How to Scale Microgrid Deployments?

Ram Rajagopal

Stanford University

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Talk partly based on “Challenges that Deter Microgrid Deployment”, Lizzy Kolar, Oluwaseyi Olaleye, Paul Walter & Raymond Zhen. Stanford B&W Tech Report 2020 and “Stanford Community Microgrid Design”, Arnab Chatterjee and Caitlin Jaeggli. Stanford B&W Tech Report 2020.

Significant practical barriers to scale microgrids

• Out of 187 microgrid developers, only 6% completed five or more microgrids (Greentech Media, 01/2020)

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What is a Microgrid?

• A localized group of electricity sources and loads that typically operates connected to and synchronous with the traditional centralized grid, but can disconnect and maintain operations autonomously as physical and/or economical conditions dictate (island-mode)

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What are key design criteria?

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• Costs and incentives

• Revenues

• Time to deploy

• Days of autonomy

• Emissions

• …

Deploying Powernet in a Farm

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• Dairy farms power consumption• 50kW per barn

• Cooling costs $100-$150k/year

E­Gauge

REV: 

7 DRAWING NO: 

1­STD­9003D SIZE: 

C SCALE: 1:1  WEIGHT:  SHEET: 1 of 1 

TITLE: 

SunTech Drive, LLC. Boulder, Colorado, USA 

One line diagram 

Fan

1 

Fan

2 

Fan

3 

Fan

4 

Fan

19 

Fan

20 

Solar 20 Solar 3 Solar 1 

Circuit 2 3ph, 230V 

Circuit 1 3ph, 230V 

South facing barn roof 

NOTES: 

­ There will be 20 PicoBlender systems with 5 solar PV panels each connected to each fan 

­ 10 PicoBlenders will be installed on Circuit 1, as shown above – odd fans 

­ 10 PicoBlenders will be installed on Circuit 2, as shown above – even fans 

­ Solar arrays will be roof mount and consist of 5 PV panels of 325W per PicoBlender/fan 

­ Solar systems will be installed on the eve of the roof, symmetrically mounted over the I­bean above the fan, 

to provide a direct connection to the PicoBlender 

­ Two Sonnen systems with 16kWh of storage each will be installed in the tuff shed, with mini­split AC, lights and 2 120Vac outlets 

­ Sonnen Eco #1 will be grid­tied only and used for peak­power shaving 

­ Sonnen Eco #2 should have a Protected Load Panel (PLP) , where 2kW of solar panels are connected through SMA inverter,  

­ The mini­split AC, together with lights and 2 120Vac outlets will attached to a plug that can either be connected to the PLP panel or 

  or 120V from the transformer inside of the shed

Transformer 

480/240V 

3ph, 460V 

Solar 19 Solar 4 Solar 2 

240V, 40A

Disconnect 4 

240V, 200A

Disconnect 1 

240V, 40A

Disconnect 3 

3ph, 240Vac Inside Tuff shed 

3ph, 240Vac 

240V, 80A

Disconnect 2 

240V 3ph

2 x 40A/240V

Circuit breakers 

120V 1ph

Outlet 

 

#2 

Sunny

Boy 2kW

Inverter 

2kW 

Solar

Array 

Lights 

Mini Split 

Plug #1Plug #2

Plug #3240V 3ph

• Powernet system for barn • Solar offsets summer consumption

• Direct load control

• Battery 32kWh capacity

• IOT sensors

• System coordinated via cloud

Powernet at Farms: Challenges

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• Complex system integration of IOT sensors, inverters, load controllers and weather station

• Balancing a three-phase system solution remains a challenge

• Six months to deploy and debug

• Outage support would require additional coordination and switching

System Costs

• Total system integration cost including controls was 22% (30%+ in the future)

Designing a Microgrid for Stanford

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• Design a microgrid solution to support 3-day campus islanding

• Prioritize costs and low emissions

• 30 MW buildings

• 10 MW cooling/heating facility

• Existing backup diesel generation 3.7MW

Stanford Microgrid: Options

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10.3 c/kWh

14.8 c/kWh28.0 c/kWh

• Explore design options (Homer)

Stanford Microgrid: Challenges

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• Integration costs ~30% and > 1 year permitting and build time required

• Coordination of 3.7MW of Diesel Generators and individual building switches very challenging

• Limited ability to explore scenarios that include integration with markets and stabilization

Summary

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Technology

Economic

Policy

KeyChallenges

Technology Challenges: Integrating Devices Across Vendors and Technologies

• Standards exist (e.g. IEEE 2030.7)

• Incentives to integrate across providers?

• Integration with the cloud?

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Greenfield

Brownfield

Technology Challenges: Integrating Devices Across Vendors and Technologies

• Standards exist (e.g. IEEE 2030.7)

• Incentives to integrate across providers?

• Integration with the cloud?

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Greenfield

Brownfield

Modularization and Standardization realizable?

Technology Challenges: Interfacing with the Grid

• Managing power flows

• Synchronization of devices

• Outage readiness and prediction

• Inertia

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Break before make

Make before break

Islanding Mode

Coordination

• Co-optimizing assets

• Managing network constraints

• Marketplace uGrid uGrid

Grid

Capital Costs

Fixed Assets

Distributed energy

resources

Integration services

Equipment

Controls

Economic Challenges

• Costs

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• Uncertainty of Revenue

Federal/grant partnerships

Heavy upfront capital

Value of Resiliency

• Time Horizon

Policy Challenges

• Funding availability

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New York: only 5 of 64 counties eligible

• Zoning, permitting and compliance

• Net metering

Innovation in Technology

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• System integration via cloud coordination

Innovation in Business Models

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Innovation in Regulation

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Questions?

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