GHANA GRID COMPANY LIMITED Electricity Supply Plan

Transcription

1 GHANA GRID COMPANY LIMITED 2015 Electricity Supply Plan March, 2015

2 Acknowledgement In compiling the 2015 Electricity Supply Plan, GRIDCo acknowledges the support received from the following institutions: Volta River Authority (VRA) Electricity Company of Ghana (ECG) Electricity Supply Plan

3 Electricity Supply Plan

4 EXECUTIVE SUMMARY In line with the requirement of the Ghana Grid Code, the Ghana Grid Company Limited (GRIDCo) presents in this document its Electricity Supply Plan for year The 2015 Supply Plan is an expected demand and supply scenario for 2015, based on the best available information and assumptions for load forecasts and expected generation for the year. It is intended to present the outlook for Ghana s bulk power supply system (generation and transmission) to stakeholders and the general public. The Plan captures a short-term ( ) energy and demand outlook. Expected new network construction, installation and refurbishment to improve upon power supply reliability are also captured. It also presents an overview of generation and transmission system performance and assesses the structural limitations that affected the supply of reliable power in the previous year. Demand Outlook for 2015 The projected base case coincident peak demand for year 2015 is approximately 2,341 MW, which translates into an 18.8 % growth over the 2014 recorded figure of 1,970.7 MW. In terms of real figure the growth represents a MW increase over the 2014 supplied load. This assumes one VALCO pot line operation for It should be noted that, due to generation deficit in 2014, the available generation capacity could not meet the projected peak demand for the year. The estimated peak demand for 2015 is therefore a buildup on the expected actual load for The other factors contributing to high increase in load demand is an expected increase in spot loads, prominent among them are Kpong Water Works expansion (25 MW) and Enclave Power Authority 42 MW. On going network expansion works and measures to improve the quality of distribution services by ECG and NEDCo are also expected to culminate in an increase in domestic demand. Also, the numerous rural electrification projects earmarked for commissioning in 2015 is anticipated to increase demand in both the ECG and NEDCo distribution systems Electricity Supply Plan

5 Outlook of Energy Consumption for 2015 The total expected energy consumption for 2015 is 16,039 GWh. This figure includes estimated transmission losses of 3.7 % of total energy generation. With an actual energy consumption of 13,071 GWh in 2014, the projected 2015 figure represents a growth of about 22.7 % and in absolute terms, a growth of 2,968 GWh. It should also be noted that the 2015 projected growth in consumption includes the energy that was not served in 2014 Hydro Power Generation The projected total hydro generation for 2015 is 5,963 GWh, this would be made up of 4,300 GWh, 913 GWh and 750 GWh from Akosombo, Kpong and Bui Generation Stations respectively. In terms of capacity the Akosombo hydro is expected to operate three units at a dependable capacity of 140 MW per unit giving a total of 420 MW with availability factor of 94 %. The Kpong hydro plant on the other hand is scheduled to operate three at 35 MW per unit with a total plant dependable capacity of 105 MW at an average availability factor of 90%. The Bui Hydroelectric Plant is schedule to operate two units for maximum of six hours daily at a dependable capacity of 110 MW giving a total of 220 MW. The projected low generation of 4,300 GWh for Akosombo hydro, compared with the 2014 actual generation of 6,508 GWh is due to low reservoir elevation as a result of low inflow into the dam in Thermal Power Generation for 2015 The projected total thermal generation for 2015 is 7,960.5 GWh. This would be made up of generation from the following plants: Takoradi Thermal Power Plant, Takoradi T3 Plant, TICO Plant, Sunon Asogli Power Plant, Tema T1 Power Plant, CENIT Power Plant, Mines Reserve Plant, Tema T2 Plant and the Kpone Thermal Plant. The Kpone Thermal Power Plant (KTPP) which is expected to be commissioned in the middle of the year and a number of emergency power plants are also expected to contribute to the total thermal generation. Emergency Power Plants In a bid to significantly decrease the projected supply deficit in 2015, the Government of Ghana through the Ministry of Power is in the process of contracting three Independent Power Producers to deploy a total of 715 MW emergency power plants in Aboadze and Tema in The plants includes the following: Electricity Supply Plan

6 KarPower Barge from the Karadeniz Power Group of Turkey, the expected total installed capacity is 345 MW in The company planned to install 120 MW in Takoradi and 225 MW in Tema by last quarter Another unit would be installed in Takoradi in 2016 to increase the capacity ot 225 MW The APR plant from Dubai would have a total installed capacity of 250 MW and it is to be installed at Aboadze. TEI-Trefigora, is planned to have a total installed capacity of 120 MW and is to be installed in Takoradi These plants are all expected to be commissioned into service by the end of third quarter Should these arrangements be realized on schedule the available supply would meet the projected demand for at least the quarter of Projected Generation Mix Hydro generation is expected to make up 42.8% of total energy generation for the year Assuming a 90,000 MMBtu per day of gas flow each from WAGP and Ghana Gas, a total of 7,960.5 GWh of power representing 57.2% of projected generation is expected to be produced using natural gas, Light Crude and HFO. Renewable energy generation is expected to make up 0.03% of total generation. Available Generation versus Projected Demand A comparison of projected load demand and available generation for 2015 on a monthly basis indicates a maximum shortfall in demand capacity of 702 MW for the month of March. Considering the relatively low projected availability of thermal generation units, due to frequent breakdowns and inadequate stock levels of critical spares and the uncertainty in fuel supply, the supply deficit could be higher than stated above. The Table and Chart below show a summary of monthly generation capacity versus projected Demand for For efficient operation of the power system, there should be a generation reserve margin of 18% of projected demand, however for almost all the months as shown in the Table the reserve margin is less than the required. This situation implies power supplies in 2015 will not be reliable and adequate to cope with the demand. The shortage in generation would lead to load shedding and in some cases frequency and voltage issues Electricity Supply Plan

7 MW Summary of Monthly Available Generation versus Projected Demand (MW) for 2015 Available Generation Capacity 2015 Projected Coincident Peak Jan Feb Mar April May June July Aug Sept October Nov Dec Operating Reserve MW Required Reserve Operating Reserve % -27% -32% -32% -28% -21% -18% -17% -21% -13% 9% 16% 14% Available Generation versus Projected Demand for Supply vrs Peak Demand (MW) - No Emergency Plants Available Generation Capacity Months 2015 Projected Coincident Peak Electricity Supply Plan

8 Overview of Short-Term (Three-Year) Load Forecast and Generation A short-term ( ) peak demand and energy consumption forecast is analysed and the purpose is to guide investment planning in the short-term. The system peak demand for 2016, 2017 and 2018 is expected to increase to 2,625 MW, 2,930 MW and 3,195 MW respectively. The corresponding projected energy consumptions are 17,901 GWh, 19,370 GWh and 21,821 GWh respectively. The expected spot loads for the period are the Newmont Kenyase mines (40 MW- 2017), the Azumah mines of 23 MW (2017) at Yagha (50km NW of Wa), Tarkwa mines (15 MW- 2017), Damang mines (25 MW- 2017), Esaase (34 MW -2017) and potential for a third additional pot lines of VALCO for Customer Demand (MW) Energy (GWh) Demand (MW) Energy (GWh) Demand (MW) Energy (GWh) ECG 1,571 10,477 1,659 11,060 1,753 11,692 NED 175 1, , ,368 Mines 355 2, , ,076 Direct Customers VALCO 150 1, , ,875 Exports (CEB) 152 1, , ,314 Exports (Sonabel) CIE(Ivory Coast) Inadvertent exchange EDM(Mali) Losses Coincident Peak +losses 2,625 17,901 2,930 19,370 3,195 21,829 The Table below shows the projected generation to match the forecasted demand. The expected generation capacity by 2017 and 2018 is estimated to have a reserve margin significantly higher than the required, in 2016 however the reserved margin of 297 MW is short of the required MW for reliable operation of the power system. This implies that any time there is outage on any of the big generation units, some load has to be shed to protect the stability of the power system in It is critical therefore that additional generation is sourced to ensure adequate supply capacity and reserve margin for Electricity Supply Plan

9 Summary of projected Demand for 2016, 2017 and 2018 Dependable Generation Capacity (MW) Total Projected Generation (MW) 2,922 4,042 6,242 Projected Peak Demand (MW) 2,625 2,930 3,195 Projected Reserve Margin 297 1,112 3,047 Required Reserve (18%) TRANSMISSION SYSTEM OUTLOOK Availability of Transmission Lines, Feeders and Substations All transmission lines consisting of 429 km of 330 kv, 74.3 km of 225 kv, 4,193.6 km of 161 kv, and km of 69 kv are expected to be available to transmit the projected generation. Maintenance work on transmission lines and substations are not expected to affect power supply to customers except for single transformer stations and radial lines. The network has a total of 3, MVA transformer capacity. This capacity, compared with a projected load of 2,341 MW at an average power factor of 0.9, results in a transformer utilization factor (TUF) of 67 % for Since most transformers in the network are designed with a capability of 100% continuous loading (100% TUF). The projected TUF of 67% for 2015 implies adequate transformer capacity for the supply of power in the period. Transmission System Constraints Load Flow analysis shows that the transmission network has just enough capacity to transmit the projected power generation from all generation stations to the load centers during normal operating conditions for some sections of the network. Thus in the event of a contingency on any of the critical lines such as Aboadze Prestea, Volta - Achimota, Volta A3BSP, Aboadze Volta 330 kv etc, low voltages and overloads on adjacent lines are experienced. This situation is most often than not accompanied by load shedding in order to avert system collapse. Also for the radial lines ( Esiama, Yendi, Akyempim etc) and single transformer stations such as Esiama, Akosomb0, Yendi etc, a force or planned outage on any of the lines or transformer would lead to an outage to customers Electricity Supply Plan

