This document outlines a community microgrid initiative to increase local renewable energy generation while improving grid reliability. The objectives are to reach 25% or more of total energy consumed from local renewables, achieve cost-effective outcomes for communities, and accelerate deployments through partnerships. A showcase project in Hunters Point, San Francisco is described in collaboration with PG&E using an optimization approach to determine optimal locations and sizes of distributed energy resources (DER) like solar PV and energy storage. Baseline analysis found 30 MW of new PV could be added at optimal locations equaling 25% of annual energy without adverse grid impacts.

1. Community Microgrid Initiative
Overview
Greg Thomson
Director of Programs
Clean Coalition
415-845-3872 mobile
greg@clean-coalition.org
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2. A Modern Power System: Smarter, More Distributed
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3. Community Microgrid Initiative: Accelerating the
Transition to a Modern Power System
Objectives
Reach 25% or more of total energy consumed as local
renewables while improving grid reliability
Achieve technical and economic viability with cost-effective
outcomes for communities and ratepayers
Accelerate and scale deployments by partnering with
utilities, utility commissions, and technology providers
Strengthen local economies through increased community
investment, stable energy prices, and reduced system costs
Result: A smarter distribution grid featuring more clean energy now,
improved grid performance, and stronger long-term economics
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4. Hunters Point Community Microgrid Project
Overview
Innovative project in the Bayview-
Hunters Point area of San Francisco, in
collaboration with PG&E
Showcase location demonstrating the
value of Community Microgrids,
including “DER Optimization”
Scalable approach using existing tools
that can be replicated easily by any
utility, for any community area
The Hunters Point substation serves
~20,000 customers (about 90%
residential, 10% commercial &
industrial)
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5. Methodology, DER Optimization: 4 Steps
Utility Data
• Customer &
transformer loads
• Network model &
circuit map
• Equipment list &
upgrade plans
• O&M schedule
Other data
• Solar insolation
• Weather forecasting
• Assumptions for
DR/EE/EV charging,
etc.
• Performance specs,
e.g. storage
4. Higher Capacity
• Increase storage & local reserves (e.g. CHP) to flatten peaks
and island essential services. Include system deferrals.
• Optimize via locations, sizes, types & costs
3. Medium Capacity
• Add lower-cost DER: DR, EE, storage for key peak
reduction, & EV charging. Include system deferrals.
• Optimize via locations, sizes, types & costs
2. Baseline Capacity
• Vary locations & sizes of DG to define existing substation(s)
capacity w/no upgrades. Include system deferrals.
• Use load tap changers, advanced inverters, etc. to manage
voltage issues
1. Baseline Powerflow
• Acquire all data sets, validate data accuracy
• Model existing powerflow, including existing DG
Higher Cost
DG + DER
capacity
Medium Cost
DG + DER
capacity
Low Cost
DG capacity
• Validate with utility & technology vendors
• Maintain or improve grid reliability & power quality
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6. Baseline Capacity: Optimal Locations
Two criteria for finding optimal PV
locations and sizes:
1. Robust feeder locations: less
resistance (lower Ohms) means
more capacity for local generation
2. Matching load types: higher loads
during daytime means better match
for PV generation
PV locations & sizes
Resistance in Ohms
Existing load sizes
Feeder map based on resistance (Ohms)
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7. Additional Optimization: “Substation-as-a-System”
Connected feeders enables substation-wide optimizations, such as:
1. “Crossfeeding,” e.g. over-generation on certain feeders consumed by load on other
feeders in the substation area
2. Optimizing DER such as storage and demand response across the substation feeders
3. Optimizing settings, e.g. load tap changers, across the substation feeders
Feeders connected
across substation
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8. Results: Baseline Capacity
30 MW of new PV added to the substation feeders at optimal
locations, equaling 25% of total annual energy
20 MW added to select Commercial & Industrial sites matching low
resistance locations with higher daytime loads
10 MW added to select Residential sites (multiple dwelling units)
matching more robust feeder locations
Excludes Redev Zone (feeders, expected loads, etc.)
No adverse impacts to distribution grid operations
No Out-of-Range voltages. Voltage regulation achieved using existing
Load Tap Changers (advanced inverters not needed yet).
No Backfeeding to Transmission. Some “Crossfeeding” between feeders.
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