the nearby stormwater drainage system. Alternatively, it may be discharged into public sewers if there is adequate spare capacity. A Sewerage or Drainage Impact Assessment is needed in order to examine its feasibility.
研究表明，與AACS方案相比，使用CPSSCT方案可以節約7%到17%的能量。 The study has evaluated that energy savings of between 7% to 17% can be achieved for CPSSCT schemes when compared to AACS systems.
區域性冷卻方案(DCS)District Cooling Scheme (DCS)
DCS系統由一個大型中央冷凍水機組組成，通常座落在距它服務的地區或建築很近的位置。中央冷凍水機組產生的冷凍水通過一個閉路管道分送到若干建築物。冷凍水被泵送到每一幢建築物，供空調系統使用，然後返回中央冷凍水機組央進行再(見圖1101，1601和1701)。海水能被用作水冷裝置的“非循環”熱量排除，以及/或DCS冷卻塔內部的補給水。 The DCS system comprise a large central chiller plant normally located within close proximity of the district or buildings being served. The central chiller plant produces chilled water for distribution to a number of buildings via a closed loop pipe network. The chilled water is pumped to individual buildings for use in the building air conditioning system and then returned to the central chiller plant for re-chilling (ref. Figures 1101, 1601 and 1701). Seawater can be used for either “once through” heat rejection for water-cooled chillers and/or freshwater for make-up water within the DCS cooling tower.
通過對ＤＣＳ系統加入熱量儲存等措施，可把每一天冷卻需求高峰期的冷卻能量，轉移至冷卻負荷最小的晚間。這樣可將WACS方案設計進一步改善，以減少高峰期的電力需求，增加能量的效率，及降低每年能量和資金成本。 Further optimization of the design of WACS schemes can be achieved including reducing peak power demand, increasing energy efficiency and lowering annual energy and capital costs through measures such as adopting thermal storage for DCS systems. The thermal store shifts the production of cooling energy from the period of the day when the cooling demand is high, to nighttime when the plant has minimal imposed cooling load.
研究表明，與AACS方案相比，使用DCS方案可以節約23至32%的能量。 The study has evaluated that energy savings of between 23% to 32% can be achieved for DCS schemes when compared to AACS systems.
水冷式空調系統的優點Benefits of WACS
如果WACS方案在更廣泛的基礎上得到應用，將會有三個主要的受益者，他們是：建築物業主(也就是客戶)公眾服務商。每一個WACS方案的主要優點總結如下： There are three main beneficiaries when considering WACS schemes being adopted on a wider basis and these are (i) the building owners (i.e. the customers) (ii) the public and (iii) service providers. The following summarises the main benefits of the WACS schemes for each:
對於建築物業主：To Building Owners: 
  • 節省能源：採用CPSSCT或CPSSCC，冷卻設備，與AACS相比，可以節約每年的用電成本，實現較低的能源消耗。使用DCS方案，能源節約便能反映在服務商的收費用架構中。
  • Energy Savings; by adopting chiller plant operating under a CPSSCT or CPSSCC scheme, savings in annual power costs can be realised as a result of lower energy consumption compared to AACS. By connecting to a DCS scheme the energy savings are reflected in the charging structure of the service provider.
  • 節省空間：大多數WACS空調設備比AACS系統佔用更少的空間。於是，建築物業主就可以將節省出來的範圍用於能產生回報的目的。(說明：只有在空間被計入建築面積和沒有其它發展條件的限制下。)
  • Space Saving; most WACS air conditioning plant accommodate less space than AACS systems. Therefore, building owners have the potential to utilise these areas for revenue generating purposes instead. (Note: Only if space previously accountable for GFA and no other development controls.)
  • 減少運作和維修：對於建築物業主個人來說，選擇CPSSCC將意味著較少的運作和維修需要。選擇DCS，則大部分操作和維修資源將由專門的服務商承擔。
  • Reduced Operation & Maintenance; with CPSSCC there will be a reduced need for operational and maintenance resources by individual building owners. With DCS most of the operation and maintenance resources will be outsourced to a dedicated service provider.
  • 增加可靠性：多個集中式WACS方案一起進行設計，能享受到規模經濟的優越性，也能在操作和維修方面，比單獨的建築物業主分別運作他們自己的設備更具效果和更有效率。集中式的WACS設備都有備用發電站以保証連續運作，並可在施工時就將多個系統/設備的配送環路相互連接在一起，這樣即使有一個出現了問題，其它的機組仍可提供冷卻水。
  • Increased Reliability; centralized WACS schemes would be designed and optimized taking advantage of economies of scale and would be operated and maintained more effectively and efficiently than individual building owners who operate their own plant. The centralized WACS plant would be provided with power plant back-up for continuous operation and where multiple systems/plants are constructed the distribution loops would be interconnected, such that even if one plant were to experience problems there would still be cooling water provided from the other plants.
