Examples of Wind Curtailment 弃风案例 Kevin Porter and Sari Fink 凯文 波特，莎莉 芬科 Exeter Associates公司 Energy Foundation Meeting on Wind Integration 能源基金会美国并网经验介绍会 Beijing, China June 2010

Outline 提纲 Introduction 简介 Examples of Wind Curtailment 弃风案例 Generator interconnection 并网 Contractual 协议 Bid-based curtailment 招标法弃风 Daily operating limits 日常运行限制 By type of wind technology 依据风电技术类型 Amount of available reserves 备用电源量 Compensation 补偿 Curtailment Data 弃风数据 Conclusions 结论 Exeter Associates

Introduction 简介 风电在过去的十年中发展非常迅猛，然而在很多地方输电投资却跟不上 Wind power development has increased dramatically over the last decade, while transmission investment in many regions has failed to keep pace. Additionally, wind facility construction times are much shorter than for transmission. Wind may blow stronger at night when loads are low. This has resulted in situations where wind energy production can at times exceed the electricity system’s ability to operate reliably. Curtailment of wind energy has increased as a result. 风电在过去的十年中发展非常迅猛，然而在很多地方输电投资却跟不上 而且风电场建设所需时间远低于输电设施建设的时间 夜晚用电负荷低的时候，风资源却偏偏更好 这导致，有些时候，风电会超出电力系统的接纳能力，危及电网的安全运行 弃风成为无奈的选择 Exeter Associates, Inc.

Why Important for China 对中国的重要意义 Significant international experience and experimentation with wind curtailment. International experience can provide useful experience from both system and generation perspective. 重要的国际弃风经验和实验 这些国际经验可以从发电端和电力系统两个方面提供有用的参考 Exeter Associates, Inc.

Curtailment Data 弃风数据 缺少相关规定导致弃风数据难以获取 下表给出不同地区的一些数据 Curtailment data can be difficult to acquire as there are seldom requirements in place for reporting it. The table below gives some data for various jurisdictions. 缺少相关规定导致弃风数据难以获取 下表给出不同地区的一些数据 Entity单位 Curtailment Data弃风数据 BPA As of March 30, 2010, total cumulative capacity of wind that has been limited is 2900 MW. ERCOT In 2009, curtailed on average around 500 to 2,000 MW daily, max amount approximately 3,900 MW. ERCOT curtailed about 16% of wind generation in 2009. Midwest ISO In 2009, around 1,100 incidences of wind curtailment totaling about 200,000 MWh, representing about 1% of total wind generation. SCE About 15 MW for 3-4 hours every two days from a single wind plant in Tehachapi (contractual arrangement). Xcel In 2009, 42,359 MWh of wind generation in Minnesota and 18,991 MWh of wind generation in Colorado were curtailed. Alberta ESO Curtailed wind for about 838 hours in 2009. Denmark May curtail over 20% of marginal wind production Germany Between 2004 and 2006, approximately 74,000 MWh of wind energy was curtailed. Ireland In 2008, approximately 100 MWh of wind energy was curtailed. Spain In 2009, approximately 54,000 MWh of wind curtailed, or about 0.15% of total wind production. Expected to increase dramatically to as much as 6.8%. Exeter Associates

Condition of Generator Interconnection 并网情况 Wind generators connecting to the grid are required (like all generators) to execute interconnection agreements. These interconnection agreements can include clauses whereby wind facilities agree to curtail generation, on request from the grid operator, if transmission constraints or system conditions require it. 与其他电力供应商一样，联网项目的风电供应商也被要求执行并网协议. 并网协议会有一些条款，规定受输电条件约束或系统条件制约的情况下，电网运营商可以要求风电供应商弃风，风电供应商要接受。 Examples: E.On Netz and BPA E.On Netz in Germany required wind generators to accept ‘wind power management’ for interconnecting in certain areas until transmission upgrades were completed. Bonneville Power Administration in Western U.S. includes curtailment procedures in large generation interconnection agreements for wind facilities. 实例: E.On Netz 和 BPA 德国E.On Netz 要求那些在特定地区并网的风电供应商，在该地区输电设施升级完成之前，要接受‘风电管理’ 。 美国西部的邦维尔电力局在大规模发电并网协议中针对风电增加了弃风程序要求。 Exeter Associates, Inc.

Contractual 协议 Some individual utilities include wind curtailment conditions in power purchase agreements. Under these agreements, wind facilities often provide a set amount of wind generation curtailment for a specified amount of time each year at no cost or reduced cost to the purchasing utility. 部分电力公司在购电协议中添加了弃风条款 依据这些协议，风电场方面常常是就一个每年特定时长内无补偿或低补偿的固定弃风量和购电方进行约定。 实例: Xcel 能源 Xcel 能源和明尼苏达州和科罗拉多州的风电场达成协议，约定固定的弃风量。 至2008年，科罗拉多州的Logan风场签订协议 允许最高达14 吉瓦时的年度免补偿弃风量。 明尼苏达州的各风场轮流承担弃风任务，Xcel 能源和这些风场就集体弃风总量达成协议。 Example: Xcel Energy Xcel Energy has contractual agreements with wind plants in Minnesota and Colorado to provide set amounts of curtailment. The Logan Wind plant in Colorado has a contract to provide up to 14 GWh of annual curtailment at no cost, as of 2008. Wind plants in Minnesota curtailed on a rotational basis and are made whole by Xcel for the curtailed energy. Exeter Associates, Inc.

