DOE Solar Energy Technologies Program Peer Review

Technical Track: Evaluation, Validation, and AnalysisProject Name: PV Grid Integration

Principal Investigator: Ben Kroposki

Denver, ColoradoMarch 9-10, 2009

This presentation does not contain any proprietary or confidential information.

Relevance/Impact of Research

Grid-Connected Distributed PV Growth 2001–2006, Projected to 2015 • Solar America Initiative

(SAI) should produce high growth in the number of installed PV systems.

• The Grid Integration Project supports the goals of SAI by conducting R&D to reduce barriers for high penetration of solar technologies into the electric power system.

• This project addresses both technical and economic issues and develops solutions for high penetration grid integration.

Currently seeing PV in high penetration on selected distribution feeders.

Could see PV in high penetration on high numbers of distribution feeders.

Quality, Productivity, Accomplishment

PV Grid Integration is a Joint NREL/Sandia Project• The NREL Team

– Ben Kroposki, PhD, PE – Principal Investigator– Peter McNutt, PE – Fielded PV Systems Testing– Josh Hambrick, PhD – Distribution System Modeling – Ray George - Resource Characterization and PV Modeling– Tom Basso – Standards and Codes– Mike Coddington – Utility Background, Standards and Codes

• Experience in distributed and renewable system integration, standards and codes, technical modeling and analysis of distribution systems, monitoring and measuring PV system and power system performance

Organization FY07 Budget FY08 Budget FY09 BudgetSandia $700K $400K $400KNREL $1,950K $400K $400K

NREL and Sandia coordinate this project with Office of Electricity projects to increase productivity and eliminate duplication of effort

Quality, Productivity, Accomplishment

– Grid Advances• Power System Planning: Emerging Practices Suitable for Evaluating the Impact of High-Penetration Photovoltaics (GE)• Advanced Grid Planning and Operations (EPRI)• Distribution System Performance Analysis for High Penetration PV (GE)• Transmission System Performance Analysis for High Penetration PV (GE)• Cyber Security Analysis (Sandia)

– Technology Advances• Advanced PV System Designs and Technology Requirements (BEW) • Enhanced Reliability of PV Systems with Energy Storage and Controls (GE)

– Tests and Demonstrations• Test and Demonstration Program Definition to Support High PV Penetration (BEW)

– Analysis• Utility Models, Analysis and Simulation Tools (EPRI)• Production Cost Modeling for High Levels of PV Penetration (NREL)• Value Analysis (Navigant)• PV Business Models (Navigant)• PV Market Penetration Scenarios (Navigant)• Solar Resource Assessment: Characterization and Forecasting to Support High PV Penetration (NREL)

Accomplishments: Renewable Systems Interconnection Study

available at:http://www1.eere.energy.gov/solar/solar_america/rsi.html

Completed in 2008, discusses current state-of-the art and what is needed to address high penetration PV grid integration – inputs from the study laid foundation for approach

Scientific/Technical Approach

PV Grid Integration Approach1. Advanced PV System Technology Development

• Conduct R&D at the labs (NREL and Sandia) on advanced PV system functionality and integration with energy storage, loads, and control systems (unfunded)

• SEGIS – industry partnerships (funded separately)

2. Advanced Distribution System Integration• Development of new power system integration techniques for

high penetration PV including: smart grids and microgrids (unfunded)

3. System Level Tests and Demonstrations• Develop specific laboratory tests that evaluate high penetration

PV scenarios (unfunded)

• Collect data from fielded systems in high penetration scenarios to develop analysis tools and understand impact on utility grids (funded at NREL to support SMUD and Alamosa)

Scientific/Technical Approach

PV Grid Integration Approach4. Distributed Renewable Energy System Analysis

• Develop methodology that can be implemented in grid analysis tools and simulation programs to evaluate high penetrations (unfunded)

5. Solar Resource Assessment • Develop high temporal and spacial resolution solar

resource data and forecasting techniques to address high penetration of PV into the grid. (Funded at NREL to work with WWSIS)

6. High Penetration Standards and Codes• Looking ahead at future scenarios, what changes are

necessary to existing standards and codes to allow for a smooth transition to high penetration levels (unfunded)

