能源效益/环保
在香港推广水冷式空调系统的初步顾问研究执行摘要《中英文版 》

机 电 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

合约编号CE44/98
在香港推广水泠式空调系统的初步顾问研究
执行摘要
Agreement No. CE 44/98
Preliminary Phase Consultancy Study on Wider Use of Water-cooled Air Conditioning Systems in Hong Kong
Executive Summary

介绍
目标与目的		INTRODUCTION
Aims & Objectives
进行研究的目的如下： The objective of the study is as follows:
本研究旨在考察在香港推广水冷式空调系统(WACS)，使之用于非住宅项目的可行性。研究将提供充分的独立调查结果和推荐意见，使香港特别行政区政府能够看到整个地区使用水冷式空调系统在工程、环境和经济方面的可行性，能够体现经过验证的世界技术和创新设计的可用节能工程方案，及研究和项目实施的主体阶段所采用的中长期策略。 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.

研究表明水冷式空调系统是技术上可行的，并且有一些水冷式空调系统方案无论在经济上和财务皆是可行的。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.

研究结果摘要Summary of Findings
研究显示，采用水冷式空调系统有益于节约能源，可使本土地区范围内减少温室气体排放(GHG)，减少发电站所用的进口矿物燃料，减缓发电站的建设和降低对环境的影响。 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，要实施更广泛的采用水冷式空调系统也有一些限制的条件，尽管这不是不能克服的，因此建议特区政府在计划进一步时需配合另外一些行动。 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.
水冷式空调系统的背景 
在香港目前的总用电量中，有超过60%是消耗在商业建筑物上，而其中又有约40%消耗在空调系统上(即是总用电量的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，大部分在港装有空调的建筑物皆配备了将热量从建筑内部传送出来，再散发到大气中的空调系统。这些系统通常被称作气冷式空调系统(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).
气冷式空调系统在香港占主导的地位，很大程度上归因于目前水务署对使用政府喉管供水用于空间舒适调节设备的蒸发式冷郤用途所实施的限制。这些用水限制从六十年代开始在港实施，是由于香港地区水源匮乏，而从广东省提供可靠和持续的食水供应之前，这些限制已生效了。 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，在近几年中，通过“非循环”海水供应去消散建筑物空调系统产生的热量，已被接受为一个节能的建筑物冷却系统方案，特别是采用于那些靠近海岸线的建筑物上。这就促进了一定数量的公共和私人海水引入泵房和水管系统的发展，并遍布整个地区，直接为大型建筑物空调冷却的散热装置供应海水。现在有大约一百个这样的系统为政府建筑物，医院，综合性开发项目和大型交通项目的空调系统散热提供海水。 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.
水冷式空调系统的优点和缺点
水冷式空调系统方案的类型		BENEFITS AND DISBENEFITS OF WACS
Types of WACS Schemes
作为研究的一部分，本研究对三种不同类型的水冷式空调系统方案进行了评估，这三个是所有方案中比较具吸引力，且有潜力在香港被广泛采用的。集中式管道供应冷凝器冷却水系统。 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:
集中式管道供应冷凝器冷却水系统(CPSSCC)Centralized Piped Supply System for Condenser Cooling (CPSSCC)
此类型系统是由一个海水引入装置和泵水站组成，通过管网或配送环路(见图0201)向几个建筑提供大量的海水。海水被泵入每个建筑物机房的水冷式冷冻水机中，用于消散从冷冻水机组排出的热量。变热后的水通过另一个包含增压管网和海洋排水口的独立系统排放到海洋中。排出的热水也可再被作为建筑物冲洗水途。 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，与AACS方案相比，使用CPSSCC方案可以节约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.
