aged asset replacement at garbutt 132/66/11kv zone … · with; 3 bus sections, 11 x feeder bays, 2...

Aged asset replacement at Garbutt 132/66/11kV

Zone Substation

Notice on screening for non-network options

Publication Date: 18 June 2018

Disclaimer

While care was taken in preparation of the information in this Non Network Options Notice, and it is provided in good faith, Ergon Energy Corporation Limited accepts no responsibility or liability for any loss or damage that may be incurred by any person acting in reliance on this information or assumptions drawn from it. This document has been prepared for the purpose of inviting information, comment and discussion from interested parties. The document has been prepared using information provided by a number of third parties. It contains assumptions regarding, among other things, economic growth and load forecasts which may or may not prove to be correct. All information should be independently verified to the extent possible before assessing any investment proposal

Notice on screening for non-network options; Aged Asset Replacement at Garbutt Substation.

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Executive Summary

This notice of no credible non-network option has been prepared by Ergon Energy in accordance with the requirements of clause 5.17.4(d) of the National Electricity Rules (NER).

Ergon Energy has determined that there is not a non-network option that is potential credible option, or that forms a significate part of a potential credible option to address the identified need at the Garbutt Substation. Ergon Energy published their notice under clause 5.17.4(d) of the National Electricity Rules. This Report includes information relating to the following matters:

• A description of the identified need Ergon Energy is investing in; • The assumptions used in identifying the need; • A description of each credible option assessed by Ergon Energy and their;

o associated quantified market benefits; o applicable cost, including breakdown of operating and capital expenditure;

• a detailed description of the methodologies used in quantifying each class of cost and market benefit;

• reasons why Ergon Energy determined that a class or classes of market benefits or costs do not apply to a credible option;

• results of a net present value analysis of each credible option and supporting explanatory statements;

• identification of Ergon Energy’s proposed preferred option, including: o details of the technical characteristics; o the estimated construction timetable and commissioning date; o indicative capital and operating cost; o a statement of accompanying detailed analysis that the proposed preferred option

satisfies the RIT-D; and

Ergon Energy Corporation Limited (Ergon Energy) is responsible (under its Distribution Authority) for electricity supply to the Townsville area in North Queensland.

Garbutt 132/66/11kV (T046) substation (GARB) is a Powerlink Queensland (PLQ) / Ergon Energy (EE) shared site with outdoor 132kV and 66kV assets and indoor 11kV assets, which supplies 48,500 customers and 86MVA of load (directly and indirectly). Development of the substation commenced in 1958 with upgrades and augmentations in subsequent years. Garbutt Substation is now an integral node within the Townsville sub transmission (66kV) network linking; two PLQ feeders to seven zone substations (inclusive). There is minimal forecast load growth at the substation however many assets are approaching or at the end of service life, with some equipment and the majority of structures 40-60 years old.

Ergon Energy is confident that no non-network option exists that is technically or economically viable to remove the need for Garbutt Substation aged asset replacements within the required timeframe. It is therefore essential that the aged asset replacement project proceeds to ensure the safe, reliable and efficient supply to the customers in Townsville region. Consequently, a Non-Network Options Report has not been prepared in accordance with rule 5.17.4(c) of the National Electricity Rules.

The only credible option is the network solution for Garbutt 66kV Switchgear replacement with 66kV gas insulated switchgear at the existing Garbutt Substation. The estimated preferred project


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cost is $28,381,619 with an estimated average annual maintenance cost of $52,029. The project delivery is commencing design in 2019/2020 and construction completed by 2021/2022.

This notice has been prepared under cl. 5.17.4(d) of the NER and summarises Ergon Energy’s determination that no non-network option is, or forms a significant part of, any potential credible option for this RIT-D. In particular, it sets out thereasons for Ergon Energy’s determination, including the methodologies and assumptions used. A full justification for functional like-for-like aged asset replacements can be found in the Final Project Assessment Report (FPAR).


