• Operating the Electricity Transmission


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    • Abstract: Operating the Electricity TransmissionNetworks in 2020Initial ConsultationJUNE 2009 Why has National Grid published this document?National Grid operates the transmission networks across Great Britain under

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Operating the Electricity Transmission
Networks in 2020
Initial Consultation
JUNE 2009
Why has National Grid published this document?
National Grid operates the transmission networks across Great Britain under
the terms of its Transmission Licence.
This licence stipulates that we should operate the transmission networks in an
efficient, economic and co-ordinated manner.
In meeting this obligation we need to be aware of the technical characteristics
and capabilities of electricity generation and demand.
We must also make assumptions regarding the future behaviour of energy
market participants and how this will impact on the way the transmission
networks can be operated. These assumptions are relevant to other
stakeholders and many of them are relevant to any assessment of security of
energy supply.
The location, type and size of generators connected to the transmission
networks has started to change as have patterns of consumer demand.
The pace and magnitude of this change will grow as emission and
renewable energy targets are met. At National Grid we believe that we
need to develop a plan in order to deliver these changes effectively.
This document has therefore been published at this time to set out and seek
views on:
Our assessment of the technical challenges presented to us in our role in
operating the networks and as 'residual balancer';
Our thoughts on how these challenges could be met; and
Our assumptions regarding how energy market participants will respond
to events in operational timescales.
About National Grid
National Grid owns and operates the high voltage electricity transmission system
in England and Wales and, as Great Britain System Operator (GBSO), we
operate the Scottish high voltage transmission system. National Grid also owns
and operates the gas transmission system throughout Great Britain and through
our low pressure gas distribution business we distribute gas in the heart of
England to approximately eleven million offices, schools and homes. In addition
National Grid owns and operates significant electricity and gas assets in the US,
operating in the states of New England and New York.
In the UK, our primary duties under the Electricity and Gas Acts are to develop
and maintain efficient networks and also facilitate competition in the generation
and supply of electricity and the supply of gas. Our activities include the residual
balancing in close to real time of the electricity and gas markets.
Through our subsidiaries, National Grid also owns and maintains around 18
million domestic and commercial meters, the electricity Interconnector between
England and France, and a Liquid Natural Gas importation terminal at the Isle of
Grain.
Operating the Electricity Transmission
Networks in 2020
Initial Consultation
CONTENTS
1 FOREWORD 1
2 SUMMARY 2
National Grid's Role 2
Network Operation 3
New Technology and New Opportunities 4
Managing Intermittency 4
Operating Margin 5
Interactions with Energy Markets 6
3 INTRODUCTION 7
Purpose of Consultation 7
Scope of Consultation 7
Objectives and Approach 7
Responding to This Consultation 8
4 BACKGROUND 9
Climate Change and Emissions Target Context 9
The 'Gone Green' Scenario 9
Electricity Market Arrangements 10
National Grid's role as System Operator 11
Related Work 13
5 DEVELOPMENTS IN ELECTRICITY GENERATION AND DEMAND 15
Electricity Generation 15
Electricity Demand 22
6 RESERVE AND OPERATING MARGIN 28
Operating Reserve Requirement in 'Gone Green' 28
Reserve Costs in 'Gone Green' 30
Periods of Low Wind 34
Operating Margin in 'Gone Green' 37
Operating at Minimum Demands in 'Gone Green' 41
7 OPERATING THE NETWORKS 46
Real-Time Energy Balancing 46
Network Management 53
Embedded Generation 55
Black Start 57
8 BALANCING SERVICES 58
Balancing Services Requirement in 2020 58
Future Service Providers 59
Applicability of Technologies to Different Balancing Services 65
Meeting the Future Requirement 66
APPENDIX A DERIVATION OF RESERVE LEVELS
APPENDIX B GENERATION ASSUMPTIONS
APPENDIX C STORR COSTS
APPENDIX D DESCRIPTION OF BALANCING SERVICES
APPENDIX E CONSULTATION QUESTIONS
Figures
Figure 1: Generation capacity in 'Gone Green' ...................................................................... 15
Figure 2: Typical wind turbine power curve............................................................................ 16
Figure 3: Recorded wind load factors 2008............................................................................ 17
Figure 4: Persistence errors in forecasting wind .................................................................... 18
Figure 5: Matching vehicle charging to the current electricity demand profile ....................... 26
Figure 6: 'Gone Green' view on future STORR ...................................................................... 29
Figure 7: 'Gone Green' additional average STORR for wind ................................................. 29
Figure 8: Incremental reserve costs versus wind generation capacity................................... 33
Figure 9: Weather Station Locations ...................................................................................... 34