集中式管道供应冷却塔用水系途(CPSSCT)Centralized Piped Supply System for Cooling Towers (CPSSCT)
此系统与CPSSCC系统有类似的基本构造装置，然而，这种系统是通过管道网络或分配送环路，向几个建筑供应相对较少量的海水或淡水(见图0701或0801)。海水或淡水被用做冷却塔的补给水送往那些通常位于每一座建筑屋顶的冷却塔。这种冷却水代替了会因蒸发、流失和飘走而失去的循环水流。从冷却塔产生的流失或废水是断断续续排放出来的，可即场进行处理后，排入附近的雨水管道。另外，如果公共污水管有足够的富余量，也可将其排入公共污水管道。为了验证此等排放之可行性，将需进行一个排污或排水影响评估。 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，与AACS方案相比，使用CPSSCT方案可以节约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.
区域性冷却方案(DCS)District Cooling Scheme (DCS)
DCS系统由一个大型中央冷冻水机组组成，通常座落在距它服务的地区或建筑很近的位置。中央冷冻水机组产生的冷冻水通过一个闭路管道分送到若干建筑物。冷冻水被泵送到每一幢建筑物，供空调系统使用，然后返回中央冷冻水机组央进行再(见图1101，1601和1701)。海水能被用作水冷装置的“非循环”热量排除，以及/或DCS冷却塔内部的补给水。 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.
通过对ＤＣＳ系统加入热量储存等措施，可把每一天冷却需求高峰期的冷却能量，转移至冷却负荷最小的晚间。这样可将WACS方案设计进一步改善，以减少高峰期的电力需求，增加能量的效率，及降低每年能量和资金成本。 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，与AACS方案相比，使用DCS方案可以节约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.
水冷式空调系统的优点Benefits of WACS
如果WACS方案在更广泛的基础上得到应用，将会有三个主要的受益者，他们是：建筑物业主(也就是客户)公众服务商。每一个WACS方案的主要优点总结如下： 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:
对于建筑物业主：To Building Owners: 
  • 节省能源：采用CPSSCT或CPSSCC，冷却设备，与AACS相比，可以节约每年的用电成本，实现较低的能源消耗。使用DCS方案，能源节约便能反映在服务商的收费用架构中。
  • 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.
  • 节省空间：大多数WACS空调设备比AACS系统占用更少的空间。于是，建筑物业主就可以将节省出来的范围用于能产生回报的目的。(说明：只有在空间被计入建筑面积和没有其它发展条件的限制下。)
  • 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.)
  • 减少运作和维修：对于建筑物业主个人来说，选择CPSSCC将意味着较少的运作和维修需要。选择DCS，则大部分操作和维修资源将由专门的服务商承担。
  • 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：多个集中式WACS方案一起进行设计，能享受到规模经济的优越性，也能在操作和维修方面，比单独的建筑物业主分别运作他们自己的设备更具效果和更有效率。集中式的WACS设备都有备用发电站以保证连续运作，并可在施工时就将多个系统/设备的配送环路相互连接在一起，这样即使有一个出现了问题，其它的机组仍可提供冷却水。
  • 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.
  • 减少投入资金：使用集中式的WACS方案，建筑物业主只需用较少的机械和设备，因而必要的初始资金和后续所需的替换及升级资金也就较少。对于DCS方案，除了大型建筑要求有几个热能交换设备外，建筑物中无需单独的冷却设备，资本和再投入的资金便会减少得更多。
  • 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.