10 Furthermore during peak load conditions, a minimum of 300 MW (3 generating units) should produced at Aboadze to ensure voltage stability of the network. be CONCLUSIONS The following conclusions are drawn in respect of the electricity supply and demand situation for 2015: a total system demand is projected to be 2,341 MW, this figure represents 18.8 % growth over the 2014 figure of 1,970.7 MW. The factors contributing to high increase in load demand is an expected increase in spot loads prominent among them are Kpong Water Works expansion (25 MW) and Enclave Power Authority 42 MW. b. The projected 2015 energy consumption for 2015 is 16,039 GWh, however only 13, 928 GWh is expected to be supplied as follows: i. Hydro - 5,963 GWh representing 42.8% of the total energy supply ii. Thermal - 7,960.5 GWh representing 57.2% of total energy supply iii. Renewable Solar GWh representing the remaining 0.03% The remaining 2,111 GWh hour would have to be shed because of expected supply deficit in 2015 c. The uncertainties related to gas supply from the WAGP could impact negatively on the ability of the power generating companies to meet the forecasted demand since this situation could result in the inability of Sunon Asogli Power Plant (SAPP) particularly to generate power. The cost of thermal generation would also increase because of the relatively higher cost of LCO as substitute for gas. d. Also the low levels of Akosombo reservoir as a result poor inflows into the Dam and the retrofit works on the Kpong Hydroelectric plant is expected to reduce generation from Hydro sources significantly. e. The current inadequacies in transformer capacities could lead to overloading at some major substations during normal operation conditions. This state of affairs is exacerbated during contingency conditions and normally results in load reduction. f. The transmission system has inadequate firm transfer capability to some of the major load centers (of Accra, Kumasi, Tarkwa etc) mostly at peak. This situation results in low voltages, Electricity Supply Plan

11 overloading of lines and increase in transmission system losses. A significant percentage of network loads are islanded in case of outage on some single lines. g. Voltages at Kumasi, Accra and surrounding areas are low because of inadequate installed reactive power and high loading of transmission lines. The timely implementation of the system expansion works would eliminate most of these critical states of the network. h. Generation scheduling has significant impact on system losses. System losses are lower with maximum generation at the west compared to losses with maximum generation at the east. i. It has been established through load flow studies that a minimum of 300 MW has to be always online in Aboadze to ensure network voltage stability. RECOMMENDATIONS Based on the above conclusions, the following recommendations have been made: a. The planned 2015 grid expansion programmes especially those connected with transmission upgrades should be expedited and completed on schedule. b. Major system expansion projects such as the Prestea-Kumasi 330 kv line, Aboadze Prestea double circuit 330kV line, Kpando-Kedjebi and Volta A3BSP-Achimota Mallam line upgrade Project should be expedited to enable early completion to meet the expected increases in demand and generation. c. Timely completions of Kpone Thermal Power Plant KTTP, TICO HRSG and the injection of 715 MW emergency power plant by third quarter of 2015, otherwise the generation deficit would increase. d. ECG should be advised to provide reactive power compensation on its distribution network. e. A well-coordinated generating plant and transmission facilities maintenance program should be pursued by generators and GRIDCo Electricity Supply Plan

12 TABLE OF CONTENTS ELECTRICITY COMPANY OF GHANA (ECG)... 1 EXECUTIVE SUMMARY INTRODUCTION DEMAND OUTLOOK FOR OUTLOOK OF ENERGY CONSUMPTION PROJECTED MONTHLY ENERGY CONSUMPTION GENERATION OUTLOOK HYDRO GENERATION THERMAL POWER GENERATION FOR RENEWABLE ENERGY PROJECTED GENERATION MIX PLANNED GENERATION AND MAINTENANCE SCHEDULE OF GENERATING PLANTS FUEL FOR THERMAL ENERGY GENERATION PROJECTED GENERATION SUPPLY SCENARIO MONTHLY ENERGY GENERATION IMPORT AVAILABLE GENERATION CAPACITY AND PROJECTED LOAD DEMAND GENERATION SUPPLY RISK ASSESSMENT INADEQUACY IN SUPPLY WITH ADEQUATE SPINNING AND RESERVE CAPACITIES SENSITIVITY ANALYSIS ON GENERATION CAPACITY OVERVIEW OF SHORT-TERM (THREE-YEAR) LOAD FORECAST TRANSMISSION SYSTEM OUTLOOK Electricity Supply Plan

13 4.1 STATUS OF GHANA TRANSMISSION GRID AVAILABILITY OF TRANSMISSION LINES, FEEDERS AND SUBSTATIONS SYSTEM ANALYSES - STEADY STATE SUMMARY OF SYSTEM ANALYSIS RESULTS TRANSMISSION SYSTEM CONSTRAINTS ELECTRICITY TRANSMISSION RISK ASSESSMENT ADEQUACY IN TRANSMISSION CAPACITY ADEQUACY IN TRANSFORMATION CAPACITY TRANSMISSION SYSTEM IMPROVEMENT PROJECTS FOR POWER TRANSFORMER TRANSMISSION LINES SUBSTATION PERFORMANCE REVIEW MAXIMUM SYSTEM DEMAND ENERGY CONSUMPTION GENERATION PERFORMANCE RESERVOIR ELEVATION PERFORMANCE GENERATING PLANTS AVAILABILITY FOR PROJECTED VERSUS ACTUAL ENERGY EXPORT, IMPORT AND WHEELING OF POWER ENERGY TRANSMISSION NETWORK PERFORMANCE TRANSMISSION LINES FEEDERS Electricity Supply Plan

14 5.10 TRANSMISSION SYSTEM LOSSES COMMISSIONED PROJECTS GENERATION PLANTS TRANSMISSION LINES SUBSTATION/TRANSFORMERS CONCLUSIONS RECOMMENDATIONS APPENDICES Appendices Electricity Supply Plan

15 1.0 INTRODUCTION In line with the requirement of the Ghana Grid Code, the Ghana Grid Company Limited (GRIDCo) presents in this document its Electricity Supply Plan for year The 2015 Supply Plan is an expected demand and supply scenario for 2015, based on the best available information and assumptions for load forecasts and expected generation for the year. It is intended to present the outlook for Ghana s bulk power supply system (generation and transmission) to stakeholders and the general public. The Plan captures a short-term ( ) energy and demand outlook. Expected new network construction, installation and refurbishment to improve upon power supply reliability are also discussed. It also presents an overview of generation and transmission system performance and assesses the structural limitations that affected the supply of reliable power in The report is envisioned to be a living document which evolves in response to the needs of market participants for the coming year Electricity Supply Plan

16 2.0 DEMAND OUTLOOK FOR 2015 The projected base case coincident peak demand for year 2015 is 2,341 MW, which translates into an 18.8 % growth over the 2014 recorded figure of 1,970.7 MW. In real figures the growth represents a MW increase over the 2014 supplied load. This assumes one pot line operation of VALCO for It should be noted that, due to generation deficit in 2014, the available generation capacity could not meet the projected peak demand for the year. The estimated peak demand for 2015 is therefore a build-up on the expected actual load for The other factors contributing to high increase in load demand is an expected increase in spot loads prominent among them are Kpong Water Works expansion (25 MW) and Enclave Power Authority 42 MW. On going network expansion works and measures to improve the quality of distribution services by ECG and NEDCo are also expected to culminate in an increase in domestic demand. Also, the numerous rural electrification projects earmarked for commissioning in 2015 is anticipated to increase demand in both the ECG and NEDCo distribution systems Electricity Supply Plan

17 Table 1: Summary of 2015 Projected Demand Demand Domestic Consumption Customer 2015 Estimated Demand (MW) ECG 1, NEDCo Mines Direct Customers New Obuasi Obuasi New Tarkwa Prestea Ahafo/Kenyase (Newmont) New Abirim (Newmont) Akyempem (Wexford) Ayamfuri (Central Ashanti) Bogosu Akwatia Konongo Adamus Gold Akosombo Textiles Aluworks Ghana Water Company Ltd Enclave Power Company Diamond Cement Generation Plants Station Service Volta Hotel Savana Cement (Buipe) VRATownships Losses+Network Usage 98.6 Total Domestic 2, Exports Total CEB CIE SONABEL VALCO Peak Demand MW 2, Electricity Supply Plan

18 Chart 1: System Peak Demand for 2015 by Customer 2015 Projected Peak Demand ExportsLOSSES VALCO DIRECT 6% 4% 3% 4% MINES 12% NEDCo 7% ECG 64% Chart 1 shows system peak demand for 2015 by customer, ECG demand constitute 64% of the total system peak followed by Mines 12%. VALCo at one potline represents 5%, NEDCo 7%, Exports to CEB and SONABEL 6% Electricity Supply Plan

19 2.1 Outlook of Energy Consumption The total expected energy consumption for 2015 is 16,039 GWh. This figure includes estimated transmission losses of 3.7 % of total energy generation. With an actual energy consumption of 13,071 GWh in 2014, the projected 2015 figure represents a growth of about 22.7 % and in absolute terms, a growth of 2,968 GWh. It should also be noted that the 2015 projected growth in consumption includes the energy that was not served in The summary of 2015 estimated energy consumption is presented in Table 2 below: Table 2: Summary of projected 2015 Energy Consumption Energy Customer 2015 Estimated Consumption (GWh) Domestic Consumption ECG 9,920.0 NEDCo 1,142.3 Mines 2,100.9 Direct Customers Losses+Network Usage Total Domestic 14,331.0 CEB Total Exports CIE SONABEL 1,088.0 VALCO Total Energy 16, Electricity Supply Plan

