“German Experience on High Penetration through · PDF file“German Experience on High Penetration through Renewables-Challenges for ... synchronous condenser Reactive power

siemens.com/power-technologies© Siemens AG 2015 Alle Rechte vorbehalten.

“German Experience on High Penetration through Renewables -

Challenges for System Stability”

Dr. Edwin Lerch, Siemens AG, EM DG PTI PSC DYS

E for E Seminar, Bangkok, August 2016

© Siemens AG 2015 Alle Rechte vorbehalten.Seite 2 Dr. Edwin Lerch/EM DG PTI PSC DYS

Content

Global trends in the development of electrical systems

Generator and grid stability

The role of renewables in the future

Actions to be taken

Outlook


Global developments until 2030

1 % Population Growth per year

3.0 % average Economic Growth per year

2.8 % average increase in power demand per year

in industrialized countries (OECD Countries) app. 1.3 % per year, additional power demand of 37 % by 2030 in total

developing and emerging countries more than 4.0 % per year,power demand of more than 250 % by 2030 in total


Developments in power generationGlobal Tendency: Renewables become an important share of generation of the future

Installed Capacityin Gigawatt

21%16%20%

6%37%

1990

19%13%

27%7%

34%

2000

14%

7%

44%

9%

29%

2030

Western EuropeEastern Europe / CIS

Asia / Pacific

Africa / Middle East

Americas

Regionally

2,8353,620

8,800

12%17%15%

32%1%

23%

1990

10%22%14%

30%2%22%

2000

8%

26%

5%

29%

14%

18%

2030

Nuclear

Gas

Oil

Coal

By Energy Sources

2,8353,620

8,800

HydroRenewablesOther

Source: Siemens Energy, E ST MOP 3 - 2008


Development of renewable generation in IndiaRadical new generation approach

Gen. Capacity 2016: 303 GW, 1106 TWh, peak deficit up to 10%

Growth 8 % / a, necessary generation capacity 2017 up to 440 GW

Wind generation 26.8 GW, PV 6.7 GW

3433 MW added wind power capacity 2015-2016

3019 MW added solar power capacity 2015-2016

31472 solar pumps installed 2015-2016

Target : >5 times increase in renewable power to 175 GW by 2022 (28%)


Development in power generation Generation mix

SPP

Cost, efficiency and environmental concern drive technology development

Strong development in non-OECD

CCPP/SCPP

Efficiency improvement

Carbon capture technologies

Key solution to firm the intermittency of RES

Solar

PV, c-Si dominant and new technologies emerging

CSP heat transfer innovations

Wind

Strong market growth, China US as leaders

Technology innovations (direct drive; blades)

Others

i.e. Ocean power (tidal and wave power)

Hydro

Two types of technologies with steady growth

Strong development in China and Brazil

CCPP = combined cycle PP SPP = small PPSCPP = simple cycle PP CSP = concentrating solar power


ENTSO-E – the European Grid Organizationsince 2009 – under one common grid code

since 2010


German electric power supply system (614 TWh)Key data and selected issues – Transmission bottlenecks

Key data of German power system Peak demand 2014 80,000 MW Installed capacity 2014 194,000 MW Gas 15 % conventional 55 % Hard Coal 11 % Lignite 11 %

Wind 18 % (0.3 %) renewable 45 % PV 20 %

Supply non-availability 20.4 min/a 2014 renewables 25,3 % of energy generation To be built, 2014 – 2018 6,500 MW To be rebuilt 2014 – 2018 11,800 MW

Transmission bottlenecks North-South East-West International interconnections


Motivation, Targets and Challenges to rebuild the GermanPower System (“Energiewende” energy turnaround)

Motivation: Replacement of fossil sources by renewable source

Reduction of CO2

Retirement of NPP‘s (Fukushima 2011)

Targets: Co2 reduction 80 % until 2050

Retirement of NPP‘s until 2022

Stake of renewables 45 % (2020) and 70 % (2040)

Challenges: Maximum utilization of renewables (potential, storage, losses)

Balancing of fluctuating sources by conventional power plants


Developments in power generation Trends in Europe

NET ELECTRICITY GENERATING INSTALLATIONS IN THE EU 2000-2014 (MW)