Figure 10: Measured Wind Speeds at times of Winter Peak Demands ................................. 35
Figure 11: Wind output at peak electricity demand for 2008/09............................................. 36
Figure 12: Operating Margins in 'Gone Green'....................................................................... 39
Figure 13: Influence of Wind assumptions on Operating Margins ......................................... 40
Figure 14: Average renewable generation output at summer minimum under 'Gone Green' 43
Figure 15: High renewable generation output under 'Gone Green' at summer minimum...... 44
Figure 16: Number of Bid Offer Acceptances Issued ............................................................. 47
Figure 17: Energy Traded Through Bid Offer Acceptances ................................................... 47
Figure 18: Average BOA Duration.......................................................................................... 48
Figure 19: Future NIV under 'Gone Green' ............................................................................ 49
Figure 20: Future number of Bid Offer Acceptances under 'Gone Green' ............................. 50
Figure 21: Requirement for new Reserve Providers .............................................................. 58
Figure 22: Indicative Potential for Demand Management from Specific Domestic and Light
Industrial sectors in 2020......................................................................................................... 62
Tables
Table 1: Total Transmission Contracted Generation Capacity in 'Gone Green' ...................... 9
Table 2: Renewable Energy Contribution to Electricity Generation in 'Gone Green' at 2020 10
Table 3: Historic reserve volumes and weight applied ........................................................... 31
Table 4: Forecast STOR & BM Start Up costs for 2009/10.................................................... 31
Table 5: Reserve volume increases in the 'Gone Green' Scenario........................................ 32
Table 6: Generator Availability Assumptions across the Winter Period ................................. 38
Table 7: Minimum demand background assumptions............................................................ 42
Table 8: Generation availability assumptions for minimum demand assessment ................. 42
Table 9: Costs of managing summer minimums under 'Gone Green' ................................... 45
Table 10: Net Imbalance Volume 2006 to 2009 ..................................................................... 49
Table 11: Potential Ramp Rates in 2020................................................................................ 51
Table 12: Comparison of Energy Storage Technologies........................................................ 63
Table 13: Comparison of Battery Technologies ..................................................................... 64
Table 14: Mapping of Technology to Balancing Service Capability ....................................... 66
Legal Notice
National Grid has prepared this consultation document in good faith, and has endeavoured to
prepare this consultation document in a manner which is, as far as reasonably possible,
objective. While National Grid has not sought to mislead any person as to the contents of this
consultation document, readers of this document should rely on their own information (and
not on the information contained in this document) when determining their respective
commercial positions. National Grid accepts no liability for any loss or damage incurred as a
result of relying upon or using the information contained in this document.
Copyright
Any and all copyright and all other intellectual property rights contained in this consultation
document belong to National Grid. To the extent that you re-use the consultation document, in
its original form and without making any modifications or adaptations thereto, you must
reproduce, clearly and prominently, the following copyright statement in your own
documentation: © National Grid plc, all rights reserved.
1 Foreword
This consultation document describes and examines the likely issues relating
to operating the electricity transmission networks in 2020. Our assessment is
based on a vision for 2020 of an electricity transmission system which
evolves to connect extensive renewable generation to achieve climate
change objectives. This sustainability objective must be achieved whilst
maintaining a diverse generation background and appropriate network
standards in order to maintain security of supply and to do so affordably.
Since June 2008, we have worked with other energy companies, Government
and Ofgem within the Electricity Networks Strategy Group (ENSG1). In March
2009, ENSG published its Vision of the network reinforcements required to
meet the 2020 renewable energy target.
This ENSG Vision was based on an energy scenario developed by National
Grid and tested within ENSG covering the UK’s total energy demand across
the electricity, heat and transport sectors. This scenario, known as ‘Gone
Green’ set out the requirement to:
• connect circa 32 GW of renewable wind capacity; around 20 GW
offshore and 10 GW onshore by 2020;
• account for an unprecedented churn in the generation fleet due to;
• the closure of older, coal and oil fired generating plant because of
the Large Combustion Plant Directive;
• the retirement due to age of existing nuclear capacity; and
• the expected connection of 12 GW of new gas-fired generation in
the same timescales.