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Table of Contents

Executive Summary ........................................................................................................................ 1

1. Aged asset replacement at Garbutt 132/66/11kV Zone Substation .......................................... 4

2. Network characteristics ............................................................................................................ 5

2.1. Geographic region ............................................................................................................ 5

2.2. Existing supply system ...................................................................................................... 6

3. Forecast load, capacity, and Substation Condition at Garbutt Substation ................................ 7

3.1. Capacity and Load Forecast ............................................................................................. 7

3.2. Substation Condition ....................................................................................................... 10

4. Proposed preferred network option is 66kV Gas Insulated Switchgear at Garbutt Substation 12

5. Assessment of non-network solutions .................................................................................... 14

6. Conclusion ............................................................................................................................. 14

List of Figures and Tables

Figure 1: ROAMES image of Garbutt Substation ........................................................................ 4 Figure 2: Townsville’s 132kV transmission and 66kV sub transmission Networks ................. 5 Figure 3: Existing Townsville Network Arrangement (Sub-transmission) ............................... 6 Figure 4: Townsville SCADA Overview ...................................................................................... 7 Figure 5: Garbutt 66kV Load Profile ........................................................................................... 7 Figure 6: Garbutt Substation 11kV Typical Daily Load Profile ................................................. 8 Figure 7: Draft GA Plan view for Garbutt 66kV redevelopment .............................................. 13 Figure 8: Proposed Garbutt 66kV SLD ..................................................................................... 13

Table 1: Garbutt Transmission Connection Points 5 year Forecast (Summer 50% POE) ....... 8 Table 2: Subtransmission Feeder Forecast ................................................................................ 9 Table 3: 11kV Feeder Forecast ..................................................................................................... 9 Table 4: Recommended asset replacements ........................................................................... 10


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1. Aged asset replacement at Garbutt 132/66/11kV Zone Substation

Garbutt 132/66/11kV (T046) substation (GARB) is a Powerlink Queensland (PLQ) / Ergon Energy (EE) shared site with outdoor 132kV and 66kV assets and indoor 11kV assets, which supplies 48,500 customers and 86MVA of load (directly and indirectly). Development of the substation commenced in 1958 with upgrades and augmentations in subsequent years. Garbutt Substation is now an integral node within the Townsville sub transmission (66kV) network linking; two PLQ feeders to seven zone substations (inclusive). While Townsville has seen much growth over the past 20 years this has not greatly impacted Garbutt Substation as its surrounding area was already well established and the construction of the connected Belgian Gardens Substation during this period has reduced the connected distribution load. However many assets at the substation are approaching/at the end of service life, with some equipment and the majority of structures 40-60 years old. A ROAMES satellite image of the Garbutt Substation is seen below (Figure 1.)

Figure 1: ROAMES image of Garbutt Substation

The asset boundary between EE and PLQ is the 66kV bushing of each 132/66kV PLQ owned transformer. In addition to 2 x 132/66kV PLQ owned transformers, GARB substation has a large number of EE assets; 2 x 66/11kV power transformers, 2 x 66kV capacitor banks, 66kV ring bus (solid and strung bus), 7 x 66kV feeders, 1 x AFLC injecting into the 66kV bus, 11kV switchboard with; 3 bus sections, 11 x feeder bays, 2 x 11kV capacitor banks, 2 x local supply transformer bays, 2 x local supply transformers and associated RMUs, and a large number of 66kV and 11kV instrument transformers.


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A Structural engineering report in 2016 identified a number of at risk aged structures. Consequently a substation condition assessment report (SCAR) was completed in early 2018 which identified the assets which are nearing (or at) end of life. The predominant assets which were identified for replacement was the 66kV outdoor switchgear including; circuit breakers, voltage and current transformers, insulators stacks, isolators, the strung bus, the solid bus and all their supporting structures. A project has been raised to redevelop the Garbutt Substation replacing the 66kV aged assets with gas insulated switchgear within the Garbutt substation boundary. This aged asset replacement project is not driven by augmentation due to load growth requirements as demonstrated in 2018 Garbutt Substation Planning report.

2. Network characteristics

2.1. Geographic region

The geographic region covered by this RIT-D is Garbutt Substation and connected substations; this consists of approximately 48,500 customers and is located in the Townsville area of the Northern Region of Ergon Energy’s Network.

