Public Disclosure Authorized

Public Disclosure Authorized Technical assistance to integrate VRE technologies into the electricity grid of Central American countries

Public Disclosure Authorized Maximum Solar PV Generation in Nicaragua v0.1

Public Disclosure Authorized

February 2018 A 0383 – R 1040/17

Contents 1. INTRODUCTION ...... 3 2. POWER FLOW ANALYSIS ...... 3 2.1. Methodology ...... 3 2.2. Base cases ...... 4 2.3. Results ...... 5 3. CONCLUSIONS ...... 7 4. REFERENCES ...... 7 5. APPENDIX ...... 7 5.1. Descripción del sistema[1] ...... 7

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1. INTRODUCTION This report presents reference values of the maximum solar PV generation that could be installed in individual nodes of the Nicaraguan transmission system. Scenarios of minimum, medium and maximum total system load for summer and winter were assessed for the years 2020, 2024 and 2028. The maximum power was calculated from a load flow screening of various scenarios under full network conditions. It was assumed that all the transmission system reinforcements and new generation projects included in the PSSE database provided by the CNDC will be in service in the corresponding scenario. The results presented in this report are intended to be used as reference values only. More detailed studies including static analyses under N-1 conditions, and transient stability analyses are required to accurately determine the requirements for the installation of solar PV generation into a particular node. The results presented in this report should also be complemented with other factors such as the orography, population density and radiation indexes.

2. POWER FLOW ANALYSIS

2.1. Methodology The maximum solar generation capacity is calculated a set of candidate 230 and 138 kV busbars in the Pacific coast from power flow calculations under full network conditions. The candidate busbars are listed in Table 1.

Table 1. Geographical coordinates of the candidate busbars.

PSS/E PSS/E Short Capacity COORD_LAT, COORD_LONG, Name Voltages (kV) Type X,N,19,11 Y ,N,19,11 Number Name name (MVA) C,50 C,50 T R ANS MIS IO N 4800 VIRG‐230 LA VIRGE N VIR 120 230/138/24,9 11,394163 ‐85,797060 631245 1259835 DISTRIBUCION 4803 E OLO‐230 PT A, E OLO EOL 50 230/13,8 GENER AC ION 11,350632 ‐85,742238 637248 1255046 T R ANS MIS IO N 4404 MS Y ‐230 MAS AY A MS Y 275 230/138‐138/13,8 12,004299 ‐86,086289 599468 1327194 DISTRIBUCION 4402 S ND‐230 S ANDINO S ND 0 230/230 T R ANS MIS ION 12,200722 ‐86,728852 529495 1348764 T R ANS MIS IO N 4406 T C P‐230 T IC UANTE PE II T C PII 156,25 230/138‐138/13,8 12,031463 ‐86,201468 586920 1330159 DISTRIBUCION T R ANS MIS IO N 230/138‐138/ 4401 LBS ‐230 LOS BR AS ILES LBS 265 DISTRIBUCION 12,167242 ‐86,340808 571716 1345134 13,8‐13,8/0,48 GENERACION T R ANS MIS IO N 4827 VIR LA VIRGE N VIR 120 230/138/24,9 11,394163 ‐85,797060 631245 1259835 DISTRIBUCION 4330 RIV‐138 R IVAS R IV 40 138/24,9 DIS T RIBUC ION 11,451827 ‐85,834375 627148 1266196 4307 C AT ‐138 C AT AR INA C AT 0 138/138 T R ANS MIS ION 11,916034 ‐86,079910 600195 1317435 T R ANS MIS IO N 4319 MS Y ‐138 MAS AY A MS Y 275 230/138‐138/13,8 12,004299 ‐86,086289 599468 1327194 DISTRIBUCION T R ANS MIS IO N 4340 T C P‐138 T IC UANTE PE II T C PII 156,25 230/138‐138/13,8 12,031463 ‐86,201468 586920 1330159 DISTRIBUCION T R ANS MIS IO N 230/138‐138/ 4315 LBS ‐138 LOS BR AS ILES LBS 265 DISTRIBUCION 12,167242 ‐86,340808 571716 1345134 13,8‐13,8/0,48 GENERACION 4342 NG2‐138 NAGAROT E II NAGII 75 69/13,2‐138/13,2 DIS T RIBUC ION 12,280658 ‐86,575350 546179 1357625 For each scenario an equivalent generator is connected to one candidate busbar at a time, and its active power dispatch is increased from zero in steps of 50 MW until a series (line or 2/3- winding transformer) element overload is observed. The equivalent generator controls its terminal voltage at the value corresponding to the power flow solution of the base case (without the additional generator). The PSS/E model provided by the CNDC for this study comprises the full Nicaraguan transmission system only isolated from the rest of the regional system. Therefore the original swing bus (bus

