Plans for High DER Penetrations: With Examples from PG&E’s Distribution Resources Plan Distribution Systems and Planning Training for NASUCA 2018 Mid-Year Meeting, June 24-27, 2018

PG&E’s Distribution Resources Plan 2015 PG&E’s traditional distribution planning process includes: Forecasting load and peak demand Power flow modeling to simulate performance to determine needs Identifying and developing capacity additions to meet needs The goal of the DRP is to integrate DERs into the distribution planning process California AB 327requires the 3 major utilities to file DRP Determine system capacity to integrate DERs Determine methodology for locational values of DERs Forecast growth of DERs and demonstrate projects Identify issues surrounding safety, data, and tariffs that can help or hinder DER development PG&E, DRP Webinar, 2015

PG&E’s Distribution Resources Plan 2015 2. Integration Capacity 3. Locational benefits and costs 1. DER Growth Scenarios 4. Demonstrations CPUC asked for these four pieces in the DRP Adapted from PG&E, DRP Webinar, 2015

Ten DERs were examined PG&E, DRP Webinar, 2015

Three scenarios were created 1. DER Growth Scenarios Three scenarios were created These Scenarios looked out ten years PG&E, DRP Webinar, 2015

DERs may significantly impact peak load 1. DER Growth Scenarios DERs may significantly impact peak load Let’s turn to the key findings of their growth scenarios This shows how many MW they expect DER to contribute at their system peak hour in Aug of 4-5pm By 2025 they expect nearly 7 GW in their BAU scenario and 12 GW in their very high growth scenario Just for comparison their peak load (net of BTM DG) is 21-22GW so this is like half of system peak that is served by DERs PG&E, DRP Webinar, 2015

Energy efficiency and solar have greatest impact on peak load 1. DER Growth Scenarios Energy efficiency and solar have greatest impact on peak load A second finding is that of the 10 DERs examined, the ones that had the biggest impact at peak load hour were energy efficiency and PV. PG&E, DRP Webinar, 2015

Impacts depend on DER characteristics and local load profiles 1. DER Growth Scenarios Impacts depend on DER characteristics and local load profiles PG&E, DRP Webinar, 2015

Other findings from growth scenarios 1. DER Growth Scenarios Other findings from growth scenarios DERs likely to cluster To estimate DERs, we need to understand load and adoption patterns Past behavior may not be indicative of future behavior PG&E, DRP Webinar, 2015

Hosting capacity analysis - granularity 2. Integration Capacity Analysis Hosting capacity analysis - granularity PG&E has over 3000 feeders Each feeder is broken down into line sections which are in between line devices like voltage regulators or protection devices. Sections are further broken down into segments in between nodes On average each feeder has 34 sections PG&E, DRP Webinar, 2015

What tools did PG&E use? PG&E, DRP Webinar, 2015 2. Integration Capacity Analysis What tools did PG&E use? PG&E recently upgraded its planning tools to handle increased DER penetrations For load and generation hourly profiles, they use LoadSEER (as does SDG&E) If you have a lot of SCADA devices and monitoring points, using that data may be best If you have a lot of AMI data then that data may be aggregated and used PG&E used SCADA and AMI and other customer info to create profiles For the load flow analysis, PG&E, similar to SCE, used CYME. PG&E, DRP Webinar, 2015

Which power system criteria did PG&E evaluate? 2. Integration Capacity Analysis Which power system criteria did PG&E evaluate? Note that in the more recent hosting capacity analysis that PG&E undertook for their Demo A project, the compared their streamlined or simplified approach to the detailed or iterative method that SCE/SDG&E use They examined steady state V, V regulator impacts and V variations PG&E, DRP Webinar, 2015

PG&E analyzed 102,000 line sections within >3000 circuits 2. Integration Capacity Analysis PG&E analyzed 102,000 line sections within >3000 circuits Note that these utilities are just modeling the primaries, not the secondaries. I don’t’ know of any hosting capacity that models the secondaries. PG&E focused on large centralized DER impacts PG&E’s streamlined method doesn’t directly place DER in the model but rather uses an algorithm to consider distribution of DER placement PG&E, DRP Webinar, 2015

PG&E map of hosting capacity 2. Integration Capacity Analysis PG&E map of hosting capacity From PG&E DRP Web Tool, 2016