Figure 2: Townsville’s 132kV transmission and 66kV sub transmission Networks (PLQ Sites Orange, PLQ/EE Sites Green, EE sites Blue)


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2.2. Existing supply system

GARB is supplied via a double circuit transformer ended 132kV feeder from Alan Sherriff Substation. Providing voltage support for PLQ at GARB is two 15Mvar 66 kV capacitor banks. Providing demand management is an Audio Frequency Load Control System. Supplying the local 11kV network is two 66/11kV 35MVA transformers, two 2.5Mvar 11kV capacitor banks and eleven outgoing 11kV feeders. These provide electricity to approximately 1233 commercial/industrial customers and 3956 domestic customers in the surrounding areas.

Geographic and schematic views of the network area are provided in Figure 3, 4 and 5.

Figure 3: Existing Townsville Network Arrangement (Sub-transmission)

The Townsville 66kV network is a meshed ring seen in Figure 4, in which Garbutt is a crucial node. The following Zone substation would be directly impacted for a GARB 66kV bus outage:

• Garbutt 11kV network (complete loss of supply) • Belgian Gardens (complete loss of supply) • Alan Sheriff (T150) (supplying substation) • Bohle (N-1) • Neil Smith (N-1) • Townsville Port (N-1) • Aitkenvale (N-1) • Hermit Park (N-1) • Oonoonba (N-1) • Cranbrook (N-1)


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Figure 4: Townsville SCADA Overview

3. Forecast load, capacity, and Substation Condition at Garbutt Substation

3.1. Capacity and Load Forecast

Figure 5 and 6 below show the actual daily load profile for Garbutt Substation with Figure 5 showing the 66kV nett Load profile and Figure 6 showing the typical 11kV load profile.

Figure 5: Garbutt 66kV Load Profile


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Figure 6: Garbutt Substation 11kV Typical Daily Load Profile

Table 1 below shows the total substation delivered summer demand forecast (50% PoE) forecast out to 2021. Table 2 shows the 66kV feeders’ forecast and Table 3 the 11kV feeders’ forecast.

Table 1: Garbutt Transmission Connection Points 5 year Forecast (Summer 50% POE)

Delivered Summer Demand Forecast (50% PoE) (Excluding Embedded Generation)

2016/17 2017/18 2018/19 2019/20 2020/21

Region TNI TCP Substation MW MVAru MW MVAru MW MVAru MW MVAru MW MVAru

NQ QGAR Garbutt BSP 82.31 25.95 82.10 25.80 83.00 26.07 82.14 25.68 82.85 25.87


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Table 2: Subtransmission Feeder Forecast

Table 3: 11kV Feeder Forecast

Description Value SD SE SNM SD SE SNM SD SE SNM SD SE SNM SD SE SNMGarbutt - Aitkenvale 66 kV Rating (A) 372 372 372 372 372 372 372 372 372 372 372 372 372 372 372Garbutt - Aitkenvale 66 kV Loading (A) 170 169 201 171 169 202 184 165 197 166 165 197 167 165 198Garbutt - Aitkenvale 66 kV Power Factor 0.84 0.84 0.74 0.83 0.84 0.74 0.77 0.83 0.73 0.83 0.83 0.74 0.83 0.84 0.74Garbutt - Aitkenvale 66 kV

Garbutt - Belgian Gardens 1 66 kV Rating (A) 794 794 794 794 794 794 794 794 794 794 794 794 794 794 794 Garbutt - Belgian Gardens 1 66 kV Loading (A) 48 48 48 48 48 48 48 48 48 48 48 48 48 48 48

Garbutt - Belgian Gardens 1 66 kV Power Factor 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Garbutt - Belgian Gardens 1 66 kV Garbutt - Belgian Gardens 2 66 kV Rating (A) 794 794 794 794 794 794 794 794 794 794 794 794 794 794 794 Garbutt - Belgian Gardens 2 66 kV Loading (A) 48 48 48 48 48 48 48 48 48 48 48 48 48 48 48

Garbutt - Belgian Gardens 2 66 kV Power Factor 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Garbutt - Belgian Gardens 2 66 kV

