Dr. Robert Balog
Department of Electrical and
Computer Engineering
Texas A&M University
Mitigating Variability of High Penetration
Photovoltaic Systems in a Community Smart
Microgrid
Dr. Robert S. Balog, PhD PE
Assistant Professor, Department of Electrical and Computer Engineering
Director, Renewable Energy & Advanced Power Electronics Research Laboratory
Teaching, Research & Public Outreach
• DOE and the Texas State Energy
Conservation Office grant
• Unique partnership between athletics,
faculty, and facilities
• Equivalent to 5-10 home systems
• In plain view of 83,000 spectators –
diverse target audience
• Data used in classroom and research
http://solarags.tamu.edu
STEM outreach - high school teachers
Grid-tied inverters
27.6 kW rooftop demonstration PV array
High Penetration Perceptions
•
High Penetration of Photovoltaic (PV) Systems into the Distribution Grid
(https://www1.eere.energy.gov/solar/pdfs/pv_grid_penetration.pdf)
• More than 30% penetration, indicating very high penetration
•
Grid Operations and High Penetration PV
(http://www1.eere.energy.gov/solar/pdfs/2010ulw_ellis.pdf)
– High penetration is a concern when...
• Adverse system performance and reliability
• Cost of mitigation would be unreasonable
– Distribution operations issues
• Feeder characteristics impedance
• Voltage and frequency control
• Protection
• Load characteristics (sometimes a load, sometimes a source)
May 25th, 2012, Germany generated 22.4GW, setting the world record for PV
generation and nearly 40% penetration. Their grid did not go unstable.
Variability of Grid-Connected Solar Energy
Variable power output of PV
Community Microgrid
Power
Electronic
Interface
Load & PV Module
Power
Electronic
Interface
Load & PV Module
MicroGrid Bus
Central
Battery Bank
Power
Electronic
Interface
Load & PV Module
Power
Electronic
Interface
Results in variable power
from the utility
Power
Electronic
Interface
Load & PV Module
Existing
Distribution System
Power
Electronic
Interface
Mitigation of Variability
1. Temporal resolution of planning data
– Hourly vs. 10 second
2. Community storage - shared resource
3. Photovoltaic array geometry
– Planar vs. Non-Planar
Temporal Resolution
Hourly data with storage
120
Exporting
Importing
105
75
60
Controllable
Source
Uncontrollable Load
45
30
15
0
NET
Zero
Number of hours
90
kWh
Temporal Resolution
High-rate temporal data with storage
120
Exporting
Importing
105
75
60
Increased
control
Decreased variability
(frequency and intensity)
45
30
15
0
NET
Zero
Number of hours
90
kWh
Optimized Community Storage
Planer PV without Storage (High-rate Temporal Data)
Exporting
Importing
120
105
75
60
Controlled
Source
Uncontrolled Load
45
30
15
0
kWh
NET
Zero
Number of hours
90
Optimized Community Storage
Planer PV with Storage (High-rate Temporal Data)
Exporting
Importing
120
105
75
60
Increased
control
Decreased variability
(frequency)
45
30
15
0
kWh
NET
Zero
Number of hours
90
Terracotta Solar Roof Tiles
Non-planer PV with storage with same foot print as Flat (High-rate Temporal Data)
Exporting
Importing
120
105
75
60
Increased
control
Eliminated variability
45
30
15
0
kWh
NET
Zero
Number of hours
90
Electric Power and Power Electronics Courses
Graduate courses (17 existing)
New graduate courses (3)
ECEN 611
General Theory of Electromechanical Motion Devices
ECEN 689
ECEN 612
Comp. Aided Design of Electromech. Motion Devices
Energy Conversion for
Renewable Energy
ECEN 613
Rectifier and Inverter Circuits
ECEN 689
ECEN 614
Power System State Estimation
Electrical Aspects of Sustainable
Energy Production, Storage, and
Utilization
ECEN 615
Methods of Electric Power Systems Analysis
ECEN 689
ECEN 616
Power System Electromagnetic Transients
Engineering and Economics of
Sustainable Energy Systems
ECEN 630
Analysis of Power Electronic Systems
ECEN 632
Motor Drive Dynamics
ECEN 643
Electric Power System Reliability
ECEN 666
Power System Faults and Protective Relaying
ECEN 667
Power System Stability
ECEN 668
High Voltage Direct Current Transmission
ECEN 677
Control of Electric Power Systems
ECEN 679
Computer Relays for Electric Power Systems
ECEN 686
Electric and Hybrid Vehicles
ECEN 690
DC-DC converters
ECEN 711
Sustainable Engineering
Undergraduate courses (5)
ECEN 459
ECEN 460
ECEN 438
ECEN 441
ECEN 442
Electric Power Systems I
Electric Power Systems II
Power Electronic
Electric Motor Drives
DSP-Based Electromechanical
Motion Control
Total Faculty: 10
Graduate students: 65
Electrical & Computer Engineering Department
•
Students:
~850 undergrad (Dept)
~545 graduate (Dept)
~65 graduate (Power)
• Faculty:
70
• Rankings
(US News and World Report):
7 Focus Areas:
• Analog & Mixed Signal Electronic Circuits
• Biomedical Imaging & Genomic Signal
Processing
• Computer Engineering
• Electromagnetics & Microwave Devices
• Power Systems & Power Electronics
• Solid State, Nano Electronics & Electro optics
• Telecommunications, Controls & Signal
Processing
Fall 2012*
Dwight Look College of Engineering
• 11,281 engineering students
(21% of University total)
8,398
Undergraduate
Engineering Students
• 3rd largest undergraduate
engineering program in the
U.S. (ASEE, Fall 2011)
2,883
Graduate
Engineering
Students
• 8th largest graduate program
in the U.S. (ASEE, Fall 2011)
• 82 New National Merit
Scholars (52% of University
total)
• 2nd highest research
expenditures in the U.S.
53,187
Total Students at
Texas A&M University
* Official 12th day data, Texas A&M University Data and Research Services
• 5,586 research projects
• 943 collaborations
• 2,743 industrial research
sponsors
• 1,379 students supported
in research activities
M. Katherine Banks, Ph.D.,
P.E.
Vice Chancellor and Dean of Engineering
Director, Texas A&M Engineering
Experiment Station
Harold J. Haynes Dean’s Chair Professor
Dimitris C. Lagoudas, Ph.D.,
P.E.
Deputy Director, Texas A&M Engineering
Experiment Station
Senior Associate Dean for Research
Associate Vice Chancellor for Engineering
Research
John and Bea Slattery Chair Professor
$140.7 M in
Sponsored
Research
(FY12)
THANK YOU
Dr. Robert Balog
Department of Electrical and
Computer Engineering
Texas A&M University