Market Bid-Based 市场招标制 Example: New York ISO In 2009 the NYISO implemented new market rules for wind energy. Wind plants can bid price curves, up to 11 price-quantity pairs into the real-time energy market for each operating hour. NYISO altered its economic dispatch software to accept negative prices. Wind generators must participate in the NYISO’s wind forecast and be able to accept electronic basepoint dispatch signals. 案例:纽约电力调度中心（NYISO） 2009年NYISO 实施了新的风电市场规定.风电场可以按价格曲线投标，竞标实时电力市场多达十一种的分小时“电价-电量”组合。NYISO 调整了其经济调度软件以实现负电价进入计算范围。风电供应商必须提供NYISO要求的预测，而且得能接受电子调度信号。 Some regions with wholesale energy markets are integrating wind energy into their economic dispatch. 一些地区的电力批发市场正在把风电纳入其经济调度的范围 Wind generators bid price curves into wholesale markets indicating at what prices and amounts they are willing to generate. 风电供应商在电力批发市场中以“价格曲线”的形式投标售电，这可以揭示出他们能够接受的最低价格和数量水平 Due to tax credits/incentives in United States, wind plants may want to produce at negative prices. 由于美国的税收优惠/激励政策，风场有可能愿意接受“负电价”发电 Prices may fall to point that wind economically curtails. 价格下降到一定程度风电供应商就会选择弃发。 Exeter Associates, Inc.

Daily Operating Limits 日常运行限制 Example: ERCOT Wind facilities developed rapidly in the less-populated wind-rich areas of West Texas. Because of a lack of adequate transmission, the Electric Reliability Council of Texas (ERCOT) instituted daily operating limits on wind plants in the McCamey area. ERCOT used day-ahead load projections to calculate and assign operating limits to the wind plants for the next day. ERCOT stopped using daily operating limits in 2009. 案例:得州电力可靠性理事会（ERCOT） 在人口稀少但是风资源优越的西得克萨斯地区，风电发展非常迅速。 由于输电能力的欠缺,得州电力可靠性理事会(ERCOT)制定执行了麦卡米地区风场每日运行限制规定 。 ERCOT 利用提前一日做出的电力负荷预测来计算和布置风场次日运行限制。2009年ERCOT 停止了风场每日运行限制。 Some grid operators have imposed daily operating limits on wind farms. 一些电网运营商设定了风场每日运行限制 This is generally done on an area-specific basis when there is a concentration of wind plants developed in a single transmission constrained region. 这种限制通常发生在风电场分布密集且电网线路能力有限的区域 Wind plants must match their output to the daily limit. 风场须按照当日限制生产。 Exeter Associates, Inc.

Differentiated by Technology 按不同技术种类 Example: ERCOT In west Texas, ERCOT also created two categories of wind plants – rapid response (RRWF) and slow response (SRWF). During congested times RRWF’s could reduce production within 15 min and SRWFs would be able to respond within 30 minutes. In the following hour, pro-rata shares would be adjusted to allow RRWFs to recoup the extra lost production. 案例:得州电力可靠性理事会（ERCOT） 在西得克萨斯地区，ERCOT还搞了两个风场类别—快速反应风场（RRWF）和缓慢反应风场(SRWF)。 在调度高峰期间，快速反应风场能在15分钟内减少发电，而缓慢反应风场则需要半小时。 在下面一个小时里，ERCOT可以调整分时发电限制来弥补快速反应风场在先前的调度中快速弃风带来的发电损失。 Wind technology has evolved quickly over the last decade. 风电技术在过去十年发展很快 Newer wind plants have more advanced control capabilities. 新建的风电场比原来的有更强的控制能力 Some grid operators have taken advantage of the advanced control capabilities for faster response to system events. 一些电网运营商已经从先进的控制技术上受益，能够更快的响应系统变化。 Exeter Associates, Inc.

Availability of Reserves 可用的备用电源 Example: BPA The Bonneville Power Administration (BPA) manages and sells hydro power from federal dams in the Pacific Northwest. BPA also has integrated over 2,700 MW of wind and says it is running low on reserves. To manage reserves, BPA requires wind generators to reduce schedules to the lower of their scheduled amount or actual generation, once 90% of these balancing reserves have been utilized . 案例: BPA 邦维尔电力局(BPA) 负责管理和出售 “西北太平洋”联邦大坝的水电。BPA 也同时接入了2700多兆瓦的风电，并表示备用电源日趋紧张。为加强对备用电源的管理，BPA 要求风电供应商，在备用电源90%进入运行的情况下，必须按照其预计发电量或发电能力的下线缩减发电。 Some grid operators have tied wind curtailment to the availability of generation reserves. 一些电网运营商已经把备用电源的情况和弃风联系到了一起 When generation reserve use reaches a set level, wind is asked to curtail production to the lower of their scheduled amount or actual operating amount. 当备用电源的使用达到了一定程度，风电就得应要求弃发一定比例，降低发电量。 This reduces the need to acquire additional reserve generation. 这样可以减少对备用电源的需求 Exeter Associates, Inc.