Garbutt - Bohle 66 kV Rating (A) 551 582 524 551 582 524 551 582 524 551 582 524 551 582 524Garbutt - Bohle 66 kV Loading (A) 277 273 303 277 273 303 292 272 303 279 275 305 278 274 305Garbutt - Bohle 66 kV Power Factor 0.62 0.61 0.55 0.62 0.61 0.55 0.58 0.59 0.55 0.6 0.59 0.53 0.6 0.58 0.53Garbutt - Bohle 66 kVGarbutt - Hermit Park 66 kV Rating (A) 345 359 320 345 359 320 345 359 320 345 359 320 345 359 320Garbutt - Hermit Park 66 kV Loading (A) 183 178 180 184 178 183 189 184 186 182 178 180 183 178 180Garbutt - Hermit Park 66 kV Power Factor 0.95 0.98 0.94 0.95 0.98 0.95 0.95 0.97 0.95 0.95 0.98 0.94 0.95 0.98 0.94Garbutt - Hermit Park 66 kVGarbutt - Neil Smith 66 kV Rating (A) 257 295 272 257 295 272 257 295 272 257 295 272 257 295 272Garbutt - Neil Smith 66 kV Loading (A) 72 72 73 72 72 73 72 72 73 72 72 72 72 72 73Garbutt - Neil Smith 66 kV Power Factor 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89Garbutt - Neil Smith 66 kVGarbutt - Townsville Port 66 kV Rating (A) 257 295 272 257 295 272 257 295 272 257 295 272 257 295 272Garbutt - Townsville Port 66 kV Loading (A) 80 79 82 78 76 78 75 78 78 75 75 75 74 75 74Garbutt - Townsville Port 66 kV Power Factor 0.44 0.5 0.35 0.37 0.45 0.38 0.38 0.4 0.29 0.42 0.43 0.41 0.42 0.43 0.41

2022 2018 2019 2020 2021

UG OH5yrs 10yrs (A) (A)

GA-02 SD 0.65 0.65 230 299 208 209.4 210.7 212.1 213.5 214.8 216.2 217.7 219.1SN 0.65 0.65 230 316 208 209.4 210.7 212.1 213.5 214.8 216.2 217.7 219.1

GA-03 SD 0 0 300 299 183 183 183 183 183 183 183 183 183SN 0 0 300 316 132 132 132 132 132 132 132 132 132

GA-04 SD 0.65 0.65 218 299 18 18.1 18.2 18.4 18.5 18.6 18.7 18.8 19.0SN 0.65 0.65 218 316 26 26.2 26.3 26.5 26.7 26.9 27.0 27.2 27.4

GA-05 SD 0 0 300 299 212 212 212 212 212 212 212 212 212SN 0 0 300 274 181 181 181 181 181 181 181 181 181

GA-06 SD 0.65 0.65 218 299 113 113.7 114.5 115.2 116.0 116.7 117.5 118.2 119.0SN 0.65 0.65 218 316 112 112.7 113.5 114.2 114.9 115.7 116.4 117.2 118.0

GA-07 SD 0.65 0.65 400 299 148 149.0 149.9 150.9 151.9 152.9 153.9 154.9 155.9SN 0.65 0.65 400 316 115 115.7 116.5 117.3 118.0 118.8 119.6 120.3 121.1

GA-08 SD 0 0 280 299 193 193 193 193 193 193 193 193 193SN 0 0 280 316 184 184 184 184 184 184 184 184 184

GA-10 SD 0 0 218 299 114 114 114 114 114 114 114 114 114SN 0 0 218 316 108 108 108 108 108 108 108 108 108

GA-11 SD 0 0 400 299 52 52 52 52 52 52 52 52 52SN 0 0 400 372 49 49 49 49 49 49 49 49 49

GA-26 SD 0 0 280 142 142 142 142 142 142 142 142 142SN 0 0 280 138 138 138 138 138 138 138 138 138

GA-12 SD 0 0 400 258 258 258 258 258 258 258 258 258SN 0 0 400 236 236 236 236 236 236 236 236 236

Substation 11kV Forecast Total (MVA) 31.3 31.3 31.4 31.4 31.5 31.6 31.6 31.7 31.8Substation N-1 Capacity 43.6 (MVA) 11 100%

Feeder Rating

GARB Garbutt Bulk Supply Substation

Growth Rate (%)

Load Forecast

Voltage (kV)

2016/17 2017/18 2018/19 2019/20

Setpoint

2020/21 2021/22 2022/23 2023/24 2024/25


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3.2. Substation Condition

The SCAR completed in early 2018 has identified a number of known limitations at GARB substation;

• Ageing and failing pre-1980 concrete support structures cover most of GARB substation switchyard site

• Around 10 x 66kV isolators have hazard tags fitted, with most of these built using segmentation post insulators with rusty pins.

