Changing Electricity System Fabian Hinz 15th IAEE European - - PowerPoint PPT Presentation

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Changing Electricity System Fabian Hinz 15th IAEE European - - PowerPoint PPT Presentation

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Faculty of Business and Economics , Chair of Energy Economics, Prof. Dr. Mst The Influence of Voltage Stability on Congestion Management Cost in a www.ee2.biz Changing Electricity System Fabian Hinz 15th IAEE European Conference Vienna,

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Faculty of Business and Economics, Chair of Energy Economics, Prof. Dr. Möst

www.ee2.biz

The Influence of Voltage Stability on Congestion Management Cost in a Changing Electricity System Fabian Hinz

15th IAEE European Conference Vienna, September 2017

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TU Dresden, Chair of Energy Economics, Fabian Hinz 2 06.09.2017

Future scenario 2025 4 Staus Quo 2014 3 Model Development 2 Motivation 1

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TU Dresden, Chair of Energy Economics, Fabian Hinz 3 06.09.2017

Congestion management causes high cost

Development of congestion mgmt. cost, causes Congestion mgmt. cost [mio. EUR] 198 159 2013 2015 269 750 2014 2012 45 2006 2011 2008 164 32 30 2009 2007 58 2010 Redispatch & Countertrading Curtailment Loop flows

Loop flow via PL, CZ and AT Direct flow from North to South

Load vs. generation Load distribution Wind distribution

  • Load concentrated in the South and West
  • Wind concentrated in the North
  • Power flows from

North to South cause loop flows via Eastern Europe

  • Phase shifting

transformers being installed

Source: BNetzA Monitoring Reports 2007 - 2016

Challenge Current / Real power

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TU Dresden, Chair of Energy Economics, Fabian Hinz 4 06.09.2017

Future supply Conventional supply Electricity feed-in 110 kV grid Medium / low voltage grid Transmission grid

Availability of reactive power in the transmission grid declines

Reactive power supply: conventional and future scenario

Source: Kraftwerksliste BNetA 2015, Netzentwicklungsplan 2015

Reactive power supply

  • Conventional supply through

large power plants

  • Availability in the

transmission grid decreases

  • Supply can be replaced by

RES in the distribution grid Reactive power consumption Reactive power consumption

38% 51% 59% 62% 42% 28% 13% 2035 2025 2014 8%

DSO Offshore TSO Controllable reactive power

Challenge Voltage / Reactive power

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TU Dresden, Chair of Energy Economics, Fabian Hinz 5 06.09.2017

Redispatch measures conducted in order to solve current and voltage problems

Current- and voltage-induced redispatch

Voltage-induced redispatch Current-induced redispatch Real power Reactive power

Redispatch Situation Power plant 1 not dispatched Power plant 2 fully dispatched Current too high Power plant 1 ramped up Power plant 2 ramped down Current okay Power plant 1 not dispatched Power plant 2 Reactive power Voltage too low Voltage okay Power plant 1 Reactive power Power plant 2 Reactive power Voltage okay Voltage okay

expan- sive cheap expan- sive cheap expan- sive cheap

Q

expan- sive cheap

Q Q

More expansive power plant ramped up in

  • rder to alleviate transmission line

More expansive power plant ramped up in

  • rder to provide reactive power

 Redispatch cost

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TU Dresden, Chair of Energy Economics, Fabian Hinz 7 06.09.2017

Future scenario 2025 4 Staus Quo 2014 3 Model Development 2 Motivation 1

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TU Dresden, Chair of Energy Economics, Fabian Hinz 8 06.09.2017

Redispatch cost calculated in a 3-step approach

Model approach

Step 1 Market model Step 3 Reactive power: voltage-induced redispatch Step 2 Real power: current-induced redispatch

  • Electricity market model (copper plate) for

Germany and neighboring countries to generate power plant dispatch

  • NTC-based trade between market zones
  • Only real power (P) dispatch

Reactive power behavior of 380 KV line

  • 100

100 200 300 400 500 600 500 1000 1500

Reactive power [Mvar] Line load [MVA]

Q_cap Q_ind Q_tot

Iterative calculation of quadratic inductive reactive power behavior

  • Estimation of current-induced redispatch based on

a transmission & 110 kV distribution grid model

  • Usage of ELMOD to calculate load flows, overloads

and least-cost redispatch

  • Penalty cost for international redispatch
  • Estimation of reactive power dispatch and voltage-

induced redispatch

  • Usage of ELMOD LinAC, a linearized AC model to

account for voltage stability and reactive power flows

  • Iterative approach to account for quadratic

reactive power behavior of electricity lines

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TU Dresden, Chair of Energy Economics, Fabian Hinz 9 06.09.2017

