Statistical Arbitrage in Balancing Markets
and the Impact of Time Delay Stefan Kermer, Derek Bunn
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Markets and the Impact of Time Delay Stefan Kermer, Derek Bunn 1 - - PowerPoint PPT Presentation
Statistical Arbitrage in Balancing Markets and the Impact of Time Delay Stefan Kermer, Derek Bunn 1 Agenda Introduction Austrian Imbalance Settlement Design Market Players Perspectives Predicting the Conditional Distribution
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– Austrian Imbalance Settlement Design – Market Players‘ Perspectives
– Quantile Regression Model – Results with different time delays
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Source: APCS, July 2015
imb 𝑞𝐶𝐵 𝑞 𝐶𝑏𝑡𝑗𝑡
𝑗𝑛𝑐𝑛𝑏𝑦
𝑉𝑛𝑏𝑦
System long System short Under Production Short position Over Production Long position
𝑞𝐶𝑏𝑡𝑗𝑡 min ptert,pID , pDA for imb<0 and activated tertary min pID, pDA for imb<0 and no tertiary max ptert,pID , pDA for imb>0 and activated tertary max pID, pDA for imb>0 and no tertiary 𝑈 = min(𝑉𝑛𝑗𝑜 + 𝑉𝑛𝑏𝑦 − 𝑉𝑛𝑗𝑜 imb𝑛𝑏𝑦
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× 𝑗𝑛𝑐2 ; 𝑉𝑛𝑏𝑦) 𝑞𝐶𝐵 = 𝑞𝐶𝑏𝑡𝑗𝑡 ± 𝑈
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+
𝑤 = ( 𝑦 𝑗𝑛𝑐 − 𝑁𝐷) ∗ 𝑦𝐶𝐵 Pay off function for rational decisions Needs a rational expectation for 𝑗𝑛𝑐
Information update Imbalance Wind and solar error EPEX spot last price DPI IL DI DI … decision and internal schedule transmission DPI… delivery period internal schedule changes (15 minutes) IL… TSO processing information lead time is 10 minutes for imbalance, furthermore we assume the same lead time for solar-, wind error IT… Information time delay IT
Physical Player e.g. gas turbine
IL DE DE … decision and internal schedule transmission DPE… delivery period internal schedule 60 minutes à 15 minutes balancing prices IL… TSO processing Information lead tim10 minutes for imbalance, furthermore we assume the same lead time for solar-, wind error PLE… TSO processing lead time for external schedule nomination (45 minutes) IT… Information time delay DPE1 DPE2 DPE3 DPE4 PLE IT
Non-Physical Player (external schedules)
Information perspective Decision perspective
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imbi j = βi1 ∗ imbi j−r + βi2 ∗ EPEXi j−r + βi3 × wind_ei j−r + βi4 ∗ solar_ei j−r + c𝑗
We identified 4 explanatory variables to describe the response variable 𝑗𝑛𝑐𝑗 𝑘: 𝑗𝑛𝑐𝑗 𝑘−𝑠 Imbalance(j-r) autoregressive parameter with a time lag of j-r. 𝐹𝑄𝐹𝑌𝑗 𝑘−𝑠Last price EPEX(j-r) EPEX spot intraday trading closes at j-r. 𝑥𝑗𝑜𝑒_𝑓𝑗 𝑘−𝑠Wind error(j-r) is calculated as the difference between the day ahead forecast and the actual measured. 𝑡𝑝𝑚𝑏𝑠_𝑓𝑗 𝑘−𝑠Solar error(j-r) is calculated as the difference between the day ahead forecast and the actual measured value. 𝐽𝑁𝐶 q2.5 q10 q20 q30 q40 q50 q60 q70 q80 iq90 q97.5 Time lags 1 to 8 Parametrizing 2 months (January and July) Outcome: A conditional distribution
Information time delay in [minutes]
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𝑿𝒊𝒃𝒖 𝒆𝒑 𝒙𝒇 𝒉𝒇𝒖 𝒈𝒔𝒑𝒏 𝒖𝒊𝒃𝒖 𝒃𝒐𝒃𝒎𝒛𝒕𝒋𝒕? Lag 1 model Lag 8 model A more accurate portrayal of the relationship between the response variable and the observed explanatory variables
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𝑛𝑏𝑦𝑙 𝐹𝑊(𝑦𝑙) =
𝑗∈𝐽
𝑤𝑗 𝑙 𝜍(𝑡𝑗)
The expected value for a given course of action is the weighted sum of possible pay offs for each
for each course of action multiplied by the probabilities 𝜍(𝑡𝑗) associated with each state of nature 𝑡𝑗. The course of action 𝑦𝑙 is chosen which has the highest expected value 𝐹𝑊(𝑦𝑙).