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4601 PCA-U1) is set as PV bus and equivalent generators were connected to the following 230 kV boundary nodes, which were set as swing buses: 4408, 4412, 4411, 4407. Therefore, when the equivalent generators’ dispatch are increased, the original dispatch scenario remains unchanged and the excess of generated power is exported to the neighboring countries. In the cases in which the active power flow interchange with either Costa Rica or Honduras is specified, the corresponding boundary busbars are set as PV and the equivalent generators connected to them are dispatch at the given value. The loading of transmission lines is calculated in percentage of the Rate A specified in the PSS/E model. In this model, the Rates A and B they are identical and correspond to a calculated capacity that takes into account different factors such as the type of conductor, the voltage level, the wind speed, the ambient and conductor temperatures. The Rate C corresponds to the setting of the overcurrent protection, according to the capacity of the current transformers.

2.2. Base cases The CNDC provided for this project PSS/E scenarios of minimum, intermediate and maximum demand for summer and winter for each year between 2019 and 2028. These scenarios consider the energy and demand projections provided by the Ministry of Energy and Mines. A description of the current transmission system is provided in Appendix 5.1. Table 2 presents a summary of the base case scenarios. The CNDC informed most solar PV generation projects will inject power into Sandino Substation (bus 4402 of the PSSE model).

Table 2. Summary of the base case scenarios. Year Scenario Total load (MW+MVArj) 2020 NI_2020_INV_MAX (791+264.) 2020 NI_2020_INV_MED (602. +221.) 2020 NI_2020_INV_MIN (437. +161.) 2020 NI_2020_VER_MAX (809. +269.) 2020 NI_2020_VER_MED (614. +245.) 2020 NI_2020_VER_MIN (447. +165.) 2024 NI_2024_INV_MAX (948. +315.) 2024 NI_2024_INV_MED (721. +287.) 2024 NI_2024_INV_MIN (522. +192.) 2024 NI_2024_VER_MAX (969. +322.) 2024 NI_2024_VER_MED (736. +293.) 2024 NI_2024_VER_MIN (535. +197.) 2028 NI_2028_INV_MAX (1147. +380.) 2028 NI_2028_INV_MED (874. +347.) 2028 NI_2028_INV_MIN (634. +233.) 2028 NI_2028_VER_MAX (1160. +385.) 2028 NI_2028_VER_MED (881. +350.) 2028 NI_2028_VER_MIN (639. +234.)

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2.3. Results This section summarizes the maximum solar generation that could be separately injected into one candidate node at a time, assuming zero additional solar PV generation in the other candidate nodes.

2.3.1. Default interchange The four boundary busbars are set as swing buses, and the power interchange between Nicaragua and its neighbouring countries approximately matches the additional solar PV generation injected into each candidate busbar. Table 3 presents the maximum solar PV injection per node for three years in the period of analysis. For each year this table specifies the lowest and highest values of maximum active power that could be injected into each candidate node in the six scenarios.