• Segmented insulators with rusty pins on most 66kV isolators • There are also some segmented bus support post insulators and bridging insulators with

rusty pins (these are being replaced under a separate project to address a network access restriction)

• Ageing protection relays, particularly on the 66kV bus, 66kV capacitor banks and 11kV feeders, including dedicated MCSU relays for 11kV feeder SEF protection

• Failed testing 11kV capacitor bank circuit breakers • 66kV capacitor bank CBs require a high frequency of maintenance • Some aged 66kV instrument transformers • Many of the protection relays and associated CTs and VTs are aged and provide limited

protection functionality, reliability and accuracy. • There are some aged silicon carbide, porcelain housed surge arresters which offer the

limited lightning protection • There are some corroding bolted connections on busbars and equipment terminals

The SCAR also identified a number of operating constraints;

• Inability to operate some 66kV isolators due to sticky contacts, hazard tags, and rusty pins on many segmented insulators

• This has resulted in hazard tags on 10 of the aged 66kV isolators, highlighting their inability to operate or only be operated dead. This has greatly impacted the switching and access operations at the site.

• Risk of reduced section clearances if the strung bus sags over the solid bus during switching

• Both PLQ transformers are connected to one end of the 66kV bus which means outages of the solid bus requires load to be diverted via the strung bus which is not an optimal arrangement. If these transformers were connected to each side of the rigid bus, then the strung bus may not be necessary

The outdoor 66kV busbar is more than 50 years old. The existing substation configuration prevents further expansion. More than half the 11kV CBs are around 50 years old. Approximately 10 outages in the last three years have been linked to mal-operation of the CBs.

Based on a Condition Based Risk Management (CBRM) analysis of the effect of current condition and ageing on the expected life of the asset, the following have been deemed to reach retirement age as follows:

Table 4: Recommended asset replacements

Assets recommended for replacement ASAP Asset Location Asset Types


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132/66kV tfmr No. 1 66kV bay VT, ISO, busbars & supports, surge arresters

132/66kV tfmr No. 2 66kV bay VT, ISO, busbars & supports, surge arresters

66kV Cap No. 1 bay Unbalance CT, VT 66kV Cap No. 2 bay CB, VT 66kV Neil Smith fdr bay ISO 66kV Hermit Park fdr bay ISO 66kV Aitkenvale fdr bay ISO, CT 66kV Bohle fdr bay ISO 66kV Rigid buses 2, 3, 4, 5, 6, 7 ISO Between 66kV rigid buses 6 & 7 CT 11kV capacitor bank # 1 Complete bank 11kV capacitor bank # 2 Complete bank 66kV bus zone protection scheme Complete scheme 66kV capacitor bank # 1 & # 2 protection & control relays

All protection and control relays

Assets recommended for replacement within 5 to 10 year window 66/11kV tfmr No. 3 66kV bay ISO c/w support structure 66kV Cap No. 1 bay ES c/w support structure, CB, ISO 66kV Cap No. 1 bay Reactor support structures, busbars and

supports 66kV Cap No. 2 bay ES c/w support structure; ISO c/w

support structure 66kV Cap No. 2 bay Busbars and supports 66kV Neil Smith fdr bay Busbars & cable termination support

structures 66kV Hermit Park fdr bay Busbars & cable termination support

structures 66kV Aitkenvale fdr bay Busbars support structures, surge

arresters 66kV Spare bay located between 132/66kV tfmr bays

All assets in the bay

66kV Rigid buses 2, 3, 4, 5, 6, 7 All bus support structures including segmented insulators and concrete structures

66kV Strung bus 1 Bus support structures and segmented insulators

PLQ owned 415V AC board Complete board 66kV GARB-HEPA protection schemes Pilot wire protection scheme and pilot

wire 11kV Protection schemes All feeder protection schemes Protection & Control Panels Remove old tunnel board ALFC system components AFLC controller, coupling cell and

transmitter RTUs RTUs 1 & 2 Communications assets All pilot wire protection cables emanating

from GARB substation Substation duct covers Replace missing lids & repair cracked

concrete ducts Lightnining masts Replace those on pre-1980 concrete

structures


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4. Proposed preferred network option is 66kV Gas Insulated Switchgear at Garbutt Substation

The only credible network option is the Garbutt 66kV Switchgear replacement with 66kV GIS located in an industrial shed and modular control room at the existing Garbutt Substation. The estimated preferred project cost is $28,381,619. The project delivery timeline is design commencing in 2019/2020 and construction completed by 2021/2022.