  • 減少投入資金：使用集中式的WACS方案，建築物業主只需用較少的機械和設備，因而必要的初始資金和後續所需的替換及升級資金也就較少。對於DCS方案，除了大型建築要求有幾個熱能交換設備外，建築物中無需單獨的冷卻設備，資本和再投入的資金便會減少得更多。
  • Reduced Capital Investment; with a centralized WACS scheme, less plant and equipment is required by the building owner, therefore less initial capital investment is necessary and investment for subsequent replacement and upgrading of plant. For the DCS schemes, the reduction in capital and recurrent investment is greater as there is no requirement for any chiller plant within the individual building except for possibly a few heat exchangers for large buildings.
對於公眾：To the Public: 
  • 減少能源的消耗：WACS系統使用較少能源去供應泠卻能力。這能源節約在單獨設施的水平上轉為減少電力的需求，以及隨之減少的一次燃料需求。實際的節約水平受以下因素影響：(i)AACS與相關WACS系統每單位面積能源消耗的差別；(ii)預期的總建築面積；(iii)建築面積與每種空調系統類型的比例。單位能源消耗數據需經過能源分析決定。在研究中，根據不同假設的巿場需求去採用一組建築面積的數據。在開發出的幾個巿場調整方案中，描述了AACS和WACS系統二十多年內不同時期的巿場佔有率。這些方案表明(對於預期的建築面積)，到2018年的使用期內，節約能源的範圍從620百萬度(假定到2018年，有空調的商業建築仍有70%的面積使用氣冷空調)直至實際上限的1600百萬度(對應有50%採用WACS，其中20%是DCS)。這些節約出來的能源相當於在相同條件下使用AACS所消耗的商業用空調能量的5%到10%。需注意這是最終用途量的節約估算值。在發電方面的節約程度還稍高於最終用途量的節約，這是由於減少了邊際輸電的流量損失和配電損失。
  • Energy Reductions; WACS systems use less energy to provide a given amount of cooling. These energy savings at the individual facility level translate into reduced electricity generation requirements, and hence reduced primary fuel requirements. The actual level of savings would depend on: (i) the difference between the energy consumption per unit area of AACS and the relevant WACS systems; (ii) the total floor area projected; and (iii) the proportion of floor area given over to each type of air conditioning system. The unit energy consumption data were determined by energy analysis. A set of floor area projections was adopted for the study as described under market and demand assumptions. Several market take-up scenarios describing various market shares of AACS and WACS systems over twenty years were developed. These scenarios show that (for the gross floor area projections assumed ) the end-use energy savings by 2018 range from 620 GWh (which assumes that 70% of air conditioned commercial GFA remains served by air-cooled systems in 2018) up to a practical upper limit of 1,600 GWh (which corresponds to 50% adoption of WACS of which comprises 20% of DCS). These energy savings represent 5% to 10% of the commercial air-conditioning energy use that would otherwise be consumed by AACS. Note that these are end-use savings estimates. The savings in electricity generation requirements would be slightly higher than the end-use savings, due to flow-on reductions in marginal transmission and distribution losses.
  • 環境方面：由於使用WACS可以減少對能量的要求，在更廣泛的範圍內應用WACS就能減少香港各發電站冷卻水的排放，這樣就有機會減少含熱污水排放和處理系統的化學物質之有關影響。此外，相對於AACS來說，WACS設備的優點在於一個人口高度密集的城巿環境中，所產生的噪音影響較少。香港電力的一部分是來自核電站，不散發溫室氣體，但還有部分是通過煤和天然氣體發出的電，而會排放溫室氣體。由於部分中期及高峰期的電力是從煤及天然氣電廠發出的，實施WACS帶來的節能效果將減少電力需求。因此，WACS的節能可以減少溫室氣體的排放。排出的溫室氣體主要成分是發電產生的二氧化碳(CO2)-發電過程和使用冷煤所產生的其它氣體相對CO2都可忽略不計。在廣泛採用WACS條件下，到2018年，溫室氣體的每年排放量較高和較低估計值僅分別為超過90萬噸CO2(對應上文所述1600百萬度的節能情況)，以及34萬噸CO2(對應上文所述630百萬度的節能情況)。
  • Environmental; given the reduced energy requirements of WACS, the wider use of WACS has the potential to reduce cooling water discharges from Hong Kong's power stations, thus reducing impacts associated with the discharge of heated effluents and system treatment chemicals. In addition, WACS plant have the advantage over AACS in that they are less likely to cause adverse noise impacts in a densely populated urban environment. Some of Hong Kong's electricity is generated by nuclear plants, which do not emit greenhouse gases and some from coal and some from gas, each of which do emit greenhouse gases. Energy savings from the implementation of WACS would reduce electricity generation requirements from plants that supply the daytime intermediate and peak loads, which are coal and gas plants. Hence WACS energy savings would reduce greenhouse gas emissions. The dominant greenhouse gas emitted is carbon dioxide (CO2) from electricity generation - emissions of other gases from electricity generation and from use of refrigerants are negligible by comparison. Upper and lower estimates of annual greenhouse gas emissions by 2018 through the wider adoption of WACS are about 900 kilotonnes of CO2 (which corresponds to the 1 600 GWh of energy savings described above) and about 340 kilotonnes of CO2 (which corresponds to the 620 GWh of energy savings described above).
