Dr Emil Hillberg has an international career within the power system area, including previous positions at ABB, SINTEF Energy Research, and STRI, in Switzerland, Norway and Sweden. Since March 2018 he is a Researcher in the field of power systems and high voltage technology at RISE – Research Institutes of Sweden. Emil is the Swedish representative in CIGRE Study Committee C4 on Power System Technical Performance, and is the Technical Lead of Annex 6 on Power Transmission and Distribution Systems within ISGAN (International Smart Grid Action Network).
Transcript
Dr Emil Hillberg has an international career within the power system area, including previous positions at ABB, SINTEF Energy Research, and STRI, in Switzerland, Norway and Sweden. Since March 2018 he is a Researcher in the field of power systems and high voltage technology at RISE – Research Institutes of Sweden. Emil is the Swedish representative in CIGRE Study Committee C4 on Power System Technical Performance, and is the Technical Lead of Annex 6 on Power Transmission and Distribution Systems within ISGAN (International Smart Grid Action Network).
RISE Research Institutes of Sweden
NEED OF FLEXIBILITY IN THE FUTURE POWER SYSTEMEmil Hillberg
September 2018
• An evolving power system• What is flexibility?• Flexibility aspects:
• Supply; Transfer; Demand; Storage; Market
• Summary
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Need of flexibility in the future power system
An Evolving Power System
Major trends influencing operation and planning: Increasing the maximum utilisation level Increased DG, new solutions for ancillary services
and market structures More and larger interconnections PE interfaced components taking over roles of
rotating machines
Challenges to maintain secure and stable operation: Identification of true operational state and limits New system and operational criteria Increasing need of information exchange Changed dynamic response
An Evolving Power System
Generator trip & Alteration of generator models
Pow
er p
rodu
ctio
n [M
W]
Time [s]
Synch. Gen.
SG decreasing droop & inertia
Static load – Const. PStatic load – Const. Z
An Evolving Power System Example: Changed dynamic response due to increased PE interfaced generation (Hillberg 2017)
How does a group of generators respond to a trip of a production unit in the system?
What is the system and local impact? How best to model a realistic behaviour?
Flexibility: How can PE interfaced generation best be
utilised to provide local and system wide support?
Flexibility – a buzz word?Focus clusters1. Power System Modernisation2. Security and System Stability3. Power System Flexibility4. Power System Economics & Efficiency5. ICT & Digitalisation of Power System
Topical subjects of all sessions• Innovative Components & Asset
Cities• Resiliency & Reliability• Digital Transformation, Artificial
Intelligence & Cybersecurity
ENTSO-E R&I roadmap 2017-2026 CIRED 2019
• Several definitions, Council of European Energy Regulators propose: • “Flexibility is the capacity of the electricity system to respond to changes that may
affect the balance of supply and demand at all times” (CEER 2018)
• Flexibility may be seen as having a two dimensions:• Technical capabilities - utilised for the grid (preventing congestions and supporting
voltage) and for the system (as reserves and for frequency support)• Commercial capabilities – transaction based on market requirement and
regulations
• Flexibility may be provided and handled by several parties. In the following we look deeper into the flexibility aspects from the perspectives of:
• Supply; Transfer; Demand; Storage; Market
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What is flexibility?
