An Integrated Grid Path for Solar Thomas Key, EPRI Senior Technical Executive ISES Webinar April 22, 2016
Changing Landscape: An Integrated Grid is a Better Grid Combined Heat & Power Demand Response Energy Management Rooftop Solar Two Way Power Electric Vehicles Energy Storage 2
US, March 2016 Electricity Report History of U.S. Net Generation (billion kwh) From EIA Database 3
PV Module Price Noting History PV Module Price Trajectory $100,000 $10,000 $1,000 Source: SPV Market Strategies (adapted by EPRI) $100 0.00 0.01 0.10 1.00 10.00 100.00 1000.00 Cumulative Sales, GW P This illustrates how the historical average module selling price has declined by about 20% with each doubling of sales over several decades.. 4
Noting History Cell Efficiency Trajectory 5 Efficiency Data Points from NREL
Solar PV, a key driver of change US Future? 302 GW PV by 2030 Germany Now Power Demand for one week in May 2015 60 GW Export Import DOE SunShot Vision Study, Released February 2012 Is the grid ready for PV? 6
US Solar compared to Germany Solar Fastest growing generation technology, ~200 GW worldwide U.S. total capacity ~25 GW at beginning of 2016 U.S.: >25 GW in 2016 Germany: >40 GW (Solar Resource Availability: NREL, PV Capacity Additions: SEPA) 7
Solar PV Radiation the poster at Latitude child Tilt of grid edge assets Fastest growing of of all all renewable technologies ~180 GW GW installed worldwide, Germany leads with with ~38 ~38 GW GW U.S. total total capacity ~18 ~18 GW GW at at beginning of of 2015 U.S. U.S. 201515 >20 >20 GW, GW, ~ ~ 5 kwh/m 5 2 /day 2 /day Germany 2015 >40 >40 GW, GW, ~ ~ 3.2 3.2 kwh/m 2 /day 2 /day (Solar (Solar Resource Availability: NREL, NREL, PV PV Capacity Additions: SEPA, SEPA, total total solar solar radiation latitude latitude tilt) tilt) 8
Solar Potential by country assuming residential PV Costs 2014 2025 Source: Bloomberg New Energy Finance 9
Interconnection Challenge: Solar output variability Calendar based on irradiance, 1-min averages at 30 fixed tilt, Knoxville April 2014 Sun Mon Tue Wed Thu Fri Sat 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 10
Single-Module Ramp Events on 1-MW Site in TN Measured 1-sec output from a 224-W module with micro-inverter Single-Module PV System Power Production Profile 0.25 X: 29-Sep-2011 13:10:09 Y: 0.2183 X: 29-Sep-2011 13:11:40 Y: 0.2219 0.2 AC Power (kw) 0.15 0.1 0.18kW in 24 sec (3.3% per sec) +0.18kW in 9 sec (9.1% per sec) 0.05 0 X: 29-Sep-2011 13:10:23 Y: 0.03976 X: 29-Sep-2011 13:11:31 Y: 0.03838 (Sep 29, 2011)... 13:10 13:11 13:12 13:13 13:14 Local Date & Time (Eastern) 11
PV variable output on distribution feeder Circuit map showing locations of pole-mount systems in Rome, GA = DPV Site Substation 1 km 2 grid 0.0 mi. 0.5 mi. 1.0 mi. Google Map data Google 12
Spatial- and time-based PV-feeder demo 13 Search: Youtube Epri Pv Penetration
Power (per-unit) Potential Grid Issues with PV Variability Voltage Control Overvoltage Voltage variations Equipment Operation Feeder regulators, Load tap changers Switched capacitor banks Demand/Energy Masking peak demand Unbalancing supply and demand System Protection Relay desensitization, networks Breaker reduction of reach Unintentional islanding Power Quality Harmonic generation Flicker worries 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 7 8 9 10 11 12 13 14 15 16 17 18 19 Hour 14
Maximum Feeder Voltages (pu) Example: Overvoltage related hosting capacity Minimum Hosting Capacity Maximum Hosting Capacity Total PV: 1173 kw Voltage violation ANSI voltage limit 2500 cases shown Each point = highest primary voltage Increasing penetration (kw) No observable violations regardless of size/location Possible violations based upon size/location Observable violations occur regardless of size/location Total PV: 540 kw 15
Individual feeder PV Hosting Capacity is important PV Systems Baseline No PV PV Penetration 1 PV Penetration 2 PV Penetration 3 Beyond Increase Penetration Levels Until Violations Occur voltage protection power quality thermal Process is repeated 100 s of times to capture many possible scenarios 16
Mapping Feeder Hosting Sample Chattanooga, TN, USA *hosting capacity System Hosting Capacity (~ 300 distribution feeders) Substation-level Hosting Capacity Substation Marker Feeder-level Hosting Capacity *Initial analysis results from TVA/EPB study, results not finalized 17
Inverter Role in PV Plants PV inverter converts DC energy from solar modules in to AC energy and interface the PV system with electricity grid DC Power AC Power Traditional Inverter Functionality Matching PV output with grid voltage and frequency Providing safety by providing unintentional islanding protection Disconnect from grid based on over/under voltage/frequency Smart Inverter Functionality Voltage Support Frequency Support Fault Ride Through (FRT) Communication with grid 18
Planning with DER - Mitigation Analytics Screening Hosting Capacity Reliability DER/Grid Modeling Tools Advancing commercial tools Open-source (OpenDSS) Mitigation Smart inverters Grid-side enhancements Training Engineering Guidelines Planning with DG Voltage (pu) 1.05 1.025 1 0.975 0.95 0.925 0.9 Improved Integration with Smart Inverters Baseline No PV Primary Voltage 20% PV 20% PV with smart inverter 0 4 8 12 16 20 Hour 24 Hour Simulation Often least-cost solution Increased hosting capacity 19
Advanced Inverters Have Significant Upside ANSI voltage limit ANSI voltage limit EPRI White Paper summarizing ~ 5 years of research on the Integration of DER. Search EPRI and 3002004777 20
Conclusions: Key Takeaways Variable PV works better with the grid We need to leverage our existing grid, cultivate hosting capacity Grid upgrades and reinforcements increase hosting, see PVGrid Future DG to provide grid support with Smart Inverters An integrated grid approach will help to transform the power system Integrated The Whole is Greater than the Sum of its Parts Transforming the Power System will be a Journey not a Destination 21
Questions? Tom Key, tkey@epri.com www.epri.com Together...Shaping the Future of Electricity The Integrated Grid Online Community http://integratedgrid.epri.com 22