Evolution of ancillary services needs to balance the Belgian control area towards 2018

56 Pages·2013·1.41 MB·English

Evolution of ancillary services needs to
balance the Belgian control area towards 2018
May 2013
This study analyses the needs for ancillary services to balance the Belgian control area in
2018 and thecapacity of the existing resources in the Belgian system to meet these needs. Itis
performed upon request by the CREG in its decision (B)120621-CDC-1162 on the approval
of the applicable reserve volumes for 2013, issued on the 21th of June 2012. This study does
not address the long-term issues of security of supply and generation adequacy; instead it
focuses on the reservesrequired for the TSOtoperformreal-time balancing.

Ancillary servicesstudy-horizon 2018
Contents
1 Glossary......................................................................................5
2 Executive summary.....................................................................7
2.1. Evolution of system reserve needs......................................................7
2.1.1. Frequency containment reserves (FCR)....................................7
2.1.2. Frequency restoration reserves (FRRa and FRRm) .....................7
2.1.3. Replacement reserves (RR)....................................................11
2.2. Available reserve resources in 2018...................................................12
2.2.1. FCR and FRRa resources........................................................12
2.2.2. Upward manual FRR .............................................................13
2.2.3. Downward manual FRR.........................................................13
3 Introduction and objectives ......................................................15
3.1. European network codes ..................................................................15
3.2. Needs for different types of reserves..................................................16
3.3. Available reserve resources ..............................................................16
4 Context......................................................................................19
4.1. Responsibilities of TSO and BRP ........................................................19
4.2. Increasing need for system flexibility.................................................20
4.3. Game changers for dimensioning of reserves......................................21
4.3.1. Increase in installed capacity of VRE.......................................21
4.3.2. HVDC interconnector.............................................................22
5 Estimated FCR needs in 2018....................................................23
6 Estimated FRRa and FRRm needs in 2018 .................................25
6.1. Methodology...................................................................................25
6.1.1. Methodology........................................................................25
6.1.2. Desaturation of FRRa by FRRm...............................................26
6.2. Inputs used for FRR dimensioning......................................................27
6.3. Scenarios.......................................................................................28
6.4. Resulting FRRa and FRRm needs in 2018............................................31
6.5. FRR dimensioning conclusions...........................................................33
7 Replacement Reserves..............................................................35
8 Reserve resources available in the system................................37
8.1. Flexibility........................................................................................37
8.2. Available reserve resources in 2018...................................................38
8.2.1. FCR....................................................................................38
8.2.2. FRRa...................................................................................39
8.2.3. Upward FRRm......................................................................41
8.2.4. Downward FRRm..................................................................42
9 Conclusions...............................................................................45
References....................................................................................46
Annex 1: Extract from CREG decision ............................................47
Annex 2: FRR dimensioning methodology .....................................48
Annex 3: Imbalance drivers ..........................................................50
Historical imbalances................................................................................50
HVDC interconnector................................................................................51
Outages of units and HVDC interconnector..................................................52
Unit outages...................................................................................53
HVDC interconnector........................................................................53
2018 estimated residual imbalances due to FOs ..................................53
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PV and wind residual forecast errors...........................................................54
PV forecast errors............................................................................54
Wind forecast errors........................................................................54
PV and wind ramping imbalances.......................................................55
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1 Glossary
ACE Area Control Error
ACER Agency for the Cooperation of Energy Regulators
BRP Balancing Responsible Party
CCGT Combined Cycle Gas Turbine
CHP Combined Heat and Power Generation
CIPU Contract for the Injection of Power Units
CREG Commission for the Regulation of Electricity and Gas
DA Day-ahead
DSM Demand Side Management
DSO Distribution System Operator
ENTSOe European Network of Transmission System Operators for electricity
FCR Frequency Containment Reserves, currently called primary reserves (R1)
FO Forced Outage
FRR Frequency Restoration Reserves
FRR- Downward Frequency Restoration Reserves
FRR+ Upward Frequency Restoration Reserves
Automatic Frequency Restoration Reserves, currently called secondary
FRRa
reserves (R2)
Manual Frequency Restoration Reserves, currently called tertiary reserves
FRRm
(R3)
GCT Gate Closure Time
GT Gas Turbine
GWh GigaWatthour
Platform for the exchange of electrical energy within the Belgium control
HUB
area.
HVDC High Voltage Direct Current
ID Intraday
MW MegaWatt
Largest single instantaneous incident in a control block resulting in a system
N-1
imbalance considered in the dimensioning of the FRR.
NC LFC&R Network Code Load Frequency Control and Reserves
NRV Net Regulation Volume
NWE North Western-Europe
OCGT Open Cycle Gas Turbine
Pdef Deficit probability
PV PhotoVoltaic production unit
Qh Quarter hour(ly)
RES Renewable Energy Sources
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RG CE Regional Group Continental Europe
RR Replacement Reserves
RT Real-time
SI System imbalance
TJ Turbojet
TSO Transmission System Operator
UK United Kingdom
VRE Variable Renewable Energy resources
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2 Executive summary
This study was requested by CREG in its decision on the applicable reserves volumes for
the year 2013 [1]. The objectives of the study are to:
 estimate the system reserves needs in 2017/2018;
 verify whether sufficient reserve resources are expected to be available in the
power system to cover the reserve needs in 2017/2018.