The purpose of this document is to complement the ENSG work and examine
the issues of system operation against the same Gone Green scenario. The
document outlines our initial views on the key issues we will face in our role
as System Operator of the electricity transmission networks and provides an
indication of the services we are likely to require as 'residual balancer', along
with the potential providers of those services. We welcome comments on the
views expressed in this document.
In undertaking our assessment, it has been necessary to make a set of
underlying assumptions on the role of the market and likely market behaviour
in maintaining security of supply and how this impacts on our role. We
believe the information contained in this document on items such as
Operating Margins (the difference between forecast demand and the
available generation) and how wind is assumed to contribute to capacity for
security of supply analysis, provides a useful platform for a wider debate on
the market requirements associated with maintaining security of supply as we
move towards 2020. In advance of those discussions we welcome any
comments on the assumptions we have made in this document.
We believe the combination of the work undertaken for ENSG in identifying
the electricity transmission network reinforcements required to meet the 2020
renewable target, this document identifying the system operation issues and
the further work we recommend on assessing the market requirements
associated with maintaining security of supply can make a significant
contribution to the UK energy policy debate.
1
The ENSG homepage is at: http://www.ensg.gov.uk/
Operating the Electricity Transmission Networks in 2020
2 Summary
Renewable energy and carbon emission reduction
targets mean that the type and size of generation
connected to the electricity transmission networks in
Great Britain and Offshore will change.
Patterns of electricity demand will also change due to
energy efficiency measures and the possible
introduction of active and passive demand management.
We have used a scenario based approach to assess the
challenges presented by this development to us in our
future role as System Operator of the transmission
networks in Great Britain and Offshore. The scenario
we have focussed on is identical to that referenced by
the Electricity Networks Strategy Group report of March
2009 which set out a strategy for transmission network
investment to 2020.
The scenario helps us to quantify these challenges and
establish the timescales over which they are likely to
transpire. At this point we believe they can be
addressed by building on our experience in operating
transmission networks and by seeking out innovative
solutions which allow more parties, including electricity
consumers, to play a role in securing the nation's
e n e r g y s u p p l y.
Our views are based on certain assumptions about how
energy markets will behave and how this behaviour will
in turn affect our ability to fulfil our responsibilities.
We seek stakeholders' views on our assumptions and
believe that this consultation exercise provides a useful
springboard for further debate.
National Grid's Role
2.1 National Grid's role as the System Operator of the electricity transmission
networks in Great Britain carries with it the responsibility for economic and
efficient operation of the networks on behalf of electricity consumers.
2.2 In performing our System Operator role, we need to have tools in place to
manage the networks which are effective in both technical and commercial
terms. This means we need to make assumptions about how wholesale
energy markets will perform as their behaviour sets the background for and
the size of the operational challenge we face.
2.3 This role includes the position of 'residual balancer', the party responsible for
managing the short term balance of electricity generation and demand within
statutory technical limits. The term 'residual' is used as energy markets have
been designed such that the bulk of the task of matching electricity
generation and demand, including investing in new generating infrastructure
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Operating the Electricity Transmission Networks in 2020
where required, is performed by generators and suppliers as driven by market
forces.
2.4 We believe it is valuable to set out our thinking on the operational challenge
we will face, alongside the assumptions behind our thinking. We hope this
consultation can provide context for future debate on efficient transmission
network operation, wholesale energy market development and security of
supply assessment.
Network Operation
2.5 Day to day operation of the transmission networks will become more complex
because of the combination of:
• The impact of generation intermittency on the minute by minute
national balance between electricity generation and demand;
• Changes in the way electricity is consumed and managed;
• A need to manage the networks more actively, itself triggered by:
• The impact of generation intermittency on network flows;
• New transmission access arrangements;
• Interactions between transmission constraints and a growing
requirement for operating reserve; and
• The general need to accommodate low load factor generation
efficiently by sharing network capacity.
2.6 National Grid's job will change as we learn to deal with the fluctuations in
electricity generated from renewable sources as well as the fluctuations in
electricity demand we are already used to dealing with. We will have to
deploy more sophisticated control solutions which make our networks even
more 'smart' than they are today.