  • 延遲發電站的增建：使用WACS系統過程中的能量節約，也減少了電力系統在高峰時的負荷，主要是那些夏季商業用空調的用電量。高峰期負荷需求的減少導致了對發電能力要求的降低，所帶來的好處就是延遲增建發電站。對使用期峰值負荷減少量的簡單估算，是通過節能計算和假定每年連續運作3800小時得到的。到2018年，估計值的變化是從160兆瓦(對應上文所述每年1600百萬度節能量)至實際中的最高限值432兆瓦(對應上文所述1600百萬度節能量)。這是比較保守的估計值，因為每年的實際耗電量與設施系統的峰值，會在夏天較高而在冬天較低，也因為實際中發電的減少量會略高於使用期高峰段負荷的減少量，其歸因於減少了邊際輸電產生的流量損失、配電損失和後備邊際量要求。
  • Power Station Deferment; The reduced energy consumption of WACS systems throughout their hours of use, also brings about reduced contribution to electricity system peak loads, which are driven by summer day commercial air conditioning use. Reduction of peak demand leads to reduced need for generation capacity, the benefits of which may be realised from deferment of power stations. The simple estimates of end use peak load reduction use the energy saving calculations and assume constant operation throughout 3 800 hours of operation per year. The estimates by 2018 range from 160　y saving calculations and assume constant operation throughout 3 800 hours of operation per year. The estimates by 2018 range from 160　MW (corresponding to the scenario with 620 GWh annual energy savings described above) to the practical upper limit of 2 MW (which corresponds to the 1 600 GWh energy saving figure above). These are conservative estimates, because actual consumption would be higher in summer and lower in winter, coinciding with the utility system peak, and because the actual reduced generation capacity requirement would be somewhat higher than the end-use peak load reduction due to reduction in marginal transmission and distribution losses and reserve margin requirements.
對於服務商：To Service Providers: 
  • 商業機會：WACS為私人參與提供有關冷卻水的服務創造了機會。此商機與20年保証期加上與建築物業主簽定的合同，可刺激長期投資動機。長期合同使服務商能夠長遠地規劃和設計空調負荷，也確保了一定的投資回報率。
  • Business Opportunity; WACS provides opportunities for private sector participation in the provision of cooling water services. The business opportunities associated with the securement of 20-year plus contracts with building owners provides incentives for long term investments. The long-term contracts enable the service provider to plan and design for air conditioning loads in the long-term and ensure a rate of return on investment.
  • 規模經濟：服務商能夠建造高效率的機組，並能比獨立建築物業主更有效地運作。如果一套機組的規模很大，它也許有資格協商一個更有吸引力的大量用電的收費標準。服務商也有機會利用技術使方案更加完善以降低成本，例如熱量的存儲。
  • Economies of Scale; the service provider can build very efficient plants and operate them more efficiently than can individual building owners. If a plant is very large it may qualify for bargaining a more attractive bulk electricity tariff rate. There are also opportunities for the service provider to reduce his costs using technologies which can optimise a particular scheme such as thermal storage.
  • 改進荷載系數：將冷卻水設施與熱量存儲接合?來，把空調負荷轉移至非高峰段(如夜間)的動力。這種高峰期動力需求的減少改善了發電站的荷載系數，也能使服務商通過對收費標準的管理，使用更便宜的非高峰電力而得到好處。
  • Improved Load Factor; combining cooling water services with thermal storage shifts air conditioning load to off-peak (night time) power. This reduction in peak power demand improves the power station load factor and also provides benefit to the service provider in terms of cheaper off-peak power through a tariff arrangement.
  • 客戶服務機會：一個冷卻水服務商受委托提供冷卻水時，如果安排得當，也可提供其它增值服務，例如改進能源效益，測試運行，運作和維護，以及遠距離的監測和控制建築物。
  • Customer Service Opportunities; a cooling water service provider entrusted to supply cooling water would be well positioned to offer additional services such as energy efficiency retrofits, commissioning, operation and maintenance, and remote monitoring and control of building.

