Power systems with very large wind and solar …...SA Energy Storage 2017 Power systems with very...

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SA Energy Storage 2017 Power systems with very large wind and solar generation - what is needed for a stable and secure operation? Dr.-Ing. Markus Pöller - MOELLER & POELLER ENGINEERING (MPE) www.moellerpoeller.de/www.moellerpoeller.co.uk

Transcript of Power systems with very large wind and solar …...SA Energy Storage 2017 Power systems with very...

SA Energy Storage 2017

Power systems with very large wind and solar generation - what is needed for a stable and secure

operation?

Dr.-Ing. Markus Pöller - MOELLER & POELLER ENGINEERING (MPE)

www.moellerpoeller.de/www.moellerpoeller.co.uk

Phase 1 – First VRE installations

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Phase 2 – VRE noticeable at system level

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Phase 3 – Flexibility becomes a priority

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Flexibility issue

Phase 4 – (Frequency) Stability becomes an issue

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Stability limits

Large flexibility requirements

Phase 4 – with Storage

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stability limitReduced flexibility requirements

The four phases of VRE deployment

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Phase 1:

First installations

Phase 2:

VRE noticeable at system

level

Phase 3:

Flexibility becomes relevant

Phase 4:

Stability becomes relevant

• VRE not noticeable at system level

• System operations not affected

• Only local grid issues

• VRE becomes noticeable to the system operator

• VRE forecast should be introduced

• VRE has impact on power plant dispatch (electricity market)

• Power plant dispatch highly influenced by VRE

• VRE forecast essential

• VRE must contribute to ancillary services

• Flexible, dispatchable power plants are required

• All dispatchable power plants must be flexible

• System characteristics are dominated by VRE

• VRE limited by stability constraints

According to: IEA: Getting Wind and Sun onto the grid – A manual for policy makers

Potential flexibility issues in systems with high VRE

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Variability

Increased number of start-

ups

Increased number of load

following ramps

Lower minimum stable

point of operation

Increased Operating

Reserve Requirements

Flexibility issues and solutions

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Variability

Increased number of start-

ups

Increased number of load

following ramps

Lower minimum stable

operating point

Increased Operating

Reserve Requirements

Short-term storage

(E/P=1-4h)

Mid-term storage

(E/P=1-4d)

Flexible power

plants

VRE contribute to

Operating Reserve

Demand Response

Flexibility Requirement Flexibility Resource

Stability - Systems with large VRE share – What’s different?

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GGVRE

VRE VREVRE

Non-synchronous generation

Remote location

Lower voltage level

G

Potential stability issues in systems with high VRE

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Non-synchronous

generation

Remote locations/lower

voltage levels

Reduced inertia

Reduced voltage support

Reduced synchronizing

torque

Reduced contribution to

short circuit currents

Stability issues and solutions

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Non-synchronous

generation

Remote

locations/lower

voltage levels

Reduced inertia

Reduced voltage support

Reduced synchronizing

torque

Reduced contribution to

short circuit currents

Short-term storage

(E/P=1-4h)

Mid-term storage

(E/P=1-4d)

Synchronous

Condenser

MSC/SVC

STATCOM

Stability Issue Mitigation Option

And beyond phase 4?

Phase 5 is characterised by occasional excess of VRE generation

Mid-term storage required for avoiding PV and wind curtailments.

Phase 6 is characterized by (almost) 100% VRE

Long-term storage (E/P>1 month) is required for compensating monthly/seasonal

variations of wind and PV

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Short-Term Storage (E/P=1-4h, e.g. super-caps, flywheel, battery):

Provision of fast (enhanced) frequency control

Provision of Instantaneous Reserve

Provision of Regulating and 10-Minute Reserve

Mid-Term Storage (E/P=1-4d, e.g. battery, flow battery, pumped-hydro):

Increases the minimum level of synchronous generation in the system, which

mitigates numerous stability issues.

Reduces flexibility requirements of dispatchable power plants (ramping, start-ups)

Can contribute to the equivalent firm capacity (Capacity Credit)

Long-Term Storage (E/P>1month, e.g. hydrogen, methane):

Balances long-term (weekly/monthly/seasonal) variations of VRE

Mandatory required in systems with (almost) 100% VRE

How storage supports systems with large share of VRE

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Today’s applications in e.g.

U.K. or Germany

Summary

Flexibility can be provided by:

Flexible power plants (e.g. gas turbine generators)

Demand response

Storage

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The future power system needs flexibility

Storage can provide flexibility and stability