Non-Firm Access Connections for Distribution Connected Distributed Generators
• In Ireland most 110kV substations are equipped with two 110kV transformers. ESB Networks’ current planning standards assume that one of these transformers is not available, for example due to maintenance, when calculating the available capacity in a substation. This is known as the N-1 (Normal-1) policy which ensures that there is redundancy on both 38kV and MV networks.
• For example in Kilkenny 110kV substation the combined rating of the transformers is 126MVA however using the N-1 policy only one 63MVA transformer can be considered in the calculation. The same policy is implemented at 38kV substations with two transformers.
• ESB Networks have been investigating over the last 2-3 years whether the second transformer in the substation could be used for generator connections. These are known as NFA (Non-Firm Access) connections. In this scenario a generator could connect to the second transformer and if there is an issue with that transformer then the generator will be turned off until it has been resolved.
• ESB published a guide to NFA connections in September 2020. Initially NFA is only being made available at a small number of substations but it is hoped later in the decade it will be rolled out at more substations.
• Any substation in the proposed study area where a NFA connection is possible has been accounted for in this review.
15. Transformer Capacity at the Kilkenny node substations
Table 3: Available 110/38kV transformer Capacity in Kilkenny 110kV substation.
• Table 3 below outlines the available capacity on the 110/38kV transformers in Kilkenny considering varying amounts of generation.
• There appears to be capacity available on the 110/38kV transformers in Kilkenny after all of the generation has been considered for future generation.
• The 50-60MW solar farm in planning 4km south of Kilkenny and the 80-90MW windfarm near Ballyhale and are assumed to be a transmission projects and as such have not been considered in this transformer calculation.
• It should be noted that there may be additional projects in planning or with planning consent in the area that have not been included in this calculation.
• Currently connections at 110/38kV substations are not viable for a community project (5MW or less) due to the high cost of connecting at these voltages.
Project Name Technology MEC 38kV Substation Status Minimum
Demand(MW)
Ballytobin Biogas (1) (BEOFS) Biogas 0.18 Callan Connected
Nicholas Mosse Small Hydro 0.029 Purcells Inch Connected
Ormond Mills Hydro (1) Small Hydro 0.05 Purcells Inch Connected
Bleach Green Elec Hydro (1) Small Hydro 0.075 Talbots Inch Connected
Ballytobin Solar PV Solar 4 Callan Contracted
Castlekelly Solar PV Farm Solar 4 Goresbridge Contracted
Knocktopher Solar Solar 4.00 Ballyhale ECP-2.1
Clashmagrath PV Solar 4.99 Goresbridge ECP-2.1
Keatingstown Solar Fam Solar 6 Talbots Inch ECP-2.1
Derrynahinch & Kiltorcan Solar 15.00 Ballyhale Planned Project
8.3 8.3 23.3 38.3
Sionhermitage BESS Battery Storage 80
Castlebanny WF Wind 84.00
Clashwilliam Solar Farm Solar 56.44
25 41
56.3 19.1
Total Subtotal Connected, Contracted,ECP-1 and ECP-2.1 Subtotal Connected, Contracted and ECP-1 Subtotal Connected and Contracted
16. Ballyhale 38kV Substation
38kV Substation Ballyhale
Feeding 110kV Substation Kilkenny
Number of Transformers & MVA Rating 2x5
Transformer Configuration T42(10kV)
Secondary Voltage Level 10kV & 20kV
Connected Generation(MW) 0.0
Available Firm Capacity(ESB)(MW) 5.4
Available Non-Firm Capacity(ESB)(MW) 3.3
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 0.0
Available Capacity(MG)(MW)(All
Generation) 0.0
Risk of Chargeable Transformer Upgrades High
Risk of 38kV Network Upgrades High
Development Potential Low
Comment
There does not appear to be capacity at this substation for new generation.There are multiple solar farms associated with Ballyhale 38kV substation. There is 1x4MW solar project that was successful in the ECP-2.1 batch at Ballyhale and an additional 15MW of planned solar generation at the substation.