对于公众：To the Public: 
  • 减少能源的消耗：WACS系统使用较少能源去供应泠却能力。这能源节约在单独设施的水平上转为减少电力的需求，以及随之减少的一次燃料需求。实际的节约水平受以下因素影响：(i)AACS与相关WACS系统每单位面积能源消耗的差别；(ii)预期的总建筑面积；(iii)建筑面积与每种空调系统类型的比例。单位能源消耗数据需经过能源分析决定。在研究中，根据不同假设的巿场需求去采用一组建筑面积的数据。在开发出的几个巿场调整方案中，描述了AACS和WACS系统二十多年内不同时期的巿场占有率。这些方案表明(对于预期的建筑面积)，到2018年的使用期内，节约能源的范围从620百万度(假定到2018年，有空调的商业建筑仍有70%的面积使用气冷空调)直至实际上限的1600百万度(对应有50%采用WACS，其中20%是DCS)。这些节约出来的能源相当于在相同条件下使用AACS所消耗的商业用空调能量的5%到10%。需注意这是最终用途量的节约估算值。在发电方面的节约程度还稍高于最终用途量的节约，这是由于减少了边际输电的流量损失和配电损失。
  • 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.
  • 环境方面：由于使用WACS可以减少对能量的要求，在更广泛的范围内应用WACS就能减少香港各发电站冷却水的排放，这样就有机会减少含热污水排放和处理系统的化学物质之有关影响。此外，相对于AACS来说，WACS设备的优点在于一个人口高度密集的城巿环境中，所产生的噪音影响较少。香港电力的一部分是来自核电站，不散发温室气体，但还有部分是通过煤和天然气体发出的电，而会排放温室气体。由于部分中期及高峰期的电力是从煤及天然气电厂发出的，实施WACS带来的节能效果将减少电力需求。因此，WACS的节能可以减少温室气体的排放。排出的温室气体主要成分是发电产生的二氧化碳(CO2)-发电过程和使用冷煤所产生的其它气体相对CO2都可忽略不计。在广泛采用WACS条件下，到2018年，温室气体的每年排放量较高和较低估计值仅分别为超过90万吨CO2(对应上文所述1600百万度的节能情况)，以及34万吨CO2(对应上文所述630百万度的节能情况)。
  • 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).
  • 延迟发电站的增建：使用WACS系统过程中的能量节约，也减少了电力系统在高峰时的负荷，主要是那些夏季商业用空调的用电量。高峰期负荷需求的减少导致了对发电能力要求的降低，所带来的好处就是延迟增建发电站。对使用期峰值负荷减少量的简单估算，是通过节能计算和假定每年连续运作3800小时得到的。到2018年，估计值的变化是从160兆瓦(对应上文所述每年1600百万度节能量)至实际中的最高限值432兆瓦(对应上文所述1600百万度节能量)。这是比较保守的估计值，因为每年的实际耗电量与设施系统的峰值，会在夏天较高而在冬天较低，也因为实际中发电的减少量会略高于使用期高峰段负荷的减少量，其归因于减少了边际输电产生的流量损失、配电损失和后备边际量要求。
  • 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.
对于服务商：To Service Providers: 
  • 商业机会：WACS为私人参与提供有关冷却水的服务创造了机会。此商机与20年保证期加上与建筑物业主签定的合同，可刺激长期投资动机。长期合同使服务商能够长远地规划和设计空调负荷，也确保了一定的投资回报率。
  • 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.
  • 规模经济：服务商能够建造高效率的机组，并能比独立建筑物业主更有效地运作。如果一套机组的规模很大，它也许有资格协商一个更有吸引力的大量用电的收费标准。服务商也有机会利用技术使方案更加完善以降低成本，例如热量的存储。
  • 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.
  • 改进荷载系数：将冷却水设施与热量存储接合?来，把空调负荷转移至非高峰段(如夜间)的动力。这种高峰期动力需求的减少改善了发电站的荷载系数，也能使服务商通过对收费标准的管理，使用更便宜的非高峰电力而得到好处。
  • 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.
  • 客户服务机会：一个冷却水服务商受委托提供冷却水时，如果安排得当，也可提供其它增值服务，例如改进能源效益，测试运行，运作和维护，以及远距离的监测和控制建筑物。
  • 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的缺点
Disbenefits of WACS

