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CDM Consolidated Methodology for Electric Sector Baselines – Issues and Proposed Answers. Duane T. Kexel, Vice President Power System Engineering Madison, WI USA kexeld@powersystem.org Buenos Aires, December 8, 2004. Background of My Comments.
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CDM Consolidated Methodology for Electric Sector Baselines – Issues and Proposed Answers Duane T. Kexel, Vice President Power System Engineering Madison, WI USA kexeld@powersystem.org Buenos Aires, December 8, 2004
Background of My Comments • Dozens of Power Supply, IRP, and Feasibility Studies In Numerous Countries • Czech Standardized Electric Sector Baseline • Hungarian Biomass Project • Poland Standardized Sector Baseline • Flies, Birds and Elephants
CDM Quality Assurance Troika CDM Meth Panel Validators Verifiers
Baseline Uses • Ex Ante Allocation • Forgone Opportunities for Buyers • Underdelivery Penalties for Sellers • Inaccurate Methods Chill The Market • Ex Post Disbursement • Does Not Depend Totally On Forecasts • Should Make Maximum Use of Actual Data • Impacts Risk Split Between Buyer and Seller • Never Forget That The Common Goal of All Is To Reduce Emissions of GHG
Czech Electric Sector Standard Baseline Objectives • Minimize Transactions Costs For Multiple Small Projects • Consistent Comparative Standard for Renewable Electric Generation • Simple and Dynamic • Recognize Key Features of Czech Grid • Both Screening and Monitoring By Local CEA Staff/Consultants • About One Day Per Project Per Year For Analysis • Requires Only Readily Available Data With A Known Publication History and Expected Future • Defaults Are Defined In Case Data Are Not Available • Conservative but Competitive
Key Czech Grid Considerations • Impact of Temelin (2,000 MW Nuclear, 11,000 MW System) Addition • Additions Before 2010 Not Load Driven • 8% Renewable Target by 2010 • Many Small Renewables Not Dispatchable • Large Blocks of Must Run Units – IPP CHPs • Coal Dominance - Gas Limited • Marginal Not Average Fuel Mix Matters • Operating Margin - Not Build Margin is Relevant
CDM ACM0002 – Operating Margin • EF is calculated as a combined margin (CM) of the operating margin(OM) and the build margin (BM) • OM (a) – Simple OM – Weighted average of generation by fuel above non-displaceable sources • OM (b) – Simple Adjusted – Adjusts for “excess” non-displaceable sources above minimum load – then the weighted average of generation by fuel • OM (c) – Hourly Dispatch Using Top 10% Mix in Each Hour • In all cases, data from last available years or ex post monitoring is acceptable
OM (c1) Methodology • OM (c) – Conceptually correct but literal data demands are excessive and often not practical • Use of 3 year historic average can very seldom be justified. • Concept can be used but much more simply applied – that is (c1). • Czech method only needs the split of marginal hours by fuel and the average conversion efficiency for the class of marginal plants (Hg and Hc and maybe Hn). • Three methods of estimating marginal hours by fuel
OM (c1) vs OM (c) • OM (c1) Statistical method requires only monthly generation by fuel – Typically easily available and reliable data – Self testing. • OM (c1) Screening curve requires more data and calculation but dramatically less data than hourly generation by unit • Proxy unit hours are useful check if such units can be identified. • Statistical method is easily applied going forward with other methods as checks if results are bizarre. Default bounds can be reasonably set.
Proxy Unit Method • Look at average operating hours of peaking units on the system. • Would work well if system has conventional peaking CTs. • Czech case, IGCC and pumped storage hydro cover some of the peak. These are actually coal equivalent units. • Gas-fired CTs are minimal and the only sizeable unit is often used for voltage support rather than load. • For CR, it is more useful to track gas-fired generation.
What About OM (b)? • More than gas and coal may be displaced. • It is critical to check for displacement of non-displaceable generation – “Above the knee”. • For Czech Republic, just completing 2,000 MW of new nuclear generation. Also, many coal-fired CHPs dispatched for heat load. • Czech method calculates from energy data like OM (b). • Still must decide on dispatch order of low-cost units. Must-run cannot be displaced. For CR, nuclear was chosen.
Summary on OM Methods • OM (a) will generally overstate emissions • Marginal rather than average fuel displacement should be used based on marginal hours. • Within fuel types, average unit efficiencies can be used and will provide conservative results with reasonably accessible data • OM (c1) is correct and preferable if data can be obtained and project can justify the transactions costs. • Three year historic average would only be reasonable in very few cases and could be very misleading.
Select Additional Key OM Issues • Time Resolution of The Analysis • Load Curve Representations • Liberalization of Power Markets • Complete Calculation Method
Proper Time Resolution For OM • Fuel mix may change significantly by month if load changes significantly by month. • Production may vary dramatically by month for wind or hydro – generally not for biomass although the maintenance month could matter. • Practical candidate periods are annual, seasonal, monthly. • Hourly load data can be used to identify monthly distribution of peak hours and of low load hours.
