1. Solar Energy Commercialization
SEC598S19
Solar Energy Commercialization
Session 04
Utility Operations 2
Generation, Transmission, Distribution
Operations
January 16, 2019

2. Session 04 - Value to class members
A continuation of overview of the electricity business
Generation, Transmission, Distribution
Introduction to Operations

3. Utility Operations (References)
B.Shively and J.Ferrare, Understanding Today’s Electricity Business, Enerdynamics, 2012 (
R.H.Miller and J.H.Malinowski, Power System Operation, McGraw-Hill, 1994
A.J.Wood, B.F.Wollenberg, G.B.Sheble, Power Generation, Operation,and Control, Wiley, 2014
US Energy Information Administration (

4. The Electricity Business - Introduction
The Electricity Business is a complicated web:
Consumers
Generation
Transmission
Distribution
Operations
Delivery Chain Operations
The Market Structures (Traditional and Restructured)
Market Dynamics
Regulation
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5. The Electricity Business – Generation
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6. The Electricity Business – Generation
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7. The Electricity Business -- Generation
Baseload
Runs 24 hrs/day
Nuclear, coal and natural gas, some renewables
Some units run at minimum levels
Intermediate
Runs mid-morning to evening
Combined-cycle gas, hydropower
Units ramped up from minimum load
Peaking
Runs early-afternoon to early-evening
Single gas turbine, hydropower, pumped hydropower
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8. The Electricity Business – Generation Portfolio
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9. The Electricity Business – Demand Side Management
An alternative to generation is carry out a program that reduces the size of the electrical load (demand)
Demand Side Management has as a main goal to reduce demand at peak periods
Energy efficiency
Demand response
Demand Response
Emergency demand response
Economic demand response
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10. The Electricity Business – Economic Demand Response
Real-time pricing
Customers pay hourly prices – same-day or day-ahead market conditions
Voluntary load response
Customers offered payment to curtail load (day-ahead)
Curtailable capacity call
Customers paid a capacity payment to allow utility the right to curtail load
Automatic load response
Same as above, but done automatically
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11. The Electricity Business – Transmission
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12. Sinusoidal Analysis – Three Phase Electricity
At most power plants, AC electricity is generated in 3-phase format
Many industrial customers expect 3-phase AC electricity
Three voltage waveforms are produced (transmitted) with the same amplitude and frequency, but 1200 phase differences:

13. Sinusoidal Analysis – Three Phase Electricity
Balanced 3-phase system – only wire voltage drops, no current (or voltage drops) in the neutral (ground) line
The sum of the real power components are constant in time

14. The Electricity Business – Transmission
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15. The Electricity Business – Transmission System Operations
The generators and transmission systems must be operated in synch to respond effectively to customer demand
Transmission line capacity is largely established by wire size and voltage
High transmission voltages mean lower current and lower i2R power losses
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16. The Electricity Business – Transmission System Operations
Optimal capacity determined by three constraints
Thermal/current constraints
Voltage constraints
System operating constraints
Operations are carried out by
The utility in the regulated market
An Independent System Operator (ISO) in the deregulated markets
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17. The Electricity Business – Distribution
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18. The Electricity Business – Distribution System Operations
Usually carried out by the utility
A distribution operations center supervises the operation employing SCADA systems
Monitor loads
Status of circuit breakers
Voltage levels and frequencies
Power Factor and VARs
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19. The Electricity Business – Overall System Operations
The four interconnect transmission systems generally operate independently
Within each interconnect, there are various control areas, and each has a system operator
Vertically integrated utility
Municipal utility
Federal Power Agency
Power pools (groups of utilities)
Independent System Operator (ISO – also known as a Regional Transmission Organization (RTO))
System operators are coordinated through the North American Electric Reliability Corporation (NERC)
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20. The Electricity Business – Overall System Operations
NERC has established reliability standards (overseen by FERC)
One important requirement is the following: Operators must plan for forecast demand but also a reserve factor to cover mis-forecasts and unplanned contingencies.
The reserves equal the greater of
A percentage of the forecasted loads
The single most severe contingency
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21. The Electricity Business – Scheduling
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22. The Electricity Business – Scheduling
Preferred schedule (Least-Cost Dispatch)
Unit 4 ($25/MWh) – 200MW
Unit 2 ($35/MWh) – 100MW
Unit 3 ($40/MWh) – 80MW
Above schedule is not feasible (Line B overloaded)
Revised schedule (lowest to highest cost)
Unit 1 ($45/MWh) – 80MW
Transmission schedule
Line A – 180 MW
Line B – 200 MW
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23. The Electricity Business – Scheduling
Reserves Calculation
Greatest single loss contingency – 200MW on Line B
If Line A were also to be lost, reserves from Unit 1 would not be available
So the safest place is to reserve 200MW for Unit 5 (expensive!) and 200MW reservation for transmission on Line C
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24. The Electricity Business – Overall System Operations
Planning Ancillary Services
Automatic Generation Control
Manages minute-by-minute fluctuations
Load-following Resources
Manages five minute fluctuations
Spinning Reserves
Units not providing power, but already synchronized ready in 10 minutes
Non-spinning Reserves
Supplemental Reserves
Voltage Support
Black Start
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