17. Callan 38kV Substation
38kV Substation Callan
Feeding 110kV Substation Kilkenny
Number of Transformers & MVA Rating 2x5
Transformer Configuration T41∥T42(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.5
Available Firm Capacity(ESB)(MW) 1.6
Available Non-Firm Capacity(ESB)(MW) 0.0
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 1.1
Available Capacity(MG)(MW)(All
Generation) 1.1
Risk of Chargeable Transformer Upgrades Moderate
Risk of 38kV Network Upgrades High
Development Potential Low
Comment
There is a 4MW community project currently associated with the substation. Potential for 1MW project connecting to Callan or on MV network supplied by Callan. With the addition of solar generation at Callan and Ballyhale the capacity on the 38kV loop is considered low.
18. Capacity on 38kV Loop to Ballyhale & Callan Substations
• As outlined previously Callan and Ballyhale are connected on a 38kV loop out of Kilkenny 110kV substation as is shown in Figure 12.
• As a general rule of thumb a 38kV loop circuit can accommodate c.20MW’s of generation before the thermal capacity and voltage rise along the circuit becomes a limitation on the network.
• The total existing or planned generation at Callan and Ballyhale 38kV substation is currently estimated at 23.2MW.
• Therefore it is likely that a future projects connecting to this section of the 38kV network will be required to uprate the existing 38kV network.
• There is a 4MW MEC community-led solar project connecting into Callan 38kV substation.
Figure 12: 38kV Loop to Ballyhale & Callan Substations
19. Goresbridge 38kV Substation
38kV Substation Goresbridge
Feeding 110kV Substation Kilkenny
Number of Transformers & MVA Rating 2x5
Transformer Configuration T41∥T42(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.0
Available Firm Capacity(ESB)(MW) 1.9
Available Non-Firm Capacity(ESB)(MW) 0.0
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 1.2
Available Capacity(MG)(MW)(All
Generation) 0.0
Risk of Chargeable Transformer Upgrades High
Risk of 38kV Network Upgrades Low/moderate
Development Potential Low
Comment
There does not appear to be capacity at this substation for new generation.
20. Graiguenamanagh 38kV Substation
38kV Substation Graiguenamanagh
Feeding 110kV Substation Kilkenny
Number of Transformers & MVA Rating 2x2
Transformer Configuration T41∥T42(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.0
Available Firm Capacity(ESB)(MW) 1.8
Available Non-Firm Capacity(ESB)(MW) 0.0
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 1.7
Available Capacity(MG)(MW)(All
Generation) 1.7
Risk of Chargeable Transformer Upgrades Low
Risk of 38kV Network Upgrades Low/moderate
Development Potential Moderate
Comment
Potential for small project to connect to 2MVA transformers. Due to generation upstream at Goresbridge and at Bagnalstown the risk of 38kV network upgrades is considered low/moderate.
21. McDonagh 38kV Substation
38kV Substation McDonagh
Feeding 110kV Substation Kilkenny
Number of Transformers & MVA Rating 2x10 Transformer Configuration T42 & T41(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.1
Available Firm Capacity(ESB)(MW) 11.7
Available Non-Firm Capacity(ESB)(MW) 6.7
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 8.4
Available Capacity(MG)(MW)(All
Generation) 8.4
Risk of Chargeable Transformer Upgrades Low
Risk of 38kV Network Upgrades Low
Development Potential Low/Moderate
Comment
Potential to connect a project to the 10MVA transformer in the substation however the substation is located within Kilkenny City. There is still potential for rooftop installations in Kilkenny city.