对于建筑物业主To Building Owners 
  • 长期合同：顾客通常会被要求签署一个20年的合同。这样有些业主可能不愿意参与集中式WACS方案。对DCS和CPSSCC方案就更是如此。对于CPSSCT方案，供水也许是与建筑物连接的一项基本设施。
  • 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.
  • 冷却水供应商的可靠度：建筑物业主会比较关心服务供应和其后备设施的稳妥性。这些问题需要在任何合同或协议条款中注明，例如不按合约交付服务的罚则，暂停服务要预先通告计划，提供后备设施等。
  • 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.
  • 巿场力量有可能被滥用：如果没有恰当的合同或疏于规管，DCS或CPSSCC系统的供应商有可能通过直接或间接的控制建筑物的空调设施来取得不合理的高额利润。
  • 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.
对于公众To the Public 
  • 基础设施的实施：   在WACS基础设施实施过程中所产生的施工影响，如对空气和噪音污染，产生灰尘和影响交通，由此会妨碍公众，引起反感。在现有系统改造成WACS的过程中，也可能对现有空调系统造成妨碍。
  • 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.
  • 健康影响：在冷却塔中使用淡水时会产生一些公众关注的健康问题。尽管目前有关于冷却塔使用和预防退伍军人病症的工作守则，但加强冷却塔的维修和规管，以及对退伍军人菌测试的法规和控制系统的必要性应给予考虑。因此，冷却塔使用海水应予以鼓励。
  • 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.
  • 土地的损失：有一些WACS方案需要一整块的土地或占据地下的空间，这会是一种空间可挪用作其它用途的损失。对于一个单独的WACS开发项目，如何能减少土地使用的方法将在后文中讨论。
  • 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.
  • 对海洋环境中排放：正如上文中提到的，发电站冷却水的污水排放和系统处理化学物质的有关的总量和影响有潜力被减少。然而，在更多WACS开发方案中涉及到在非循环性的使用水源，这样也可能使排放到海洋环境中的含热污水质以及系统处理的化学物数量有一定的增加。
  • 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.
对于服务商To Service Providers 
  • 庞大资金的投入：对一些WACS方案，特别是DCS方案，资本的投入非常高，并且为项目进行必要的资金筹措也十分不易。
  • 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.
  • 顾客的混淆：潜在的客户可能对迅速扩展的WACS方案的实施有混淆，另外也较难区分客户和建筑物占用人。
  • 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.
财务与经济评佑
选 项 分 析		Financial and Economic Assessment
Options Analysis
在香港，为了测试WACS系统的可行性，通过财务分析评估了较广阔范围内的各个方面，以确定系统的商业生存能力，通过经济分析从整个社会的角度确定需求度。经济分析与财务评价的不同之处在于它评价项目对于整个社会而言的成本和收益，而不是只对于WACS方案的运作公司。例如，在财务分析中，用水成本是根据水务署(WSD)的收费标准计算的。然而，这个收费率是包含了政府给予的许多补贴的。对于经济分析，是包括供水的实际成本的，也就是不计政府补贴的影响。 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个独立的WACS方案和3个以AACS为基础的实例接受了财务和经济评估。在下表中列出了评价结果的摘要，表明与以AACS为基础的实例比较和节约量的情况： 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技术和水源

