Transcript No Slide Title

Strategic Bidding in Competitive Electricity Markets
Moeljono Widjaja, Prof. R.E. Morrison and Dr. Ly Fie Sugianto
Objectives
•To design a generator bidding system in competitive electricity markets from historical market data based on a fuzzy approach.
•To develop a systematic approach to formulate an optimal bidding curve ensuring positive earning.
A Simplified Model of an Electricity Market
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load_profil e_portrait.eps
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MAT LAB, T he Mathworks , Inc .
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s imple_model_gen_bi d.eps
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MAT LAB, T he Mathworks , Inc .
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four_gen_two_bus _s ys tem.eps
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Regional Load Profiles
A Four-Generator Two-Bus System
Regional load demands are modeled as stochastic processes.
Generator A bids strategically while others bid at their marginal costs.
Marginal Bids of Generators (i.e. k=1)
A bid multiplier k is defined as the multiplier to the marginal cost
function and is used as the only bid variable.
A Fuzzy Model of Generator Bidding System
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mul ti_stage_fuzzy_relation.eps
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fi g2dev Versi on 3.2 Patc hlevel 3c
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Inputs:
•Forecasted Load Demand
•Generator’s Bid
Output:
•Estimated Profit
Projecting the Membership Function of Fuzzy Number Price
Price as a function of Load.
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fuzzy_combination.eps
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MAT LAB, T he Mathworks , Inc .
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Calculating the Parameters (mean and std) of the Gaussian-Type
Membership Function of Fuzzy Number Price as a Function of Load and Bid.
i1 pi  demand (di )  bid (ki )
m ean 
i1 demand (di )  bid (ki )
n
i 1 pi  demand (di )  bid (ki )
n
n
std 
2

n
i 1
demand ( d i )  bid ( ki )
where demand is themembershipfunctionof load demand;
Price as a function of Bid.
bid is themembershipfunctionof generator's bid; p is a vectorof spot prices;
d is a vectorof load demand;k is a vectorof generator's bid; and
n is thenumber of elementsin vectorsp, d and k.
Price as a function of Load and Bid.
Fuzzy number Dispatch is formulated with the same approach as Price.
Results and Discussion
Generated Optimum Bid Profile for Generator A
The optimum bid multiplier of generator A
is plotted against the load profile in region
one. As the load increases, the spot price is
likely to increase as well. However, when
the load is large enough (i.e. the
corresponding spot price is also high), there
is an incentive for generator A to bid low
and generate at its full capacity.
T itle:
opti mum_bid_profile.eps
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MAT LAB, T he Mathworks , Inc .
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Histograms of the Daily Profits of Generator A
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hist_profit_portrait.eps
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MAT LAB, T he Mathworks , Inc .
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•Scenario one: generator A bids at its
marginal cost.
•Scenario two: generator A bids
strategically using the proposed fuzzy
approach.
•Each scenario was simulated for 100
trading days where each trading day
consisted 48 trading intervals.
The results show that the proposed approach increased the daily profit of generator A by at least five percent on average.
The proposed fuzzy-based approach is shown to be effective in formulating an optimal bidding curve for a generator in a competitive electricity market.
Electrical and Computer Systems Engineering
Postgraduate Student Research Forum 2001