2.7 The regulated allowance for investment in our electricity system operator
systems is approximately £9m for the year 2009/10. Development of the
necessary new capability will require additional new investment at a level
within this range over each year for the next 5 to10 years. We believe that
this new investment would represent good value in the task of meeting
emission and renewable energy targets and provide a platform for reducing
the overall costs of electricity transmission borne by the consumer.
2.8 The energy industry will become more 'smart' with energy suppliers using
tariffs to manage energy consumption and possibly to accommodate charging
of electric cars. Distribution network operators may also look to get the most
from their networks, by controlling small and perhaps domestic scale
electricity generation for example. Both of these developments will change
the pattern of electricity demand we see and give us more to do in operating
the transmission networks.
2.9 Domestic and small scale electricity generation has a significant role in
meeting emission and renewable energy targets and therefore plays a big
part in the generation and demand scenario we have used in this report
(which assumes, at 15GW in capacity, almost double today's levels). It is
important to us that this type of generation can continue to operate when
network disturbances occur, in the same way that larger scale generation
does currently.
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Operating the Electricity Transmission Networks in 2020
2.10 We have not needed to have visibility of the operating plans or characteristics
of smaller generators in the past but beyond a certain scale it will be
necessary to review the information provided to us.
2.11 Under a scenario with 29.5GW of transmission connected wind generation
capacity, our Short Term Operating Reserve Requirement increases by
6.5GW in 2020 from today's levels of approximately 4GW. In today's prices,
services of a value of some £418m per year are required to meet the Short
Term Operating Reserve requirements for wind under this scenario.
2.12 These figures could decrease to nearer 4GW and £229m per year if wind
forecasting performance improves to the levels we have assumed in the
analysis presented within this document. The actual costs incurred in 2020
will be affected by market prices at the time.
2.13 We also see similar service costs of £88m per year triggered by the
connection of larger generating units (up to 1,800MW) under our scenario.
Connection of this type of unit is dependant on a change to the agreed criteria
for connection to the transmission networks which is currently subject to
consultation.
2.14 We will keep under review the contingency and emergency arrangements
which both help to protect consumers from large scale electricity supply
losses and would allow us recover should such extreme events occur. We
will seek to replace the Black Start service providers expected to close over
the next decade and seek to make the best use of new technology to
complement or replace the emergency actions available to us currently.
New Technology and New Opportunities
2.15 We believe that the generation technologies which are new to Great Britain
(wind, supercritical coal and the latest generation of nuclear power) will be or
can be made capable of meeting our requirement for flexibility in operating
the transmission networks. We seek industry views on whether this potential
will be delivered.
2.16 There will also be new opportunities for large and small electricity consumers
to provide Balancing Services to us. Energy storage, electric cars, smart
metering and smart metering enabled control systems can all play a part.
Fridges, washing machines and dishwashers could all contribute through co-
ordinated demand management in the same way that generators do today.
2.17 We estimate that there are some 8GW of additional demand side services
that could be available by 2020 to help meet our operating reserve
requirements. Significant effort is required to realise the benefits available
from these measures. We recognise that other parts of the energy industry
will also be interested in them.
2.18 We have considered whether it would be helpful for us to quantify our longer
term Balancing Services Requirements through a Ten Year Balancing
Services Requirement statement designed to better inform potential
providers. Market participants' are invited to express their views over the
value of such a statement.
Managing Intermittency
2.19 Electricity generated from wind will displace the use of scarce fossil fuels,
reducing carbon emissions in the process. It is important to remember that
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Operating the Electricity Transmission Networks in 2020
the wind is blowing somewhere across Great Britain most of the time and our
scenario assumes a sufficient geographical dispersion of wind turbines, both
onshore and offshore, to take advantage of this.
2.20 However, we have observed periods where the electricity generated from
wind within the UK, Ireland and parts of Northern Europe has been very low.
These can coincide with days of peak electricity demand when cold and still
conditions persist.
2.21 As System Operator we need to balance supply and demand minute by
minute and think it is prudent to plan for periods where the amount of
electricity generated from wind is low at times of peak electricity demand.
This does mean that other forms of generation are required at times when
wind generation output is low, but we think that demand side measures have
a growing role to play.
2.22 Interconnection between Great Britain and Northern Europe can also help.
This has the effect of sharing intermittency across a wider area and reducing
its impact. It is therefore important that we understand how European
network operators and energy markets will act as this will affect the amount of
electricity we can import if we need it. We have already engaged with our
European counterparts to start this process.