经济方面：

与相同能力AACS比较的节约量

财务方面：

与相同能力AACS比较的节约量

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 - 冲厕用水 >0% >0% CPSSCT - flushing water >0% >0%
40MW方案 40MW Scheme
CPSSCT - 淡水 2% 6% CPSSCT - freshwater 2% 6%
DCS - 冷却塔，热量存储，淡水 2% 5% DCS - cooling towers, thermal store, fresh water 2% 5%
DCS - 冷却塔，热量存储，海水 4% 4% DCS - cooling towers, thermal store, sea water 4% 4%
DCS - 冷却塔，海水 3% 3% DCS - cooling towers, sea water 3% 3%
DCS - 冷却塔，淡水 2% 5% DCS - cooling towers, fresh water 2% 5%
DCS - 管道(散热器)，海水 2% 2% DCS - piped (heat exchangers), sea water 2% 2%
DCS - 热量存储，管道，海水 1% 1% DCS - thermal store, piped (heat exchangers), sea water 1% 1%
200MW 方案 200 MW Schemes
DCS - 冷却塔，热量存储，海水 23% 23% DCS - cooling towers, thermal store, sea water 23% 23%
DCS - 管道的(散热器)，海水 22% 23% DCS - piped (heat exchangers), sea water 22% 23%
DCS - 热存储，管道的(热交还器)，海水 21% 21% DCS - thermal store, piped (heat exchangers), sea water 21% 21%
DCS - 冷却塔，热存储，淡水 21% 25% DCS - cooling towers, thermal store, fresh water 21% 25%
DCS - 冷却塔，海水 21% 23% DCS - cooling towers, sea water 21% 23%
DCS - 冷却塔，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，与AACS相比，WACS在经济和财务方面是具有优势的。基本的WACS技术在财务和经济上不具备优势的方面是在建筑物内冷却塔的废水再利用上。这些“未淨化的生活废水”的选择方案中没有一个是比AACS更为有效益的，这是由于与运行废水处理系统相关的资金和营运费用皆不能够抵消耗水方面的少量节余。 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.
结论
由此可以看出，对于任何规模的项目来说，WACS系统都比AACS系统更具有成效上的优势，尽管它的技术随规模不同而变化。为了评价结果的稳定性，此研究实施了很多次的敏感度测试，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:
  • 土地价格的变化，以反影九龙和香港岛土地成本的巿场价值；
  • variations in the price of land to reflect market values for Kowloon and Hong Kong Island land costs;
  • 对现存楼宇进行WACS方案的改造；
  • retrofitting of WACS schemes into existing buildings;
  • 减少10%的电费，以减少与能量相关的成本节约；
  • reducing power charges by 10%, so as to reduce the cost savings associated with energy efficiency;
  • 增加10%的水费；
  • increasing water charges by 10%;
  • 应用一个10%的商业实际折扣率，以及
  • using a commercial real discount rate of 10%; and
  • 将配送管网的长度延长至10公里(复盖25平方公里的地区)
  • extending the length of the distribution pipe network to 10km, (maximum coverage area of 25km2)
根据经济和财务分析，除了CPSSCC和CPSSCT方案外，在延长管网至10公里的情况下WACS方案在所有实施规模上按照敏感度测验的方案都是可行的。 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.