WACS的缺點
Disbenefits of WACS

對於建築物業主To Building Owners 
  • 長期合同：顧客通常會被要求簽署一個20年的合同。這樣有些業主可能不願意參與集中式WACS方案。對DCS和CPSSCC方案就更是如此。對於CPSSCT方案，供水也許是與建築物連接的一項基本設施。
  • Long Term Contracts; the customer would typically be required to sign a 20-year contract. This may discourage some building owners from participating in a centralized WACS scheme. This may be more so for DCS and CPSSCC schemes. For CPSSCT schemes the water supply may be an essential utility connection to the building.
  • 冷卻水供應商的可靠度：建築物業主會比較關心服務供應和其後備設施的穩妥性。這些問題需要在任何合同或協議條款中注明，例如不按合約交付服務的罰則，暫停服務要預先通告計劃，提供後備設施等。
  • Reliance of Cooling Water Provider; building owners would be concerned about the security of supply and back-up facilities. These issues would need to be addressed in the terms of any contract or Agreement e.g. penalties for non-delivery, planned shutdowns, back-up services, etc.
  • 巿場力量有可能被濫用：如果沒有恰當的合同或疏於規管，DCS或CPSSCC系統的供應商有可能通過直接或間接的控制建築物的空調設施來取得不合理的高額利潤。
  • Potential for Abuse of Market Power; without proper contracts or regulatory oversight, DCS or CPSSCC system providers might be able to earn unreasonable levels of profit as they will have direct or indirect control of air-conditioning services in the building.
對於公眾To the Public 
  • 基礎設施的實施：   在WACS基礎設施實施過程中所產生的施工影響，如對空氣和噪音污染，產生灰塵和影響交通，由此會妨礙公眾，引起反感。在現有系統改造成WACS的過程中，也可能對現有空調系統造成妨礙。
  • Implementation of Infrastructure; construction impacts during the implementation of WACS infrastructure can cause disruption and public nuisance through air and noise pollution, dust and traffic impacts. There may also be disruption to existing air conditioning systems during any conversion to WACS.
  • 健康影響：在冷卻塔中使用淡水時會產生一些公眾關注的健康問題。儘管目前有關於冷卻塔使用和預防退伍軍人病症的工作守則，但加強冷卻塔的維修和規管，以及對退伍軍人菌測試的法規和控制系統的必要性應給予考慮。因此，冷卻塔使用海水應予以鼓勵。
  • Health Impacts; there are health concerns regarding the use of freshwater in cooling towers. Although there is a current Code of Practice concerning the use of cooling towers and the prevention of Legionella the necessity of regulatory and control systems for enforcing compliance for maintenance and the monitoring of cooling towers and testing for Legionella may need to be considered. Therefore the use of seawater in cooling towers should be encouraged.
  • 土地的損失：有一些WACS方案需要一整塊的土地或佔據地下的空間，這會是一種空間可挪用作其它用途的損失。對於一個單獨的WACS開發項目，如何能減少土地使用的方法將在後文中討論。
  • Loss of Land; some of the WACS schemes could potentially require substantial parcels of land or take up underground space which may be considered as a loss of opportunity space. Methods for minimising the use of land for the sole development of WACS are discussed later.
  • 對海洋環境中排放：正如上文中提到的，發電站冷卻水的污水排放和系統處理化學物質的有關的總量和影響有潛力被減少。然而，在更多WACS開發方案中涉及到在非循環性的使用水源，這樣也可能使排放到海洋環境中的含熱污水質以及系統處理的化學物數量有一定的增加。
  • Discharge of Effluents to Marine Environment; As mentioned above, there is the potential to reduce the volume and impacts associated with cooling water discharges and system treatment chemicals from power stations. However, it is likely that for some WACS development scenarios involving the wider use of water on a once-through basis there would be a net increase in the volume of heated effluent and system treatment chemicals being discharged to the marine environment.
對於服務商To Service Providers 
  • 龐大資金的投入：對一些WACS方案，特別是DCS方案，資本的投入非常高，並且為項目進行必要的資金籌措也十分不易。
  • Large Initial Capital Investment; for some of the WACS schemes, particularly DCS schemes, the level of capital investment would be very high and it may not be easy to arrange the necessary finance for the project.
  • 顧客的混淆：潛在的客戶可能對迅速擴展的WACS方案的實施有混淆，另外也較難區分客戶和建築物佔用人。
  • Customer Confusion; potential customer confusion with the more widespread implementation of WACS schemes may exist and a clear distinction may be difficult to make between customers and occupiers of buildings.
財務與經濟評佑
選 項 分 析		Financial and Economic Assessment
Options Analysis
在香港，為了測試WACS系統的可行性，通過財務分析評估了較廣闊範圍內的各個方面，以確定系統的商業生存能力，通過經濟分析從整個社會的角度確定需求度。經濟分析與財務評價的不同之處在於它評價項目對於整個社會而言的成本和收益，而不是只對於WACS方案的運作公司。例如，在財務分析中，用水成本是根據水務署(WSD)的收費標準計算的。然而，這個收費率是包含了政府給予的許多補貼的。對於經濟分析，是包括供水的實際成本的，也就是不計政府補貼的影響。 In order to test the viability of WACS systems in Hong Kong a wide range of options have been subjected to financial analysis, to determine commercial viability, and economic analysis and to determine desirability from the perspective of society as a whole. The economic analysis differs from the financial appraisal in that it assesses costs and benefits to society at large rather than to just the firms that would be operators of WACS schemes. For example, in the financial analysis water use is costed at the rate charged by Water Supplies Department (WSD). However, this rate is heavily subsidised. For the economic analysis, the true cost of water is included, i.e. without the effects of Government’s subsidy.
共有54個獨立的WACS方案和3個以AACS為基礎的實例接受了財務和經濟評估。在下表中列出了評價結果的摘要，表明與以AACS為基礎的實例比較和節約量的情況： A total of 54 separate WACS scheme options and three base case AACS options have been subject to financial and economic appraisal. A summary of the results, showing savings against the base case AACS options are summarised in the following table:

WACS技術和水源

經濟方面：

與相同能力AACS比較的節約量

財務方面：

與相同能力AACS比較的節約量

WACS Technology

and Water Source

Economic: Savings Against Identical Capacity AACS

Financial: Savings Against Identical Capacity AACS

20MW 方 案     20 MW Schemes    
CPSSCT - 淡水

2%

6%

 CPSSCT - fresh water 2% 6%
CPSSCT - 沖厠用水 >0% >0% CPSSCT - flushing water >0% >0%
40MW方案 40MW Scheme
CPSSCT - 淡水 2% 6% CPSSCT - freshwater 2% 6%
DCS - 冷卻塔，熱量存儲，淡水 2% 5% DCS - cooling towers, thermal store, fresh water 2% 5%
DCS - 冷卻塔，熱量存儲，海水 4% 4% DCS - cooling towers, thermal store, sea water 4% 4%
DCS - 冷卻塔，海水 3% 3% DCS - cooling towers, sea water 3% 3%
DCS - 冷卻塔，淡水 2% 5% DCS - cooling towers, fresh water 2% 5%
DCS - 管道(散熱器)，海水 2% 2% DCS - piped (heat exchangers), sea water 2% 2%
DCS - 熱量存儲，管道，海水 1% 1% DCS - thermal store, piped (heat exchangers), sea water 1% 1%
200MW 方案 200 MW Schemes
DCS - 冷卻塔，熱量存儲，海水 23% 23% DCS - cooling towers, thermal store, sea water 23% 23%
DCS - 管道的(散熱器)，海水 22% 23% DCS - piped (heat exchangers), sea water 22% 23%
DCS - 熱存儲，管道的(熱交還器)，海水 21% 21% DCS - thermal store, piped (heat exchangers), sea water 21% 21%
DCS - 冷卻塔，熱存儲，淡水 21% 25% DCS - cooling towers, thermal store, fresh water 21% 25%
DCS - 冷卻塔，海水 21% 23% DCS - cooling towers, sea water 21% 23%
DCS - 冷卻塔，淡水 20% 24% DCS - cooling towers, fresh water 20% 24%
CPSSCC - 海水 6% 6% CPSSCC - seawater 6% 6%
CPSSCT - 海水 3% 3% CPSSCT - sea water 3% 3%
CPSSCT - 淡水 2% 6% CPSSCT - fresh water 2% 6%
上表表明，與AACS相比，WACS在經濟和財務方面是具有優勢的。基本的WACS技術在財務和經濟上不具備優勢的方面是在建築物內冷卻塔的廢水再利用上。這些“未淨化的生活廢水”的選擇方案中沒有一個是比AACS更為有效益的，這是由於與運行廢水處理系統相關的資金和營運費用皆不能夠抵消耗水方面的少量節餘。 The table illustrates those options that are economically and financially viable when compared to AACS. The principal WACS technology that appears to have no merit in financial or economic terms is the reuse of waste water in cooling towers of buildings. None of these “grey water” options are more cost-effective than AACS as the capital and operating costs associated with operating waste water treatment systems do not offset the small savings in water consumption that are realised.
結論
由此可以看出，對於任何規模的項目來說，WACS系統都比AACS系統更具有成效上的優勢，儘管它的技術隨規模不同而變化。為了評價結果的穩定性，此研究實施了很多次的敏感度測試，包括：		Finding
It can therefore be seen that at any scale of implementation, WACS systems are likely to have cost advantages over AACS, although the preferred technology does change with scale. In order to assess the robustness of the results a wide number of sensitivity tests have been undertaken. These include:
  • 土地價格的變化，以反影九龍和香港島土地成本的巿場價值；
  • variations in the price of land to reflect market values for Kowloon and Hong Kong Island land costs;
  • 對現存樓宇進行WACS方案的改造；
  • retrofitting of WACS schemes into existing buildings;
  • 減少10%的電費，以減少與能量相關的成本節約；
  • reducing power charges by 10%, so as to reduce the cost savings associated with energy efficiency;
  • 增加10%的水費；
  • increasing water charges by 10%;
  • 應用一個10%的商業實際折扣率，以及
  • using a commercial real discount rate of 10%; and
  • 將配送管網的長度延長至10公里(覆蓋25平方公里的地區)
  • extending the length of the distribution pipe network to 10km, (maximum coverage area of 25km2)
根據經濟和財務分析，除了CPSSCC和CPSSCT方案外，在延長管網至10公里的情況下WACS方案在所有實施規模上按照敏感度測驗的方案都是可行的。 Under both the economic and financial analysis, WACS options remained viable at all scales of implementation under the sensitivity test scenarios, except for a few CPSSCC and CPSSCT options with 10km pipe network.

