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2014 Electricity Supply Plan 1

Acknowledgement

We acknowledge the support of the following institutions in the write up of the 2014 Electricity Supply Plan:

• Volta River Authority (VRA)

• Electricity Company of Ghana (ECG)

• CENIT Thermal Power Plant

• Sunon Asogli Power Plant

• Takoradi International Company

• Bui Power Authority

• Northern Electricity Distribution Company

• Volta Aluminum Company

• Ministry of Energy

2 2014 Electricity Supply Plan

EXECUTIVE SUMMARY

The 2014 Supply Plan is an estimated demand and supply scenario for 2014, 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 (2015- 2017) energy and demand outlook.

It also presents an overview of generation and transmission system performance in 2013.

Projected Demand and Energy Consumption for 2014

The projected base case coincident peak demand for year 2014 is 2,179.5 MW, which represents a 12.2 % growth over the 2012 recorded figure of 1,942.9 MW. This assumes VALCO’s one potline operation.

The total expected energy consumption for 2014 is 14,721.25 GWh. With an actual energy consumption of 12,927.53 GWh in 2012, the projected 2014 figure represents a growth of 13.9 %.

Projected Hydro and Thermal Power Generation

The projected total hydro generation for 2014 is 7,400 GWh, this would be made up of 5,683 GWh, 1,017 GWh and 700 GWh from Akosombo, Kpong and Bui Generation Stations respectively.

The projected total thermal generation for 2014 is 7,317.3 GWh. This would be made up of Generation from the following plants: TAPCo (2,102 GWh), TICO (1,321 GWh), Takoradi-T3 (672 GWh), TT1PP (745 GWh), TT2PP (335 GWh), MRP (152 GWh), SAPP (1240 GWh) and CENIT (745 GWh).

Available Generation versus Projected Demand and Consumption

A comparison of projected demand and available generation for 2014 on a monthly basis indicates a shortfall in capacity of 240 MW to 400 MW in the first half of 2014 assuming a reserve margin of 18% of projected peak. A total of 99.5 GWh of energy is projected to be shed in the first half of 2014. There would however be reasonable capacity to meet the load in the last half of the year. It should be noted that this analyses assumes availability of fuel at all times and it did not factor force outage on units. This presupposes that any shortage in gas supply or LCO for thermal generation could result in severer load shedding than projected.


Fuel Cost

Sources of fuel for thermal energy generation are expected to consist of 38,770,000 MMBtu of Natural Gas, 6,992,000 barrels of LCO and 81,000 barrels of DFO.

The total cost of fuel for thermal generation is estimated at USD 1,140,098,660.


SHORT-TERM (3 YEARS FORECAST) CONCERNS

The system peak demand for 2015, 2016 and 2017 is assumed to increase at a steady rate of 2,573.7MW, 2,866.8 MW and 3,065.9 MW respectively. The corresponding projected energy consumption for 2015, 2016 and 2017 are 17,699.0 GWh, 19,678.1 GWh and 21,022.7 GWh respectively. Taking planned maintenance works of generation units into consideration the maximum monthly available generation in 2015 would be about 2,650 MW. This includes the yet to be commissioned TICO Steam (100 MW), and two units of Kpone plant (200 MW). As shown in the Table below, the reserve margin for 2015 would be 26.3 MW or 3% of the projected load.

With no expected generation addition the maximum available generation capacity is projected to remain same at 2,650 MW in 2016, the peak load is however expected to increase to 2,886.3 resulting in a high deficit in supply of 216.8 MW.

Summary of projected generation and demand for 2015, 2016 and 2017

Since the required reserve margin for reliable supply is 18%, the power supply for 2015 to 2017 would not be adequate to meet demand and maintain the acceptable reserve margin. It is therefore critical to source additional generation capacity of about 500m MW to be provided within 2015.

TRANSMISSION SYSTEM OUTLOOK

The transmission infrastructure has enough capacity to transmit the projected generation for 2014. All transmission lines consisting of 219 km of 330 kV, 74.3 km of 225 kV, 4,017.6 km of 161kV, and 138.8 km of 69 kV are expected to be available to transmit the projected energy for 2014.

The network has a total of 3,870.9 MVA transformer capacity which is more than enough for the supply of power in 2014.


TABLE OF CONTENTS

EXECUTIVE SUMMARY…………………………………………………….…………….....…...........………2

1.0 INTRODUCTION………………………………………………….…………….....……........................7

2.0 FORECAST DEMAND…………………………………………….…………….....…..........................8

2.1 ENERGY CONSUMPTION OUTLOOK.......................................................................................9

2.2 MONTHLY ENERGY CONSUMPTION.......................................................................................11

3.0 PROJECTED GENERATION………………………………………….……….....….........................12

3.1 HYDRO PLANT AVAILABILITY AND POWER GENERATION............................................12

3.2 THERMAL POWER GENERATION.............................................................................................12

3.3 RENEWABLE ENERGY...................................................................................................................12

3.4 GENERATION MIX........................................................................................................................13

3.5 PLANNED MAINTENANCE SCHEDULE OF GENERATING PLANTS..............................13

3.5.1 AKOSOMBO HYDRO PLANT...............................................................................................................14

3.5.2 KPONG HYDRO PLANT.........................................................................................................................14

3.5.3 BUI HYDROELECTRIC PLANT..............................................................................................................14

3.5.4 TAKORADI THERMAL PLANT T1................................................................................................. .....14

3.5.5 TAKORADI THERMAL PLANT T2......................................................................................................15

3.5.6 SUNON ASOGLI POWER PLANT........................................................................................................15

3.5.7 TEMA THERMAL PLANT TT1PP & TT2PP........................................................................................15

3.5.8 MINES RESERVE POWER PLANT.........................................................................................................15

3.5.9 TAKORADI THERMAL PLANT T3......................................................................................................15

3.5.10 CENIT THERMAL PLANT......................................................................................................................16