Operating Margin
2.23 There is a great deal of uncertainty over how electricity operating margins
(the difference between forecast demand and the available generation) will
develop over the next decade. This is driven by uncertainty in underlying
energy demand linked to economic activity, uncertainty over the rate of
growth in small scale generation and uncertainty over the introduction and
impact of energy efficiency measures. There is further uncertainty over the
rate at which new generation can be constructed and how this can contribute
once in operation.
2.24 National Grid makes its contribution to the management of future operating
margins by providing information over various timescales in its Seven Year
Statement (SYS) and Winter and Summer Outlook reports2. This information
is intended in part to help energy market participants evaluate the need for
investment in new electricity generation balanced against the prospects for
electricity demand. We believe it is helpful at this stage to explore the issues
around future operating margin assessment using our 'Gone Green' scenario
in our familiar 'Winter Outlook' style.
2.25 Our analysis highlights that in order for stakeholders to assess the
implications of future electricity operating margins they will need to come to a
view on:
• The contribution of renewable generation;
• Flows across interconnectors;
• The required operating reserve;
• Energy consumers' reaction to price signals; and
• The value of specific measures which have the effect of reducing peak
electricity demand compared to the value of additional electricity
generating capacity.
2
The SYS, Winter Outlook and Summer Outlook can be found at: http://www.nationalgrid.com/uk/Electricity/SYS/
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Operating the Electricity Transmission Networks in 2020
Interactions with Energy Markets
2.26 We have based our thinking on an assumption that electricity market
participants continue to take actions to minimise their exposure to 'imbalance'
(the difference between the energy they have contracted to produce and/or
consume and the energy actually produced or consumed, whether due to
forecast error or plant 'failure').
2.27 We will continue to be reliant on this market participant action to operate the
transmission networks efficiently, increasingly so as installed wind capacity
increases. It is important though that market participants give us their views
on whether the necessary operational capacity and flexibility will be available
to us.
2.28 We expect there to be further debate over our assumption that markets will
'balance' and the mechanisms and obligations which allow security of supply
objectives to be met.
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Operating the Electricity Transmission Networks in 2020 Introduction
3 Introduction
Purpose of Consultation
3.1 Targets for energy production from renewable sources and carbon emission
reductions mean there will be significant changes in the:
• Location, type and size of generators connected to the electricity
transmission systems in Great Britain and offshore; and
• Short and long term trends in consumers' demand for electricity.
3.2 This consultation document seeks to articulate the range of new technical
challenges we will face in operating the transmission networks which are
triggered by these changes in electricity generation and demand.
3.3 The document also explores how these challenges could be addressed and
seeks views on:
• National Grid's assessment of the potential size and timescales of the
challenges;
• How these challenges could be addressed using existing technologies
and commercial arrangements; and
• The opportunity for new technologies to provide new services.
Scope of Consultation
3.4 This document focuses on the short term technical and operational issues
which National Grid deals with currently under its licensed activity of System
Operator for the electricity transmission networks in Great Britain, and in the
near future, offshore.
3.5 We have used certain assumptions concerning energy market participants'
behaviour as it affects operation of the transmission systems as a basis for
our analysis and thinking. These are based on recent and historic
experience.
3.6 We believe that it is useful at this stage for us to address these specific
'System Operator' issues whilst acknowledging that wider questions will
persist over how energy markets can best be developed. This development
may in turn impact on the assumptions we should be making about market
participants' behaviour in the future.
3.7 In practical terms, this means that this document concentrates on:
• The 'Short Term Operating Reserve' required to manage uncertainties
in the period approximately 4 hours ahead of real time;
• The way that electricity generation and demand can be balanced
within this period; and
• The way that the electricity transmission networks can be configured
and reconfigured in this period.
Objectives and Approach
3.8 Our views and analysis as presented in this consultation are guided by three
key policy objectives:
• To enable the attainment of government climate change targets;
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Operating the Electricity Transmission Networks in 2020 Introduction
• To maintain current levels of security of supply in our residual
balancing role;
• To minimise cost to consumers.
3.9 For the purposes of this consultation, we have used our 'Gone Green'
scenario at 2020 to help quantify particular operational issues. This approach
is consistent with that taken by the Electricity Networks Strategy Group
chaired jointly by Ofgem and DECC.