实施问题及限制：

巿场评价及需求预测

IMPLEMENTATION ISSUES & CONSTRAINTS

Market Assessment and Demand Forecast
通过向一些目前正在营运水冷式空调系统的主要地产发展商和建筑物业主，以及本港的两间大型电力公司进行咨询，来明确提出有关在香港实施WACS的关键问题。 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.
可以确定，对于在香港介绍和推广WACS是有普遍兴趣的，但也有一些关注的问题要在此提出。这些问题包括政府与私人机构分别扮演的角色，财务可行性，与整体供应有关的保证，以及在现有地区范围内实施地区系统的可能性。如果这些问题有满意的解决方案，那么会有一定数量的被咨询者原则上有兴趣在某一地区成为一个WACS系统的客户或营运商。因此，只要制度，财务和实施上的问题都得到了解决，可以认为，对服务的提供和接受两方面都有潜在的需求。 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.
土地与地产Land and Property
许多的潜在问题和限制，往往涉及土地和地产方面。政府有必要考虑如何为最终的WACS营运商在基础设施的实施方面安排土地。 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.
在实施WACS时有土地方面的需求，但假设WACS在“土地恢?条例”或土地政策方面并不代表“公共用途”，这便有必要明确如何能获得这些土地。这也意味着需考虑为管道和其他基础设施所发出的地役权及执照权的措施。 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.
共同开发WACS基础设施和商业地产的机会将需要根据土地政策，商业可行性和实际的实施问题等作进一步调查。 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.
评价土地补偿金和有关道路通行费用的途经也需要建立，依靠所采用的制度框架来促进WACS的实施。 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.
制度和规则Institutional and Regulatory
WACS系统的引进或会为占优势的WACS供应商提供机会，通过垄断地位获得不合理的超额利润。至于DCS和CPSSCC方案，建筑物的拥有人、占有人、及租户可能会对部分空调基础设施失去控制权。 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.
这与气冷式或冷却塔系统的情况不同，除了水电供应外，空调系统包含在建筑物自身之中。在这种系统类型下，建筑物拥有人通常会收空调费。当收费标准固定下来，所有业主皆会意识到高额的空调费用将影响租赁价值。 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.
如果一个DCS或CPSSCC供应商不是建筑物的业主，他不会关心这个问题，因为租价的下跌不会影响他的收入。不过，当一栋建筑物连接到一个地区范围的系统，并且不再有能力提供给自己舒适的冷气(特别与新建筑相关)，则外间的供应者具有实际上的垄断。 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.
这与目前电力供应的情况类似，而且这也是为什么电力公司根据控制方案受到监管。然而，在很大程度上根据所拥有人的性质而定。以下图表识别了所有不同业权类含义： 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.
安排优点缺点ArrangementAdvantageDisadvantage
私 人 / 公 共 设 施 公 司 基 于 成 本 回 收 ， 典 型 的 回 报 率 和 利 润 形 式 ， 私 人 / 公 共 设 施 公 司 十 分 愿 意 投 资 在 造 价 昂 贵 但 效 率 高 的 设 施 上 潜 在 滥 用 巿 场 力 量 获 取 不 合 理 的 的 利 润 。 投 资 额 大 ， 只 有 少 数 公 司 有 足 够 资 源 开 发 系 统 。 由 于 营 运 成 本 可 转 嫁 用 者 ， 对 高 效 运 行 不 会 有 很 高 的 积 极 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.
发展商 承租人通常是在有保证的合理租金之下参与，对大型开发项目较理想。 升级困难。经常缺乏计量。开发商将为较低的安装费用而牺牲能源效益。由于营运成本可转嫁用者，不会对高效运行有很高的积极性。 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.
独立拥有人/政府 与政府系统在收费上没有争议。升级基于整个建筑/院区的远景规划 政府组织通常需要更多的时间来作出升级的决定。单独业主的系统还可能服从行动契约 ( 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).
基于潜在客户担心巿场力量有可能被滥用，实施上便潜在一定障碍。克服这些障碍的可选择方案将在后文中提出。 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.
技术Technical
WACS方案的位置、开发和实施在很大程度上决定在哪个区域或地区将被开发。研究结果表明，在新开发区实施项目将比在现有城区内实施更为简易。 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.
无论对于新区还是现有区，与WACS有关的主要技术限制都是大规模基础设施的实施，如巨大的供应管，排放系统，岸边泵水站和地区性的大型冷冻机组(DCS)等，以及对地方有关供水，排污和排水的基础设施之影响。 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.
环境Environmental
广泛的使用WACS可以对环境产生明显的益处，然而，对于资源的运用是有潜在的影响。在香港，更广泛应用WACS的主要资源实质是与用水有关的。CPSSCC方案和DCS方案，是将热量排放到海洋环境，需要直接的海水供应，而组成冷却塔的系统能够使用水务署供应的淡水/海水，以及其它的的水源，如未淨化的生活废水。在明确地表达WACS实施策略时，供水问题需要在整体上，以及个别的基础上进行调查。 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.
关于WACS潜在的环境影响，最大的潜在影响是由WACS产生污水的排放导致的。CPSSCC方案和DCS方案(将热量散发到海洋环境中)产生的物质因为涉及到的量很大，通常要排入海洋。由于这些污水含热的特性，以及它们含有化学处理用物质的负荷，使得环境对它们的可接受性应当在累积上，以及个别的基础上进行调查。使用冷却塔散发热量的CPSSCT和DCS方案的污水，一般应在排到雨水系统之前处理。如一些国家一样，采用将污水排入公共污水管的做法，应该注意到现有和规划中的污水管的容量，以及污水处理能力只能满足房屋计划和预期人口增长带来的迫切需要。因此，只有当实施了进一步的详细调查，并确定对于具体的方案有足够的富余能力，不会在任何方面对基本污水设施造成影响，才可以将该些废水排入公共污水管。 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.
任何包括冷却塔的淡水WACS方案中，与有关退伍军人菌的人体健康风险都必须给予考虑。在任何WACS实施策略的发展过程中，防止退伍军人菌疾病的工作守则一定要严格执行，同时还应有规程，以有效地对冷却塔进行注册，维修，控制和检测。 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.
在这份初步阶段研究中，没有任何不能解决的环境问题，然而，它指出当具体影响十分明显，以及在某些特定的环境下，需要在下一阶段的实施过程中进行排污和排水影响的评估。 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.