3.6 AKOSOMBO RESERVOIR ELEVATION PROJECTION FOR 2014....................................20

3.7 BUI HYDRO PLANT......................................................................................................................21

3.7.2 PLANT OPERATIONS PLAN................................................................................................................21

4.0 TRANSMISSION SYSTEM OUTLOOK........................................................................22

4.1 AVAILABILITY OF TRANSMISSION LINES, FEEDERS AND SUBSTATIONS.................22

4.2 TRANSMISSION SYSTEM ANNUAL MAINTENANCE PROGRAM................................22

4.3 CHALLENGES OF THE TRANSMISSION NETWORK..........................................................22

4.3.1 NITS EVACUATION CAPACITY......................................................................................................................22

4.3.2 VOLTAGE STABILITY..........................................................................................................................................22


4.4 TRANSMISSION SYSTEM IMPROVEMENT PROJECTS FOR 2014................................22

4.4.1 TRANSMISSION LINES.....................................................................................................................................23

4.4.2 SUBSTATIONS........................................................................................................................................23

4.4.3 POWER TRANSFORMER CAPACITY...............................................................................................24

4.4.4 SHUNT CAPACITOR BANKS..............................................................................................................24

5.0 ELECTRICITY DEMAND-SUPPLY BALANCE……………………….……………..........……...25

5.1 AVAILABLE GENERATION CAPACITY VERSUS PROJECTED LOAD DEMAND.....................26

5.2 PROJECTED MONTHLY ENERGY GENERATION AND CONSUMPTION.................................27

6.0 RELIABILITY OF SUPPLY…………………….…………….....…….........................................28

6.1 GENERATION SUPPLY RELIABILITY ASSESSMENT......................................................................................28

6.1.1 INADEQUACY OF AVAILABLE GENERATION (WITH ADEQUATE SPINNING AND

RESERVE) CAPACITIES....................................................................................................................................28

6.2 SENSITIVITY ANALYSIS ON GENERATION CAPACITY.............................................................................30

6.4 POWER TRANSMISSION RELIABILITY ASSESSMENT................................................................................31

6.4.1 ADEQUACY OF TRANSMISSION CAPACITY.................................................................................31

6.4.2 ADEQUACY OF TRANSFORMATION CAPACITY ......................................................................32

7.0 OVERVIEW OF SHORT-TERM (3 YEARS) FORECAST………………….………….....….....33

8.0 PROJECTED COST OF ELECTRICITY SUPPLY............................................................................35

8.1 FUEL COST .........................................................................................................................................35

8.2 ELECTRICITY TRANSMISSION COST.......................................................................................35

8.2.1 DIRECT AND INDIRECT COST........................................................................................................................35

8.3 COST OF 2014 PLANNED TRANSMISSION SYSTEM IMPROVEMENT

PROJECTS.................................................................................................................................................35

SYSTEM PERFORMANCE REVIEW FOR 2013...................................................................37

9.0 CONCLUSIONS………………….…………….....……............................................................40

APPENDICES………….…………….....……................................................................................42


1.0 INTRODUCTION

The past decade has registered an annual electricity demand growth well above 10% which had put considerable strain on the power system, specifically on generation which over the years had not been able to match up to demand adequately.

Hence the supply of electric power (Generation, Transmission and Distribution) over the coming years will need to expand to meet the growing demand for electricity. There will be broad ramifications for the diverse economy of the country depending on how fast; the production of electricity develops compared to the load demand.

This report presents the 2014 Electricity Supply Plan; it discusses the critical issues for the supply of power in the coming year considering a baseline projected scenarios.

Among the critical issues discussed are the projected demands for electricity, the total available electric generating capacity, and fuel sources for thermal generation, generation mix, and the capacity of the transmission network to deliver the generation to the load reliably.

The 2014 Electricity Supply Plan is an attempt to balance supply and demand based on the available power generation resources in the country, and any imports taking into consideration the challenges in the energy sector.

The Plan further analyzes the factors that could adversely affect the reliability of the generation sources and transmission network and presents measures to minimize the impact of the scenarios on the security and reliability of power delivery for 2014.

A short-term (2015 - 2017) energy and demand outlook is also presented. Expected new transmission network construction, installation and refurbishments to improve upon power supply reliability are also discussed.

In preparing the 2014 Electricity Supply Plan, every effort had been made to provide the most current information on the forecast and performance of the Ghana Power Sector based on data provided to GRIDCo by Volta River Authority, Electricity Company of Ghana and other institutions. GRIDCo will provide updates and quarterly reviews to the Supply Plan in order to assist market participants in their decision-making.


2.0 FORECAST DEMAND

The projected Electricity Coincident Peak Demand for the year 2014 is 2,179.5 MW. This represents an increase of 236.6 MW and a growth of 12.2 % over the 2013 actual peak which was 1942.9 MW.

The increase would primarily occur in the Mines, industrial, commercial, residential and new loads emanating from rural electrification projects.

Numerous rural electrification projects earmarked for commissioning in 2014 is anticipated to increase demand in both the ECG and NEDCo distribution systems. The projects include the SECO Project in the Central Region which is expected to increase demand by 5.3 MW and energy of 66.14 GWh. The second major project is that of Weldy Lamont in the Central, Western and Northern region expected to increase demand by 35.26MW and energy of 440.04GWh.

In all, a total of 1,949 communities would be connected to the National Grid, under the Rural Electrification Project.

Furthermore, the American US Exim bank loan for the construction of Kintampo, Mim and Atebubu substation, the Sunyani – Mim and Kintampo – Atebubu transmission lines is expected to connect many rural communities to the national grid.

The additional loads that are expected to increase the demand in 2014 are the following:

• Spot Loads

I. Exclave Power Authority - 33 MW

• ECG Load Forecast - 1421 MW

• NEDCo/VRA Forecast - 156 MW

• VALCO demand - 75 MW (one potline)

• Export

I. Togo/Benin (CEB) - 115 MW

II. Burkina Faso (SONABEL) - 9 MW

A summary of the 2014 projected peak demand is presented in the table 1 below:

The detailed breakdown of the 2014 maximum demand forecast is included in the Appendix A.