實施問題及限制：

巿場評價及需求預測

IMPLEMENTATION ISSUES & CONSTRAINTS

Market Assessment and Demand Forecast
通過向一些目前正在營運水冷式空調系統的主要地產發展商和建築物業主，以及本港的兩間大型電力公司進行咨詢，來明確提出有關在香港實施WACS的關鍵問題。 Consultations have been undertaken with a number of leading property developers and building owners which currently operate water cooled air conditioning systems, as well as with the two major power companies in Hong Kong, with a view to identifying the key issues associated with implementation of WACS in Hong Kong.
可以確定，對於在香港介紹和推廣WACS是有普遍興趣的，但也有一些關注的問題要在此提出。這些問題包括政府與私人機構分別扮演的角色，財務可行性，與整體供應有關的保証，以及在現有地區範圍內實施地區系統的可能性。如果這些問題有滿意的解決方案，那麼會有一定數量的被咨詢者原則上有興趣在某一地區成為一個WACS系統的客戶或營運商。因此，只要制度，財務和實施上的問題都得到了解決，可以認為，對服務的提供和接受兩方面都有潛在的需求。 It was identified that there was a general interest in the introduction and extension of WACS in Hong Kong, but that a number of key concerns need to be addressed. These concerns include the respective roles of the Government and the private sector, financial viability, guarantees with regard to integrity of supply and the practicability of implementing district wide systems within existing urban areas. It was established that, subject to the satisfactory resolution of such issues, a number of the consultees would be interested in principle to become either customers or operators of a WACS system in individual districts. It is, therefore, considered that there is potential demand both to provide and receive the service, provided that institutional, financial and implementation issues can be resolved.
土地與地產Land and Property
許多的潛在問題和限制，往往涉及土地和地產方面。政府有必要考慮如何為最終的WACS營運商在基礎設施的實施方面安排土地。 A number of potential issues and constraints exist from a land and property perspective. It will be necessary for the Government to consider how it intends to allocate land for the implementation of infrastructure to the eventual operator of any district wide WACS scheme.
在實施WACS時有土地方面的需求，但假設WACS在“土地恢?條例”或土地政策方面並不代表“公共用途”，這便有必要明確如何能獲得這些土地。這也意味著需考慮為管道和其他基礎設施所發出的地役權及執照權的措施。 In the event that any land acquisition is required in order to implement the scheme it will be necessary to establish how such acquisition is to be undertaken, given that the introduction of WACS on a district basis may not represent a "public purpose" in terms of the Lands Resumption Ordinance or from the perspective of land policy. The means via which easements and licenses can be created for pipelines and other infrastructure will also need to be considered.
共同開發WACS基礎設施和商業地產的機會將需要根據土地政策，商業可行性和實際的實施問題等作進一步調查。 The opportunities for joint development of WACS infrastructure and commercial property will need to be further investigated in terms of land policy, commercial viability and practical implementation issues.
評價土地補償金和有關道路通行費用的途經也需要建立，依靠所採用的制度框架來促進WACS的實施。 The approach to the assessment of land premium and fees for easements and wayleaves will also need to be established, depending upon the institutional framework that is adopted to facilitate the implementation of WACS.
制度和規則Institutional and Regulatory
WACS系統的引進或會為佔優勢的WACS供應商提供機會，通過壟斷地位獲得不合理的超額利潤。至於DCS和CPSSCC方案，建築物的擁有人、佔有人、及租戶可能會對部分空調基礎設施失去控制權。 The introduction of WACS systems could potentially provide opportunities for dominant WACS suppliers to use a monopoly position to make unreasonably high profits. In the case of DCS and CPSSCC schemes, a part of the air conditioning infrastructure could be outside the control of the tenants and the building owner and occupier of the property.
這與氣冷式或冷卻塔系統的情況不同，除了水電供應外，空調系統包含在建築物自身之中。在這種系統類型下，建築物擁有人通常會收空調費。當收費標準固定下來，所有業主皆會意識到高額的空調費用將影響租賃價值。 This is unlike the situation for air-cooled or cooling tower systems where, apart from water and power supplies, the air-conditioning system is self-contained within a building. With these types of systems, the building owner typically will determine air-conditioning charges. When setting charges, the owner is aware that high cooling charges will detract from rental values.
如果一個DCS或CPSSCC供應商不是建築物的業主，他不會關心這個問題，因為租價的下跌不會影響他的收入。不過，當一棟建築物連接到一個地區範圍的系統，並且不再有能力提供給自己舒適的冷氣(特別與新建築相關)，則外間的供應者具有實際上的壟斷。 If a DCS or CPSSCC provider is not the building owner, this will not be a concern, as the decline in rental values would not affect his income. Moreover, once a building has invested in connecting to a district-wide system, and no longer has the capacity to provide its own comfort cooling (particularly relevant for new buildings), the external supplier has a de facto monopoly.
這與目前電力供應的情況類似，而且這也是為什麼電力公司根據控制方案受到監管。然而，在很大程度上根據所擁有人的性質而定。以下圖表識別了所有不同業權類含義： This is similar to the situation with electricity supply at present, and is why the power companies are regulated by the scheme of control. However, much will depend on nature of the owner. The following table identifies the implications of different types of ownership.
安排優點缺點ArrangementAdvantageDisadvantage
私 人 / 公 共 設 施 公 司 基 於 成 本 回 收 ， 典 型 的 回 報 率 和 利 潤 形 式 ， 私 人 / 公 共 設 施 公 司 十 分 願 意 投 資 在 造 價 昂 貴 但 效 率 高 的 設 施 上 潛 在 濫 用 巿 場 力 量 獲 取 不 合 理 的 的 利 潤 。 投 資 額 大 ， 只 有 少 數 公 司 有 足 夠 資 源 開 發 系 統 。 由 於 營 運 成 本 可 轉 嫁 用 者 ， 對 高 效 運 行 不 會 有 很 高 的 積 極 性 。 Private / Utility Company Strong incentive to invest in more expensive, but efficient equipment due to recovery of cost and typically rate of return type of profit. Potential for abuse of market power to gain unwarranted profits. Very cost intensive, small number of companies with sufficient resources to develop system. As operating costs are simply passed through, may not have big incentive toward efficient operation.
發展商 承租人通常是在有保証的合理租金之下參與，對大型開發項目較理想。 升級困難。經常缺乏計量。開發商將為較低的安裝費用而犧牲能源效益。由於營運成本可轉嫁用者，不會對高效運行有很高的積極性。 Developer Based Tenant representation hence often assured of reasonable rates. Ideal for large developments. Difficult to upgrade. Metering often lacking. Developer will sacrifice energy efficiency for lower installation cost. As operating costs are simply passed through, may not have big incentive toward efficient operation.
獨立擁有人/政府 與政府系統在收費上沒有爭議。升級基於整個建築/院區的遠景規劃 政府組織通常需要更多的時間來作出升級的決定。單獨業主的系統還可能服從行動契約 ( Deed of Mutual Covenant - DMC )