3.10 As far as is possible, we have tried to articulate issues in a way which is
relevant to the many other credible scenarios which may be used as a basis
of analysis elsewhere.
Responding to This Consultation
3.11 We would welcome responses (in specific or general terms) to the questions
raised within this document from all interested parties. We are particularly
interested in the views of parties who have a stake in:
• Future energy demand volumes and patterns;
• Future generation development (scale and technology);
• Provision of Balancing Services; and
• New network and energy management technologies.
3.12 If you wish to respond to some or all of the questions raised in this document,
please reply to us at [email protected] by 14th August 2009.
3.13 Responses will be published on our website unless they are marked as
confidential. These will be used as the basis of a report which National Grid
will publish in autumn 2009, which will set out actions and next steps as well
as providing an update on related areas of work.
Page 8 of 67
Operating the Electricity Transmission Networks in 2020 Background
4 Background
Our thinking as presented in this consultation
document has been formulated in the context of
government policy objectives, existing market
mechanisms and our licence obligations as operator
of the electricity transmission networks in Great
Britain.
Further and related work is underway which we
believe is relevant and we have therefore described
this below.
Climate Change and Emissions Target Context
4.1 The UK Government is required to reduce greenhouse gas emissions by 80%
by 2050 under the Climate Change Act. The draft UK Renewable Energy
Strategy is aimed at supplying 15% of energy from renewable sources by
2020.
4.2 Prior to these dates, implementation of the Large Combustion Plant Directive
will mean that 12GW of generating capacity in use today will need to stop
generating before 2016. We may see further early generation closures driven
by the proposed Industrial Emissions Directive.
4.3 Our 'Gone Green' generation background and demand forecasts have been
validated against these targets as currently proposed. We have therefore
accounted for the significant contributions from the heat and transport
sectors, as well as advances in energy efficiency, when forming a view of the
electricity sector's contribution within 'Gone Green'.
The 'Gone Green' Scenario
4.4 The analysis and discussion presented in this document is based on our
'Gone Green' scenario. We believe this scenario illustrates a set of plausible
outcomes for 2020 and beyond which are useful in illustrating the challenges
we face, even though other scenarios are equally plausible and consistent
with the relevant policy objectives.
Generation Type 2009/10 2020/21
Coal 28.4 19.8
Nuclear 10.4 6.9
Gas 27.5 34.6
Oil 3.4 0
Pumped storage 2.7 2.7
Wind 2.4 29.4
Interconnectors 2.1 4.2
Hydro 1.0 1.1
Other 1.3 2.5
Total 79.2 101.2
Table 1: Total Transmission Contracted Generation Capacity in 'Gone Green'
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Operating the Electricity Transmission Networks in 2020 Background
4.5 Table 1 above illustrates the transmission contracted generation mix featured
in our 'Gone Green' scenario in 2020. Table 2 shows the electrical energy
output from all renewable sources (including 'embedded') within the scenario.
4.6 Within our 'Gone Green' electricity demand forecasts, we have included
allowances for economic growth, growth in the number of electric vehicles
and the electricity demand from applications such as heat pumps. This
growth is partially offset by greater energy efficiency. The scenario also
incorporates an increasing contribution from embedded generation which has
the effect of reducing the growth in demand seen on the electricity
transmission networks. Peak demand levels are therefore broadly similar to
today's out to 2020 under this scenario.
4.7 Under 'Gone Green', we see 36% of the total electricity demand being met
from renewable sources by 2020. This combined with our view of the heat
and transport sectors results in the target of a 15% share of the EU 2020
target being met along with maintaining the 'flightpath' of emissions reduction
to 2050.
Renewable Energy in 'Gone Green'
19.4GW offshore,
Wind Capacity and Energy 12.9GW onshore,
98TWh of energy generated
49TWh (biomass 18, hydro 6, Tidal &
Other Renewable Energy Wave 6 & other 19 {incl CHP and solar
PV})
Total Renewable Energy 147TWh
Renewable Energy
36%
Proportion %
Table 2: Renewable Energy Contribution to Electricity Generation in 'Gone Green' at 2020
4.8 The electricity generation and demand background in 'Gone Green' is
explored further in Section 5.
Electricity Market Arrangements
4.9 The electricity market arrangements within Great Britain are designed to
promote trading of wholesale electricity between electricity generators,
suppliers and traders at a bilaterally agreed price.
4.10 Electricity consumers commit to paying for their


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