Table 1: Summary of 2014 Projected Demand

Chart 1: System Peak Demand for 2014 by Customer class

Chart 1 shows the anticipated system peak demand for 2014 by customer class. ECG’s demand constitutes 65% of the total system peak followed by the mines at 11%. VALCO’s demand at one pot line constitutes 4%, NEDCo’s demand is 7% whilst Exports to CEB, CIE and SONABEL is 6%.

2.1 Energy Consumption Outlook

Total energy consumption including transmission network losses is estimated to be 14,721.25 GWh. This represents a 13.9% growth over the energy consumed in 2013 which was 12,927.53 GWh.


The summary of 2014 estimated energy consumption is presented in Table2.

Table 2: Summary of projected 2014 Energy Consumption

Chart 2: 2014 Projected Energy consumption by customers

From Chart 2, ECG’s energy consumption of 9,489.08GWh is the highest of all the customer groupings constituting about 65% of the total projected energy consumption for 2014. It is fol-lowed by the Mines with a projected consumption of 1,823.84 GWh representing 12% of total consumption for 2014.


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3.0 PROJECTED GENERATION

With the commissioning of Bui Hydroelectric plant, the country’s total system installed capacity is now 2,837 MW. However, the firm or dependable capacity would be 2,515 MW. Hydroelectric generation would represent 55% of the dependable capacity. The remaining 45% would largely be made up of thermal generation. There is a contribution from renewable generation (Solar energy) constituting less than ½ % of total capacity. The generation capacity is expected to increase in the third quarter of the year by another 240 MW after the commissioning of the Kpone Thermal Power Plant in December 2014. This would bring the total installed capacity to 3,077 MW.

3.1 Hydro Plant Availability and Power Generation

The Ghana power system now has three major hydroelectric plants namely Akosombo, Kpong and Bui Hydroelectric Plant. The Akosombo plant is expected to operate at a dependable capacity of 150 MW per unit which translates into a total Plant output of 900 MW with availability factor of 94%. The Kpong Hydroelectric Plant on the other hand is scheduled to operate at 35 MW per unit with a total Plant dependable capacity of 140 MW at an average availability factor of 94%.

The Bui Hydro-electric plant is planned to operate at a dependable capacity of 120 MW per unit and the plant dependable capacity is 360 MW during peak only at an availability of 94%.

A total of 7,400 GWh of energy is expected to be generated from the three hydroelectric plants in the period.

3.2 Thermal Power Generation

The projected total thermal generation for 2014 is 7,317.3 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.

3.3 Renewable Energy

About 2 MW 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.


3.4 Generation Mix

Chart 5: 2014 Energy Generation per Type of Fuel

Hydro generation would constitute 50% of total energy generation required in 2014. It is anticipated that 27 % of the energy requirement would be produced from natural gas and 23% from LCO. A small proportion would be from solar.

Chart 6 below shows projected generation for 2014.

Chart 6: Projected Energy Generation

3.5 Planned Maintenance schedule of generating plants

In order to improve upon the reliability and efficiency of the 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.


3.5.1 Akosombo Hydroelectric Plant

Annual maintenance works and exciter replacement are planned to be carried out on Generator unit 2 and 3 in January. This would result in the shutdown of the units during the period. After bringing the two units back to service another Annual Maintenance and exciter replacement works would be carried out on unit 3 in February. Splitter Vane inspection, exciter replacement would be carried out on unit 4 in the May. Unit 5 and 1 would undergo exciter replacement, splitter vane inspection and annual maintenance in the months of June and July respectively. Units 6 and 3 would both undergo Splitter Vane inspection in the months of August and September; however units 6 would further have its power transformer replaced in August as well. All the maintenance works are expected to results in outages for most part of the respective months. Considering the shut downs of the generating units for planned maintenance, it is anticipated that availability of generation from Akosombo hydroelectric plant would be about 94%, which would give total available capacity of 900 MW and energy generation of 5,683GWh

3.5.2 Kpong Hydroelectric Plant

The Kpong hydro plant is scheduled to be undergoing a major retrofit starting from September; unit 2 would thus be shut throughout the year. Unit 1 is also programmed to undergo preventive maintenance in January and July. Unit 3 would have preventive maintenance in April and October. The preventive maintenance for unit 4 is planned for May and November. Hence availability of generation from the Kpong hydroelectric plant would be 94% that would be able to provide 135 MW of power and 1, 017 GWh of energy.

3.5.3 Bui Hydroelectric Plant

The Bui Hydroelectric Plant is planned to be inspected for every 2000 hrs run under the current contract. The annual preventive maintenance of the plant is therefore planned to be carried within the inspection period. Also since two units will be committed to the generation plan, the third can be inspected.

Below are the details of the maintenance schedule to be undertaken during the year.

Generation Unit Proposed Period for MaintenanceUnit 3 March 2014Unit 2 June 2014Unit 1 September

3.5.4 Takoradi Thermal Plant T1

The plant generator unit 1 would be shut down in February for heat exchange and cooling water system upgrade. It is scheduled for another shut down on unit 2 in April for hot gas inspection and Mark VI upgrade. The steam component is planned to undergo cooling system inspection in


June and a once through Cooling Tie-In in December. Also the unit’s operating software (Mark VI) upgrade would be carried out in the same month. It is envisaged therefore that the plants would be available 85% of the time within the year to provide a combined capacity of 100 MW and an energy production of 2,102 GWh in 2014.

3.5.5 Takoradi thermal Plant T2

The Takoradi thermal plant T2 unit 1 would be shutdown to enable a Tie in of the HRSG in January through February. The second unit would follow with a shutdown also to enable the tie in of the HRSG in March. There would be other shutdown of unit 2 in February to allow for hot gas path inspection and in June for both HRSG tie in and compressor change. Due to the planned maintenance of the plant among others, availability of the plant would be about 85%, which would be capable of generating 200 MW capacity and 1,321 GWh energy in 2014.