22. Purcells Inch 38kV Substation
38kV Substation Purcells Inch
Feeding 110kV Substation Kilkenny
Number of Transformers & MVA Rating 1x5,1x10 Transformer Configuration T42&T41(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.6
Available Firm Capacity(ESB)(MW) 7.0
Available Non-Firm Capacity(ESB)(MW) 7.0
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 7.0
Available Capacity(MG)(MW)(All
Generation) 7.0
Risk of Chargeable Transformer Upgrades Low
Risk of 38kV Network Upgrades Low
Development Potential High
Comment
Potential to connect a project to the 5MVA and 10MVA transformer in the substation. Substation is located on outskirts of Kilkenny City
23. Rosehill 38kV Substation
38kV Substation Rosehill
Feeding 110kV Substation Kilkenny
Number of Transformers & MVA Rating 2x10 Transformer Configuration T42&T41(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.0
Available Firm Capacity(ESB)(MW) 11.9
Available Non-Firm Capacity(ESB)(MW) 6.7
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 8.7
Available Capacity(MG)(MW)(All
Generation) 8.7
Risk of Chargeable Transformer Upgrades Low
Risk of 38kV Network Upgrades Low
Development Potential High
Comment
Potential to connect a project to the 10MVA transformer in the substation. Substation is located on the outskirts of Kilkenny City
24. Talbots Inch 38kV Substation
38kV Substation Talbots Inch
Feeding 110kV Substation Kilkenny
Number of Transformers & MVA Rating 2x5
Transformer Configuration T41∥T42(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.2
Available Firm Capacity(ESB)(MW) 5.8
Available Non-Firm Capacity(ESB)(MW) 0.0
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 5.3
Available Capacity(MG)(MW)(All
Generation) 0.0
Risk of Chargeable Transformer Upgrades High
Risk of 38kV Network Upgrades Low
Development Potential Low
Comment
There does not appear to be capacity at this substation for new generation.
25. Transformer Capacity at Carlow 110kV Substation
Table 4: Available 110/38kV transformer Capacity in Carlow 110kV substation.
• Table 4 below outlines the available capacity on the 110/38kV transformers in Carlow considering varying amounts of generation.
• There appears to be no available capacity on the 110/38kV transformers in Carlow after all of the generation has been considered.
• Carlow is equipped with 2x63MVA transformers which is the largest 110/38kV transformer in ESB’s standards, as a result they cannot be uprated.
• Therefore some of the generation planning to connect to a 38kV substation fed from Carlow may have to connect directly to a new 110kV transformer in Carlow 110kV substation in the future.
• Until more information is available from ESB on how they plan to connect the ECP-2.1 and future generation at Carlow it is difficult to determine the available capacity on the existing transformers in Carlow substation.
• It should be noted that there may be additional projects in or with planning in the area that have not been included in this calculation.
Project Name Technology MEC 38kV Substation Status Minimum
Demand(MW)
Avonmore Foods Hydro (1) Small Hydro 0.11 Bagnalstown Connected
Ballon Wind Wind 0.499 Bagnalstown Connected
Gortahile 1 Wind 21 Graigue Connected
Strongstream Electric Hydro (1) Small Hydro 0.38 Graigue Connected
Ballynultagh Windfarm Wind 0.499 Shillelagh Connected
Cronelea Upper Wind 2.55 Shillelagh Connected
Cronelea Upper (2) Wind 1.7 Shillelagh Connected
Cronelea 1 Wind 4.99 Tullow Connected
Cronelea 2 Wind 4.5 Tullow Connected
Tullow Mushroom Growers Ltd Wind 0.133 Tullow Connected
Muine Bheag Wind Wind 0.5 Bagnalstown Contracted
Kilcarrig Solar Solar 4 Bagnalstown ECP-1 Live
Bilboa Wind Farm Wind 15 N/A ECP-1 Live
Loan PV Solar 4.99 Castlecomer ECP-2.1
Bilboa Wind Farm Ext. Wind 6 Graigue ECP-2.1
Farm Power Generation Solar 5 Tullow ECP-2.1
Ardenhue PV Solar 4.99 Pollerton Planned Project
Johnstown Solar farm Solar 10.00 N/A Planned Project
Friarstown Solar Park Solar 11.40 N/A Planned Project
Friarstown/Tullow Solar 8.45 Pollerton Planned Project
36.9 55.9 71.9 106.7
0
Subtotal Connected and Contracted Subtotal Connected, Contracted and ECP-1 Subtotal Connected, Contracted,ECP-1 and ECP-2.1 Total
20.3 12.1 0
26. Bagenalstown 38kV Substation
38kV Substation Bagnalstown
Feeding 110kV Substation Carlow
Number of Transformers & MVA Rating 2x5
Transformer Configuration T41∥T42(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.1
Available Firm Capacity(ESB)(MW) 0.9
Available Non-Firm Capacity(ESB)(MW) 0.0
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 0.6
Available Capacity(MG)(MW)(All
Generation) 0.6
Risk of Chargeable Transformer Upgrades High
Risk of 38kV Network Upgrades Moderate
Development Potential Low
Comment
There does not appear to be capacity at this substation for new generation. The available capacity on the 38kV network may be limited.