20 Chart 2: 2015 projected Energy consumption by customer 2015 Projected Energy Mines 13% Exports Direct Customers 7% 3% Losses 4% VALCO 4% NEDCo 7% ECG 62% As shown in Chart 2, ECG s consumption is the highest of all the customer groupings constituting about 62% of the total energy consumption for the year 2015, it is followed by the mines with a projected consumption of 13%. 2.2 Projected Monthly Energy Consumption The annual projected energy consumption is further broken down into monthly energy consumption. The monthly energy breakdown would assist in the weekly and daily energy planning and supply scheduling in accordance with generating plants maintenance schedules. A summary of the monthly energy consumption is indicated in Table 3 below. Table 3 Summary of Expected 2015 Monthly Energy Consumption (GWh) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec VALCO ECG NED Mines Direct Customers SONABEL Exports CEB CIE Losses Totals 1, , , , , , , , , , , , Electricity Supply Plan

21 3.0 GENERATION OUTLOOK The country currently has an installed generation capacity of 2,846.5 MW, the mix includes: Hydroelectric 1,580 MW, Thermal 1,264 MW and Renewable 2.5 MWp. There are three ongoing generation expansion projects, these are: Kpone Thermal Power Plant (220 MW), TICo HRSG (110 MW and expansion of Tema Thermal Power Plant 2(TT2PP) to 80 MW from 49.5 MW. These projects are expected to be commissioned into service in Thus, the country s total generation installed capacity is projected to increase to 3,246.5 MW by third quarter of However only 1,570 MW, 1,800 MW, 2110 MW would be available in the first, Second, and third quarters of the year. There would therefore be a deficit in supply throughout the three quarters of the year since the available supply would not meet the projected 2,341 MW peak demand. The low availability of generation units is attributed to the following: Low levels of reservoirs as a result of insufficient rainfall in the catchment areas of the lake in 2014,the generation from the hydro units would therefore be far lower than their installed capacities The ongoing retrofitting work of Kpong Hydroelectric units is also expected reduce output from the plant Insufficient and erratic nature of Gas supply from Nigeria via WAGP is expected to impact generation from thermal units Forced outage and breakdown of thermal units would also hinder generation from the thermal units. In a bid to help bridge the power supply deficit in 2015 and meet the growing demand, the Government of Ghana through the Ministry of Power is in the process contracting three Independent Power Producers to deploy a total of 715 MW emergency power plants in Aboadze and Tema Electricity Supply Plan

22 3.1 Hydro Generation The projected total hydro generation for 2015 is 5,963 GWh, this would be made up of 4,300 GWh, 913 GWh and 750 GWh from Akosombo, Kpong and Bui Generation Stations respectively. In terms of capacity the Akosombo hydro is expected to operate three units at a dependable capacity of 140 MW per unit giving a total of 420 MW with availability factor of 94 %. The Kpong hydro plant on the other hand is scheduled to operate three units at 35 MW per unit with a total plant dependable capacity of 105 MW at an average availability factor of 90%. The Bui Hydroelectric Plant is scheduled to operate two units for maximum of six hours daily at a dependable capacity of 110 MW giving a total of 220 MW. Reservoir Elevation Projection for 2015 The projected Akosombo Trajectory as presented below was developed based on the following assumptions: Planned Akosombo and Kpong hydro generation of 5,213 GWh. A total of 24 MAF is expected to be discharged to generate 5,213 GWh. January 1, 2015, lake elevation of ft. Projected minimum elevation of ft by August, 15. Projected Maximum Elevation of 255 ft assuming an inflow of 25 MAF. Based on the above assumptions from the 1 st of January or the beginning of the year the lake level would be ft. A projected amount of 24 MAF of water is expected to be discharged to generate 4,300 GWh and 913 GWh from Akosombo and Kpong Generation Stations respectively. The lake would bottom up at ft around mid-august and with the expected inflow of 25 MAF for the period the lake would peak at 255 ft by mid-november. The projected draw down elevation by the end of the year is ft. Table 4 and Chart 3 show the projected draw-down lake trajectory for Electricity Supply Plan

23 Table 4: Projected Draw-down Elevation for 2015 Level Height (ft) Maximum design elevation Minimum design elevation Maximum recorded elevation in Elevation at the end of 1 st January, Projected draw down elevation at the end of the dry season in Chart 3: 2015 Projected Volta Lake Trajectory Electricity Supply Plan

24 3.2 Thermal Power Generation for 2015 The projected total thermal generation for 2015 is 8,241 GWh. This would be made up of generation from the following plants: Takoradi Thermal Power Plant, Takoradi T3 Plant, TICO Plant, Sunon Asogli Power Plant, Tema T1 Power Plant, CENIT Power Plant, Mines Reserve Plant and Tema T2 Plant. The Kpone Thermal Power Plant (KTPP) which is expected to be commissioned in the middle of the year is also expected to contribute to the total thermal generation. Emergency Power Plants In a bid to significantly decrease the projected supply deficit in 2015, the Government of Ghana through the Ministry of Power is in the process of contracting three Independent Power Producers to deploy a total of 715 MW emergency power plants in Aboadze and Tema. The plants includes the following: KarPower Barge from the Karadeniz Power Group of Turkey, the expected total installed capacity is 345 MW in The company planned to install 120 MW in Takoradi and 225 MW in Tema by last quarter The APR plant from Dubai would have a total installed capacity of 250 MW and it is to be installed at Aboadze. TEI-Trafigura, which is planned to have a total installed capacity of 120 MW in Takoradi These plants are expected to be commissioned into service by the end of third quarter Should these arrangements be realized on schedule the available supply would meet the projected demand from the end of third quarter through to the end of Renewable Energy About 2.5 MWp of power and 4 GWh of energy is expected to be generated from the VRA Solar Plant in the Upper west region. This power would be fed directly into the distribution network Electricity Supply Plan

25 3.4 Projected Generation Mix Chart 4: 2015 projected energy generation mix 2015 Projectd Generation Mix Renewable 0% Hydro 43% Thermal 57% As shown in Chart 4, hydro generation is expected to make up 42.2% of total energy generation for the year Thermal generation would make up 57.8% and the contribution from renewable generation is expected to be 0.03% for the period. 3.5 Planned Generation and Maintenance schedule of generating plants In order to improve upon the reliability and efficiency of generating units and their auxiliaries, planned preventive and predictive maintenance of all generation plants, both hydro and thermal units would be carried out. This is also expected to culminate in the achievement of maximum availability of the units. TAPCO (T1) Combined Cycle Plant-. The plant is scheduled to be operated at 300 MW in combine cycle mode at an availability factor of 80%. The unit 1 is expected to be shut down for 15 days in February for Accessory Gear Replacement, the unit 2 would also be taken out for 4 days for Fuel Nozzle inspection in December. The unit 2 would again be shut down for Fuel Nozzle/ vent fan replacement in February. The steam component of the plant would undergo a Minor inspection and sea water tie in system in March. A total of 2,103.0 GWh is expected to be generated from T1. T2 Combine Cycle Plant- The tie in of the HRSG unit into the existing gas turbine units is expected to be carried out in February and March. The Units 2 (gas turbine) is also expected to undergo Major maintenance in February and March. The T2 plant is projected to be operated at 300 MW combine cycle mode from April to December when the steam component planned to come on line. It would Electricity Supply Plan

26 operate at an availability of 85% in base load mode. A total of 1,791 GWh is expected to be generated from T2 during the period. TT1PP-The 100 MW plant will be required to be base loaded at all times the unit is available at an availability of 85%. A total of 680 GWh is expected to be generated from the plant during the period. The plant is scheduled to undergo major inspection in July and August for a period of 30 days. SAPP- SAPP is projected to operate at a dependable capacity 170 MW during the period at plant availability of 89 %. The six generation units would be taken out one after the other for major maintenance in October and November, this would reduce the plant capacity to 125 MW during the maintenance period. The plant is expected to be in operation at all times that gas and the units are available. A total of 1,278 GWh is expected to be generated from the plant during the period. 80 MW Mines Reserve Power Plant (MRP) - The plant is scheduled for hot section inspection and Major Field inspection in various quarters of the year. A total of 40 MW of the plant installed capacity of 80MW is expected to be available from January September. Work is currently ongoing to increase the current dependable capacity to 70 MW from September to December. The plant is expected to operate at an availability of 75%. A total of 148 GWh is expected to be generated from the plant during the period. TT2PP Plant-The TT2PP plant is expected to operate at a dependable capacity of 45 MW at an availability of 85%. A total of 166 GWh is expected to be generated from the plant during the period. The plant is expected to be shut down for maintenance in June and July for a total of 30 days outage. T3 Combine Cycle- The plant has total capacity of 132 MW but only 35 MW would be available in the first quarter of the year. It is expected therefore to operate at a dependable capacity of 35 MW at an availability of 85% from January to April. The plant is planned for a shut down from April to December for engine replacement. A total of 124 GWh is expected to be generated from the plant during the period Electricity Supply Plan