3.5.6 Sunon Asogli Power Plant

The plant is planned for outage to enable Filter replacement and Major inspection of Unit 4 and 1 in December. Due to the downtime of the plant, it is anticipated that the plant would be available 96% within the year to provide 180 MW dependable capacity and generate a total energy of 1,240 GWh in 2014.

3.5.7 Tema Thermal Plant TT1PP and TT2PP

The TT1PP plant would not undergo any major maintenance work that would require a long outage in the period. It is expected be shut down for a maximum period of 3 days for compressor inspection and fuel nozzle inspection. The plant is projected to have an availability of 85% and generate a 110MW of power and 745 GWh of energy.

The TT2PP units 5 and 6 would not be available from January to April, it is scheduled to undergo engine swap in April and May. The units 1 and 2 are scheduled for type II inspection in October and November. It is therefore expected to operate at an average capacity of 21 MW for the first quarter and 45 MW for the second and third quarters of 2014. Hence it would be available 75% within the year to generate a total energy of 335 GWh

3.5.8 Mines Reserve Power Plant

The MRP plant would be shut down for major inspection in the months of March, June, September and November. It would have plant availability of 75 % for the period and it is expected to generate a total of 152 GWh at 70 MW output.

3.5.9 Takoradi Thermal Plant T3

This is a new combined cycle thermal plant with an installed capacity of 132 MW and a dependable capacity is 120 MW. It was commissioned in March 2013, but suffered an explosion in June 2013.


This resulted in the shutdown of the entire plant for diagnosis works. Also an independent audit into the cause of the explosion had been carried. Major repair works are under way to bring the plants back to operation by the end of first quarter 2014. The plant would be expected to generate about 672 GWh of Energy in 2014. Combustion Inspections are scheduled for the fourth quarter of 2014. Availability of the plant would be 85%.

3.5.10 CENIT Thermal plant

The Plant is expected to operate at a dependable capacity of 100 MW and generate a total energy of 745 GWh. One hot gas path inspection is scheduled during 2014. The plant availability factor is projected to be 85%.

Table 4 outlines the planned maintenance schedule of all generating plants and Table 5 indicates the resulting availability factors and projected energy generation from each of the power plants in 2014.

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Table 5: Expected Plant Availability and Energy generation

3.6 Akosombo Reservoir Elevation Projections for 2014The projected Akosombo Reservoir Trajectory as presented below was developed based on the following assumptions:

• Planned Akosombo and Kpong hydro generation of 6,700 GWh.• A total of about 35.41 MAF is expected to be discharged to generate 6,700 GWh.• January 1, 2014, lake elevation of 258 ft.• Projected minimum elevation of 245 ft.

Based on the above assumptions from the 1st of January, 2014 the lake is expected to bottom down at 245 ft around mid-August. Table 6 and Chart 7 show the projected draw-down lake trajectory for 2014.

Table 6: Projected Draw-down Elevation for 2014


Chart 7: 2014 Projected Volta Lake Trajectory

3.7 Bui Hydro Plant

The third and last unit of Bui Hydroelectric Project which has a total capacity of 400 MW was commissioned in December 2013. This was after dry and wet tests, which were to verify proper, complete and satisfactory erection of the entire sub systems were successfully carried out, the three (3) generating units, which have the capacity to generate 133 MW each, were commissioned in May, July and November 2014.

3.7.1 Plant Operations Plan

The Plant is planned to be operated as follows:• Operate two units in normal generation mode (120 MW each) for 6 hours/day from January

1 to July 31, 2014.• Run two units in normal mode at (120 MW each) for 13 hours/day from August 1 to

December31, 2014.• The plant is scheduled to generate an estimated amount of 700 GWh of energy in 2014.Also each available Unit that is not producing active power would be available to run as a synchronous condenser to provide reactive power into the grid. This is expected to improve voltages in the north.


4.0 TRANSMISSION SYSTEM OUTLOOK

4.1 Availability of Transmission Lines, Feeders and Substations

• All transmission lines consisting of 219km of 330kV, 74.3km of 225kV, 4,030.6km of 161kV, and 138.8km of 69kV are expected to be available to transmit the projected energy for 2014.

• 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 3,870.86 MVA transformer capacity. This capacity, compared with a projected load of 2,179.53 MVA at an average power factor of 0.9, results in a transformer utilization factor (TUF) of 62.6 % for 2014. Since most transformers in the network are designed with a capability of 100% continuous loading (100% TUF). The projected TUF of 62.6% for 2014 implies adequate transformer capacity for the supply of power in 2014.

4.2 Transmission System Annual Maintenance program

The transmission systems equipment maintenance would be planned and executed to have a minimal impact on customer outages. The average feeder availability would be about 98.15 %. For periods where maintenance works results in customer outages, the outage period would be as indicated in the 2014 Schedule of Planned Customer Load Interruption Due to Transmission Equipment Outages (Appendix C).

4.3 Challenges of the Transmission Network

4.3.1 NITS Evacuation Capacity The current transmission network has the capacity to evacuate the maximum generation of 670 MW from the eastern (Tema) section of the transmission system. For the maximum western generation (from Aboadze), the power flow shows that all the 620 MW western generation can be evacuated. However a high line loading condition is observed on the Volta –A3BSP station during peak period

4.3.2 Voltage StabilityWith the commission of Static Var Compenstor and Capacitor banks in Tamale the voltage profile in the northern part of the network improves significantly. However during peak load conditions, a minimum of 300 MW (3 typical thermal generating units) power is required to be operating at Aboadze to ensure voltage stability of the network.

