Dr. Robert BalogDepartment of Electrical and Computer EngineeringTexas A&M University

Mitigating Variability of High Penetration Photovoltaic Systems in a Community Smart MicrogridDr. 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

27.6 kW rooftop demonstration PV array

http://solarags.tamu.edu

Grid-tied inverters

STEM outreach - high school teachers

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.

Power Electronic Interface

Power Electronic Interface

Power Electronic Interface

Power Electronic Interface

Load & PV Module

Load & PV Module

Load & PV Module

Load & PV Module

Existing Distribution System

Variability of Grid-Connected Solar EnergyVariable power output of PV

Results in variable power from the utility

Central Battery Bank

Power Electronic Interface

Community Microgrid

Power Electronic Interface

Power Electronic Interface

Mic

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Power Electronic Interface

Power Electronic Interface

Power Electronic Interface

Load & PV Module

Load & PV Module

Load & PV Module

Load & PV Module

Existing Distribution System

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

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Hourly data with storage

Exporting Importing

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Controllable Source

Temporal Resolution

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High-rate temporal data with storageExporting Importing

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Decreased variability(frequency and intensity)

Increased control

Optimized Community Storage

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Planer PV without Storage (High-rate Temporal Data)Exporting Importing

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Uncontrolled LoadControlled Source

Optimized Community Storage

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Planer PV with Storage (High-rate Temporal Data)Exporting Importing

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Decreased variability(frequency)

Increased control

Terracotta Solar Roof Tiles

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Non-planer PV with storage with same foot print as Flat (High-rate Temporal Data)Exporting Importing

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Increased control Eliminated variability

Electric Power and Power Electronics CoursesGraduate courses (17 existing)

ECEN 611 General Theory of Electromechanical Motion Devices

ECEN 612 Comp. Aided Design of Electromech. Motion Devices

ECEN 613 Rectifier and Inverter Circuits

ECEN 614 Power System State Estimation

ECEN 615 Methods of Electric Power Systems Analysis

ECEN 616 Power System Electromagnetic Transients

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

New graduate courses (3)

ECEN 689 Energy Conversion for Renewable Energy

ECEN 689 Electrical Aspects of Sustainable Energy Production, Storage, and Utilization

ECEN 689 Engineering and Economics of Sustainable Energy Systems

Undergraduate courses (5) ECEN 459 Electric Power Systems I

ECEN 460 Electric Power Systems II

ECEN 438 Power Electronic

ECEN 441 Electric Motor Drives

ECEN 442 DSP-Based Electromechanical Motion Control

Total Faculty: 10Graduate 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

Dwight Look College of Engineering

8,398 Undergraduate

Engineering Students

2,883Graduate

Engineering Students

Fall 2012*

53,187Total Students at

Texas A&M University

* Official 12th day data, Texas A&M University Data and Research Services

• 11,281 engineering students (21% of University total)

• 3rd largest undergraduate engineering program in the U.S. (ASEE, Fall 2011)

• 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.

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

• 5,586 research projects• 943 collaborations • 2,743 industrial research sponsors • 1,379 students supported in research activities

$140.7 M in Sponsored Research (FY12)

THANK YOU

Dr. Robert BalogDepartment of Electrical and Computer EngineeringTexas A&M University