Table 3. Maximum solar PV injection per node. Year 2020 Year 2024 Year 2028 PSS/E Busbar Low High Low High Low High Number Name (MW) (MW) (MW) (MW) (MW) (MW) 4307 CAT-138 50 150 100 150 100 150 4315 LBS-138 300 400 250 350 200 300 4319 MSY-138 150 450 300 500 250 500 4330 RIV-138 100 200 100 200 150 200 4340 TCP-138 200 350 200 350 150 300 4342 NG2-138 100 150 250 300 300 350 4401 LBS-230 500 500 350 500 400 500 4402 SND-230 500 500 500 500 500 500 4404 MSY-230 500 500 500 500 500 500 4406 TCP-230 500 500 500 500 500 500 4800 VIRG-230 450 500 450 500 500 500 4803 EOLO-230 500 500 350 450 350 400 4827 VIR 138KV 150 200 150 200 150 200

2.3.2. 600 MW injection from Costa Rica The two boundary busbars with Honduras were set as swing buses, and the two boundary busbars with Costa Rica were set as PV buses with equivalent generators injecting 300 MW into each of them, totalling 600 MW of injection from Costa Rica into the 230 kV network. Table 4 presents the maximum solar PV injection per node for three years in the period of analysis. For each year this table specifies the lowest and highest values of maximum active power that could be injected into each candidate node in the six scenarios.

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Table 4. Maximum solar PV injection per node. Year 2020 Year 2024 Year 2028 PSS/E Busbar Low High Low High Low High Number Name (MW) (MW) (MW) (MW) (MW) (MW) 4307 CAT-138 0 100 100 150 100 150 4315 LBS-138 0 150 150 150 150 150 4319 MSY-138 0 200 150 150 150 150 4330 RIV-138 0 100 0 100 50 100 4340 TCP-138 0 200 50 150 50 150 4342 NG2-138 0 150 150 150 150 150 4401 LBS-230 0 200 150 150 150 150 4402 SND-230 0 200 150 150 150 150 4404 MSY-230 0 200 100 150 50 150 4406 TCP-230 0 200 50 150 0 150 4800 VIRG-230 0 200 50 150 100 150 4803 EOLO-230 0 200 50 150 100 150 4827 VIR 138KV 0 100 0 100 50 150

2.3.3. 600 MW injection from Honduras The two boundary busbars with Costa Rica were set as swing buses, and the two boundary busbars with Honduras were set as PV buses with equivalent generators injecting 300 MW into each of them, totalling 600 MW of injection from Honduras into the 230 kV network. Table 5 presents the maximum solar PV injection per node for three years in the period of analysis. For each year this table specifies the lowest and highest values of maximum active power that could be injected into each candidate node in the six scenarios.

Table 5. Maximum solar PV injection per node. Year 2020 Year 2024 Year 2028 PSS/E Busbar Low High Low High Low High Number Name (MW) (MW) (MW) (MW) (MW) (MW) 4307 CAT-138 50.0 50.0 50.0 50.0 0.0 0.0 4315 LBS-138 50.0 50.0 50.0 50.0 0.0 0.0 4319 MSY-138 50.0 50.0 50.0 50.0 0.0 0.0 4330 RIV-138 50.0 50.0 0.0 50.0 0.0 0.0 4340 TCP-138 50.0 50.0 50.0 50.0 0.0 0.0 4342 NG2-138 50.0 50.0 50.0 50.0 0.0 0.0 4401 LBS-230 50.0 50.0 50.0 50.0 0.0 0.0 4402 SND-230 50.0 50.0 50.0 50.0 0.0 0.0 4404 MSY-230 50.0 50.0 50.0 50.0 0.0 0.0 4406 TCP-230 50.0 100.0 50.0 50.0 0.0 0.0 4800 VIRG-230 50.0 50.0 0.0 50.0 0.0 0.0 4803 EOLO-230 50.0 50.0 0.0 50.0 0.0 0.0 4827 VIR 138KV 50.0 50.0 0.0 50.0 0.0 0.0

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3. CONCLUSIONS Reference values of the maximum solar PV generation that could be installed in individual nodes of the Nicaraguan transmission system were calculated from a load flow screening of various scenarios under full network conditions. Scenarios of minimum, medium and maximum total system load for summer and winter were assessed for the years 2020, 2024 and 2028.