Redispatch models use linearized real and reactive power flow calculations

Simplified model formulation of redispatch models

1) Un / Um... Voltage magnitude at node n / m Θn / Θm... Voltage angle at node n / m gn,m / bn,m... Conductance / susceptance between node n and m

Target function Market model

Voltage-induced Redispatch Current-induced Redispatch

Restrictions 𝐍𝐣𝐨 ෍

𝒐∈𝑶

𝒅𝒑𝒕𝒖𝒐

𝒏𝒃𝒔𝒉 ∙ 𝑯𝒇𝒐𝒐 𝑸 − 𝒉𝒇𝒐𝒐 𝑸,𝒏𝒃𝒔𝒍𝒇𝒖

Thermal limit: 𝑴𝒋𝒐𝒇𝑫𝒗𝒔𝒔𝒇𝒐𝒖𝒎 ≤ 𝑼𝒊𝒇𝒔𝒏𝒃𝒎𝒎𝒋𝒏𝒋𝒖𝒎 Voltage TS: 𝟏, 𝟘𝟖 𝒒. 𝒗. ≤ 𝑽𝒐 ≤ 𝟐, 𝟏𝟒 𝒒. 𝒗. Voltage DS: 𝟏, 𝟘𝟓 𝒒. 𝒗. ≤ 𝑽𝒐 ≤ 𝟐, 𝟏𝟕 𝒒. 𝒗 𝑯𝒇𝒐𝒐

𝑸,

𝑯𝒇𝒐𝒐

𝑹

∈

GenP GenQ

Grid balance Real power: 𝑯𝒇𝒐𝒐

𝑸 − 𝑬𝒇𝒏𝒐 𝑸 = σ𝒏∈𝑶 𝒉𝒐,𝒏 𝑽𝒐 − 𝑽𝒏 − 𝒄𝒐,𝒏(𝜾𝒐−𝜾𝒏)

Reactive power: 𝑯𝒇𝒐𝒐

𝑹 − 𝑬𝒇𝒏𝒐 𝑹 − 𝑴𝒑𝒕𝒕𝒐 𝑹 =

σ𝒏∈𝑶 −𝒄𝒐,𝒏 𝑽𝒐 − 𝑽𝒏 − 𝒉𝒐,𝒏(𝜾𝒐−𝜾𝒏)

Iterative calculation

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TU Dresden, Chair of Energy Economics, Fabian Hinz 10 06.09.2017

Current and voltage are represented reasonably well by the redispatch model

Model quality of ELMOD AC and ELMOD LinAC

Current [A]

Comparison between redispatch model (ELMOD LinAC) and AC load flow model (ELMOD AC), Germany, 16 grid situations

1) Adjusted Mean Absolute Percentage Error: adjusted in relation to nominal voltage / thermal limit 2) On 380 kV level

Voltage [p.u.]

LinAC MAE RSME aMAPE1) I [A] 22.9 39.6 0.69% LinAC MAE RSME aMAPE1) U [kV]2) 2.0 2.5 0.53%

Good fit for current Reasonable fit for voltage

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TU Dresden, Chair of Energy Economics, Fabian Hinz 11 06.09.2017

110 kV grid set developed based on OSM data and other public sources

Data set for grid model Power plants / RES

Attribution to nodes

  • Plants: based on

addresses and coordinates

  • RES: based on OSM

data / RES database

Load

  • Attribution based on

GDP and population of surrounding area Nodes: ~5700 Lines: ~6500 Substations: ~370

380 kV 220 kV 110 kV

OSM data

  • Substations

380 / 220 / 110 kV

  • Electricity lines

380 / 220 / 110 kV

  • Nodes with

generation and demand

  • Auxiliary nodes
  • Lines start / end,

technical parameters updated with TSO static grid models

  • Transformers

380 / 110 kV 220 / 110 kV

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TU Dresden, Chair of Energy Economics, Fabian Hinz 12 06.09.2017

Future scenario 2025 4 Staus Quo 2014 3 Model Development 2 Motivation 1

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TU Dresden, Chair of Energy Economics, Fabian Hinz 13 06.09.2017

Good fit between congestions in model and reality

Congested grid elements: Model results vs. reality Model results 2014 Monitoring report 2014

Frequency of congested grid elements

  • Good fit between for

border areas to Poland, Czech Republic and Denmark

  • Fit for Remptendorf-

Redwitz line

  • Congestions in the

North West and Center not reliably recognized

  • Distribution grid

congestions in the North fit local curtailment compensation

Source: BNetzA Monitoring Report 2015

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TU Dresden, Chair of Energy Economics, Fabian Hinz 14 06.09.2017

Current-induced Current- and voltage induced

Taking into account voltage stability, redispatch patterns change

Results

  • Ramp-down of power plants in the North
  • Curtailment mainly in Schleswig-Holstein
  • Ramp-up in the South and Austria
  • Additional redispatch in the South to cover

reactive power requirements

  • Additional ramp-downs in the North

High load and high wind feed-in situation: current- and voltage-induced redispatch