Source THE EUROPEAN WIND ENERGY ASSOCIATION, WIND IN POWER, 2014 EUROPEAN STATISTICS, February 2015


Development of Renewables in Germany

Installed capacity PV

PVWind onshore Wind offshore

Wind onshore Wind offshore

peak load Germany: ca. 80 GW (constant)Expected load until 2025

energy demand Germany 2011: app. 600 TWh (constant)Expected energy until 2025

installed 2020:Wind PV

51,0 GW + 51,7 GW∑ 102,7 GW

harvest 2020:Wind PV

138,8 TWh + 54,2 TWh∑ 193 TWh

:Wind on-shore 2000kWh/kW ->3000kWh/kW

Wind off-shore 4000kWh/kWPV 1000kWh/kW


Predictability and Dynamics of Wind PowerExample: Vattenfall Europe

Windpower infeedLoad

12000

03/020

8000

4000

10/02 17/02 24/02

Powerin MW

Wind Power forecast

Error: -60%Error: +280%

Source: IfR, TU-Braunschweig, Vattenfall Europe Transmission, Feb. 2008


Wind and PV infeed in Germany in 2011/12Time period 01.10.2011 to 31.03.2012

Source: EEG/KWK Transparenzplattform der ÜNB

peak PV peak wind

wind

PV


Grid stability

Stability of generators after disturbances

Interarea oscillations

Frequency behaviour after generation outages

Balancing of frequency

Primary reserve stability

Voltage stability

Bottlenecks in transportation


Inertia – Key parameter of system stability

TS = 2·XG·2HU2· N

K= f (machine param.)2·HdS =

G1G2

PL1=0

PG1

XL=0

QG1=0 SG2>>SG1H1

XG=Xd=Xq

SG1

U oscillation time

oscillations damping

Oscillation time depends on H, not on PG or SGOscillation damping depends on HTypical oscillation frequency 0.7 – 1.3 Hz (f = 1/T)


System behavior after outage of generation

50

49

∆fs

app. 5 s

dtdPP

PHff

r

rd

22

2

r

r

PP

Hftf

2

/

fr grid frequency (Hz)H system inertia (MWS/MW)ΔP power lost (MW)Pr total power (MW)dP/dt activated reserve power (MW/S)


Inter-area oscillation through system growth

0.1 to 0.5 Hz large inter-area in both systems

weak coupling

interarea oscillations

local modeIn system 1

local modein system 2

Interarea modesystem 1 and 2


Primary Control Reserve in ENTSO-E(to cover outage of 2 NPP at one location)


Wind Power Incidents in China

Wind Power Incidents in China

80 trip incidents In 2010, (15 resulted in the loss of 100 MW to 500 MW)*

193 turbine trip incidents in 2011, (54 resulted in the loss of 100 MW to 500 MW)*

* Wind Power Incidents in China: Investigation and Solutions Ming, Xue Song, Li Ling-yun, Cheng Huan, and Zhang Ge, School of Economics and Management, North China Electric Power University

“Offshore windfarms 'wild west' of renewable energy”

The Guardian


Inter-Area Oscillations in Central Europe


Voltage Stability Former NPP ‘Biblis A’ became synchronous condenser Reactive power to support voltage profile and voltage stability

Biblis A nuclear power plant shut down after Fukushima incident Generator 1,500 MVA

Modification into synchronous condenser Largest synchronous motor worldwide Reactive power support from -400 to

+900 MVAr Commissioned in February 2012


Synchronous condenser supports voltage profileOperation of synchronous condenser Biblis A 13. to 19.03.2012

Volta

ge a

t Bür

stad

t 400

kV

subs

tatio

n

underexcited during

weekend and night

Reactive

power

output

reactive power

voltage


Predictability and Dynamics of Solar Power

Source: Michael Weinhold & friends

Sunny Day, April: 1,9 MWh

Cloudy Day, April: 1,2 MWh


Solar eclipse March 2015

Load and PV forecast normal Load and PV forecast during SOEC

Netzlastverlauf

PV-Einspeisungwolkenlos

PV-Einspeisungbedeckt

00:00 03:00 06:00 09:00 21:0018:0015:0012:00

PV-Einspeisungwolkenlos

PV withclouds

00:00 03:00 06:00 09:00 21:0018:0015:0012:00

Netzlastverlauf

forecast

load load

PV without clouds PV without clouds

PV with clouds


Destabilization of grid frequency by renewables

large penetration by renewables → destabilisation of frequency stability

No share of synchronizing torque → ROCOF (rate of change of frequency) is

increasing

Normal value < 0.5 Hz/s

Expected up to 1 Hz/s (today), up to 3 Hz/s (in the future)

reasons:

- underexcited operation of PP‘s with low load

- airgap torque very small

- large ROCOF are combined with large oscillations

- less generation with full load instead of many generators in part load (H reduced)


Dec. 2014 grid instability in Ireland by 37 % wind(part load → full load (H = 2 sec)

Source: Uni Rostock


Dena* Investigation: Necessary primary reserve

alternative sourcesconventional

*German Net Agency


Elimination of conventional power plantwinter scenario

Quelle: Uni Rostock



Quelle: Uni Rostock



Quelle: Uni RostockOverflow of production



Quelle: Uni RostockOverflow of production


2016, May 15: Marking a milestone for chancellorAngela Merkels ‚Energiewende*‘ - policy

May 8 clean energy 95 % of power needs

May 15 clean energy (wind & solar) met pretty much 100 % ofGermany‘s power needs (45.8 GW)

• for several 15 min power price turned negative (57 $ / MW)

• Commercial customers were being paid to consume electricityfor few hours

Power system still to regid for suppliers and consumers to respond quicklyto price signal

*Energiewende: energy turnaround


Highly efficient Combined-Cycle Power PlantIrsching 4 will be retiered?

ƞ= 60,7 %world record 2011

Perspective 2015 (E.ON): „the economic perspective of the plant is very critical“


Ancillary services for system operation and stabilityAll parties involved have to contribute

frequencyvoltage supply operation

• reactive power

• voltage

• power

transportation

• power control

• re-dispatch

• primary

reserve

• black start

capability

• congestion

management

• monitoring

• generation

management

• DSA / PSA

• adjust market for renewables to support ancillary services• coordination between all parties concerned• guaranty of profitability for all parties• timely requirements are necessary

What isnecessary?


Technical Capabilities of Offshore Wind Farms for the Provision of Ancillary Services


Technical Capabilities of Offshore Wind Farms for the Provision of Ancillary Services

The Future: Synthetic Inertia Capability

power of WF

breaking energyfrequency

wind energy

ancillary energy


Solar Inverter

Central Inverter

Parallel PVs are connected to the same DC input of the central inverter

(high efficiency, low losses) ↔ reliablity depending on power of working PV cells)

String Inverter

Modularization by parallel strings: max. power tracking peak at DC side

grid-tied at AC side

Advantage: decoupling of modules and shadow

high reliability

master-slave concepts

team concepts


Power Electronics for grid-connected PV systems

PV arrayBoostDC-DCconverter

Ipv Pac

DC Output~Vpv

single-phaseDC-ACinverter

Pac(t) iac

> >> >Vpc

energystorage

PV set pointto MPP

generateiac in phasewith Vac

Operate PV array at MPP

Generate AC output current in phase with AC grid voltage

Achieve high power conversion efficiency

Provide energy storage to balance difference between Ppv and pac(t)


From PV array current to Ppv

Source ECEN2060

depending on sun intensive and temperature

adjust Ipv = Iref to operate at MPPPV converter operates as CCI (current controlled inverter)


Comparison of synchronous generators and inverters


The „electrical meaning“ of inertia


Proposed frequency controller for VCI‘s


Simulations – Mixed Scenario


50.2 Hz Problem in Germany

• Problem:

PV converter are disconnected at 50.2 Hz (grid wide)

With 25 % PV disconnected suddenly high risk of black out

• Countermeasures

Change of converter >10 KW (LV), >30 KW (MV)

Change of power generation by PV plants between 50.2 – 51.5 Hz with 40 % gradient reduced /increased (droop characteristic)


Challenges for all parties concerned

Storage- realistic solutions: gas storage, LNG - decentralized solutions today available- combination of wind power and pump storage plants- storage of energy at wind generators (DFIG with capacitor banks)

Stability- limited by inertia of conventional plants- faster control (FACTS, faster and more flexible conventional plants)- renewables with virtual inertia- power electronic (PE) with inherent ‘inertia’ / current source control -> voltage source control

Fluctuation- stress, wearout and high dynamic (conventional and renewable plants)

Frequency gradient- 0.5 Hz/s – 3 Hz/s acceptable for the grid? → countermeasures through PE


Challenges for all parties concerned

Ancillary services• are necessary from all parties concerned

System dynamic• lifetime reduction – intelligent maintenance concepts• more flexible power plants• faster reaction• part load operation• more start/stop cycles• faster start up (Irsching CCPP warm startup to 100 % in 30 min)• new concepts (CCPP, single shaft with couplings between turbines and generators)