27 CENIT Plant- The plant is expected to operate at a dependable capacity of 100 MW at an availability of 85%. A total of 677 GWh is projected to be generated from the plant during the period. It is expected to be shut down for maintenance in February for 15 days. Imports- In 2015, it is assumed that VRA would not be obtaining any power imports from CIE of Cote d Ivoire. However depending on the cost and availability of imports, VRA may consider obtaining power imports from CIE. 3.6 Fuel For Thermal Energy generation Source of Fuel for thermal energy generation would consists of natural gas from Nigeria through WAGP, Indigenous Gas from Ghana Gas, Light Crude Oil (LCO) and Diesel Fuel Oil (DFO). The natural gas from Nigeria via the West African Gas Pipeline (WAGP) and Ghana Gas would constitute principal source of fuel for thermal energy generation, followed by LCO which is mostly used as a substitute in the event of failure by WAGP to supply adequate gas. DFO is largely used for start-up and shut down of the units. The Table 5 below show the projected fuel requirement for power thermal generation in the period. Table 5: Summary of total fuel requirement Description of Fuel QTY Energy (GWh) DFO - - LCO 2,025, 000 bbl / 5 Cargoes Natural Gas WAGP 34,695,500 MMBtu (year) / 90,000 MMBtu/Day 2,978.0 Ghana Gas 2,367,625 MMBtu (year) / 95,000 MMBtu/Day 3,682.0 HFO Electricity Supply Plan

28 3.7 Projected Generation Supply Scenario In 2015, the proportion of supply to meet demand by the various Generating Plants is summarised in Table 6 below. It is worth noting that the projected energy generation by the various Plants takes into consideration the planned maintenance schedules and the corresponding units availability values. For the first quarter of the 2015 the total available generation capacity is estimated to be 1,585 MW. In the second quarter the figure is expected to increase to 1,810 MW after the commissioning of TICO HRSG and bringing back online the second Gas Turbine unit. The capacity situation improves further to 1,910 MW after the commissioning of Kpone Thermal Power Plant (220 MW). The available capacity is expected to increase further to 2, 660 MW after the commissioning of the APR, TEI-Energy 120 MW, Karpower Emergency power Plant 225 MW and 120 MW in Tema and Takoradi respectively. Table 6: Nominal Capacity and Available Generation Levels of Existing Plants Plant Akosombo Hydroelectric Plant Kpong Hydroelectric Plant Nominal Capacity (MW) Dependable Capacity (MW) Availability Factor 1 st quarter Available Capacity 2 nd quarter 3 rd quarter 4 th quarter Bui Hydroelectric Plant Takoradi Thermal Power Plant-T1 (TAPCO) Takoradi Thermal Power Plant-T2 (TICO) Takoradi Thermal Power Plant-T Tema Thermal Power Plant-T1 (TT1PP) Mines Reserve Plant (MRP) Tema Thermal Power Plant-T2 (TT2PP) Sunon Asogli Power Plant (SAPP) Kpone Thermal Power Plant (KTPP) CENIT Electricity Supply Plan

29 Karpower-Tema Karpower-Takoradi APR TEI-Trefigora Total 3,873 3,400 1,585 1,810 1,910 2,660 Table 7 below compares Available Generation Capacity with projected Monthly Peak Load. The results as indicated in the Table show supply deficit throughout the year with the exception of the last quarter of the year when the proposed emergency power plants is expected to have been commissioned. The emergency power plant is projected to contribute about 625 MW of dependable capacity to the system. The injection of the Emergency plant would move the supply deficit into a surplus of up to 374 MW in last quarter. The potential reserve margin at peak period for first through to the third quarter of 2015 is in the negative with the highest being -32% in March, this represents a shortage in supply of about 702 MW. The last quarter is estimated to have a reserve margin of up to 16% of the projected peak (less than the required reserve of 18%), however considering the required reserve of 18% of peak demand for efficient operation of the power system it implies power supply in 2015 could not be reliable for all the months. It is important to also note that the computation in Table 9 assumes that with the exception of planned maintenance, the generation capacity is available at all times of the year, with no unforeseen or inadvertent electro-mechanical failures or fuel shortages. Taking into consideration unplanned downtimes of the various generating units, especially forced outages and plant unavailability due to fuel shortages, the above reserve margin could further be reduced to a negative figure depending on the capacity of the unit on outage. This clearly shows that power supply in 2015 is likely to encounter serious deficit in the event of a contingency (forced outage or shortage in fuel supply) on any of the generating units. As could also be deduced from table 9, there is no planned import of power from CIE for the period apart from the inadvertent exchanges. However depending on system load demand and the availability of imports VRA /GRIDCo may consider obtaining power imports from CIE Electricity Supply Plan

30 Table 7: Available Generation Capacity Vrs Projected Monthly Demand for 2015 Projected Available Generation Capacity for 2015 (MW) Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Projected Peak Demand(MW) Generation/Supply Akosombo G.S Kpong G.S Bui Hydro Total Hydro Takoradi Thermal (TAPCO (T1)) TICO TT1PP TT2PP T MRP CENIT Sunon Asogli KTPP APR Kar Power Tema KarPOwer Takoradi TEI-Trafigura Total Thermal Total Supply (MW) 1,585 1,500 1,500 1,610 1,760 1,810 1,770 1,670 1,910 2,465 2,660 2,660 Projected Surplus/(Deficit) Reserve Margin % -27% -32% -32% -28% -21% -18% -17% -21% -13% 9% 16% 14% Required Reserve 18% of Peak Electricity Supply Plan

31 3.8 Monthly Energy Generation In accordance with the projected monthly energy consumption indicated in Table 8, the projected monthly energy generation based on the estimated availability factors of the generating plants and planned maintenance schedule is presented in Table 10 below. Table 8: Summary of Projected Monthly Generation (GWh) Plant Projected Monthly Energy Generation GWh Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total Akosombo GS Kpong GS BUI Hydro TAPCO T TICO TT1PP SAPP MR P TT2PP CENIT KTPP VRA Solar KarPower-Takoradi KarPower-Tema APR TEI Totals 1, ,077 1,006 1,120 1,059 1,279 1,107 1,125 1,380 1,366 1,438 13, Electricity Supply Plan

32 Chart 5: Projected energy generations by plants for 2015 Chart 5 above shows the percentage share of generation from all existing and proposed generation units. Generation from Akosombo Hydro constitutes 31% representing highest single unit generation followed by TAPCo and TICO. 3.9 Import There is no planned import in 2015 apart from the usual inadvertent exchanges. However depending on the cost and availability of imports in 2015, VRA may consider obtaining power imports from CIE Electricity Supply Plan

33 MW 3.10 Available Generation Capacity and Projected Load Demand A comparison of projected load demand and available generation for 2015 on a monthly basis indicates a maximum shortfall in demand capacity of 702 MW for the month of March. Considering the relatively low projected availability of thermal generation units, due to frequent breakdowns and inadequate stock levels of critical spares and the uncertainty in fuel supply, the supply deficit could be higher than stated above. Table 9 and Chart 6 show a summary of monthly generation capacity versus projected Demand for For efficient operation of the power system there should be a generation reserve margin of 18% of projected demand, however for almost all the months as shown in the Table below the reserve margin is less than the required. This situation implies power supplies in 2015 will not be reliable and adequate to cope with the demand. The shortage in generation would lead to load shedding and in some cases frequency and voltage issues. Table 9: Summary of Monthly Available Generation versus Projected Demand (MW) for 2015 Available Generation Capacity 2015 Projected Coincident Peak Jan Feb Mar April May June July Aug Sept Octobe r Operating Reserve MW Required Reserve Operating Reserve % -27% -32% -32% -28% -21% -18% -17% -21% -13% 9% 16% 14% Nov Dec Chart 6: Available Generation versus Projected Demand for Supply vrs Peak Demand (MW) - No Emergency Plants Available Generation Capacity Months 2015 Projected Coincident Peak Electricity Supply Plan

34 3.11 Generation Supply Risk Assessment This section analyses the possible risks to meeting the supply requirements for 2015 from the perspective of: Adequacy of available generation with adequate spinning and reserve capacities to meet the projected demand under all system conditions Low level Akosombo reservoir and projected less than average inflows in 2015 Security of fuel supplies such as gas supply from WAGP, Ghana Gas and adequate stocks of LCO and DFO Major planned maintenance works especially when the maintenance period goes beyond the planned schedule due to the age of the Units, especially the Thermal generating units. Potential of WAGP and Ghana Gas not being able to meet scheduled amount of gas Inadequacy in Supply with adequate Spinning and Reserve Capacities a) Capacity With the current supply situation beset with a number of problems, the supply of 2,341 MW or in energy terms 16,039 GWh in 2015 could encounter a number of challenges; the major ones Being the following: Lower plants availability rates than expected resulting from high units outage rates and longer planned maintenance periods due mostly to the unavailability of critical spares. Inadequate fuel stocks to run the Thermal Plants. Whenever a generating company is not able to secure the required financing to purchase the required quantity of fuel or if for any reason the delivery of fuel is delayed, there would be supply deficit and some load may have to be shed. For instance the unavailability of gas will result in a complete shutdown of SAPP (170 MW) and increase cost of generation for VRA power plants because LCO would have to be used. Reactive power requirements at Akosombo GS would limit the amount of energy that could be obtained from Akosombo GS. Hence considering the deficit in supply in the first through to third quarter of the year and very low reserve capacity of -32% for first quarter to 16 % in the last quarter, any situation that results in any of the plants going out of service would pose a major risk and worsen supply security in Electricity Supply Plan

