Does a Smarter Power Grid Really
Matter Anyway?
… A Reflection of Challenges Experienced in the UK
Professor William Hung
MBA, PhD, BSc, CEng FIET
Director/WH Power Systems Consultant Ltd
Honorary Professor/ University of Warwick
Technical Director/ Cardiff University
University of Warwick School of Engineer Seminar - 29 January 2016
Presentation Overview
• Development of Electricity Supply Industry in the UK
and its implications on Key Stakeholder relationships
• Review of frequency control issues
• Collaborative effort between stakeholders since
privatization
• Future Challenges in a Low Carbon Economy
• Contributions not only from a smarter grid but smarter
demands
• Extension of Stakeholder Engagement Activities
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2
Electricity Supply Industry – Key Stakeholders
Generating
Companies
Transmission
Companies
Suppliers
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Distributors
10/15/2015
3
Changes in the UK Electricity Supply Industry
• Privatization – 1990
• Dash for Gas – around 1993
• Liberalization of electricity market - 1999
• NETA- March 2001
• Dash for Wind – ROC payment -2002
• BETTA- April 2005
• EU Large Combustion Plant Directive
• Renewable Obligations
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Implications on Key Stakeholders Relationship
• Change of industry structure and generation mix - significant
implications on system security from a frequency control
perspective.
• From separation of Generation and Transmission businesses
after privatization, to dash for gas then for wind and finally
the renewable obligations challenges, National Grid in the UK
has worked closely with key stakeholders to ensure the
transmission Licence obligations are met.
• Be transparent and share concerns with relevant stakeholders
in a timely manner to seek collective resolution options
• Developing financial incentives to reward service providers
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Frequency Control Issues
• Frequency control requirements
• Nominal level: 50Hz
• Statutory limits: +/- 0.5 Hz
• Operational limits: +/- 0.2 Hz (standard deviations 0.07 Hz)
• Cover instant generation loss was up to 1320MW
• Avoid automatic load disconnections
• Above 48.8 Hz
• If triggered - could be up to 9 stages and 60% load disconnection
• System needs responsive and flexible plant
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Typical Frequency Incidents
50.10
Note:
On this occasion
Gas Turbines started
at 12:29:20
50.00
49.90
49.80
49.70
49.60
49.50
Primary Response 0 - 30 secs
freqcont.ppt 009 24/02/99
12:29:00
12:26:00
12:25:00
12:24:00
49.20
12:28:00
Secondary Response 30 secs - 30 mins
49.30
12:27:00
49.40
Frequency Control Analogy
Frequency Control/ Wheel Pulling Analogy
Generators
Vehicles
Frequency
Demand level
Load variations
Wheel speed
TV pickup
Largest generation loss
Blackout
Big rock
Slope gradient
Bumpy road
Largest truck stalled
Wheel run away
Improve Frequency Service Provision
after Privatization
• Define frequency services
• Primary, Secondary and High Frequency Response services
• Establish payment mechanism
• Establish contract format
• Validate plant capability through dynamic plant testing
• On-line monitoring – gain confidence on service delivery
• Enhance Grid Code minimum technical requirements
• Liaise with main plant suppliers to improve plant/control design
• Collaborate with Generators to improve plant performance
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Plant Response (MW)
Frequency Change (Hz)
Primary & Secondary Responses
-0.5 Hz
S
P
10s
30s
time
30 min
Plant Response (MW)
Frequency Change (Hz)
High Frequency Response
+0.5 Hz
H
10s
time
Frequency Response Contract Format
On-line Monitoring
• Feedback to System Operator
 Confirm contracted level of delivery
 Improve confidence level in service despatch
 Optimise frequency response service cost
• Feedback to Generators
 Improve plant performance, if required
 Increase incentive for plant control improvement
 Gain confidence level in service delivery
• Evidence to support frequency incident investigations
On-line Monitoring - Example 1
50.3
490
450
50
440
49.9
430
49.8
420
410
49.7
49.6
400
17:44:00
17:43:00
17:42:00
17:41:00
17:40:00
17:39:00
17:38:00
17:37:00
17:36:00
17:35:00
17:34:00
17:33:00
17:32:00
17:31:00
17:30:00
17:29:00
17:28:00
17:27:00
17:26:00
17:25:00
17:24:00
17:23:00
17:22:00
17:21:00