Results with 50 MW are presented in Sections 2.3.1, 2.3.2 and 2.3.3 for the cases with no initial power interchange with neighboring countries, and 600 MW injected either from Costa Rica or Honduras into the 230 kV Nicaraguan grid, respectively. The results presented in this report are intended to be used as reference values only. More detailed studies including static analyses under N-1 conditions, transient stability analyses and the assessment of alternative transmission system and generation expansion plans are required to accurately determine the requirements for the installation of solar PV generation into a particular node.

4. REFERENCES [1] Empresa Nacional de Transmisión Eléctrica (ENATREL), “Plan de Obras 2018” presentado al ente regulador de Nicaragua, Instituto Nicaragüense de Energía (INE).

5. APPENDIX

5.1. Descripción del sistema[1]

5.1.1. Sistema de Transmisión y Subestaciones El Sistema Nacional de Transmisión está constituido por 2,694.6 km de líneas, de los cuales 2,307.8 km pertenecen a ENATREL y 386.8 km a agentes del Mercado Eléctrico de Nicaragua. Estas longitudes de líneas de transmisión están desglosadas por niveles de tensión de la Tabla 6.

Tabla 6. Kilómetros de línea de transmisión instalados en Nicaragua* LINEAS AÑO 2017 Tensión Total ENATREL OTROS kV km km km 230 771 461 311 138 1279 1237 42 69 644 610 34 Total 2694.6 2307.8 386.8

*Datos propios de ENATREL al mes de marzo del 2017 y no incluyen las nuevas obras. Estas cantidades incluyen las interconexiones internacionales en 230 kV hasta las fronteras con Honduras y Costa Rica, cuyas subestaciones terminales en Nicaragua son las Subestaciones León, Amayo, Sandino y Ticuantepe respectivamente, las líneas secundarias de transmisión pertenecientes a los productores privados y grandes consumidores y las líneas de propiedad estatal perteneciente a ENATREL. Se incluye en “otros” la línea propiedad de la EPR en 230 kV. La interconexión entre los centros de generación y los centros de carga se hace por medio de 91

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subestaciones desglosadas según la función que desempeñan de la siguiente manera:

Tabla 7. Subestaciones Instaladas y Capacidad de MVA instalado en el SIN

TOTAL PROPIEDAD DE ENATREL PROPIEDAD DE OTROS

CAPACIDAD CAPACIDAD TIPO No. CAPACIDAD (MVA) No. No. (MVA) (MVA) Enlace 303000 Enlace/ Reductoras 11 1320 11 1,320 0 0 Elevadoras 27 2436 11 483 16 1953 Reductoras 50 990 44 951 6 39.5 TOTAL 91 4746 69 2,753 22 1,993 Datos propios de ENATREL actualizados al mes de marzo del 2017

El SIN cuenta con una capacidad instalada de 4746 MVA en capacidad transformación, con 91 subestaciones de las cuales 69 pertenecen a ENATREL y 21 subestaciones a agentes privados del mercado.

5.1.2. Interconexiones Eléctricas Internacionales Nicaragua está interconectada con los sistemas eléctricos de Costa Rica y Honduras por medio de 4 líneas de transmisión de 230 kV cuyas subestaciones terminales en Nicaragua son León I, Amayo, Ticuantepe y Sandino, correspondiendo a la Empresa Propietaria de la Red (EPR) 2 interconexiones y 2 a ENATREL.

5.1.3. Cobertura del SNT Geográficamente el Sistema Nacional de Transmisión cubre toda la costa del Pacífico desde El Viejo en el Occidente del país, hasta Rivas en el Sur, la región central y la región norte hasta Santa Clara, en la RAAN hasta Siuna, la costa este del lago de Nicaragua hasta San Carlos, Río San Juan. Por el este del país llega hasta la zona de Nueva Guinea y en el extremo oriental hasta Bluefields.