35 b) Energy As mentioned earlier, the total energy requirement for 2015 is 16,039 GWh, including a loss component of 3.7%. With hydro projected to provide a total of 5,963 GWh and thermal (including emergency plants) would contribute 7,961 MW, renewable generation from VRA would add 4.3 GWh. The remaining supply deficit of either 2,115 GWh is the energy expected not to be served due insufficient generation. With uncertainties surrounding the availability of fuel supply to run the thermal plants coupled with long maintenance periods than planned, higher outage rates and other organisational constraints, the energy supply security in 2015 could suffer even worse shortages than stated above. Also a delay in the deployment of Emergency power plants as outline in Table 7 could further increase the supply deficit in c) Low Level of Akosombo and Bui Hydroelectric Reservoirs The Akosombo, Bui and Kpong dams depend solely on good inflow of water occasioned by adequate rainfall around the catchment area of the lake. White Volta river basin is very crucial in feeding the Volta River. The White Volta River and its main tributaries in the northern part, the red Volta (nazinon) and the Kulpawn/sisili rivers, take their sources in the central and north-eastern portions of Burkina Faso. The White Volta accounts for 22 percent of the waters of the Volta River; river Oti accounts for 28 percent; and the Black Volta also accounts for 18 percent. Scientific analysis of water inflow into the dam has shown that the Akosombo Dam is expected to record poor inflow of water in the next two years, which will lead to a reduction in electricity generated from plant. The minimum operating water level for Akosombo Dam is pegged at 240 feet.however, the water inflow into the lake has recorded consistent reduction from The lake level in 2010 was ft, ft in 2011; ft in 2012; ft in Recorded net inflow into the Akosombo reservoir as of December 31, 2014 was MAF and this is about 22% below the Long term average. Total plant discharge for the period was MAF. The reservoir drawdown during the depletion season (Jan. 1- Aug. 28) was ft. The rise recorded during the flood season was 7.15 ft. (Aug. 28 Nov.1, 2014) The reservoir elevation was ft at the beginning of the year. However, the maximum elevation at the end of the flood season was only ft.the elevation as of December 31, 2014 was ft Electricity Supply Plan

36 d) Potential of WAGP/Ghana Gas not being able to meet scheduled amount of gas. This sensitivity analysis is to evaluate the electricity supply possibilities in the event of failure by WAGP or Ghana Gas to supply adequate gas to run the thermal generating units. The role of Sunon - Asogli Power Plant (SAPP) is very critical in the overall supply chain, given that it contributes about 9 % of total generation capacity. However SAPP can operate only on gas, supply of which has been irregular. Thus anytime there is no gas supply for any period, SAPP cannot operate (loss of 170 MW dependable capacities) and this would impact significantly on power supply reliability for 2015 with the resultant effect being the need to shed load Sensitivity Analysis on Generation Capacity This section looks at the supply scenario with a contingency on any of the major generation facilities within the power system. It is also considers the scenario for delay in the installation of Emergency Power Plants and the commission of ongoing projects such as TICO HRSG and Kpone thermal power plant. a) Delay in the Deployment of Emergency Power Plant A possible delay in the deployment of Emergency Power Plants would lead to severe load shedding and postponement of scheduled maintenance works of generation units. Table 10 and chart 7 indicate the load to be shed if the Emergency power plants are not injected into the system by the last quarter of Table 10: Operating Reserve Margin with No Emergency Power Plant Available Generation Capacity (MW) 2015 Projected Coincident Peak (MW) Jan Feb Mar April May June July Aug Sept Octobe r Supply Deficit (MW) Required Reserve MW Operating Reserve % -27% -32% -32% -28% -21% -18% -17% -21% -13% -18% -11% -13% Nov Dec Electricity Supply Plan

37 Chart 7: Supply deficit with No Emergency Plant The Table show a supply deficit for the entire year, with the month of March having the highest supply shortage Electricity Supply Plan

38 3.13 Overview of Short-Term (Three-Year) Load Forecast This section presents the short-term ( ) demand and energy consumption forecast and the purpose is to guide planning in the short-term. The system peak demand for 2016, 2017 and 2018 is expected to increase to 2,625 MW, 2,930 MW and 3,195 MW respectively. The corresponding projected energy consumptions are 17,901 GWh, 19,370 GWh and 21,821 GWh respectively. The expected spot loads for the period are the Newmont Kenyase mines (40 MW-2017), the Azumah mines of 23 MW(2017) at Yagha (50km NW of Wa), Tarkwa mines (15 MW- 2017), Damang mines (25 MW- 2016), Esaase ( 34 MW -2017) and potential for a third additional pot lines of VALCO for A summary of the peak demand by major consumers is as presented in Table 11 below Table 11: Summary of projected Demand for 2016, 2017 and 2018 Customer Demand (MW) Energy (GWh) Demand (MW) Energy (GWh) Demand (MW) Energy (GWh) ECG 1,571 10,477 1,659 11,060 1,753 11,692 NED 175 1, , ,368 Mines 355 2, , ,076 Direct Customers VALCO 150 1, , ,875 Exports (CEB) 152 1, , ,314 Exports (Sonabel) CIE (Ivory Coast) Inadvertent exchange EDM(Mali) Losses Coincident Peak +losses 2,625 17,901 2,930 19,370 3,195 21, Electricity Supply Plan

39 Existing Plants Planned Generation Table 12: Summary of projected Demand for 2016, 2017 and 2018 Generation Dependable Capacity Akosombo Kpong Bui TAPCo T TICo T T TT1PP CENIT Sunon Asogli Plant PH I MRP Siements TT2PP VRA SOLAR Aboadze Enclaze Emergency Plant APR Amandi Jacobson Rotan 450 VRA T TICO Expansion GT+Steam Kar Power New Barge GE Tema Enclaze KTPP Asogli II Expansion TT1PP+CENIT CCGT CEN Power KarPower Ship Domunli VRA Power Renewable Solar Savana Renewable Wind VRA NEC TOTAL Projected Generation Projected Peak (MW Projected Reserve Margin Required reserve Table 12 shows the projected generation versus the forecasted demand. It indicates that there would be adequate generation to supply the projected load for the three years period if the Planned Generation investment is realised and on time. The expected generation capacity by 2017 and 2018 is estimated to have a reserve margin higher than the required by a significant margin, however in 2016, the reserved margin of 297 MW would be short of the 473 MW required for reliable operation of the power system. This means that any time there is outage or contingency on any of the big generation units some loads have to be shed to protect the stability of the power system. It is critical therefore that additional generation is sourced to ensure adequate supply capacity for Electricity Supply Plan

40 4.0 TRANSMISSION SYSTEM OUTLOOK 4.1 Status of Ghana Transmission Grid Ghana s high voltage transmission network is made up of four voltage levels which are 330 kv, 225 kv, 161 kv and 69 kv. The transmission network consist of about 4,625.7 circuit kilometers of high voltage lines connecting generation centers of Akosombo, Kpong, Tema, Bui and Aboadze to fifty nine (59) Bulk Supply Centers across the nation. This is made up of 219 km of 330 kv, 4,193.6 km of 161 kv and km of 69 kv lines. In addition there is a single circuit 225 kv tie-line of 74.3 km connecting linking GRIDCo network with CIE of Cote d Ivoire. The network also features a 3, MVA of transformer capacity distributed across the nation. There is a System Control Centre (SCC) which controls and monitors the transmission network and 59 number substations. The SCC uses Supervisory Control and Data Acquisition (SCADA) System; to both monitor various power system parameters and control switching operations from a control center located in Tema. The communication system for the SCADA system is a combination of Optical Fibre and Power Line Carriers (PLC).The Optical Fibre is embedded in the ground wire on the transmission network and it also provides channels for transmission line relaying and voice communication. 4.2 Availability of Transmission Lines, Feeders and Substations All transmission lines consisting of 219km of 330kV, 74.3km of 225kV, 4,193.6km of 161kV, and 138.8km of 69kV are expected to be available to transmit the projected. Maintenance work on transmission lines and substations are not expected to affect power supply to customers except for single transformer stations and radial lines. The network has a total of 3, MVA transformer capacity. This capacity, compared with a projected load of 2,341 MW at an average power factor of 0.9, results in a transformer utilization factor (TUF) of 67 % for Since most transformers in the network are designed with a capability of 100% continuous loading (100% TUF). The projected TUF of 67% for 2015 implies adequate transformer capacity for the supply of power Electricity Supply Plan

41 4.3 System Analyses - Steady State To evaluate the overall impact of the demand-supply scenario on the security and reliability of the transmission system, requisite network analyses have been carried out. The analyses were mostly of the steady state nature to determine transmission line loadings, substation bus voltages and losses across the transmission network. In particular, the analyses performed sought to investigate the following: Possible constraints to secure a reliable power evacuation from the generating stations to the load centres from the perspective of transmission line loadings. Substations bus voltages in relation to overall network stability. The ability of the entire power system to withstand a contingency (i.e. outage) of a single network element (e.g. transmission line, generator, transformer, etc). Levels of reactive power generation from the generators. Adequacy or otherwise of overall reactive power compensation in the transmission network in achieving acceptable system voltages. The overall transmission system losses both during peak and off-peak periods. This way, the average annual transmission losses could be estimated. Security of generation schedule, this is to determine the best generation schedule to achieve voltage stability and minimum losses. 4.4 Summary of System Analysis Results 1. Transmission line losses are high, in the order of 4.58% of total generation during the peak period for the first half of the year; the figure reduces to 4% during the second half of the year due to increased generation from the west and completion of planned network improvement projects. We note that these levels of losses are instantaneous values. The regulated level of transmission losses is 3.5% in energy terms. 2. The load flow simulation analyses show that the increase in losses is largely due to resistive loads than reactive power demand, most lines are carrying power significantly above their SIL limits, and there is therefore the need to build more transmission lines to reduce overall system resistance. 3. The load flow analyses also indicate that the current power system could evacuate all the 470 MW from the eastern section of the transmission system. For the maximum western generation, the power flow shows that, up to 900 MW western generation could be evacuated Electricity Supply Plan