4.4 Transmission System Improvement Projects for 2014

Projects aimed at increasing the capacity and reliability of the power system have been earmarked for completion in 2014. This is in line with GRIDCo’s current objective of systematic improvements


of the National Interconnected Transmission System (NITS). The completion of these projects is expected to improve overall system reliability, security and general quality of supply. The projects are as follows:

4.4.1 Transmission LinesThe under listed transmission line projects (Table 9) have been planned for completion in 2014, to improve upon the transfer capabilities, reduce overloading and enhance the reliability of the transmission network. Table 7: Transmission Lines to be constructed in 2014

4.4.2 Substations

Table 8: Substation to be commissioned in 2014

Major project works are currently on-going for the construction of additional substations at Tema (Smelter II), Tumu, Wa, Mim, Juabeso Kumasi Second BSP and the expansion of A3BSP station. The works are at various stages of completion and they are expected to be commissioned into service as shown in the schedule above.


4.4.3 Power Transformer Capacity

Table 9: Transformer to be installed in 2014

A total of 594 MVA of transformer capacity is expected to be added to the network to improve upon reliability and approach N-1 operation as close as possible. Table 9 shows the transformers scheduled to be installed in various substations across the nation.

4.4.4 Shunt Capacitor BanksThere are ongoing projects to install an additional 108 MVar of shunt capacitor banks at selected substations in 2014 as shown in the table 10 below. These projects are expected to improve upon the voltage profile of the network, reduce transmission system losses and reduce the generation of reactive power from power generating plants.

Table 10: Capacitor banks to be installed in 2014


5.0 Electricity Demand-Supply BalanceIn the first and second quarter of 2014 the system would suffer a shortage in generation capacity due to outage on units for scheduled maintenance.

The third and last quarters of the year is expected to have a maximum available generation capacity of 2,550MW, compared to a projected peak load of 2179.5 MW, the system would have an average reserve capacity of 17% which is close to the required reserve of 18%. There would therefore be adequate and reliable supply during that period.

The total energy that would be generated from hydro plants including the Bui plant would be about 7,400 GWh, while the total energy that would be generated from thermal sources would be about 7,317.3 GWh. These available power generations would be used to meet the following composite loads in 2014.

1. Electricity Company of Ghana (ECG)ECG is currently the largest customer on the network with a total projected consumption of 9,489.08 GWh constituting 65% of total energy demand. The corresponding coincident maximum demand is estimated to be 1,421.48 MW. ECG load is made up of residential, commercial and industrial loads. It is largely placed in the southern part of the country. Considering the available generation in 2014, the ECG load would largely be met. However, sporadic load curtailment would be experienced in the event of shortage in the supply of natural gas and also due to outage on generating units to allow for planned and unplanned maintenance works.

2. Northern Electricity Distribution Company (NEDCo)NEDCo’s electricity demand is estimated at 155.9 MW and a corresponding energy of 1,040.8 GWh. It is largely made up of residential and commercial loads with scanty industrial loads. It is located in the northern part of the country. Similarly, the electricity demand of the company would largely be met with intermittent load shedding as and when generation deficit occurs.

3. VALCO The total power demand of VALCO is 375 MW, with an energy requirement of 3,125 GWh which represent a single highest electricity demand of the power system, specifically from a single industrial estate. Considering the inadequacy of the present available generation capacity to meet such a demand, only 75 MW of power and 620 GWh of energy would be made available to VALCO to operate only one potline out of 5 lines.

4. MinesA total of 1,823.84 GWh of energy and a corresponding coincident maximum demand of 244.9 MW is estimated for the all the major mines grouped together. The total electricity demand of the Mines would be fully met in 2014 but with a few intermittent load curtailments if the power system experiences any unanticipated generation deficit.


5. Direct Customers. The combined coincident maximum demand of these groups of loads is about 60 MW and their total energy is about 368.2 GWh, which would be fully met in the year. However, as and when the power system experiences disturbances and generation shortages that would require load curtailment, a few of the loads of individual customers would be shed.

6. ExportDirect electricity supply to Togo/Benin and Burkina Faso would be fully met under normal operating condition. Thus it is anticipated that their combined electricity requirement of about 124.3 MW, 809.5 GWh would be supplied in 2014.

7. ImportUnless forced generation outage occurs, or unanticipated shortage of gas or LCO occurs, Ghana would not import power from Cote d’Ivoire. There would however be intermittent exchanges of about 3 MW and a corresponding energy of 9 MW on the tie line.

5.1 Available Generation Capacity versus Projected Load Demand

Table 11 below compares the available generation capacity and projected demand on monthly bases. The Table indicates shortage in generation with a negative reserve margin of -2% and -3% for the months of February and June respectively. It also shows there would be adequate generation and a reasonable surplus (reserve margin) to reliably supply the projected load for only six months (May, July, August, October, November and December) in 2014.

Table 11: Summary of Monthly Available Generation versus Projected Demand (MW) for 2014

Even though the months of February and June shows deficits in generation, it should be noted that planned maintenance on the units could be reschedule depending on its criticality to make units available to supply the projected load.

It should also be noted that, this analysis also assumes that with the exception of planned maintenance, the generation capacity is available at all times of the year, with no incidence of unforeseen or inadvertent electro-mechanical failures or fuel shortages.


The actual reserve margin or deficit could therefore be far less than the above, if unplanned downtimes of the various generating units, especially forced outages and Plant unavailability due to fuel shortages were considered. This means that in the event of a forced outage or shortage in fuel supply, load would be shed in the months with inadequate reserve margin.

5.2 Projected Monthly Energy Generation and Consumption

The Table below presents the anticipated monthly energy generation of the plants versus projected monthly consumption: It was computed based on the availability factors of the plants.

Table 12: Summary of Projected Monthly Generation and Consumption (GWh)

The Table indicates that there is enough generation to meet the projected consumption of 14,721.25GWh for 2014. This was made with the assumption that some of the not too critical maintenance works for the months of the February and June would be reschedule to allow for enough generation to the meet the demand for the months with generation deficit.

It should again be noted that, shortage in fuel supply and force outage on units could results in severe generation shortage and a load shedding as a result of it.