Operation, Monitoring• more flexibility (LV transformers with on-load tap changer)• fast re-dispatch• more information are necessary• PMU monitoring (and control)• DSA for operation at the system stability limits


Net Metering in Germany

Two meters (infeed, consumption) or bi-directional meter

Often not attractive as feed-in-tariff, depending on solar intensity and capital amortization

Actual market price not easy to calculate depending on power consumption under different customer profiles

Typical price per kWh 28.7 ct

Infeed compensation tendency(<30 kW):

<2009 50 ct/kWh

2010-2012 39-24 ct/kWh

2016 13 ct/kWh


The future of renewables in Thailand (1)

Bangkok Post April 2016:

- Solarelite plans 15 PP‘s concentrating solar power (135 MW)

- Farm cooperatives have won the right to sell 280 MW of solar power to the national grid

- 167 cooperatives to enter lucky draw (835 MW) – restricted supply infeed capacity

„The day when even small households households will be able to sell the solar power theygenerate back to big power companies and the government, and make a profit from it, isfast approaching“

2005 2007 2009 2011 2013 2015

24 MW 32.5 MW 43.2 MW 243 MW 823 MW 1330 MW


The future of renewables in Thailand (2)

“During my term of office as the EGAT Governor for 1 year and 10 months, I will focus on community development to show that power plants can stay with the communities in harmony. At the same time, I will develop renewable energy to the full extent of its potential together with coal power to balance the energy use, strengthen power security, and maintain proper cost of electricity for the competitiveness of the country with the concern on global warming solutions” (Mr. Kornrasit Pakchotanon, July 1, 2016)


Economic consequences following the „Energiewende“ (energy turnaround)

e.on (German TNO) worth 100 billion $ before the turnaround 2011

worth new 20 billion $ !

Do not under-estimate the speed of change from a classical energy system

to a system with high penetration of renewables

with all technical and economical consequences


The future are renewables

When we stop and control the challenges power systems with high penetration of renewables

can be operatedsave and reliable


Thank you very much for your attention!

Dr. Edwin LerchPrinciple Expert System DynamicEM DG PTI PSC DYS, Siemens AG

Head of “Grid Control and System Guidance” VDE association, Germany

Tel.: +49 (9131) 7-34052Fax: +49 (9131) 7-35159Mobil: +49 (171) 7682176

E-Mail: [email protected]


Thailand: Power Generation Capacity (2012)

Fossil Fuel 28 GW

Hydro Plants 3.4 GW

Hydro Import 2.2 GW

Renewables 2.8 GW

Biomass 1.96 GW

Solar 0.39 GW

Wind 0.11 GW

Small Hydro 0.1 GW

→ PV Roof top Program 2013

Solar Power Target 2036 6 GW (2013 - 0.7 GW, 2015 - 2.5 GW)


Solar Potential and PV Development in Thailand

• 14 % of the country has solar exposure of 20 MJ/m2/day

• 50 % of the country has solar exposure of 18-19 MJ/m2/day

• Bangkok 5.04 h of sun per day

• 2015 adder schema replaced by feed-in tariff (new 1000 MW potential)

PV Development

2005 2007 2009 2011 2013 201524 MW 32.5 MW 43.2 MW 243 MW 823 MW 1330 MW

On-grid 1299 MWOff-grid 30 MW


Map of Renewable Energy Power Plant in Thailand


Net Metering

• Allows consumers who generate some (or all) of their own electricityto use it anytime instead of when it is generated

• Meter works in 2 directions (measure power purchase larger power production or measure power return to grid (customer pays thenet of both directions)

• Originated in the US (small wind turbines, small PV plants)

• Used in UK, Canada, Philippines, Brazil, Australia, Denmark, Italy, Spain…


Net Metering

• Controversy of different interests

• Benefits of distributed energy overweights in costs

• Shared by all ratepayers

• Reduces needs of centrelized power plants

• Grows of rooftop solar

• Social benefits

• Owners of generation system do not pay the full cost of service to use the grid

• Shift of generation owner shares to customers without distributed generation (paid by other users)

• Solar rooftop owners still rely on the grid to receive electricitywhen generation is not available


Net Metering

Different tariffs

Feed-in-tarifs above retail, reduces to retail as the percentageof adopters increase

Net-metering at retail, not technically compensatedmay become compensated if there is excessgeneration and payments are allowed by utility

Power purchase agreement compensation below retailcan be above (solar at peak load conditions)

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“German Experience on High Penetration through · PDF file“German Experience on High Penetration through Renewables-Challenges for ... synchronous condenser Reactive power