42 4. During peak load conditions, a minimum of 300 MW (3 generating units) power should be produced at Aboadze to ensure voltage stability of the network. 4.5 Transmission System Constraints The Load Flow analysis shows that the transmission network has just enough capacity to transmit the projected power generation from all generation stations to the load centers during normal operating conditions for some sections of the networks. Thus in the event of a contingency on any of the critical lines such as Aboadze Prestea, Volta - Achimota, Volta A3BSP, Aboadze Volta 330 kv etc, low voltages and overloads on adjacent lines are experienced. This situation is most often than not accompanied by load shedding in order to avert system collapse. Also for the radial lines ( Esiama, Yendi, Akyempim etc) and single transformer stations such as Esiama, Akosomb0, Yendi etc a force or planned outage on any of the lines or transformer would lead to an outage to customers. The results of simulation further show low voltages in Kumasi and Accra zones as shown in the Table below. Table 13 Load Flow results of selected bus voltages Electricity Supply Plan

43 Figure 8: Load Flow results of selected bus voltages In order to address the above network constraints the following transmission line upgrades needs to be carried out: Upgrading of Achimota Mallam 161 kv transmission line from 170 MVA to 488 MVA, twin Tern ACSR 2x430 sqmm line would improve bus voltages at Achimota and its environs. It would also reduce overall transmission losses and loading on the lines. Upgrade of the Takoradi Tarkwa 161 kv transmission line into a double circuit twin Tern ACSR 2x430 sqmm line is critical to forestall the existing high loadings on the line and increase power evacuation capacity from the west towards the north. Upgrade of the 161 kv Aboadze- Mallam transmission line into a double circuit twin Tern ACSR 2x430 sqmm line. Upgrade of the 161 kv Aboadze -Takoradi transmission line into a double circuit twin Tern ACSR 2x430sqmm line Electricity Supply Plan

44 Upgrade of the 161 kv Takoradi - Esiama transmission line into a double circuit twin Tern ACSR 2x430 sqmm line. Upgrade of 161 kv Tarkwa New Tarkwa into a single circuit twin Tern ACSR 2x430 sqmm line. Upgrade of 161 kv Takoradi Tarkwa into a single circuit twin Tern ACSR 2x430 sqmm line Electricity Supply Plan

45 4.6 Electricity Transmission Risk Assessment Adequacy in Transmission Capacity On the transmission network, the major risks to supply security and reliability are: Inadequacy in transmission capacity which could lead to transmission line overloads. This phenomenon which is characteristic of the network mostly during the peak period is due to growth in demand over the years, which has not been accompanied by commensurate expansion or reinforcement of the transmission network. Insufficient reactive power compensation which could lead to poor customer supply voltage. This condition is due to low customer-end power factors, leading to high generator reactive power output and transfer of such reactive power over long distances. The resultant effect is high transmission line losses and higher voltage drops which invariably affect the quality of supply voltage. Inability of the transmission network to withstand some single contingencies. This is as a result of low investment in the transmission network, such that the network does not satisfy what is called n-1 criterion a measure of a transmission network s ability to withstand an outage of a single network element. A significant percentage of the transmission network is radial, a contingency on any of these radial lines results in outages to consumers Electricity Supply Plan

46 4.6.2 Adequacy in Transformation Capacity Table 14 shows the transformer loadings for the month of November Table 14: Summary of key Substations Transformers and their Loading Levels Substation Transformer Code Rating (MVA) Loading November 2014 % of Rating 5T The criterion for normal operating conditions requires that transformers should not be 5T Achimota 5T T T T Mallam 37T T T T T New Tema 4T T T T T T Kumasi 13T T T Takoradi 8T T Tamale 28T T loaded above 100% of their rated capacities, such that under emergency or contingency conditions, the loading could increase to 120% of the rated for a short time. However, as shown in the Table above, this important criterion is not being respected in some few substations. In fact in Achimota, Mallam and Kumasi an overload conditions are already being experienced during the normal operating conditions as shown in the table above Electricity Supply Plan

47 4.7 Transmission System Improvement Projects for 2015 In line with the current GRIDCo s objective of implementing strategic and systematic improvement of the National Interconnected Transmission System (NITS), the following projects have been earmarked for installation and commissioning in These projects are expected to improve overall system reliability, security and general quality of supply Power Transformer A total of 297 MVA transformer capacity is expected to be added into the network to improve upon reliability and ensure N-1 operation and a maintenance criterion is achieved. The table below shows the transformer planned to be installed in various substations across the nation. Table 15: transformers scheduled for installation in 2015 NAME OF SUB STATION NO. VOLTAGE(kV) CAPACITY (MVA) Achimota 1 161/ /66 A3BSP 2 161/ /66 Dunkwa 1 161/ /33 Winneba 1 161/ /66 Takoradi 1 161/ /66 The commissioning of the above transformers will improve upon system stability and reduce overloading of transformers especially during contingency situations Electricity Supply Plan

48 4.7.2 Transmission Lines In a bid to increase transmission line capacities, reduce overloading on existing ones and improve upon reliability of the entire transmission network, a number transmission line projects were started in 2014/2015. The works are expected to be completed in 2015/2016. The following are the projects: Tumu Bolga 161 kv Transmission line Mim Juabeso Asawinso 161 kv Transmission line Volta A3BSP-Achimota transmission line upgrade-(construction of a double circuit 161kV twin bundle Tern) to be completed in Mallam - Achimota transmission line upgrade to be completed in Termination of Takoradi Prestea line at Tarkwa. Aboadze Prestea 330 kv double circuit transmission line. Sunyani Brekum 161 kv transmission line. 4.8 Substation Major project works are currently on-going for the construction of three additional substations at Tema, Juabeso and Brekum. The works are at various stages of completion and they are expected to be commissioned into service in 2015 and 2016 as shown in the schedule below: Table 16: Substation to be commissioned in 2014 Substation Planned Completion Date Brekum 2016 Juabeso 2016 Kpone Thermal Electricity Supply Plan

49 5.0 SYSTEM PERFORMANCE REVIEW FOR Performance Review This section of the report seeks to review and compare the 2014 actual network performances with the projection for the National Interconnected Transmission System (NITS) of Ghana. It compares the estimated peak demand, energy consumption, the corresponding generation scenario against the actual figures recorded within the review period. Other system conditions such as voltages and transmission system losses are also assessed. 5.2 Maximum System Demand The maximum demand recorded for the period was 1,970.9 MW which occurred on January 16, 2014.The projected peak demand for the year was 2,179.5 MW which was estimated to occur in December However due to load shedding as a result of insufficient generation the projected load could not be supplied. The generation shortage was largely the results of erratic supply of gas from WAGP, low Volta lake elevation and forced outage or breakdown of thermal units. The summary of the projected and the actual peak demands recorded in the year are as presented in the Table 17: Table 17: System Peak Demand for 2014 and Projection Major Customers System Peak(MW) Actual 2014 System Peak (MW) Projection 2014 Difference(MW) (Projection-Actual) Domestic/Ghana Peak Export Valco System Peak (coincident) Electricity Supply Plan

50 5.3 Energy Consumption The period under review registered a total energy consumption including losses of 13,071.0 GWh as against the projected total energy consumption of 14,721 GWh. Compared to the 2013 consumption of 12,906.5 GWh, the 2014 figure represents a growth of 1.3% or 165 GWh increase over that of 2013 figure. The low growth was due to load shedding carried out in the period because of insufficient generation. A summary of the 2014 projected and actual energy consumption is presented in Table 18 below: Table 18: Summary of Energy Consumption for 2014, actual vs. projection Customer Projection (GWh) Actual (GWh) 2014 Actual (GWh) 2013 % Growth 2014 ECG ,370 8, % NED % Mines ,553 1, % VALCO % Export % Direct Customers % Losses % Total Energy 14, , , % The details of the maximum demand and energy consumption per Bulk Supply Points are included in Appendix B. 5.4 GENERATION PERFORMANCE 5.5 Reservoir Elevation Performance Recorded net inflow into the Akosombo reservoir as of December 31, 2014 was MAF and this is about 22% below the Long term average. Total plant discharge for 2014 was MAF. The reservoir drawdown during the depletion season (Jan 1- Aug. 28) was ft. The rise recorded during the flood season was 7.15 ft. (Aug. 28 Nov.1, 2014).The reservoir elevation was ft at the beginning of the year. However, the maximum elevation at the end of the flood season was only ft. The elevation as of December 31, 2014 was ft. This is approximately 7 ft above the minimum operating level of the reservoir Chart 9: Generation mix for Electricity Supply Plan

51 5.6 Generating Plants Availability for 2014 As shown in Table 19 below all the generation plants performed higher than their projected availability with exception of TAPCo, T3, TICO and TT2PP plants. The low availability of the T3 plant was due to a design defect which resulted in a damaged to the units after running 4,000 hours continuous operation. The TICo plant on the other hand was shut down for HRST connection and to fix a turning gear mechanism problem. Table 19 presents the actual generating plants availability in comparison to the forecast values for the period under review. Table 19: Generating Plants actual and estimated availability for 2014 Plant Forecast (%) Availability 2014 Actual (%) Availability 2014 Akosombo Hydroelectric Plant Kpong Hydroelectric Plant Bui 94 - Takoradi Thermal Power Plant-T1 (TAPCO) Takoradi Thermal Power Plant-T2 (TICO) Tema Thermal Power Plant-T1 (TT1PP) Mines Reserve Plant (MRP) Tema Thermal Power Plant-T2 (TT2PP) Electricity Supply Plan