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5.1.4. Diagrama unifilar del SIN año 2017 (sin obras)

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5.1.5. Diagrama unifilar del SIN año 2017 (con nuevas obras)

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5.1.6. Diagrama unifilar del SIN año 2021 (con nuevas obras 2017-2021)

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5.1.7. Nomenclatura de Subestaciones y Plantas del SIN [1]

Nº Código Subestación Nº Código Subestación

1 ABR Alba Rivas 54 NGA Nagarote Nicaragua Sugar Limited 2 ACH Acahualinca 55 NSL (Planta Ingenio San Antonio ) 3 ACY Acoyapa 56 OCT Ocotal 4 ALT Altamira 57 ORT Oriental 5 AMR Amerrisque 58 PALBA Planta Alba Motores 6 AMY Planta Eolica Amayo 59 PAR Planta Alba Rivas 7 ASO Asososca 60 PBP Planta Blue Power 8 AST Asturias 61 PCA Planta Centro America 9 BLW Bilwi 62 PCAS Planta Casitas 10 BCO Boaco 63 PCASUR Planta Casur 11 BLF Bluefields 64 PCG 1‐9 Plantas Che Guevara (Albanisa) 12 BTH Batahola 65 PDT El Periodista 13 BZN Benjamin Zeledon 66 PEC Planta Energetica Corinto (AEI) 14 CAR Villa El Carmen 67 PEOLO Planta Eolo 15 CAT Catarina 68 PEN Polarys Energy Nic.(Planta San Jacinto ) 16 CEN Planta Amtels 69 PHCF‐1‐2 Planta Hugo Chávez 1 y 2 17 CHG Chichigalpa 70 PHT Punta Huete 18 CHN Chinanadega 71 PABR Planta Alba Rivas 19 CMX Canal (CEMEX) 72 PLB Planta Las Brisas (Gecsa) 20 COR Corinto 73 PMR Planta Ingenio Monte Rosa 21 CTO Corocito 74 PMT Planta Momotombo 22 DRB Diriamba 75 PMTL Planta Montelimar 23 ENC Enacal 76 PNI Planta Nicaragua (Geosa) 24 ENC‐2 Enacal 2 (Kyoto) 77 PCF Planta Carlos Fonseca 25 EAP El Aeropuerto 78 PTPC Planta Tipitapa Power 26 EPZ Esperanza 79 PTM Planta Pantasma (Hidropantasma) 27 ESC El Sauce 80 PTZ Portezuelo 28 ELC El Cua 81 RIV Rivas 29 EST Estelí 82 ROS Rosita 30 ETM El Tuma 83 SBT San Benito 31 EVJ El Viejo 84 SEB Sebaco 32 JOB El Jobo 85 SJS San Juan del Sur 33 GAT La Gateada 86 SIU Siuna 34 GRD Granada 87 SKL Santa clara 35 GUA Guanacastillo 88 SMA Santa Maria 36 HLC Holcim 89 SMT San Martin 37 LAB Las Banderas 90 SNC San Carlos 38 LAR Larreynaga 91 SND Sandino 39 LBS Los Brasiles 92 SNM San Miguelito 40 LCN Las Colinas 93 SRM San Ramon 41 LDA La Dalia 94 SJS San Juan del Sur 42 LN‐I León ‐ I 95 SRS San Rafael del Sur 43 LN‐II León ‐ II 96 TEB Terrabona 44 LPC La Paz Centro 97 TCP Ticuantepe 45 MGA Managua 98 TCP‐2 Ticuantepe‐2 46 MGU Matiguas 99 TPT Tipitapa 47 MLP Malpaisillo 100 TTM Triton Minera 48 MLN Mina El Limón 101 VIR La Virgen 49 MSY Masaya 102 VNA Villa Nueva 50 MTG Matagalpa 103 YGA Yalagüina 51 MTF Monte Fresco 104 IND Zona Franca Index 52 MTP Masatepe 105 WAS Waslala 53 NDE Nandaime

VRE Integration in Central American Countries – Maximum Solar PV Generation in Nicaragua