27. Transformer Capacity at Waterford 110kV Substation
Table 5: Available 110/38kV transformer Capacity in Waterford 110kV substation.
• Table 5 below outlines the available capacity on the 110/38kV transformers in Waterford considering different amounts of generation.
• There appears to be available capacity on the existing transformers in Waterford 110kV substation for future generation.
• However some parts of the 38kV network in Kilkenny that is fed from Waterford appear to be saturated with existing generation. This will be explained in greater detail in the following sections.
Project Name Technology MEC 38kV Substation Status Minimum
Demand(MW)
Benedict Behal Hydro (1) Small Hydro 0.083 Granagh Connected
Kilmacow Mill - Behal Small Hydro 0.023 Granagh Connected
Michael Aylward Wind 0.5 Mount Misery Connected
Ballymartin (2) Wind 8.28 Rosbercon Connected
Ballymartin Smithstown Wind 6 Rosbercon Connected
Rahora Wind 4.25 Rosbercon Connected
Curraghmartin Solar Park Solar 3.99 Granagh Contracted
Farranmacedmond Solar Farm Solar 4.35 Granagh Planned Project
23.1 23.1 23.1 27.5 Subtotal Connected, Contracted and ECP-1 Subtotal Connected, Contracted,ECP-1 and ECP-2.1 Total
36 41
41 29.6
Subtotal Connected and Contracted
28. Rosbercon 38kV Substation
38kV Substation Rosbercon
Feeding 110kV Substation Waterford
Number of Transformers & MVA Rating 1x2,1x5, 1x10
Transformer Configuration T41(10kV)
Secondary Voltage Level 10kV & 20kV
Connected Generation(MW) 18.5
Available Firm Capacity(ESB)(MW) 1.3
Available Non-Firm Capacity(ESB)(MW) 0.0
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 1.0
Available Capacity(MG)(MW)(All
Generation) 1.0
Risk of Chargeable Transformer Upgrades High
Risk of 38kV Network Upgrades High
Development Potential Low
Comment
Potential for 1MW project connecting to
Rosbercon but the risk of 38kV network upgrades for a project connecting here are considered high.
29. Rosbercon 38kV Loop
• Similar to Callan and Ballyhale 38kV substations, Rosbercon and New Ross 38kV substations are connected on a 38kV loop fed from Waterford 110kV substation as shown in Figure 13.
• As a general rule of thumb a 38kV loop circuit can accommodate c.20MW’s of generation before the thermal capacity and voltage rise along the circuit becomes a limitation on the network.
• The total existing or planned generation at Rosbercon 38kV substation is currently estimated at 18.5MW.
• Therefore it is likely that a future projects connecting to this section of the 38kV network will be required to uprate the existing 38kV network.