17:20:00
17:19:00
17:18:00
17:17:00
17:16:00
17:15:00
17:14:00
17:13:00
TARGET FREQ
FREQUENCY
EXPECTED RESPONSE (MW)
CAPPED COMMITTED LEVEL (MW)
GENSET OUTPUT
17:12:00
17:11:00
17:10:00
17:09:00
17:08:00
17:07:00
17:06:00
17:05:00
TIME (GMT)
FREQUENCY (Hz)
470
460
50.1
GENSET ACTIVE POWER OUTPUT (MW)
On-line Monitoring - Example 2
Coal Station 4, 28-Aug-2003
480
50.2
Low Frequency Automatic Demand
Disconnection Incident - 27th May 2008
38500
37500
19:50:00
19:52:00
19:54:00
19:56:00
19:58:00
20:00:00
20:02:00
20:04:00
20:06:00
20:08:00
20:10:00
20:12:00
20:14:00
20:16:00
20:18:00
20:20:00
20:22:00
20:24:00
20:26:00
20:28:00
20:30:00
20:32:00
20:34:00
20:36:00
20:38:00
20:40:00
20:42:00
20:44:00
20:46:00
20:48:00
20:50:00
20:52:00
20:54:00
20:56:00
20:58:00
21:00:00
21:02:00
21:04:00
21:06:00
21:08:00
21:10:00
21:12:00
21:14:00
21:16:00
21:18:00
21:20:00
21:22:00
21:24:00
21:26:00
21:28:00
21:30:00
21:32:00
21:34:00
21:36:00
21:38:00
21:40:00
21:42:00
21:44:00
21:46:00
21:48:00
21:50:00
21:52:00
21:54:00
21:56:00
21:58:00
22:00:00
Demand MW
TV Pick-up – Football World Cup
England ‘v’ Sweden (20th June 2006, 8pm)
Demand 20 June 2006
England vs Sweden
39500
20th June 2006
Half time
1800MW
37000
30th May 2006
39000
Half Time
1800MW
38000
Full Time
1600MW
Full-time
1600MW
36500
36000
Time (Local)
TV Pick Ups met using combination of coal plant,
French Interconnector & pump storage hydro
TV Pick-up – TV Soaps 25th April 2005
The more popular the TV programme, the larger the MW pick up
Dash for Gas
• CCGT were traditional designed for full load operation
not for flexible operation
• The perception was CCGT could not provide frequency
response… it would rack the turbine
• Offered service price were 8 times higher than
conventional plant
• Falling power/ falling frequency issues
• Could CCGT be exempted for frequency response
service? No but Why?
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Plant Response Capability/Flexibility
- 15% Response Capability
Impact of poor response and inflexible plant on Grid operation
a) For responsive generators, five are required to cover the loss of one generator
60
Generator
Rating55 x
x 100MW
Generator
Rating
100MW
Primary
Response44 x
x 15MW
= 60MW
Primary
Response
15MW
= 60MW
60
60
300 MW
Load
60
60
Plant Response Capability/Flexibility
- 10% Response Capability
Impact of poor response and inflexible plant on Grid operation
b) For less responsive generators, six are required to cover the loss of one generator
50
Generator Rating 6 x 100MW
Primary Response 5 x 10MW = 50MW
50
50
300 MW
Load
50
50
50
Dash for Wind
• Traditionally wind turbines were distribution connected
• Generally smaller size units
• Not designed for ridding through system fault disturbances
• ‘If in doubt, trip it out’ were the design concept
• The successful integration of large volume of wind farm
connections to the Grid will require the review of wind turbine
design by the manufacturers, eg
• Fault ride through capability
• Frequency and voltage control capability
• DNO will have to strengthen the minimum technical
requirement of their connected plants
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Stakeholders’ collaborations
• Visited major wind turbine manufacturers to clarify the minimum technical
requirements for wind turbine connection to the system
• Made aware of the issues to the Industry in particular the Generation community
• Worked with DNOs to enhance their Technical Codes for connection of the smaller plant
• Campaign for minimizing the impact of small embedded generation on Transmission
System performance had been a long and steady process
• First wake up call - The UCTE incident of splitting the European Network into 3 islands
and pre-mature tripping of large volume of embedded plant had helped the campaign
to drive home the message
• Second wake up call was in the UK where the frequency went down to 48.8 Hz leading
to automatic demand disconnections. Large volume of embedded generation was lost
due to weakness in the Distribution Code.
• The above had helped in strengthening the Distribution Code to ensure small embedded
plants are resilience to system disturbances
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Drivers for Renewable Obligations
Greenhouse gas emissions - reduce by at least 80% below an agreed 1990 baseline by 2050
UK Energy Landscape is Changing
A balance of energy trilemma of security of supply, affordability and sustainability