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TU Dresden, Chair of Energy Economics, Fabian Hinz 15 06.09.2017

Reactive power from the 110 kV grid decreases voltage-induced redispatch cost

Redispatch costs 2014 in Germany

20 40 60 80 100 120 140 160 180 161.3 34.6 13.3 78.1 Cost p.a. [mio. EUR] with 110 kV sources

  • 13.4

(-8%) Current-induced Current- / Voltage-induced 35.3 78.1 35.4 113.4 174.7 17.1 35.4 78.1 44.1 Curtailment U Redispatch I Curtailment I Redispatch U

  • Redispatch and curtailment

cost is mainly current- induced

  • 8% reduction possible

through reactive power from the distribution grid Redispatch cost Germany 2014

  • Comparison of voltage- /

current- induced redispatch

  • Cost reduction potential

from 110 kV grid reactive power sources

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TU Dresden, Chair of Energy Economics, Fabian Hinz 16 06.09.2017

Future scenario 2025 4 Staus Quo 2014 3 Model Development 2 Motivation 1

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TU Dresden, Chair of Energy Economics, Fabian Hinz 17 06.09.2017

Market zone split decreases redispatch cost more than 110 kV reactive power

Redispatch costs 2025 under full grid extension, combined and split DE/AT market zone

106 105 103 102 244 241 347 293 278 322 346 307 304 308

  • 18

956

  • 23
  • 179

With 110kV sources 777 933 4 759 4 Status Quo With 110kV sources 4 4 Status Quo Int. redispatch AT DE PL CZ

Com- bined zone Zone split

  • Cost reduction potential through 110 kV sources increases
  • Overall reduction of redispatch cost through splitting of DE/AT market zone

Only redispatch cost! Additionally welfare effects on wholesale markets have to be considered! Redispatch cost 2025

  • Comparison of DE/AT market zone and split
  • Cost reduction potential from 110 kV grid reactive power sources
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TU Dresden, Chair of Energy Economics, Fabian Hinz 18 06.09.2017

Considerably higher cost under grid extension delay – savings potential increases

Redispatch costs 2025 under full and delayed grid extension

293 278 14 14 703 703 4 4 178 179 249 260 241 244 445 443 304 308 105 1,930 1,894 With 110kV sources 2,825 Status Quo

  • 23

1,659

  • 46

Status Quo 106 +1,166 1,636 With 110kV sources 2,779 Grid extension PL Int. redispatch AT DE CZ

Full grid extension 5 year grid extension delay

  • Considerably higher cost under grid extension delay
  • Under grid extension delay , the cost reduction potential from 110 kV sources increases

Redispatch cost 2025

  • Comparison of full and delayed grid extension
  • Cost reduction potential from 110 kV grid reactive power sources

Annuity @ 4% WACC + 2% O&M cost

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TU Dresden, Chair of Energy Economics, Fabian Hinz 19 06.09.2017

0.0 2.8 1.2 1.8 2.2 1.6 2.4 0.2 2.6 0.6 1.4 0.8 1.0 2.0 0.4 8 HVDC 1.65 7 HVDC 1.79 1.86 0.19 2.46 2.09 1.87 0 HVDC Delayed 0.34 0.43 1.37 1.61 1.55 0.70 4 HVDC 1.49 1.44 5 HVDC Full 0.79 1.31 6 HVDC 1.29 0.61 1.31 2 HVDC 3 HVDC 0.53 1.56 1.50 2.70 1 HVDC 1.60 1.68 Total cost [bn. EUR] 0.89 1.03 1.53 Grid extension cost Total cost - Market zone split Total cost - Market zone combined

Which degree of grid extension is economically reasonable?

Relationship between grid extension and redispatch cost Redispatch cost 2025

  • Alteration of grid extension level (# of HVDC links)
  • Comparison of total grid extension cost
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TU Dresden, Chair of Energy Economics, Fabian Hinz 20 06.09.2017

Conclusions

Key take-aways

  • Current- and voltage induced redispatch will play an

important role in future electricity systems

  • Usage of 110 kV reactive power sources can slightly

limit redispatch costs

  • Market zone layout has a much higher impact
  • Grid extensions required to impede extreme cost

increases – number of HVDC links in grid development plan seems reasonable

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Faculty of Business and Economics, Chair of Energy Economics, Prof. Dr. Möst

www.ee2.biz

Thank you for your attention!

  • Dipl. Wi.-Ing. Fabian Hinz

Chair of Energy Economics Faculty of Business and Economics TU Dresden Email: fabian.hinz@tu-dresden.de Phone: +49 351 463 39896