6.0 RELIABILITY OF SUPPLY

6.1 Generation Supply Reliability Assessment

The following challenges are expected to affect the reliability of energy supply in 2014:• Inadequacy of available generation capacities to meet the projected demand under

all system conditions• Security of fuel supplies such as natural gas supply from WAGP, Ghana Gas and

adequate stocks of LCO and DFO• Potential of WAGP not being able to meet contractual quantity of gas. • Possible delay in Completion of Ghana Gas Project

6.1.1 Inadequacy of available Generation Capacities

a) CapacityAlthough the network has an installed generation capacity of 3,077 MW and a dependable capacity of 2,715, the available capacities are 2,121, 2,293, 2,365 and 2,550 for the first, second, third and fourth quarters respectively as shown in the figure below.

Fig 8: Available Generation versus Projected Demand (MW) for 2014

The available generation capacity as shown in the figure above does not fully meet the projected demand for the month of February and June 2014.

This is as a result of unit outages for scheduled maintenance works.As can be deduced from the figure above the reserve margin meets the required for only the month of August. The months of February and June have a negative reserve of -2% and -3% respectively. If planned generation is not reschedule there would be significant load shedding these months. Even the months with a reserve margin shows a very tight schedule with a slight reserve margin, meaning any forced outage on any generating unit would lead to a significant load shedding in the other months.


By taking into account the low availability and frequent breakdown of thermal Plants in the system, the certainty of achieving a dependable capacity level of 2,179.5 MW to generate an estimated total of 14,721.25 GWh of energy in 2014 could encounter a number of challenges and may be compromised. The major challenges are:

• Lower Plant availability than expected resulting from high units’ outage rates and longer planned maintenance periods.

• Inadequate LCO fuel stocks to run the dual fired (Gas, LCO) Thermal Plants in the event of interruption in natural gas supply.

• Maintenance work and reactive power requirements at Akosombo GS would limit the amount of energy that could be obtained from Akosombo GS.

• The possible overdependence on hydro generation in the event of unavailability of thermal units could affect scheduled maintenance of the hydro units. This could compromise the assumed plant availability in the Electricity Supply Plan due to possible unplanned outages as a result of unit failures.

• The current reservoir elevation at Akosombo is very low compared the previous years.

The inflow into the dam in 2013 was about 5 feet this is very low and below average. From the historic lake’s inflow pattern it is likely next year there will be equally low inflow, meaning hydro power generation for 2014 need to be significantly reduced to save the lake.With the projected low reserve capacity assuming all units to be available, any of the above situations that results in a unit going out of service would pose a major challenge to supply security in 2014.

b) EnergyHydro generation from Akosombo, Kpong and Bui is projected to contribute about 7,400 GWh of the total energy requirement of 14,721.25 GWh for 2014. The remaining 7,321.25 GWh is expected to come from largely thermal generation. A slight amount would be coming from VRA’s Solar Plant. There is the challenge of meeting the projected consumption for 2014; this is due the expected shortage in generation as a result of units’ outage due to planned maintenance and also an outage on T2 plant at Aboadze to allow for the Tie –in of new HRSG unit.

In all, about 99.5 GWh of the projected energy required, might not be served if planned maintenance works are not rescheduled in the months of February and June 2014. Also with uncertainties surrounding the availability of fuel supply to run the thermal Plants the possible longer maintenance periods than planned and higher outage rates, the energy supply security in 2014 could suffer even more serious setbacks.

c) Risk of WAPCo not Supplying Contracted quantity of Gas.Currently all the thermal generating units in the NITS have been retrofitted to run on natural gas from Nigeria via the West African Gas Pipeline (WAGP) with exception of the Mines Reserve Plant (MRP) which runs on only DFO. Work is currently on-going to retrofit the MRP Plant to run on gas. This work is expected to be completed by the end of the third quarter of 2014.


The Sunon Asogli Power Plant which has a capacity of 180 MW is designed to operate on only gas. Its role is very critical, given that it contributes about 8 % of total generation capacity. Thus any shortage of gas supply renders the SAPP inoperable (loss of 170 MW dependable capacity).This would undoubtedly impact adversely on power supply reliability for 2014. Given the very tight demand – supply balance, such a situation will result in the need to shed load.

d) Possible Delay in the completion of Ghana Gas ProjectThe 2014 Electricity Supply Plan assumed natural gas from the Jubilee fields in Ghana would be available at Aboadze by July 2014 for power generation. The projected quantity of gas is 60,000MMBtu/day for the rest of the year.

A delay in the commissioning date of the project could impact negatively on reliability of power supply as it could reduce the amount of available gas for power generation, especially in the event of shortage of gas supply from WAPCo. It could also result in high cost of generation if LCO is used as a substitute.

6.2 Sensitivity Analysis on Generation Capacity

The impact of any major contingency on any generation facility with a capacity in excess of 100 MW is evaluated in this section. The planned maintenance work on each of the generating units for the year 2014 was taken into consideration in establishing the Available Capacity of the generating units as captured in Table 13.

a) Contingency on one Akosombo UnitThe Table below shows the impact of a contingency or outage on any of the Akosombo generat-ing units. The available generation capacity reduces by 150 MW and the Reserve Margin reduces accordingly. It indicates a deficit in supply for all the quarters with exception of the last quarter of 2014. This implies a considerable quantity of power would have to shed in the event of such a contingency.

Table 13: Operating Reserve Margin with loss of one Akosombo unit


Contingency on SAPP (Failure of WAGP to supply Gas)In the event that the WAPCo fails to make gas available to the Sunon Asogli Power Plant, a sig-nificant reduction in the operating reserve margin occurs as shown in Table 14 below. The reserve margin in this scenario indicates a deficit in all quarters with the exception of the last quarter of 2014. This would require a sizeable amount of load to be shed to restore the demand –supply balance.

Table 14: Available Generation capacity with SAPP out of Operation

The details of the 10 year demand and energy forecast is attached in Appendix A.