Compensation 补偿 Compensation for lost energy production varies by jurisdiction both within the U.S. and outside the U.S. Direct compensation especially important if no limits are placed on amount of curtailment Compensation can also be differentiated by the reasons for the curtailment. Situations where wind plants may not be directly compensated include: Curtailments may be covered by contract or by agreement. Curtailments are due to a system emergency or reliability event where all generation may be curtailed. Transmission constraint was caused or aggravated by the curtailed wind plant. Curtailment is the outcome of a market-based economic dispatch process (i.e., by virtue of market bids, wind curtailment was the most economic option to curtail). 弃风补偿在美国各地或其他国家都不尽相同 如果没有对弃风量的约定，直接补偿就变得尤为重要 因弃风原因的不同，补偿高低也不一样 一些不能得到直接补偿的情况 在合同或协议中已经约定好的弃风部分。 因系统紧急状况或可靠性问题的出现而导致电源全部弃发。 个别风场引起或加剧了输电压力的情况下，这些风场须接受的弃发。 弃风是市场机制下经济调度的结果(比如, 在市场出价规则下，让风电来弃发是最经济的一种选择). Exeter Associates, Inc.

Compensation (cont.) 补偿 When provided, compensation amounts can be determined in various ways. Examples include: ERCOT paid out-of-merit energy payments for curtailments in real-time. Southern California Edison provides make whole payments for energy. Xcel Energy provides make whole payments for both fixed and variable wind plant costs in Minnesota and make whole payments, including the Production Tax Credit, for curtailments in Colorado that are above the contracted amounts. Germany provided payments equal to lost revenues. In Ireland, curtailed wind plants are paid in the energy markets as if they generated at full available output. In Spain, compensation for real-time curtailments is a percentage of the wholesale price of electricity, currently set at 15%. 一些情况下弃风可以得到补偿，补偿金额的确定有多种方法。比如: ERCOT 为优选顺序外，实时调度的弃风量提供补偿。 南加州爱迪生公司采用“能源整付”办法. Xcel 能源在明尼苏达州采取对风电给予固定成本和可变成本整付的方案，在科罗拉多州采取协议外弃风量给予包括生产税抵减优惠在内的整付方案。 德国根据实际经济损失给予等额补偿。 在爱尔兰，能源市场为风电场的弃风损失提供补偿，核定弃风时风场可实现的全额实发量，据此给予补偿。 在西班牙，实时弃风补偿根据电力批发售价的一定比例给予，现行的比率是15%。 Exeter Associates, Inc.

Conclusions 结论 Amount of wind curtailment is likely to rise in the United States, China and elsewhere, at least until transmission issues are resolved. If curtailments are necessary the following principles should be incorporated into curtailment initiatives: Grid operators should ensure that all actions that can be taken have been taken prior to curtailing any generation, such as ensuring all generation that has non-zero operating costs are running at minimum, imports have been reduced or eliminated, and export opportunities have been exhausted. If curtailments are necessary, wind should be treated comparably with all generation. Wind should not be curtailed just because it is easy to do so. To the extent that markets allow/exist, wind generators (along with all generators) should have the option/ability to bid in prices at which they are willing to be curtailed. Issue of whether generators (including wind) should be paid if curtailed (and how much) needs to be addressed. If not directly compensated, need to find ways to limit exposure to financial risk. Other measures to reduce curtailment include large balancing areas, dynamic scheduling and dynamic ratings of transmission lines. 在电力送出问题解决之前，无论是美国还是中国或者其他国家、地区，弃风量都存在继续增加的可能。 当必须执行弃风管理的时候，以下原则应考虑在内: 电网运营商应确保在弃风前已经采取一切可能的措施,比如确保所有以“非零”运行成本发电的电源已经调整到最低运行状态，对外来电力的吸收已经销减甚至取消，而向外送电的能力已经用尽。 如果弃风不可避免，也要对风电和其他电源一视同仁。不能仅仅因为风电弃发容易而让它弃发。 在市场允许的程度内，风能发电商（及其他发电商）应该有选择投标其能接受的弃风价格的权利。 需要解决发电商（包括风电）弃发是否应得到补偿（及补偿多少）的问题。如果无法直接补偿，也要找到可以约束经济风险比率的办法。 其他减少弃风的办法还有大区域管理、动态调度和动态输变线路载荷评定等。 Exeter Associates

Report 报告 Full report is at 完整报告可从以下链接获取 http://www.nrel.gov/docs/fy10osti/46716.pdf. Exeter Associates, Inc.

10480 Little Patuxent Parkway, Suite 300 Contact Information 联系方式 Kevin Porter Exeter Associates, Inc. 10480 Little Patuxent Parkway, Suite 300 Columbia, MD 21044 410-992-7500 410-992-3445 fax kporter@exeterassociates.com