For the avoidance of doubt, this study is not addressing the issue of security of supply and
generation adequacy. It is strictly looking at the specific reserves to be secured by Elia in
the context of its responsibility to ensure the availability of appropriate ancillary services,
as defined by the Electricity Law, (art. 8 §1) and the Federal Grid Code (art. 231 and 232).
2.1. Evolution of system reserve needs
2.1.1. Frequency containment reserves (FCR)
The dimensioning of FCR (currently called primary reserves) is performed at ENTSOe level.
The contribution of the Belgian control area to these reserves for the Continental Europe
electricity system was historically within a range of about 90 to 106 MW. This need is
expected to remain more or less stable until 2018, although a small increase can be
expected since:
 the European TSOs identified that, due to a deterioration of system frequency
quality, the risk of having insufficient FCR available in the system to cover
incidents increased during last years [2, 6];
 in the future the FCR share for Belgium is likely to be calculated on the basis of the
sum of net generation and consumption whereas before this was calculated on the
net generation only [2, 6]. This evolution might result in a small increase in FCR
capacity as Belgium is typically a net importer of electricity.
As a result an FCR range of 95 to 110 MW is projected for 2018.
2.1.2. Frequency restoration reserves (FRRa and FRRm)
Balancing responsible parties (BRPs) are responsible for balancing their perimeter on a 15-
minute time interval in the Belgian system [4]. BRPs have to nominate a balanced
perimeter in day-ahead and have to perform intraday adjustments according to more
accurate intraday forecasts and actual measurements of production and off-take, as the
uncertainty on the final balancing position of the perimeter decreases towards real-time.
Any residual system imbalance is in last instance resolved by Elia [3, 4] by deploying a
combination of automatic1 and manual2 frequency restoration reserves (resp. FRRa and
FRRm).
As a result, any assessment of the required reserve volumes for FRRa and FRRm crucially
depends on assumptions regarding the behaviour of BRPs.
This study assumes that major additional -compared to the actual situation-
efforts are performed by BRPs and other market parties in order to minimize the
residual imbalances in the Belgian control area. The resulting reserve needs set
forth in this study are therefore only valid under this strong assumption. A very
high increase in reserve needs and according costs for society is expected in case
of insufficient efforts and investments or in case of status quo.
The massive penetration of variable renewable energy sources (VRE) such as wind and PV,
for which the output is defined by weather conditions and not by system off-take,
increases the need for system flexibility to enable BRPs to balance their perimeter. VRE
can however also offer part of the required flexibility to the grid, subject to availability.
This study assumes that BRPs have access to –and make use of- sufficient
flexibility to balance the expected position of their perimeter on a 15-minute time
interval. As a result no structural residual imbalances due to a lack of flexibility
to cover the predicted output of VRE is taken into account in the reserves
dimensioning.
1Currently called secondary reserves
2Currently called direct activated tertiary reserves
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It is thus assumed that BRPs balance this variable output within their perimeter by
themselves. Furthermore all BRPs are expected to invest in (and improve) highly accurate
intraday forecasts of VRE production and consumption within their perimeter.
Under this assumption Elia only has to resolve the residual imbalances due to
unpredictable or partially predictable events such as near to real-time forecast errors of
load and production (VRE, conventional,…), outages of load and generation units and/or
HVDC interconnectors,...
The main drivers behind the evolutions in system reserve needs towards 20183 are
expected to be:
 the massive increase of VRE capacity in the system, resulting in increased forecast
errors and possible increased volatility of the residual system imbalance;
 the integration of the 1000 MW HVDC interconnector between UK and Belgium in
the system, called the NEMO project, creating both very large positive and
negative imbalances in case of an outage in respectively export or import mode.
Schedule changes might also result in an increase in volatility of the residual
system imbalance.
Different scenarios for the evolution of the system reserve needs towards 2018 were
simulated. The table below gives an overview of the assumptions taken for each of the
scenarios. As already explained above all of the simulated scenarios assume major
additional efforts and investments by market parties in forecasting, flexibility and market
participation, compared to the actual situation. All simulated scenarios therefore have
identical assumptions for:
 Developments in forecasting, metering, profiling
 Balancing in day-ahead timeframe
It has to be emphasized that these efforts and investments in forecasting, flexibility and
market participation, will only take place in case efficient and strong incentives are given
to BRPs and market parties in order to minimize residual system imbalances by investing
in –and exploiting all- system flexibility and by accessing electricity markets in the day-
ahead and intraday timeframe to balance their position. These incentives are given by the
imbalance tariffs set by Elia.
It is currently observed however that during some periods the current incentives tend to
be inadequate, which has to be resolved in the near future in order to avoid a significant -
and very costly- increase in system reserve needs.
Incentives given to market parties have to be adequate in order to ensure the sustainable
integration of VRE in the system without requiring a continuous structural increase in
system reserve needs due to a lack of system flexibility.