This replacement project includes replacing all the clouded assets below with GIS switchgear in a hermetically sealed structure (Figure 9 below). The design of 66kV switch building will be within the boundary of the existing site and include a modular control room. The project at a high level will include; 1) A structure to house GIS Switchgear 2) A demountable building for;

a) Protection and control panels b) Communications panels c) HDMI d) Staff Facilities

3) 15 x GIS Modular CB/Isolator/CT/VT(As required) a) 4 x 66kV Transformer Bays (2 x Plink 132/66kV, 2 x EQ 66/11kV) b) 8 x 66kV Feeder Bays (7 x existing feeders and 1 x Load control / Future Feeder) c) 2 x 66kV Capacitor Bank Bays d) 1 x 66kV Bus Tie GIS Bay

4) Feeder Works will include a) 66kV Feeder terminations to be located outside the substation b) 7 x 66kV Feeder Terminations c) 2 x 66kV cable term poles (Aitkenvale and Bohle Feeders) d) 5 x 66kV cable connections (other feeders)

5) Removal of all aged and redundant 66kV AIS bays and associated plant

See below in Figure 9 for the General Arrangement with current equipment and proposed asset removal clouded.


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Figure 7: Draft GA Plan view for Garbutt 66kV redevelopment

No.1 TX 132/66kV

No.2 TX 132/66kV

No.3 TX 66/11kV

No.4 TX 66/11kV

EA02Q00

EA01Q00 EA03Q00 EA04Q00

AFLC /Spare C1 C2

EA05Q00

EA07Q00

EA08Q00

Bus CB

GA-BG1 FDR

GA-BG2 FDR

GA-BO FDR

GA- AI FDR

EA06Q00

GA-TP FDR

EA09Q00

EA10Q00

GA- HP FDR

GA- NS FDR

EA11Q00 EA12Q00 EA13Q00 EA14Q00

EA15Q00

Figure 8: Proposed Garbutt 66kV SLD


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5. Assessment of non-network solutions

Due to the crucial nature of Garbutt Substation within the Townsville Sub-transmission 66kV area it cannot be removed or functionally changed, however consideration was given to the following non-network;

1. Demand Management (DM) a. Targeted DM on the 11kV network 31MVA load, if successful could reduce the size

of 66/11kV transformers however would not be able to negate the requirement for two transformers to meet safety net. This DM option is therefore not viable to reduce the scope of the project

b. Targeted DM at the six connected Substation (Belgian Gardens, Hermit Park, Bohle, Townsville Port, Neil Smith, Aitkenvale), if successful this could reduce the required feeder rating however again would not be able to negate the requirement for two supplying 66kV feeders to meet safety net.

2. Distributed Generation with Generation Support agreement; a. Similar to demand management, distributed generation with a generation support

agreement could assist the network during peak times to reduce the feeder and transformer ratings, however this option still would not assist with meeting safety net.

3. New Technology Option; a. The combination Distributed Energy Resources (DER) and battery storage is

becoming a realistic option for energy supply; however the size of storage required and cost is would make it unviable. Also the technology is still developing however not stable enough making it further unviable.

Due to the primary drive for this project being aged asset replacement there is no element of the scope of works which may be reduced by a viable non-network option. Demand management, generation support and distributed generation and/or storage were considered. These options are not viable to replace the function which Garbutt facilitates or remove the need for it as a node within 66kV Sub-transmission network.

6. Conclusion

Ergon Energy is confident that no non-network option exist that is technically or economically viable to remove the need for Garbutt Substation asset replacements within the required timeframe. It is therefore essential that the aged asset replacement proceeds to ensure the safe, reliable and efficient supply to the customers in Townsville region. Consequently, a Non-Network Options Report has not been prepared in accordance with rule 5.17.4(c) of the National Electricity Rules.

aged asset replacement at garbutt 132/66/11kv zone … · with; 3 bus sections, 11 x feeder bays, 2...

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