Single Owner/

Government		 No disputes on billing with Government system. Upgrades based on whole building/ campus outlook plans. Government based organisations typically require more time to make upgrade decisions. Single owner systems may still be subject to Deed of Mutual Covenant (DMC).
基於潛在客戶擔心巿場力量有可能被濫用，實施上便潛在一定障礙。克服這些障礙的可選擇方案將在後文中提出。 As potential customers are aware of the possibility for market abuse, this is a potential barrier to implementation. Possible options to overcome this are given later.
技術Technical
WACS方案的位置、開發和實施在很大程度上決定在哪個區域或地區將被開發。研究結果表明，在新開發區實施項目將比在現有城區內實施更為簡易。 The location, development and implementation of WACS schemes will be largely dependent on the area or district where the scheme is to be developed. The study has concluded that it will be more straightforward to implement WACS in new development areas than existing urban areas.
無論對於新區還是現有區，與WACS有關的主要技術限制都是大規模基礎設施的實施，如巨大的供應管，排放系統，岸邊泵水站和地區性的大型冷凍機組(DCS)等，以及對地方有關供水，排污和排水的基礎設施之影響。 The main technical constraints associated with WACS in both a new and existing area are the implementation of large-scale infrastructure such as large diameter supply pipes, discharge systems, coastal pumping stations and large district chiller plants (DCS) and the impacts on local water supplies, sewerage and drainage infrastructure.
環境Environmental
廣泛的使用WACS可以對環境產生明顯的益處，然而，對於資源的運用是有潛在的影響。在香港，更廣泛應用WACS的主要資源實質是與用水有關的。CPSSCC方案和DCS方案，是將熱量排放到海洋環境，需要直接的海水供應，而組成冷卻塔的系統能夠使用水務署供應的淡水/海水，以及其它的的水源，如未淨化的生活廢水。在明確地表達WACS實施策略時，供水問題需要在整體上，以及個別的基礎上進行調查。 Whilst the wider use of WACS has the ability to generate significant environmental benefits, there are, however, potential implications with respect to resource utilisation and knock-on environmental impacts. The major resource implication of the wider use of WACS in Hong Kong relates to the use of water. CPSSCC schemes and DCS schemes dissipating heat to the marine environment need to be supplied directly with seawater, whilst systems that incorporate cooling towers can use WSD supplied freshwater/seawater, as well as alternative water sources such as grey water. During the formulation of WACS implementation strategies, water supply issues need to be investigated on a cumulative as well as on a case-by-case basis.
關於WACS潛在的環境影響，最大的潛在影響是由WACS產生污水的排放導致的。CPSSCC方案和DCS方案(將熱量散發到海洋環境中)產生的物質因為涉及到的量很大，通常要排入海洋。由於這些污水含熱的特性，以及它們含有化學處理用物質的負荷，使得環境對它們的可接受性應當在累積上，以及個別的基礎上進行調查。使用冷卻塔散發熱量的CPSSCT和DCS方案的污水，一般應在排到雨水系統之前處理。如一些國家一樣，採用將污水排入公共污水管的做法，應該注意到現有和規劃中的污水管的容量，以及污水處理能力只能滿足房屋計劃和預期人口增長帶來的迫切需要。因此，只有當實施了進一步的詳細調查，並確定對於具體的方案有足夠的富餘能力，不會在任何方面對基本污水設施造成影響，才可以將該些廢水排入公共污水管。 With regard to the potential knock-on environmental impacts of WACS, the greatest potential impacts result from the discharge of WACS effluents. Effluents from CPSSCC schemes and DCS schemes (dissipating heat to the marine environment) generally must be discharged to sea due to the high volumes involved. Due to the heated nature of these effluents, as well as their treatment chemical load, the environmental acceptability of these discharges must be investigated on a cumulative as well as on a case-by-case basis. Effluents generated by CPSSCT schemes and DCS schemes dissipating heat to cooling tower would generally be treated prior to their discharge into the storm drain system. On the practice of discharging the effluent into public sewers as adopted in other countries, it should be noted that the existing and planned sewerage and sewage treatment capacity could barely meet the pressing demand introduced by the housing programme and the projected population growth. As a result, discharging the wastewater into public sewers may be pursued only if further detailed investigation demonstrate that there is adequate spare capacity for specific schemes without joepardizing the service to the primary sewage infrastructure users in any respect.
任何包括冷卻塔的淡水WACS方案中，與有關退伍軍人菌的人體健康風險都必須給予考慮。在任何WACS實施策略的發展過程中，防止退伍軍人菌疾病的工作守則一定要嚴格執行，同時還應有規程，以有效地對冷卻塔進行註冊，維修，控制和檢測。 Human health risk associated with Legionella must be considered for any freshwater WACS schemes that incorporate cooling towers. During the development of any WACS implementation strategy, the recommendations of the Code of Practice for the Prevention of Legionnaires’ Disease must be rigorously followed and backed up with procedures that allow for effective cooling tower registration, maintenance, control and monitoring.
在這份初步階段研究中，沒有任何不能解決的環境問題，然而，它指出當具體影響十分明顯，以及在某些特定的環境下，需要在下一階段的實施過程中進行排污和排水影響的評估。 This preliminary phase study has not identified any particular insurmountable environmental problems, however, it has indicated where specific impacts may be significant and where specific environmental, sewerage and drainage impact assessments need to be carried out during the next stages of implementation.