Physical Player Non-physical player
v𝑚𝑝𝑜 = ( 𝑗𝑛𝑐 − 𝑁𝐷) ∗ 𝑦 v𝑡ℎ𝑝𝑠𝑢 = 𝑁𝐷𝐸𝐵 −𝑞𝑏𝑡𝑡ℎ𝑝𝑠𝑢 − 𝑞 𝑦 𝑗𝑛𝑐 ) ∗ 𝑦 𝑤 = 𝑞 𝑦. 𝑗𝑛𝑐 − 𝑁𝐷𝐹𝑄𝐹𝑌 ∗ 𝑦
ma k(
𝑘
𝑗∈𝐽
𝑤𝑗 𝑘 𝑙 ∗ 𝜍( 𝑗𝑛𝑐𝑗) ) Pay offs: OUR OBJECTIVE:
Index for time 𝑘 ∈ {T} Index for state of nature 𝑗 ∈ 𝐽𝑁𝐶
Index for position 𝑙 ∈ {−100 … 0. . +100} in MWh
Assumption: Physical player is in part-load Assumption: Non-Physical player trades last price at EPEX Spot
Back Testing with observed data winter and summer month 2015 Benchmark and key performance indicators
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1.000.000 1.500.000 2.000.000 2.500.000 realized profit expected profit realized profit expected profit summer summer winter winter profit [EUR/month] physical player non-physical player
1.000.000 1.500.000 2.000.000 2.500.000 3.000.000 summer winter system costs in [EUR/mont]
physical player non-physical player 20,00 22,00 24,00 26,00 28,00 30,00 32,00 summer winter standard deviation in [MWh]
physical player non-physical player 48.000 50.000 52.000 54.000 56.000 58.000 60.000 62.000 64.000 66.000 winter summer absolute imbalance in [MWh]
physical player non-physical player
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physical player non-physical player short positions winter 380 1641 short positions summer 271 1466 long positions winter 63 867 long positions summer 53 1050
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Short information time delays would need:
external schedules
IL DE DE … decision and internal schedule transmission DPE… delivery period internal schedule 60 minutes à 15 minutes balancing prices IL… TSO processing Information lead tim10 minutes for imbalance, furthermore we assume the same lead time for solar-, wind error PLE… TSO processing lead time for external schedule nomination (45 minutes) IT… Information time delay DPE1 DPE2 DPE3 DPE4 PLE IT
Information time delay in [minutes]
Comparison with
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WINTER SUMMER
System costs System costs Absolute imbalance Standard deviation System costs System costs Absolute imbalance Standard deviation
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WINTER SUMMER
System costs System costs Absolute imbalance Standard deviation System costs System costs Absolute imbalance Standard deviation
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0% 10% 20% 30% 40% 50% 60% 70% quantity summer short positions non-physical player winter short positions physical player winter long positions non-physical player winter long positions physical player winter 0% 10% 20% 30% 40% 50% 60% 70% quantity summer short positions non-physical player winter short positions physical player winter long positions non-physical player winter long positions physical player winter 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% percentage of positions quantity of positions non-physical player summer quantity of positions non-physical player winter quantity of positions physical player summer quantity of positions physical player winter
How often do they spill/short the market? From 2683 15 minute intervals in winter/summer the physical player traded less than 20 percent
whereas the non- physical EPEX Spot trading model suggested over 90%
imbalance position.
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WINTER SUMMER
imb 𝑞𝐶𝐵 𝑞 𝐶𝑏𝑡𝑗𝑡
𝑗𝑛𝑐𝑛𝑏𝑦
𝑉𝑛𝑏𝑦 System long System short Under Production Short position Over Production Long position
System long >70 MWh decreased significantly System Short >70 MWh remained constant for physical player and increased slightly for non-physical player
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200 300 400 500 600 700 800 900 1.000 imbalance half cycles [-] half cycles winter half cycles summer
Half cycles in case of participation of the physical player increased by 80% for the lag 1 model For the physical player only a slight increase is observed.
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Research Questions: Does statistical arbitrage help the system to decrease system imbalance and system costs? What is the impact of information time delay? For the physical player YES! Short time delays decrease system costs and stabilize the system significantly. For the non-physical player a more differentiated point of view is necessary:
(profitpotential), but it is not as beneficial from system perspective
the system imbalance was long, but a slight increase for short imbalance extremes
be able to help the system, but the frequency of trades in this single player simulation was very high, which potentially would lead to overreactions in the market in a multiplayer setting.
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REF Time OLS IMB EST OLS_pBA_i mb_est_N O_x OLS_pBA_d ec x-decision imbalance_obs imb_obs+x
timized_no_t ert expected spread spread p_ID 20908 557 8,63 60,03
100,00 0,71 100,71 59,54 96,54
83,46 180,00 22851 2500
13,35
100,00
62,92 5,95 66,42
131,58 198,00