52 Sunon Asogli Power Plant (SAPP) T CENIT Projected Versus Actual Energy The projected 2014 energy generation based on the estimated availability factors of the generating plants are compared in the Table below with the actuals recorded within the period. As indicated in the Table, the three hydroelectric plants were expected to produce a total of 7,399.9 GWh during the period. The plants however, produced a total of 8,386.6 GWh, GWh higher than the projected. Table 20: Projected and actual energy generation for 2014 Projection (GWh) 2014 Actual (GWh) 2014 Hydro Thermal Solar Import Total Hydro Thermal Import Total 7, , , , , ,011.6 Chart 10: Generation mix for 2014 A total of 4,571.8 GWh of energy was generated from all thermal plants, namely; TAPCO, TICO, TT1PP, MRP, TT2PP, CENIT and SAPP with import of 53.2 GWh. The generation mix at the end of the period was thus 65%, 34.9% and 0.1 % for hydro, thermal and imports respectively Electricity Supply Plan

53 5.8 Export, Import and Wheeling of Power Energy A total of GWh in all was exported directly from Ghana, whilst GWh of energy was wheeled from Cote d Ivoire to Togo/Benin within the period via the Ghana network. A net energy value of 19.6 GWh was exported to CIE Electricity Supply Plan

54 5.9 Transmission Network Performance Transmission Lines Transmission lines recorded an average availability performance of % for the period. This figure represents a significant increase over the 2013 performance of 97.59% which is significantly above the required performance target. The increase in performance is among others attributable to numerous network upgrades and expansion projects couple with quick response to faults. It is worth noting that most of the line outages did not result in supply curtailments to customers due to alternate supply arrangements. Table21: the transmission line availability for Voltage Class Availability % 69kV 99.60% 161kV 99.64% 225kV 94.83% 330kV 99.06% System Average Availability % 99.58% Feeders The GRIDCo network registered an average feeder availability (excluding planned outages) of % for the period under review; this performance is an improvement over the 2014 figure of 99.30%. The average performance is above the regulated benchmark of 95.0%. Table 22 show the feeder availability for Table 22: Feeder availability 2014 versus 2010 Year Feeder Availability% Electricity Supply Plan

55 5.10 Transmission System Losses During the period, average transmission losses of 4.32 % or GWh was recorded as compared to the projected figure of 3.7 % or GWh. This increase in overall average transmission losses is largely due to non-optimal generation scheduling and inadequate transmission capacity. Table 23 shows system transmission losses for the period Chart 23: Transmission losses Year Transmission Losses% Commissioned Projects A summary of completed network addition and upgrade project are presented below Generation Plants No power generation plant was commissioned during the period Transmission Lines A 150 km, 161kV Tumu Wa transmission Line was commissioned during the period. The project has provided a loop in the north to improve upon supply security and reliability in the North. Also a double circuit twin toucan ACSR line was constructed to replace the 170 MVA Mistletoe Prestea Bogoso line. This was to increase the transmission transfer capacity to enable the transfer more power from Prestea to serve the mining load of Bogoso and surrounding Bulk Supply centers Electricity Supply Plan

56 5.12 Substation/Transformers During the period under review, two new Bult Supply Points (substations) were commissioned into service. The stations are the 161kV Wa and Tumu substations. The transformation capacities of the two stations are presented in Table 24 below: Table 24: Transformers commissioned in 2014 NAME OF SUB STATION NO. VOLTAGE(kV) CAPACITY (MVA) Tumu 1 161/ /33 Wa 1 161/ / Electricity Supply Plan

57 6.0 CONCLUSIONS The following conclusions are drawn in respect of the electricity supply and demand situation for 2015: a total system demand is projected to be 2,341 MW, this figure represents 18.8 % growth over the 2014 figure of 1,970.7 MW. The factors contributing to high increase in load demand is an expected increase in spot loads prominent among them are Kpong Water Works expansion (25 MW) and Enclave Power Authority 42 MW. b. The projected 2015 energy consumption for 2015 is 16,039 GWh, however only 13, 928 GWh is expected to be supplied as follows: iv. Hydro - 5,963 GWh representing 42.8% of the total energy supply v. Thermal - 7,960.5 GWh representing 57.2% of total energy supply vi. Renewable Solar GWh representing the remaining 0.03% The remaining 2,111 GWh hour would have to be shed because of expected supply deficit in 2015 c. The uncertainties related to gas supply from the WAGP could impact negatively on the ability of the power generating companies to meet the forecasted demand since this situation could result in the inability of Sunon Asogli Power Plant (SAPP) particularly to generate power. The cost of thermal generation would also increase because of the relatively higher cost of LCO as substitute for gas. d. Also the low levels of Akosombo reservoir as a result poor inflows into the Dam and the retrofit works on the Kpong Hydroelectric plant is expected to reduce generation from Hydro sources significantly. e. The current inadequacies in transformer capacities could lead to overloading at some major substations during normal operation conditions. This state of affairs is exacerbated during contingency conditions and normally results in load reduction. f. The transmission system has inadequate firm transfer capability to some of the major load centers (of Accra, Kumasi, Tarkwa etc) mostly at peak. This situation results in low voltages, overloading of lines and increase in transmission system losses. A significant percentage of network loads are islanded in case of outage on some single lines Electricity Supply Plan

58 g. Voltages at Kumasi, Accra and surrounding areas are low because of inadequate installed reactive power and high loading of transmission lines. The timely implementation of the system expansion works would eliminate most of these critical states of the network. h. Generation scheduling has significant impact on system losses. System losses are lower with maximum generation at the west compared to losses with maximum generation at the east. i. It has been established through load flow studies that a minimum of 300 MW has to be always online in Aboadze to ensure network voltage stability Electricity Supply Plan

59 7.0 RECOMMENDATIONS Based on the above conclusions, the following recommendations have been made: a. The planned 2015 grid expansion programmes especially those connected with transmission upgrades should be expedited and completed on schedule. b. Major system expansion projects such as the Prestea-Kumasi 330 kv line, Aboadze Prestea double circuit 330kV line, Kpando-Kedjebi and Volta A3BSP-Achimota Mallam line upgrade Project should be expedited to enable early completion to meet the expected increases in demand and generation. c. Timely completions of Kpone Thermal Power Plant KTTP, TICO HRSG and the injection of 715 MW emergency power plant by third quarter of 2015, otherwise the generation deficit would increase. d. ECG should be advised to provide reactive power compensation on its distribution network. e. A well-coordinated generating plant and transmission facilities maintenance program should be pursued by generators and GRIDCo Electricity Supply Plan

60 APPENDICES Electricity Supply Plan

61 Appendix A Forecast, Peak Demand and Energy Consumption A1: Projected Peak Demand A2: Projected Energy Consumption Appendix B actual Peak Demand and Energy Consumption B1: Projected Actual Energy Consumption B2: Projected Actual Peak Demand per BSP Appendix C Glossary Appendix D Grid Map Electricity Supply Plan

62 A1: Demand Peak Forecast (MW) Load forecast: Peak demand (MW) ECG 1,393 1,496 1,571 1,659 1,753 1,869 1,993 2,126 2,268 2,420 2,582 2,756 NEDCo MINES DIRECT VALCO CEB(Togo/Benin) SONABEL(Burkina) CIE(Ivory Coast) Inadvertent exchange EDM(Mali) LOSSES + Network Usage TOTAL (Coincident Peak) 2,144 2,341 2,625 2,930 3,195 3,613 3,778 3,997 4,167 4,349 4,542 4,748 GROWTH 9% 12% 12% 9% 13% 5% 6% 4% 4% 4% 5% Electricity Supply Plan

63 A2: Projected Energy Consumption (GWh) Load forecast: Energy GWh) ECG NEDCo MINES DIRECT Valco CEB(Togo/Benin) SONABEL(Burkina) CIE(Ivory Coast) Inadvertent exchange EDM(Mali) Losses + Network Usage Total Energy GWh ,545 16,039 17,901 19,370 21,829 24,850 25,955 27,416 28,542 29,750 31,029 32, Electricity Supply Plan

64 Electricity Company of Ghana-Monthly Actual Energy Consumption (GWh) by BSP s in 2014 STATIONS January February March April May June July August September October November December Total Kpong Akuse New Tema , Achimota , Mallam , Winneba Accra East Cape Coast Takoradi Essiama Prestea Bogoso Tarkwa Akyempim Dunkwa Asawinso Obuasi Kumasi , Electricity Supply Plan

65 Anwomaso Konongo Nkawkaw Akwatia Tafo Ho Kpeve Kpando Asiekpe Sogakope Aflao TOTAL , Electricity Supply Plan

66 Electricity Company of Ghana-Actual Peak Demand STATIONS January February March April May June July August September October November December HIGHEST Kpong Akuse New Tema Achimota Mallam Accra East Winneba Cape Coast Takoradi Essiama Bogoso Tarkwa Akyempim Dunkwa Prestea Asawinso Obuasi Anwomaso Kumasi Konongo Nkawkaw Akwatia Tafo Ho Kpong Kpeve Kpandu Asiekpe Sogakope Aflao TOTAL Electricity Supply Plan

67 Northern Electricity Distribution Company Actual Energy Consumption (GWh) STATIONS January February March April May June July August September October November December TOTAL Sunyani Techiman Tamale Buipe (PBC) Bol'tanga Yendi Sawla Zebilla Mim Kintampo Wa 1.0 Tumu 0.0 TOTAL Northern Electricity Distribution Company Actual Peak Demand (MW) STATIONS January February March April May June July August September October November December Maximum Sunyani Techiman Tamale Bol'tanga Yendi Sawla Buipe (PBC) Zebilla Mim Kintampo Wa Tumu TOTAL Electricity Supply Plan