Czech Rules On Time Granularity • If max and min monthly production of proposed project are within 10% of average, annual is okay. • If annual not okay, seasonal or monthly is required. • If within season variation about the mean is within 10%, seasonal is okay. • If annual and seasonal are not okay, monthly analysis is required. • Monthly is always accepted since it is more accurate.
Load Curve Representations • Relevant LDC for domestic generation is domestic consumption plus net exports. • Best basis is three year history of hourly domestic consumption. • Net exports can be adequately represented from data for peak and minimum loads plus annual total MWh. • Domestic load shapes normally shift slowly over time.
Load Curve Approximations • Linear is ideal for simplification but not adequate. • Piecewise linear was used for CR based on 2002 history and two segments. • Algebraic representation is very good for load factors between 40% and 60% • MWt = f(LF, Max, Min/Max, Pi, Hours)
ACM0002 – Build Margin • BM (1) – Ex Ante • Five Most Recent Power Plants Built, or • Most Recent Vintage That Accounts for 20% of MWh • BM (2) – Ex Post For 2008-2012, Then Ex Ante • Default Weighting of OM and BM is Equal but Proponent Can Defend Alternative Weights.
Concerns With ACM002 BM • Observed Additions Cannot Logically Represent What Was Displaced By The CDM Project Since The Displacement Was Not Built. BMs Are Inherently Based on Forecasts. • Historic Additions Are Not Good Predictors of Future Additions • Reliance on 20% of Generation Will Bias Results Toward Baseload Additions When Many Renewable Projects Do Not Displace Baseload. • Default of 50-50 Seems Arbitrary And Will Seldom Be Reasonable For Specific Years. • Should Require A Demonstration of When BM Becomes Relevant And Then It Should Get 100% Weight. Before That, Weight Is Zero.
Principles of Correct BM • Expansion Plan Should Be Constrained Least Cost Path (CLCP) • Additionality Typically Based On Investment Analysis • OM Based On Constrained Economic Dispatch • BM Should Have Same Foundation • Concept Is The Difference in CLCP With and Without Proposed Project • Many CDM Projects Will Provide Energy Only Which Is A Sticky Wicket
Constraints to CLCP • Transmission Limits Can Corrupt The Timing, The Amount, And The Mix of Capacity Additions • Must-Run Units Distort Simple Investment Sequence • Emission Limits Will Constrain Expansion Path Unless Monetized • Portfolio Standards Will Corrupt LC Mix • Poland – 25,000 MW Peak, Need To Replace 10,000 MW by 2010 – May Replace 5,000 MW • But Subject To These, It Is Still The Best Predictive Assertion
Illustrations of Problems • Czech Case • 2000 MW Nuclear Unit Is Last Addition – Accounts for about 16% of Total Generation in 2003. • With 20% Rule or With Last Five Plants BM Would Be Mostly Nuclear and Some Coal For ROR Small Hydro • In Fact, BM is Not Relevant For CR Until 2010 or Later • Displaced Future Plants Are Certainly Not Nuclear • US – Most Recent Plants are Merchant Gas CCs - Future plants are now Utility Coal • CLCP Is Always Alternating Between Fuels, Technologies, And Duty Cycles. Long Term Extrapolation of Recent Past Would Clearly Not Be the Least Cost Plan
Proposed Minimalist Solution • Start With Load Vs Capability Analysis To See If BM Is Relevant For Period of Interest – If no Capacity Change In That Period Only OM Matters. • Compare Optimum Mix With Existing Mix For Select Future Years To Establish Likely Sequence of Additions. • Establish Addition Sequence of Each Type (Peaking, Int, Base) by Year. • Find Least Cost Option For Each Type In Each Year • Determine What Type or Mix The Proposed Project Displaces • Say Biomass Displaces Baseload Coal in 2012. Then Use 100% Weight for OM through 2011 and 100% Weight for Coal Thereafter.
Generic Competitors By Type • Baseload – • Clean Coal • CC Gas or Oil • Other Renewables • Intermediate • Small Clean Coal • CC Gas • Peaking • CT Gas • Storage Hydro
Conclusions On State of the Art • Art Striving To Become Science • CDM Meth Panel Process Is Sound But • Should Retain Flexibility Based On Relatively Small Case Law Base • Should Continue To Broaden Case Base • Substantial Carbon Is Still At Issue • Dialogue Is Expanding And Needs To Expand Much Further • OM Rules Are Now Reasonable Although I Would Hope OM(c1) Will Be Recognized To Avoid Need for Dispatch Data • Three Year History Is Not Very Reliable Basis – Should Be Dynamic • BM Is Much More Complex And Should Still Evolve • 50-50 Weighting Is Weak Link And Should Not Be The Default