克服實施限制的行動

規劃與開發

ACTIONS TO OVERCOME IMPLEMENTATION CONSTRAINTS

Planning and Development
在現有的城巿地區，尋找場地來滿足與WACS有關的基礎設施是十分困難的。一旦考慮到項目會在這些地區實施，政府將需要解決土地再利用和在私人土地上建造附屬建築物的問題。這也許需要澄清，WACS的引進是否代表“一種公共用途”-允許這樣進行收地，以及一個新條例的引進，與電氣條例(建造附屬建築物)或電訊條例類似的。 In existing urban areas it will be difficult to identify sites and land to accommodate infrastructure associated with WACS. In the event that it is considered that the concept should be implemented in these areas, the Government will need to address the issue of land resumption and creation of easements through private property. This may require clarification as to whether the introduction of WACS would represent "a public purpose" to allow such land acquisition to take place and the introduction of a new Ordinance, with similar provisions to the Electricity (Creation of Easements) Ordinance or the Telecommunications Ordinance.
從新開發地區的角度來說，將有必要保証適合WACS的場地和預留地已經明確和分配好，以及完成了適當的行政和法律程序以保証土地根據“概括分區規劃(Outline Zoning Plan)”被合理劃分。 In terms of new development areas, it will be necessary to ensure that appropriate sites and reserves are identified and allocated for infrastructure associated with WACS, and that appropriate administrative and statutory procedures are completed to ensure that land is correctly zoned upon the Outline Zoning Plan.
另外，有必要從土地政策和法律規劃的角度，復核聯合用戶的發展是否可以接受，以及保証在新區規劃中存在足夠的靈活性，使得聯合用戶的發展能夠進行。也有必要對擬建項目實施關於商業可行性的進行咨詢。 It will also be necessary to review whether joint user development is considered to be acceptable from a land policy and statutory planning perspective, and if so, to ensure that sufficient flexibility exists in the planning of new areas such that joint user development can take place. It may also be necessary to undertake consultation regarding the commercial viability of the proposed development.
土地分配Land Allocation
在WACS項目由私人業主進行的情況下，主要基礎設施用地會通過私人條例或通過招標競投分配給營運商。如果是由政府部門實施，土地需通過政府土地分配的方式得到。對這種基礎設施採取短期租賃的辦法，按照預期涉及到的資本投入水平，對於私人業主來說未必是可行的。為了保証珍貴的土地資源在可能的基礎上得到了有效的利用，應當考慮與任何WACS基礎設施相聯土地系的發展權。這種做法也能從財務的角度使WACS方案的實施更具吸引力。 In the event that the WACS concept is to be pursued by the private sector, it is anticipated that land for major infrastructure would be granted to the operator by way of private treaty or on a competitive basis as part of a tender. If it were to be implemented by a Government Department, the land would be made available via a Government Land Allocation. It is considered unlikely that a Short Term Tenancy for such infrastructure would be acceptable to the private sector given the anticipated levels of capital investment involved. In order to ensure that scarce land resources are utilised as efficiently as possible, consideration could also be given to the granting of development rights in conjunction with any sites required for WACS infrastructure. Such an approach may also assist in rendering the implementation of WACS more attractive to the private sector from a financial perspective.
立法與規例Legislation and Regulation
關鍵的規管的和制度的實施，是對巿場力量被濫用進行限制，以及鼓勵採用高能源效益的空調系統的方法。 The key regulatory and institutional implementation constraints concern potential abuses of market power and measures to encourage the adoption of energy efficient air-conditioning systems.
為了防止在DCS和CPSSCC方案下，巿場力量被濫用，採取一些規管是必要的。特別是在私人公司營運，又與地產業主或租戶沒有聯系的情況下提供服務時，尤其顯得重要。如果是由一個第三方的私人營運者提供服務，則有必要採取一些形式的價格規管。可選方案在下表中列出。 In order to prevent abuses of market power with DCS and CPSSCC schemes, some form of regulation may be necessary. This will be particularly true if a private company, with no connection to property owners or tenants, provides the services. If a third party private operator is providing the service, some form of price regulation may be necessary. Potential options are set out in the table below.
規定的形式優點缺點Form of RegulationAdvantagesDisadvantages

回報：

“回報率”(根據控制協議方案)

概念簡單

易於計算，當許可的資產基礎確定後

使管理者能夠直接限制從壟斷特權獲得的利潤

需要規管人詳細地檢查設備要求和資金花費；

促使公共設施的過多建設-對設備的投資一經管理者批准，保証會有回報；固定淨資產越大，獲得的回報率越高；

不能刺激表現，因回報率有保証；

嚴重妨礙需求方面管理，除非需求方面投資被包括在資產基數中，以使回報達到至少同從供應方面資源獲得的回報相同。

Return:

“Rate of Return (as per the Scheme of Control Agreements)

Conceptually simple

Simple to calculate once the allowed asset base has been determined

Allows the regulator to constrain directly the profit earned from the monopoly franchise

Requires the regulator to examine plant requirements and capital expenditure in great detail

Creates an incentive for utilities to overbuild - once capital expenditure on plant is approved by the regulator, a return is effectively guaranteed: the larger the fixed net assets, the larger the achievable return

Provides no performance incentive -- a return is effectively guaranteed

Creates a strong disincentive to undertake demand-side management, unless demand-side investments can be included in the asset base so that they can earn a return at least equal to the return that would otherwise be earned from supply-side resources

價格：

顧客價格指數(CPI-X)的限制(一般通過燃料費用)

是一種履約規定：

一方面它允許公共事業在其控制範圍內獲得利潤收益(也就是不同於燃料價格，這也是為什麼燃料價格一般被通過)；另一方面它也允許將一些利益轉給用戶(通過“負X"動實際價格的削減)		 一旦規管期的收費機制被制定，會大大促

Price:

Consumer Price Index (CPI-X) regulation (usually with fuel cost pass-through)

A form of performance regulation:

on the one hand it allows the utility to obtain profit rewards for things within their control (i.e. other than fuel price, which is why this is usually passed through); and on the other hand it allows for some benefits to be passed through to the consumer (via the 吮inus X? automatic real price reduction)		 Once the tariffs for the regulatory period have been set, the utility has a significant incentive to increase energy sales volumes, and a disincentive to pursue demand-side management resource options

收益：

收益規定		 將銷售量同利潤分開，因此去除了價格管理系統含有的銷售量動機，使公共設施能以最低成本找到符合客戶能源服務需求。

比其他系統更難於管理，通常需要分拆成本結構；

有可能引起爭議。

Revenue:

Revenue regulation		 De-couples sales from revenue, thereby removing the sales volume incentive inherent in price regulation systems and allowing utilities to find the least cost way of meeting customers?energy service requirements

More complicated to administer than alternative systems, usually requires breakdown of cost structure

Potentially controversial