The Network Challenge: Electricity Transmission
~75GW
2010
2020
~110GW
Gas CCGT
Coal
CCS
Nuclear
Wind
Renewable
Interconnector
CHP
Other
The Changing Generation Mix
2020:
Total Connected Generation (GW)
 28GW of wind plus 9GW of
hydro, tidal, biomass
40
 11GW nuclear available post
2.5GW of closures and 3GW
new build
35
30
20
 Demand remains flat - growth is
offset by energy efficiency and
smart metering
15
 15 GW of embedded generation
10
2050:
GW
25
 30GW of nuclear now provides
majority of baseload generation
5
0
rs
e
2050
o
ct
ne
l
ab
2030
on
rc
w
ne
Re
2020
te
In
er
th
d
in
S
r
ea
cl
Nu
O
W
CC
as
al
Co
G
2010
 Increased demand with
electrification of
 Transport (mainly during
2030s)
 Heat (growth from 2020)
Further Frequency Control Challenges
• Closure of flexible and responsive plant (eg conventional coal, gas and oil stations)
• New plants are less flexibility and less responsive (eg clean coal, supercritical boiler,
IGCC, CCS, new nuclear)
• Domination of wind farms – intermittency issues
• Reduction of system inertia and increase of ROCOF risks – significant cost implications
• Secured generation loss – increased to 1800 from 1320 MW
• Significant increase of small embedded generation – less robust and invisible to
System Operators
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Forecast of RoCoF up to 2020
GCRP WG
Traditional RoCoF protection setting of 0.125 Hz/s but proposed to change to 0.5 then 1 Hz/s
Transmission reinforcement alone
is not sufficient …
Maximising capacity with smart..
..Meters
An informative
display showing
energy utilisation
and cost
Increases consumers’
sensitivity to energy prices
and thus reduces demand.
..Grids
Automation and
efficient use of
network systems
Facilitates network flexibility
in a complex generation
pattern
Automation of loads in
industrial plants,
commercial buildings,
superstores and home
Facilitates demand side
response in a world of more
inflexible generation
..Demand
Flexing generation to
meet demand
Flexing demand to
meet generation
Smart Demand meets Smart Grid Objectives
Smart Grid = Paradigm shift in providing flexibility
From redundancy in assets
to more intelligent operation
through incorporation of
demand side and advanced
network technologies in
support of real time grid
management
Dynamic Demand and Active Demand Side Management
Source-HiDEF
Electrification of Transport and Heat
Pump Sectors
Value of Smart Demand – equivalent to a saving
of almost 40GW of installed generation capacity
Source-HiDEF
Smart Fridges/Freezers – Displacing Power Stations
Wind penetration
Low
High
Cost savings £/FF/10yr
10-30
40-90
CO2 savings kg/FF/yr
15-30
30-50
Source-HiDEF
…Smart Fridges/Freezers – could help
to limit frequency fall
Source-RLTec
Active Demand Side Management –
Offset Wind Intermittency
Water
Heater
HVAC
Generation flexibility
High
Low
Cost savings £/kW/10yr
3-15
75-100
CO2 savings kg/kW/yr
<50
100-250
Source-HiDEF
Widen Downstream Stakeholder Engagement
• The growth of Demand Side Response (DSR) has been
slow for years and potential service providers were not
forthcoming
• The recent campaign led by the Grid Company is to
provide greater clarity
• Hopefully, the raise of profile in the DSR
communities will ensure DSR is a long term
investment proposition
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Future Electricity Supply Industry
Generating
Companies
Transmission
Companies
Suppliers
Distributors
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Operating the System in 2020
Active Distribution
Networks
Variable generation
Synthetic inertia
Smart Grids
& meters
Variable generation
Distributed generation
Inflexible generation
Demand
Active Demand
60
1800MW loss risk
Variable generation
Electricity Demand (GW)
55
50
Peak Commuting Time
Large generation
Peak Commuting Time
Generation
ROCOF &
Robustness
issues
2020 Demand ~ 15
GWh (daily) - 1.5
million vehicles
45
Optimal Charging
Period
Typical winter daily
demand
40
12,000 miles p.a.
35
Time of Day
How to meet these challenges in the most economic and
sustainable way whilst maintaining security of supply?
21:00
22:00
23:00
19:00
20:00
15:00
16:00
17:00
18:00
11:00
12:00
13:00
14:00
09:00
10:00
06:00
07:00
08:00
02:00
03:00
04:00
05:00
00:00
01:00
30
Time of use
tariffs
New Technology - to Make It Happen
New technology is required to evolve the Transmission network and enable
renewable generation
HVDC
Smart Tools