Quality, Productivity, Accomplishment

Accomplishments: Milestones and Deliverables (Current Funding)

FY Milestone/Deliverable Date Organization

2008 Complete final RSI reports 3/08 NREL/SNL

2008 Initiate grid integration test and field demonstration program (SMUD, Xcel, Nellis, Hawaii, etc.)

9/08 NREL/SNL

2008 Establish plan for high quality data gathering and analysis of data on fielded utility systems

9/08 NREL

2008 Develop briefing package and stakeholder meetings 9/08 NREL/SNL

2008 Develop report on energy storage technology needs for PV systems

9/08 SNL

2008 Revise RSI Multi-year Research Plan 9/08 NREL/SNL

2009 Complete IEEE Power & Energy Special Issue on Solar Integration

5/09 NREL

2009 Complete report on utility demonstration projects 9/09 NREL

2009 Report on IEA Task 11 Activities 9/09 NREL

Quality, Productivity, Accomplishment

Support for PV Grid Integration• IEA PVPS Task 11 – PV Hybrid

Systems and Minigrids– Large PV hybrid and minigrid systems are the first

places where high penetration scenarios exist. – A lot of information can be gained on how these

systems handle PV variability and integration with other power sources.

• Editor for IEEE Power & Energy Special Issue on Solar Integration

– Solar Energy Basics – NREL/DOE– Utility Experience with PV - EPRI– Planning for High Penetration PV - GE– Experience with Concentrating Solar Power – NREL/APS– Experience with PV in Germany– Experience with PV in Japan

Quality, Productivity, Accomplishment

System-Level Testing and DemonstrationSacramento Municipal Utility District (SMUD)•Currently installing data acquisition and monitoring on distribution feeder at the Anatolia Subdevelopment in Rancho Cordova, CA

•Over 600 homes planned to have 2kW of PV

Monitoring on Distribution Transformer

Quality, Productivity, Accomplishment

Sacramento Municipal Utility District (SMUD)

Voltage on Distribution Transformer

Voltage at Individual Home

Quality, Productivity, Accomplishment

Currently monitoring effects of 8.2MW PV system on distribution feeder in Alamosa, CO

Working with Xcel Energy (utility) and SunEdison (system integrator)

System-Level Testing and DemonstrationXcel Energy – Alamosa System

Quality, Productivity, Accomplishment

System-Level Testing and DemonstrationXcel Energy – Alamosa System

8MW connected to substation

High variability due to clouds

Formed ad-hoc group to discuss PV variability

Quality, Productivity, Accomplishment

Resource and PV System Variability Characterization

Working with WWSIS on solar variability

Evaluated 10 min. variability across various areas

Aggregated sites

Individual sites

Black line is NREL model

Developed model to make 10 min. resource data from hourly NSRDB datasets

Quality, Productivity, Accomplishment

NREL Publications1. Achilles, S.; Schramm, S.; Bebic, J. GE Global Research, Transmission System Performance Analysis for High-Penetration PV

(February 2008). 2. Bebic, J. GE Global Research, Power System Planning: Emerging Practices Suitable for Evaluating the Impact of High-

Penetration PV (February 2008). 3. Contreras, J.L.; Frantzis, L.; Blazewicz, S.; Pinault, D.; Sawyer, H.; Navigant Consulting Inc., PV Value Analysis (February 2008).4. Denholm, P.; Margolis, R.; Milford, J.; Production Cost Modeling for High Levels of PV Penetration (February 2008).5. Frantzis, L.; Graham, S.; Katofsky, R.; Sawyer, H. Navigant Consulting Inc., PV Business Models (February 2008). 6. Kroposki, B.; Margolis, R.; Kuswa, G., Torres, J.; Bower, W.; Key, T.; Ton, D. Renewable Systems Interconnection: Executive

Summary, NREL Technical Report (NREL/TP-581-42292) (February 2008).7. Kroposki, B., Development of microgrid technologies and standards in the U.S., PV mini-grid and Hybrid Power System

Conference, Athens Greece, (June 2008).8. Kroposki, B. R. Margolis, and D. Ton, Harnessing the Sun, IEEE Power & Energy Magazine, (Accepted for May 2009)9. Liu, E.; Bebic, J. GE Global Research, Distribution System Voltage Performance Analysis for High-Penetration PV (February