Figure 13: 38kV Loop to Rosbercon and New Ross
30. Belview 38kV Substation
38kV Substation Belview
Feeding 110kV Substation Waterford
Number of Transformers & MVA Rating 2x15 Transformer Configuration T421&T422(20kV)
Secondary Voltage Level 20kV
Connected Generation(MW) 0.0
Available Firm Capacity(ESB)(MW) 18.2
Available Non-Firm Capacity(ESB)(MW) 10.0
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 12.8
Available Capacity(MG)(MW)(All
Generation) 12.8
Risk of Chargeable Transformer Upgrades Low
Risk of 38kV Network Upgrades Moderate
Development Potential High
Comment
Potential to connect a project to the 15MVA transformer in the substation.
31. Mount Misery 38kV Substation
38kV Substation Mount Misery
Feeding 110kV Substation Waterford
Number of Transformers & MVA Rating 2x10 Transformer Configuration T41&T42(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.1
Available Firm Capacity(ESB)(MW) 10.6
Available Non-Firm Capacity(ESB)(MW) 6.7
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 7.3
Available Capacity(MG)(MW)(All
Generation) 7.3
Risk of Chargeable Transformer Upgrades Low
Risk of 38kV Network Upgrades Moderate
Development Potential High
Comment
Potential to connect a project to the 10MVA transformer in the substation.
32. Granagh 38kV Substation
38kV Substation Granagh
Feeding 110kV Substation Waterford
Number of Transformers & MVA Rating 2x5
Transformer Configuration T41∥T42(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.0
Available Firm Capacity(ESB)(MW) 1.7
Available Non-Firm Capacity(ESB)(MW) 0.0
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 1.1
Available Capacity(MG)(MW)(All
Generation) 0.0
Risk of Chargeable Transformer Upgrades Moderate
Risk of 38kV Network Upgrades Moderate
Development Potential Low
Comment
There does not appear to be capacity at this substation for new generation as there is a solar farm with consented planning in the area.
33. Transformer Capacity at Ballyragget 110kV Substation
Table 6: Available 110/38kV transformer Capacity in Ballyragget 110kV substation.
• Table 6 below outlines the available capacity on the planned 110/38kV transformers in Ballyragget considering different amounts of generation.
• It is assumed that once the substation is complete the existing project at Glanbia and the windfarm will be normally fed from Ballyragget 110kV substation.
• There is a large ECP-2.1 solar farm adjacent to the substation. It is possible that this project gets planning for additional MW’s and connects at 110kV to Ballyragget thereby allowing for more generation to connect to the 31.5MVA transformers in the substation.
• There appears to be available capacity on the planned transformer in Ballyragget 110kV substation for future generation.
• It should be noted that there may be additional projects in planning or with planning consent in the area that have not been included in this calculation.
• It is expected that once the substation is complete Castlecomer 38kV substation will be fed from Ballyragget. The existing 38kV compound at Ballyragget has also been considered in this review.
Project Name Technology MEC 38kV Substation Status Minimum
Demand(MW)
Glanbia Nat. Gas 7.5 Ballyconra Connected
INCH HYDRO Small Hydro 0.042 N/A Connected
Lisdowney Wind 9.2 Ballyconra Connected
16.7 16.7 16.7 16.7
Parksgrove Solar Farm Solar 35.00 N/A ECP-2.1
Subtotal Connected and Contracted Subtotal Connected, Contracted and ECP-1 Subtotal Connected, Contracted,ECP-1 and ECP-2.1 Total
10.8 10.8
10.8 1.7
34. Castlecomer 38kV Substation
38kV Substation Castlecomer
Feeding 110kV Substation Ballyragget
Number of Transformers & MVA Rating 2x5
Transformer Configuration T41∥T42(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.0
Available Firm Capacity(ESB)(MW) 5.9
Available Non-Firm Capacity(ESB)(MW) 0.0
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 5.3
Available Capacity(MG)(MW)(All
Generation) 0.0
Risk of Chargeable Transformer Upgrades High
Risk of 38kV Network Upgrades High
Development Potential Low
Comment
There does not appear to be capacity at this substation for new generation. The ECP-2.1 solar farm at this substation will affectively take all of the available capacity on the 38/10kV
transformers. MullanGrid understand that this part of the 38kV network is saturated.