克服实施限制的行动

规划与开发

ACTIONS TO OVERCOME IMPLEMENTATION CONSTRAINTS

Planning and Development
在现有的城巿地区，寻找场地来满足与WACS有关的基础设施是十分困难的。一旦考虑到项目会在这些地区实施，政府将需要解决土地再利用和在私人土地上建造附属建筑物的问题。这也许需要澄清，WACS的引进是否代表“一种公共用途”-允许这样进行收地，以及一个新条例的引进，与电气条例(建造附属建筑物)或电讯条例类似的。 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.
从新开发地区的角度来说，将有必要保证适合WACS的场地和预留地已经明确和分配好，以及完成了适当的行政和法律程序以保证土地根据“概括分区规划(Outline Zoning Plan)”被合理划分。 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，有必要从土地政策和法律规划的角度，复核联合用户的发展是否可以接受，以及保证在新区规划中存在足够的灵活性，使得联合用户的发展能够进行。也有必要对拟建项目实施关于商业可行性的进行咨询。 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项目由私人业主进行的情况下，主要基础设施用地会通过私人条例或通过招标竞投分配给营运商。如果是由政府部门实施，土地需通过政府土地分配的方式得到。对这种基础设施采取短期租赁的办法，按照预期涉及到的资本投入水平，对于私人业主来说未必是可行的。为了保证珍贵的土地资源在可能的基础上得到了有效的利用，应当考虑与任何WACS基础设施相联土地系的发展权。这种做法也能从财务的角度使WACS方案的实施更具吸引力。 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.
立法与规例Legislation and Regulation
关键的规管的和制度的实施，是对巿场力量被滥用进行限制，以及鼓励采用高能源效益的空调系统的方法。 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.
为了防止在DCS和CPSSCC方案下，巿场力量被滥用，采取一些规管是必要的。特别是在私人公司营运，又与地产业主或租户没有联系的情况下提供服务时，尤其显得重要。如果是由一个第三方的私人营运者提供服务，则有必要采取一些形式的价格规管。可选方案在下表中列出。 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.
规定的形式优点缺点Form of RegulationAdvantagesDisadvantages

回报：

“回报率”(根据控制协议方案)

概念简单

易于计算，当许可的资产基础确定后

使管理者能够直接限制从垄断特权获得的利润

需要规管人详细地检查设备要求和资金花费；

促使公共设施的过多建设-对设备的投资一经管理者批准，保证会有回报；固定淨资产越大，获得的回报率越高；

不能刺激表现，因回报率有保证；

严重妨碍需求方面管理，除非需求方面投资被包括在资产基数中，以使回报达到至少同从供应方面资源获得的回报相同。

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

价格：

顾客价格指数(CPI-X)的限制(一般通过燃料费用)

是一种履约规定：

一方面它允许公共事业在其控制范围内获得利润收益(也就是不同于燃料价格，这也是为什么燃料价格一般被通过)；另一方面它也允许将一些利益转给用户(通过“负X"动实际价格的削减)		 一旦规管期的收费机制被制定，会大大促

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：

收益规定		 将销售量同利润分开，因此去除了价格管理系统含有的销售量动机，使公共设施能以最低成本找到符合客户能源服务需求。

比其他系统更难于管理，通常需要分拆成本结构；

有可能引起争议。

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