PG&E map of hosting capacity 2. Integration Capacity Analysis PG&E map of hosting capacity Provide capacities for 10 different DER types/models “Uniform Generation” and “Uniform Load” types can be used for DER with constant or unspecified profiles The uniform profiles can also be used to understand storage charge and discharge capabilities with unconstrained operation times Substation (Bank and Feeder) limits are provided to inform customers that intend to interconnect to multiple line sections on a Feeder and/or Bank Line Section Level results provide a range indicating different capacities based on where interconnection on line section Many line section results have little / no difference between the two values because the granularity achieved is quite detailed You can interconnect up the minimal impact level This is a work in progress. Since the original plans, CPUC asked IOU’s to have 6 maps: PV, uniform generation, and uniform load To be run with and without reverse power flow allowed at SCADA devices From PG&E DRP Web Tool, 2016

Hosting capacity analysis for Hydro/Biogas in PG&E 2. Integration Capacity Analysis Hosting capacity analysis for Hydro/Biogas in PG&E Here’s an example of aggregated hosting capacity results in PG&E for hydro, biogas and other DER that has constant full output At the substation transformer bank level, generally the bigger banks can host more DER At the feeder level, generally the higher V lines can host more And when you get down to the line section level, generally, the devices that are clos to the head of the substation have higher hosting capacity than those at the end of the line PG&E, DRP Webinar, 2015

Hosting capacity analysis for Storage in PG&E 2. Integration Capacity Analysis Hosting capacity analysis for Storage in PG&E PG&E, DRP Webinar, 2015

Start with existing tools and add granularity 3. Locational net benefits Start with existing tools and add granularity The 3rd part of the plan is the LNBA PG&E started with E3’s DERAC calculator which is a spreadsheet valuation tool that includes avoided energy, losses, capacity, emissions, RECs and T&D capacity deferrals They then added granularity to that on the distribution system – distribution capacity split from tx; voltage and power quality; reliability; renewable integration costs PG&E, DRP Webinar, 2015

Locational value 3. Locational net benefits PG&E, DRP Webinar, 2015 One thing they noted is that distribution upgrade deferral isn’t as easy as you might think. I mentioned in the last talk about lining up these 4 criteria. Also there’s a good part of the dx system that isn’t seeing the type of load growth that would drive needs for upgrades that could be deferred. And then, if you were considering DPV to provide deferrals of upgrades, you'd have to think about the ability to DPV to reliable provide power during feeder peak. APS and EPRI do have a project examining this now but this would be hard because there’s no geographic diversity to mitigate the cloud problem. Reliability is all about statistics so if statically you’re in a place with no clouds at peak, maybe that could work. PG&E, DRP Webinar, 2015

3. Locational net benefits Locational net benefits analysis for Demo B in Southern California Edison The IOUs have been working with E3 to develop a spreadsheet based LNBA tool that takes the DERAC tool and adds in these more granular components. One piece of this is that T&D deferral module that looks at how long you might be able to defer an upgrade and how the time value of money allows you save money, like what Andrew showed. The Other pieces examine voltage support, reliability by deferring back-tie equipment, resiliency through a microgrid the LNBA tool is hoped to allow DER developers to estimate the deferral value of a DER solution by inputting location-specific values to the system level values Locations would be categorized or ranked based on the relative benefits that DERs are likely to provide What the tool does not yet do is “proactively identify those [DER] values across the entire distribution and transmission system,” They have to be input. The IOUs keep the actual deferral values confidential In their planning processes, they select deferral opportunities for a solicitation and publish them online  the LNBA tool is not ready for DER sourcing or compensation Rather than being based on a utility’s avoided costs, procurement should be based on an estimate of what it would take to get additional DERs deployed.

Medium cost project 3. Locational net benefits As an example in SCE’s web-based LNBA map you can click on a feeder and it will tell you what kind of distribution upgrade you could possibly defer. Here, it’s a switched capacitor project. 2$$ says it’s a medium cost project

Resources Consumers Energy’s Electric Distribution Infrastructure Investment Plan, 8/1/17, https://mi-psc.force.com/s/ Filing U-17990-0416 Unitil’s Grid Modernization Plan, 8/19/15, http://web1.env.state.ma.us/DPU/Fileroom/dockets/byindustry under Docket 15-121 PG&E Distributed Resources Plan, 2015, http://www.cpuc.ca.gov/WorkArea/DownloadAsset.aspx?id=5141

Acronym definition ADMS Advanced Distribution Management System AMF Advanced Metering Functionality AMI Advanced Metering Infrastructure CVR Conservation Voltage Reduction DERMS Distributed Energy Resource Management System FAN Field Area Network FLISR Fault Location, Isolation, and Service Restoration IEPR Integrated Energy Policy Report NWA Non-wires Alternatives OMS Outage Management System SAIDI/SAIFI System Average interruption Duration/Frequency Index SCADA Supervisory Control and Data Acquisition TVR Time-varying Rates VVO Volt VAR Optimization

Any Questions? Contact Debbie Lew at debra.lew@ge.com 303-819-3470