35. Ballyragget 38kV Substation
38kV Substation Ballyragget
Feeding 110kV Substation Kilkenny
Number of Transformers & MVA Rating 1x5
Transformer Configuration T42(10kV)
Secondary Voltage Level 10kV
Connected Generation(MW) 0.0
Available Firm Capacity(ESB)(MW) 5.7
Available Non-Firm Capacity(ESB)(MW) 0.0
Available Capacity(MG)(MW)(Connected,
Contracted, Live) 4.1
Available Capacity(MG)(MW)(All
Generation) 4.1
Risk of Chargeable Transformer Upgrades Low
Risk of 38kV Network Upgrades Low
Development Potential Moderate
Comment
Potential to connect a project to the 5MVA transformer in the substation.
36. EirGrid’s Tomorrow Energy Scenario (TES) Systems Analysis 2019
• The recently published 2019 TES System Needs Analysis provided information on the capacity of the transmission system in 2030 under a number of scenarios. EirGrid will use this information to identify areas of the transmission system that need reinforcements.
• MullanGrid have analysed one of the scenarios in EirGrid’s TES report that achieve the 2030 70% RES-E target. The Coordinated Action scenario is a high onshore wind scenario with approximately 4000MW of new onshore wind, 1800MW of offshore wind and 2000MW of solar generation assumed. This scenario also has relatively high levels of electrification of heat and transport.
• The overloads on the 110kV network in the Kilkenny region for the Coordinated Action and scenario mapped in Figure 14. The scenario indicates low/moderate overloads on the transmission network in the region. This is positively showing the transmission network in Co. Kilkenny has capacity for additional generation.
36. EirGrid Tomorrow’s Energy Scenarios (Contd)
Figure 14: TES Analysis: Coordinated Action 110 kV overloads for the South East
37. Southeast Area H2 ECP-1 Constraint Report
• EirGrid dispatch down the output of generation if the local transmission network is being overloaded, this is referred to as constraints.
• EirGrid have recently completed constraint analysis for the ECP-1 generators. The analysis is presented in reports for projects located in Area H2, see Figure 15.
• The analysis is focussed on ECP-1 and all preceding connected and contracted generation, and therefore does not account for post ECP-1 generation.
• The analysis only covered a relatively short timeframe of 2020-2022.
However EirGrid also included a “Future Grid” scenario that included transmission reinforcements likely to happen in the 2022 to 2030 period.
• There are multiple scenarios included in the EirGrid reports.
MullanGrid have presented the results of scenarios in the years 2020, 2022 and ‘Future Grid’. The inputs to the scenarios are displayed in Table 7.
• Initial 2020 – connected generation and network upgrades completed up to 2020.
• 2022 All - all contracted and ECP-1 generation connected in 2022, with only limited changes to the existing transmission system. It is probably the most onerous scenario and generally shows the highest constraints. Results are presented for 33%, 66% and 100% build out of all planned contracted and ECP1 generation.
• Future Grid - all contracted and ECP-1 generation connected but with planned upgrades to the transmission system complete.
• The results from these scenarios indicate low levels of constraints in 2020 and 2022, with no constraints in the Future Grid scenario.
Figure 15: EirGrid Area H2
Initial 2020 2022 All Future Grid
Generation
-Connected Generation up to 2020
Demand -2020 Demand (32.2 TWh)
-Moyle: 255/210 MW -EWIC: 530 MW
-Moyle: 210/138 MW -EWIC: 530 MW -Inertia: 17,500 MWs -Large Generator Must Run:
ROI 5, NI 3
-SNSP: 75%
-RoCoF: 1Hz/Sec -Inertia: 17,500 MWs -Large Generator Must Run:
ROI 5, NI 3
-SNSP: 80%
-RoCoF: 1Hz/Sec -Inertia: 17,500 MWs -Large Generator Must Run:
ROI 4, NI 2
ROI 4, NI 2