VSC Technology is still developing

Wide area monitoring to control power flows

2-3 year lead times for the larger cables

Dynamic circuit rating to manage constraints

Multi terminal HVDC has very limited operational
experience

Special protection schemes to facilitate additional
generation

Control system optimisation

Automated control to manage complex networks

Sub-synchronous torsional interaction (SSTI)

Congestion management control

Opportunities to implement demand side
management
Series capacitors

Review of protection settings

Sub-synchronous resonance (SSR)

Employed to control stability
All this has been used elsewhere, but not together in a densely meshed network
What is a Smart Grid?
 Smart meters
Customer Focused
Tools to engage consumers
with energy efficiency
 Improved information and awareness
 New energy services and tariffs
 Home automation & Demand response solutions
 More engaged, more efficient consumption
 Two way communication - Sensing, automation and control
 Self Healing and resilient
Network Focused
Integration of new sources
of supply & demand
 Asset optimisation
 Active power flow management
 Integration of renewable and distributed energy
 More reliable, more efficient networks
Taking Stock
• The Grid Company has been successful in providing leadership to
the industry to improve frequency response services from all
generating plant types including HVDC interconnectors
• The success has been the effective communications with developer
and their plant suppliers to ensure their early understanding of
system needs and their potential market opportunities.
• Future successes will rely on continual close collaboration within
the industry to seek resolution to any identified problems within
the legal, regulatory and commercial framework
The Way Forward
• Future of energy for the UK has never been so important and exciting
• The Electricity Market Reform (ERM), environmental legislation, energy costs
and developments in the economy will have a major impact on the future
energy landscape
• Future Energy Scenarios (FES) forum led by the Grid Company represent
transparent, holistic paths through that uncertain landscape to help the
Government, the customers and other stakeholders make informed decisions
• Base upon the energy trilemma of security of supply, affordability and
sustainability, FES helps to identify system performance requirements and
operational challenges and agree operational solutions and opportunities with
key stakeholders via the System Operability Framework (SOF) forum.