2008).10. Liu, E., J. Bebic, B. Kroposki, J. de Bedout, W. Ren, Distribution System Voltage Performance Analysis for High-Penetration PV,

IEEE 2030 Conference, Atlanta, GA, (November 2008).11. Manz, D.; Schelenz, O.; Chandra, R.; Bose, S.; de Rooij, M.; Bebic, J. GE Global Research, Enhanced Reliability of Photovoltaic

Systems with Energy Storage and Controls (February 2008).12. Paidipati, J.; Frantzis, L.; Sawyer, H.; Kurrasch, A. (Navigant Consulting, Inc.). Rooftop PV Market Penetration Scenarios

(February 2008).13. Renné, D.; George, R.; Wilcox, S.; Stoffel, T.; Myers, D.; Heimiller, D. Solar Resource Assessment, NREL (February 2008).14. Ton, D.; Kroposki, B.; Margolis, R.; Kuswa, G.; Torres, J.; Key, T. Renewable Systems Interconnection Distributed Photovoltaic

Study, 17th PVSEC, Fukuoka, Japan, (December 2007).15. Ton, D.; Kroposki, B.; Margolis, R.; Kuswa, G.; Torres, J.; Bower, W.; Hanley, C.; Boyes, J. Renewable Systems Interconnection

Distributed PV Activities; Multi-Year Research Plan (MYRP) FY 2008-FY 2013 (February 2008).16. Ton, D.; Kroposki, B.; Margolis, R.; Kuswa, G.; Torres, J; Key, T. Renewable Systems Interconnection Distributed Photovoltaic

Study, 23rd European PV Solar Energy Conference and Exhibition, Valencia, Spain (September 2008).

Future Directions

• Future plans include expanded efforts in the following areas – Advanced PV Technology Development

• Working with Office of Electricity and California Energy Commission to develop advanced inverters that provide voltage and VAR control

• Need to transfer this to industry

– Advanced Power System Integration• Working with Office of Electricity to see how PV integrates with

smart grids and microgrid technologies

– System Level Tests and Demonstrations• Planning to work with more utilities on demonstrating high

penetration scenarios• Defining testing needs for PV grid integration and working with

privately funded organizations like SolarTAC

Future Directions

SolarTAC• Privately developed solar testing area• Offers a new world-class test facility for solar technologies

http://www.solartac.org/

• Offers large-scale, behind-the-fence testing for grid integration issues

Future Directions

• Future plans also include expanded efforts in the following areas – Distributed Renewable Energy System Analysis

• Develop distribution system modeling and analysis tools that model PV systems and integrate to resource databases

– Solar Resource Assessment• Develop sub-hourly and sub-minute data sets to help determine

ramp rates of PV systems for understanding impacts of high penetration of PV systems on electric power systems

– High Penetration Standards and Codes• Develop a white paper and workshop on standards and codes needs for

high penetration PV

Relevance/Impact of Research

• In conclusion, the PV grid integration area is extremely important to the success of the DOE Solar Energy Technology Program.

• If PV costs continue to come down and reach grid parity, there will be pressure from a variety of sources to implement large-scale PV systems.

• The main goal of the PV Grid Integration Project is to reduce barriers and help make high penetration PV scenarios a reality.

• Utilities need to feel comfortable with distributed PV and understand how it will affect the electric power system.

Additional Information

NREL Distributed Energy Resources Test Facility (DERTF)

• Grid interconnection • (IEEE 1547, IEEE 1547.1,

and UL 1741)• Systems configurations

• (grid-tied, stand alone, hybrid, microgrids)

• Capabilities• 3 AC buses, 3 DC buses• 200kW grid simulation• Large variety of non-PV DG to

test for interactions• Testing integration with loads and

storage

Grid Simulator

Load Simulators

Synchronous Generators

PV Array

3 AC

B

uses

Utility Grid

Battery Banks

3 DC Buses

Inverters

Fuel Cells

Electrolyzer

Microturbines Wind Turbines

PHEV/V2G

DERTF Additional Information

130,000 sq. ft.

Design 2009Construction start 2010Occupancy late 2011