68 Mines-Energy Consumption (GWh)-2014 CUSTOMERS January February March April May June July August September October November December Total Gold Fields -New Tarkwa Prestea/Township Prestea/Ncm Prestea/ Sankofa Alpinore / Owere Konongo-Alpinore/Owere Anglogold- OBUASI Anglogold-NEW OBUASI Gcd Ltd-Akwatia Golden Star - Bogoso Golden Star Akyempim Adamus Gold - Essiama Central Ashanti Gold Central Ashanti Gold - Ayanfuri Newmont - NEW ABIREM Newmont - KENYASE TOTAL , Electricity Supply Plan

69 Mines-Peak Demand (MW)-2014 CUSTOMERS January February March April May June July August September October November December Maximum Gold Fields -NEW TARKWA PRESTEA/Township PRESTEA/NCM PRESTEA/ Sankofa KONONGO- Alpinore/Owere Anglogold- OBUASI Anglogold-NEW OBUASI GCD LTD-AKWATIA GOLDEN STAR Golden Star - BOGOSO Golden Star AKYEMPIM ADAMUS GOLD MINES Adamus Gold - ESSIAMA Central Ashanti Gold - AYANFURI NEWMONT Newmont - NEW ABIREM Newmont - KENYASE TOTAL Electricity Supply Plan

70 Glossary of Electrical Utility Terms 1000 Watt-hours = 1 Kilo Watt-hour (kwh) 1000 Kilo Watt-hour = 1 Mega Watt-hour (MWh) 1000 Mega Watt-hour = 1 Giga Watt-hour (GWh) 1000 Giga Watt-hour = 1 Tera Watt-hour (TWh) Average Day Load The average system demand is indicative of the system s load during most part of the day that is from 7: am 5: pm apart from the peak load. Capability The maximum load a generator, piece of equipment, substation, or system can carry under specified (standardized) conditions for a given time interval without exceeding approved limits. Capacitor 1) In a power system, installed to supply reactive power. 2) A device to store an electrical charge (usually made of two or more conductors separated by a nonconductor such as glass, paper, air, oil, or mica) that will not pass direct current and whose impedance for alternating current frequencies is inversely proportional to frequency. 3) In a power system, capacitors consist of metal-foil plates separated by paper or plastic insulation in oil or other suitable insulating fluid and sealed in metal tanks. Capacitor bank A grouping of capacitors used to maintain or increase voltages in power lines and to improve system efficiency by reducing inductive losses. Capacity The rated continuous load-carrying ability, expressed in megawatts (MW) or megavolt-amperes (MVA) of generation, transmission, or other electrical equipment. Installed Capacity The total of the capacities shown by the name plate ratings of similar kinds of apparatus, such as generators, transformers, or other equipment in a station or system. Combined Cycle Electricity Supply Plan

71 An electric generating technology in which electricity is produced from otherwise lost waste heat exiting from one or more gas (combustion) turbines. The exiting heat is routed to a conventional boiler or to a heat recovery steam generator for utilization by a steam turbine in the production of electricity. Such designs increase the efficiency of the electric generating unit. Conductor A substance or body that allows an electric current to pas continuously along it. Contingency In a power system, the possibility of a fault or equipment failure. First contingency disturbances (outages) involve only one system element, such as a transmission line fault or a transformer failure. A second contingency disturbance would have one system element out of service and subject the system to a fault and loss of a second element. Demand The rate at which electric energy is delivered to or by the System or part of the System and is the sum of both Active and Reactive Power, unless otherwise stated. Demand, Peak: The highest electric requirement occurring in a given period (e.g., an hour, a day, month, season, or year). For an electric system, it is equal to the sum of the metered net outputs of all generators within a system and the metered line flows into the system, less the metered line flows out of the system. Dispatch The operating control of an integrated electric system to: (1) assign specific generating units and other sources of supply to meet the relevant area Demand taken as load rises or falls; (2) control operations and maintenance of high voltage lines, substations and equipment, including administration of safety procedures; (3) operate interconnections; (4) manage energy transactions with other interconnected Control Areas; and (5) curtail Demand. Disturbance An unplanned event that produces an abnormal system condition. Any occurrence that adversely affects normal power flow in a system Fault Electricity Supply Plan

72 An event occurring on an electric system such as a short circuit, a broken wire, or an intermittent connection. Generation (Electricity) The process of producing electric energy from other forms of energy; also, the amount of electric energy produced, expressed in watthours (Wh). Giga (G) A prefix indicating a billion (1,000,000,000); 109 in scientific notation. Hence GigaWatt(GW) and GigaWatt-hour (GWh). Grid The transmission network (or highway ) over which electricity moves from suppliers to customers. Grid Operator An entity that oversees the delivery of electricity over the grid to the customer, ensuring reliability and safety. High voltage: Descriptive of transmission lines and electrical equipment with voltage levels from 100 kv through 287 kv. Independent Power Producer (IPP): An private entity that operates a generation facility and sells power to electric utilities for resale to retail customers. Insulator: The porcelain support used to insulate electric service wires from the pole. All electric lines require an insulator to attach the wires to the pole or to a residence. Interconnected System A system consisting of two or more individual electric systems that normally operate in synchronism (matching frequency, voltage, phase angles, etc) and have connecting tie lines. Kilowatt (kw) One thousand watts of electricity (See Watt). Kilo watthour (kwh): One thousand watthours Electricity Supply Plan

73 Load The amount of power carried by a utility system or subsystem, or amount of power consumed by an electric device at a specified time.may also be referred to as demand. A connection point or defined set of connection points at which electrical power is delivered to a person or to another network or the amount of electrical power delivered at a defined instant at a connection point, or aggregated over a defined set of connection points. Load Centers A geographical area where large amounts of power are drawn by end-users. Losses Electric energy losses in the electric system which occur principally as energy kilowatt-hours (kwh) to waste heat in electrical conductors and apparatus. transformation from Maximum Demand: The highest amount of electrical power delivered, or forecast to be delivered, over a defined period (day, week, month, season or year) at a defined. Megawatt (MW) One million watts of electricity (See Watt). Overload Operation of equipment in excess of its normal, full load rating or operation of a conductor in excess of ampacity, and if continued for a sufficient length of time, would cause damage or overheating. System Planning The process by which the performance of the electric system is evaluated and future changes and additions to the bulk electric systems are determined. Power System The electricity power system of the national grid including associated generation and transmission and distribution networks for the supply of electricity, operated as an integrated arrangement. Reactive Power Means the product of voltage and current and the sine of the phase angle between them measured in units of volt-amperes reactive and standard multiples thereof. Reactive power is a necessary component of alternating current electricity which is separate from active power and is predominantly consumed in the creation of magnetic fields in motors and transformers and produced by plant such Electricity Supply Plan

74 as:(a) alternating current generators (b) capacitors, including the capacitive effect of parallel transmission wires;(c) synchronous condensers. Reliability The degree of performance of the elements of the bulk electric system that results in electricity being delivered to customers within accepted standards and in the amount desired. It is a measure of the ability of a power system to provide uninterrupted service, even while that system is under stress. Reliability may be measured by the frequency, duration, and magnitude of adverse effects on the electric supply. Electric system reliability has two components -- adequacy and security. Adequacy is the ability of the electric system to supply the aggregate electrical demand and energy requirements of the customers at all times, taking into account scheduled and reasonably expected unscheduled outages of system elements. Security is the ability of the electric system to withstand sudden disturbances such as electric short circuits or unanticipated loss of system facilities. Single Contingency The sudden, unexpected failure or outage of a system facility(s) or element(s) (generating unit, transmission line, transformer, etc.). Elements removed from service as part of the operation of a remedial action scheme are considered part of a single contingency. Stability The ability of an electric system to maintain a state of equilibrium during normal and abnormal system conditions or disturbances. Supervisory Control and Data Acquisition (SCADA) A computer system that allows an electric system operator to remotely monitor and control elements of an electric system. Switching Station An installation of equipment where several transmission lines are interconnected. Does not include equipment for transforming voltage levels. Power System An interconnected combination of generation, transmission, and distribution components comprising an electric utility, an electric utility and independent power producer(s) (IPP), or group of utilities and IPP(s) Electricity Supply Plan

75 Right of Way (ROW) A corridor of land on which electric lines may be located. The Transmission Owner may own the land in fee, own an easement, or have certain franchise, prescription, or license rights to construct and maintain lines. Thermal Limit The maximum amount of electrical current that a transmission line or electrical facility can conduct over a specified time period before it sustains permanent damage by overheating or before it violates public safety requirements. Transfer Capability The amount of power, usually the maximum amount, that can be transmitted between one system and another; power flow and stability studies determine transfer capability under various outage, system loading, and system operating conditions. Transformer A device for transferring electrical energy from one circuit to another by magnetic induction, usually between circuits of different voltages. Consists of a magnetic core on which there are two or more windings. In power systems, most frequently used for changing voltage levels. Transmission System (Electric) An interconnected group of electric transmission lines and associated equipment for moving or transferring electric energy in bulk between points of supply and points at which it is transformed for delivery over the distribution system lines to consumers, or is delivered to other electric systems. Utility A public or private organization created for the purpose of selling or supplying for general public use water, electric energy, telephone service, or other items or services. Voltage The electronic force or electric potential between two points that gives rise to the flow of electricity. Voltage Stability The condition of an electric system in which the sustained voltage level is controllable and within predetermined limits. Wheeling Electricity Supply Plan

76 The use of the facilities of one transmission system to transmit power and energy from one power system to another Electricity Supply Plan

77 Electricity Supply Plan