• Rationale: • Frequency stability, voltage stability, maximise RES integration
• Classical: • Dispatch of conventional generation, P / Q control for frequency & voltage
support• HVDC fast ramping
• Semi conventional:• RES dispatch• Increased operational flexibility of thermal units (min load, ramping, start-
up time…)• Novel:
• Increased flexibility regarding fault-ride-through-capability, where RoCoFrequirements are already increasing in some power systems (e.g. Ireland)
• System services from PE interfaced production, e.g. synthetic inertia, short-circuit currents, P / Q control
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Flexibility in Supply
• Example:• Providing primary frequency response with PV generation (Pourbeik
2017) • Utilising PVs at 90% of optimum providing reserves for frequency response
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Flexibility in Supply
• Rationale: • Increased transfer capacity (maximise utilisation of assets), prevent
• Semi-conventional:• Dynamic line ratings for OHL – to cope with increased RES and/or
increased demand• Novel:
• Time variable transfer tariffs to influence behaviour for preventing peaks • Dynamic ratings and seasonal limits for cables & transformers
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Flexibility in Transfer
• Example: • Dynamic cable rating (Perez 2017)
• Assessment of cable system temperatures to increase asset utilisation• Case study utilising air temperature to model the cable temperature • Dual cable ratings (seasonal) could be feasible, increasing flexibility in cable
utilisation (with typical load levels corelating with low ambient temperatures)
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Flexibility in Transfer
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Flexibility in Demand
• Flexibility in demand may be categorised as Explicit/controllable & Implicit/uncontrollable (Nordic Council of Ministers 2017)
• Semi-conventional / new storage solutions:• Mechanical (Flywheel), chemical (Battery, Fuel cell), thermal (Heat), …
• Novel:• Increased interaction between multi-energy carrier systems (electricity,
heat, gas …)• Ancillary services from battery storages and other type of storages
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Flexibility in Energy Storage
• Example: • Battery storage as virtual line to increase system security (Pahalawaththa 2018)
• Utilising a storage to provide energy to local load for a dedicated time period, in case of faulted transmission line
• Provides flexibility to utilise a transmission corridor to its “n capacity” (instead of up to n-1)
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Flexibility in Storage
• There is a need to have market structures suitable to handle flexibilities provided by different parts of the power system.
• An example of such market by NODES:
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Flexibility Markets
• Flexibility – a broad topic, with undefined extent• Solutions for secure operation and planning of the future
power system relate to flexibility in one sense or another • How will the future look?
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Summary
• Example: Global electricity network (CIGRE C1 2018)
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Summary
• Example: Global electricity network (CIGRE C1 2018)
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Summary
• Hillberg 2017: Analysis of dynamic aspects of the Continental European power system; Hillberg, Lindahl, Pinares, Segundo Sevilla, Korba, Uhlen, Sattinger; CIGRE Symposium Dublin 2017
• CEER 2018: Council of European Energy Regulators, Distribution Systems Working Group; Flexibility Use at Distribution Level - A CEER Conclusions Paper, Ref: C18-DS-42-04, July 2018
• Pourbeik 2017: Providing Primary Frequency Response from Photovoltaic Power Plants; Pourbeik, Soni, Gaikwad, Chadliev; CIGRE Symposium Dublin 2017
• Perez 2017: Dynamisk belastbarhet för jordkablar (in Swedish); Perez, Lennerhag; Energiforsk Rapport 2017:427
• Nordic Council of Ministers 2017: Demand side flexibility in the Nordic electricity market: From a Distribution System Operator Perspective, TemaNord, Nordic Council of Ministers, https://doi.org/10.6027/TN2017-564
• Pahalawaththa 2018: Battery Storage for Enhancing the Performance of Transmission Grids; Pahalawaththa, Kingsmill, Klingenberg; CIGRE Session Paris 2018
• NODES 2018: NODES - European Marketplace for Decentral Flexibility, available at: https://www.energinorge.no/contentassets/98d80fc7d5644904b6af3a37fb925d53/nodes-standard-presentation-v.2-with-ae-np-slides.pdf
• CIGRE C1 2018: Study committee C1 Tutorial on Global Electricity Network Feasibility Study, WG C1.35, CIGRE Session Paris 2018
This work is prepared if the framework of ISGAN Annex 6: Power Transmission & Distribution SystemsPromoting solutions to enable power grids to maintain and improve security, reliability and quality of electric power supply
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Acknowledgement
ISGAN is an initiative of the Clean Energy Ministerial and an IEA Technology Collaboration Program.The vision of ISGAN is to accelerate progress on key aspects of smart grid policy, technology, and investment