In contrast to the above common assumptions, the simulated scenarios differ in:
 Balancing in intraday timeframe: the amount of available flexibility in a very
short intraday notice enabling BRPs to adjust the position of their perimeter
according to improved ID forecasts and actual metering;
 Intra-hourly balancing: the amount of available flexibility on a 15-minute
timescale enabling BRPs to balance the ramping of VRE and HVDC interconnector
within the hourly timeframe.
The low reserve needs scenario assumes that a high share of intraday and 15-minute
flexibility is available, whereas less of such flexibility is assumed to be available in the high
reserve needs scenario. More detailed information on the different scenarios can be found
in paragraph 6.3 and in Annex 3.
3This study takes the assumption that NEMO will be commissioned in 2018.
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Assumptions for simulation Low High
reserve reserve
needs needs
scenario scenario
Developments in forecasting, metering, profiling High High
Investments of BRPs in accurate intra-day forecasts of VRE
production and off-take.
Investments in smart metering and load profiling to have a
clear real-time view on the actual off-take, injection and
balancing position of the system and BRP perimeter.
Balancing on day-ahead timeframe High High
Ability of BRPs to balance the day-ahead expected position
of their perimeter, including the variable output of VRE,
ramping of off-take,…
This requires sufficient investments in system flexibility to
incorporate the high shares of future VRE capacity (in
combination with the standard daily ramping of off-take).
Balancing on intraday timeframe High Low
Ability of BRPs to adjust the position of their perimeter in
ID according to more accurate ID forecasts of VRE
production and off-take (smart metering,…).
This depends on the amount of ID flexibility within the
perimeter of the BRP (load and generation) and on the
liquidity of ID markets.
Intra-hourly balancing High Low
Ability of BRPs to balance the ramping of VRE (wind, PV,…)
and HVDC interconnectors4 within the hour.
This depends on:
 the amount of 15-minute flexibility within the BRP
perimeter (load and generation)
 the presence of a liquid 15-minutes ID market.
The figures and table below show the 2013 - 2018 interpolated system needs for FRRa and
FRRm, required to resolve residual imbalances for the different scenarios under the above
assumptions. The grey dotted lines show the very high increase in reserve needs in case
the above assumed significant efforts and investments, common for all scenarios, do not
(or only partially) take place, which would result in structural residual imbalances caused
by a lack of system flexibility or insufficient forecasting quality of VRE and system off-take.
4Depending on the final market design on the balancing responsibility for the planned BE–UK HVDC
interconnector (NEMO).
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Scenario FRRa [MW] FRRm downward FRRm upward
[MW] [MW]
2013 reference 140 695 1120
2018: low reserve 152 1138 1078
needs scenario
2018: high reserve 192 1331 1321
needs scenario
Insufficient efforts Up to >300 MW Up to >1750 MW Up to >1700 MW
& investments
These reserves are not necessarily pre-contracted by the TSO; for instance they can be
offered as non-pre-contracted reserves in the balancing market; also, the reserve needs
represent volumes with an availability of 100%, but equivalent volumes for the case of an
availability less than 100%, taking portfolio effects into account, can be calculated.
It can be concluded that the reserve needs of the system heavily depend on the
BRP behaviour. In order to avoid a very steep increase in future reserve needs
(and according costs for society) as indicated by the grey dotted lines, it is of
crucial importance that:
 BRPs invest in best practice ID forecasting of VRE production and off-take;
 BRPs make active use of markets on all timescales to balance their
perimeter;
 BRPs pro-actively foster the development of flexibility in their portfolio
(load & generation) and bring this flexibility to the markets (day-ahead,
intraday and balancing market);
 TSO, DSOs, BRPs and other market parties perform additional efforts to
achieve accurate metering and load profiling (DSO responsibility).
Adequate incentives by the imbalance mechanism are crucial to achieve this:
 all imbalance volumes must be exposed to imbalance prices;
 real-time market reaction on imbalance prices to support the balance of
the BRP perimeter and the Belgian system must be incentivized;
 imbalance prices should be sufficiently high to incentivize investments in
–and the actual use of- system flexibility by all market parties. Additional
incentives might be required to achieve this as current incentives tend to
be inadequate during some time periods.
In case insufficient system flexibility is made available to balance the output of VRE, or in
case of insufficient investments are made in accurate (intraday) forecasts, the reserve
needs of the system will increase significantly and are expected to be much higher than in
the simulated low and high reserve needs scenarios.
In addition the simulated scenarios for the estimation of the 2018 reserve needs showed
that:
 The need for FRRa will increase towards 2018 due to an expected increase in
volatility of residual imbalances caused by ramping of VRE within the hour,
the ramping of the future HVDC interconnector between Belgium and UK,
forecast errors,...
The extent of increase of FRRa will depend on the amount of quarter hourly flexibility
available in the system. This stresses the importance of
sufficient investments in quarter hourly flexibility in the BRP perimeter
o
(load and generation);
the development of a liquid coupled ID market with a time resolution
o
of 15 minutes and short gate closure times (GCT)
for the cost-effective integration of high shares of VRE in the system.
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