6.4 Power Transmission Reliability Assessment

6.4.1 Adequacy of Transmission Capacity

The major challenge to supply security and reliability on the transmission network are: Inadequacy in transmission line capacity which could lead to transmission line overloads. This phenomenon which is a 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 pow-er 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 contin-gency on any of these radial lines results in outages.


6.4.2 Adequacy of Transformation Capacity

Most BSP’s in the network now satisfies the N-1 criteria for transformers. There however some few stations with single transformers and any time maintenance work is being carried on them it results in total outages to customers. Plans are advanced to double the number of transformers in all the single transformer stations.

The current Loading on transformers for the major BSP’s in NITS for the month of December 2013 is shown in Table 15 below. The table shows some station transformers loaded above their capacity ratings. Achimota’s 5T4 and 5T5 were loaded to 100.5 and 109.1 % of their capacity.

Also Kumasi and Winneba have some of their transformers loaded above their ratings. The criterion for normal operating conditions requires that transformers should not be 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 period.

Table 15: Key Substations Transformer Loading

However, as shown in Table 17, it suggests this important criterion is being violated in some substations. It should be noted however that for some of the stations the overloading event occurred mostly during planned maintenance or contingency when loads were transferred from healthy transformers and not during normal operating conditions.

The overload situation in BSP’s across the network is gradually being eliminated through the injection of new BSP’s and the upgrade of existing stations. In this respect construction is on-going to install a 2x33 MVA transformer in Tamale, 66MVA in Kumasi and Takoradi.


OVERVIEW OF SHORT-TERM (3 YEARS) FORECAST

A short-term (2015, 2016 & 2017) demand and energy consumption forecast is presented in this section and the purpose is to guide planning in the short-term. The system peak demand for 2015, 2016 and 2017 is assumed to increase at a steady rate of 2,573.7MW, 2,866.8 MW and 3,065.9 MW respectively. The corresponding projected energy consumption for 2015, 2016 and 2017 are 17,699.0 GWh, 19,678.1 GWh and 21,022.7 GWh respectively. The expected new spot loads for the period are an increase in export of power to SONABEL with 100MW in 2017, commencement of gold mining operations at the Azumah mines in the Upper West Region of 23 MW(2014) at Yagha (50km north west of Wa), expansion of gold mining operations at the Tarkwa mines (15 MW- 2015), and Damang mines (25 MW- 2015), and start of gold mining operations at Esaase ( 34 MW -20116), increase in demand by Enclave Power Authority to 83.9MW, and potential for a three pot lines operation of VALCO for 2015.

A summary of the peak demand by major consumers is presented in Table 16 below:

Table 16: Summary of projected Demand for 2014, 2015 and 2016

Taking planned maintenance works of generation units into consideration the maximum monthly available generation in 2015 would be about 2,650 MW. This includes all the three Bui Hydro units rated at 360 MW at full capacity, TICO Steam (100 MW), and two units of Kpone plant (200 MW). As shown in Table 19 below, the reserve margin for 2015 would be 26.3 MW or 3% of the projected load.

With no expected generation addition the maximum available generation capacity is projected to remain same at 2,650 MW in 2016, the peak load is however expected to increase to 2,886.3 resulting in a high deficit in supply of 216.8 MW.


Table 17: Summary of projected generation and demand for 2015, 2016 and 2017

Since the required reserve margin for reliable supply is 18%, the power supply for 2015 to 2017 would not be adequate to meet demand and maintain the acceptable reserve margin. It is therefore critical to source additional generation capacity of about 500 MW to be provided within 2015.

It should be noted however that the projected demand for 2015-2017 includes three (3x75 MW) potlines operations of VALCo.


PROJECTED COST OF ELECTRICITY SUPPLY

This section analyses the Electricity supply Cost, for 2014. It is mainly driven by the cost of fuel and transmission service.

Fuel Cost

The fuel for the projected thermal generation of 7,317.3 GWh for the year 2014 is expected to be made up of the following:

38,770,000 MMBtu of Natural Gas, this translate into the following: an average of 90,000mmbtu/day of natural gas from Nigeria,and average of 60,000mmbtu/day of natural gas from Ghana from July 2014,6,992,000 barrels of LCO or 17.3 cargoes 81,000 barrels of DFO or 0.2 cargoes.

The natural gas from Nigeria via the West African Gas Pipeline (WAGP) and local Gas from Ghana Gas Company Limited are expected to be the largest source of fuel for thermal generation, followed by LCO which will be mostly used as a substitute fuel in the event of failure by WAGP to supply the required volume of gas. The DFO will be the used largely for start-up and shutdown of thermal units.

The total cost of fuel for the anticipated thermal generation in 2014 would be about USD 1,140,098,660.0. This cost was calculated with the assumption that VALCO will be operating on one pot line from January to December. Table 18 below shows the assumption used for calculat-ing total fuel requirement and cost:

Table 18: Fuel requirement and cost, for thermal energy generation ( VALCO on 1 potline) in 2014.

Electricity Transmission Cost

Direct and Indirect CostAt a projected total energy consumption of 14,721.25 GWh and a total transmission cost of Gh₵ 146.46 million it is estimated to cost GRIDCo 0.7 Gp to transmit a kilowatt hour of power in 2014.


Table 19: Direct and Indirect cost of Electricity Supply in 2014

Cost of 2014 Planned Transmission System Improvement ProjectsThe 2014 planned transmission system improvement work consisting of transmission lines, capacitor banks, transformers, spare towers, major maintenance works, replacement and upgrade of obsolete equipment is estimated to cost the company USD 546,860,274.Summary of the cost is shown in the Table below: Table 20: Cost of System Improvement Project for 2014


SYSTEM PERFORMANCE REVIEW FOR 2013

This section presents a summary of supply performance for 2013.

Maximum System Demand

The National Interconnected Transmission Network recorded a maximum coincident system peak load of 1,942.9 MW on December 28, 2013; this represents an increase of 214 MW and a growth of 12.4% over the 2012 figure of 1,728.9 MW. The projected figure for the period was 2016.5 MW. The summary of the peak demands recorded in the period are as presented in the table below:

Table 21: Peak Demand for 2013 & 2012

Energy Consumption

The period under review registered a total energy consumption including losses of 12,927.02 GWh. A total of 12,165.6 GWh of energy was consumed in 2012, thus the 2013 figure represents 6.3 % or 761.4 GWh increase over the 2012 recorded value. The projected energy consumption for 2013 was 13721.5 GWh. The big difference between the projected and the actual for 2013 was as result of load shedding occasioned by curtailment in gas supply for thermal generation from Nigeria.

Table 22: Summary of Energy Consumption for 2013-2012

Generation Performance

Akosombo Hydro Reservoir Elevation – Performance

The Akosombo reservoir elevation reached a height of 260.75 ft in November from a minimum elevation of 255.60 ft in June. This represents a rise in elevation of 5.15 feet.Generating Plants Availability for 2013

Table 8 presents 2013 generating Plants availability for planned plus auto outages.


Table 23: Generating Plants actual availability

Energy Generation -2013

A comparison between projected and actual energy generation for 2013 is shown in Table 10 below.

Table 24: Projected and actual energy generation for 2013

The three hydroelectric Plants produced a total of 8,179.40 GWh, this was made up of 6,726.69 GWh from Akosombo, 1,144.45 GWh from Kpong and 308.30 GWh from Bui hydro generation Plant. The 2013 hydro generation is 602.4 GWh more than the projected.

Transmission Network Performance

Transmission Lines

Transmission lines recorded an average availability of 97.59 % for the period. This is a slight drop over the 2012 figure of 98.78 % and it is slightly below the PURC performance target of 98.5%. The decline in performance is among others attributable to numerous network upgrades and expansion projects which required outages to provide safe working environment. It is also due to the short fall in generation experienced in the system thereby taking some of the lines off to shed load.

Table 11 shows the transmission line availability of 2011, 2012 and 2013.


Table 25: Transmission line Availability 2011 vs. 2012

Feeders

The GRIDCo network registered an average feeder availability of 99.30 % for the period under review; this performance was better than that of 2012 and 2011. The average performance of 99.30 % for the period is above the regulated benchmark of 95.0%.

Table 12 shows the feeder availability for 2011, 2012 and 2013.

Table 26: Feeder availability 2013


CONCLUSIONS

The following conclusions are drawn in respect of the electricity supply and demand situation for 2014:

System demand is projected to be 2,179.5 MW, this figure represents 12.2% growth over the 2013 figure of 1,942.9 MW. The expected high power demand increase can be attributed to new spot loads such as increased in demand of Enclave power Authority and Newmont New Abirem. On-going network expansion works and measures to improve the quality of distribution services by ECG are also expected to culminate in an increase in demand amongst domestic customers. Furthermore, the Self Help Electrification Projects currently on-going is expected to add a significant load onto the grid. VALCO is assumed to operate on one pot line throughout the year.The projected 2014 energy consumption of 14,721.3 GWh is to be supplied as follows:

Hydro - 7,400 GWh representing 50.3% of the total energy requiredThermal - 7,317.3 GWh representing the remaining 49.7%Solar PV - 4 GWh

The total cost of fuel for the projected thermal generation of 7,317.3 GWh is estimated at USD 1,140,098,660.0

About 99.5 GWh of energy is likely to be shed due to unavailability of generation.The current low Akosombo reservoir elevation, coupled with maintenance work and reactive power requirements would limit the amount of energy that could be generated from Akosombo GS.

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 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.

The current inadequacies in transformer capacities could lead to overloading at most major substations during normal operation conditions. This state of affairs is exacerbated during contingency conditions and normally results in load reduction. Most substation transformers are already overloaded and do not satisfy the N-1 security rule.

The transmission system has inadequate firm transfer capability to most of the major load centers (of Accra Kumasi etc) mostly at peak. This situation results in low voltages and increase in transmission system losses. A significant percentage of network loads are islanded in case of outage on single line.


Voltages at Kumasi towards the north and some mining areas in the western region are extremely low because of inadequate installed reactive power and voltage support devices to boost voltages. The timely implementation of the system expansion works for 2014 would eliminate most of these critical contingencies.

System losses reduce significantly with the implementation of all capacitor bank projects and installation of Static Var Compensator at Tamale.

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.


APPENDICES


APPENDIX A: Load Forecast

Table A-1 Demand Forecast

Table A-2 Energy Forecast

APPENDIX B: Grid Map

APPENDIX C: Glossary

APPENDIX D: 2014 Schedule of Planned Customer Load Interruption Due to Transmission Equipment Outages


APPENDIX A Table A1


Table A2


APPENDIX C

Glossary of Electrical Utility Terms1000 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 LoadThe 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.

CapabilityThe 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 non-conductor 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 bankA grouping of capacitors used to maintain or increase voltages in power lines and to improve system efficiency by reducing inductive losses.

CapacityThe 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 CycleAn 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.

ConductorA substance or body that allows an electric current to pas continuously along it.


ContingencyIn 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.

DemandThe 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.

DispatchThe 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

FaultAn 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).

GridThe transmission network (or “highway”) over which electricity moves from suppliers to customers.


Grid OperatorAn 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.

LoadThe 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 CentersA geographical area where large amounts of power are drawn by end-users.

LossesElectric energy losses in the electric system which occur principally as energy transformation from kilowatt-hours (kWh) to waste heat in electrical conductors and apparatus.

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).

OverloadOperation 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 SystemThe 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 PowerMeans 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 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 ContingencyThe 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.


StabilityThe 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 StationAn installation of equipment where several transmission lines are interconnected. Does not include equipment for transforming voltage levels.

Power SystemAn 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).

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.

TransformerA 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.

VoltageThe electronic force or electric potential between two points that gives rise to the flow of electricity.

Voltage StabilityThe condition of an electric system in which the sustained voltage level is controllable and within predetermined limits.

Wheeling The use of the facilities of one transmission system to transmit power and energy from one power system to another.


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