Micro Grids,

Renewable Generation,

Electric Power Resiliency

Patrick E. Mantey

CITRIS

Jack Baskin School of Engineering

University of California Santa Cruz

2016

Mantey Research Group / Contributors

Ali Adabi (PhD)

Rance Fredericksen*

Paul Naud*

Brandon Kinman*

Theodore Framhein*

John Jacobs*

Eric Cao (current MS candidate)

Olexiy Burov

Henry Krute**

Bryan Smith**

Tim Pace**

Pavlo Manovi**

Michael Bennett**

Nathan Abercrombie**

David Oda**

Kevin Abas**

Disruptive Future of Electrical Grid

Change from today’s dependence on a tightly connected “synchronous” grid

Reduce vulnerability / increase resiliency

Expand use of renewable energy sources

Build a system of microgrids

Federated

Local generation and storage

Grid tied for economics/ efficiency

David Crane, CTO NRG Energy

November 12, 2015 [$20M “CarbonX Prize”]

http://www.greentechmedia.com/articles/read/david-cranes-5-steps-to-tackle-climate-change

Push renewables, even when it's hard: Crane's vision for NRG has been to make it the Google or Apple of energy delivery. Wall Street hasn't responded well to the plan. NRG is now splitting its traditional business from its green business in order to appease investors. Interestingly, Crane said that investor reaction might be a positive. “When the market treats every announcement as a negative catalyst, in some ways it’s freeing,” he said. “So you say, ‘I’m not going to try to figure it out; I’m just going to do the right thing.’”

David Crane, CTO NRG Energy

November 12, 2015

http://www.greentechmedia.com/articles/read/david-cranes-5-steps-to-tackle-climate-change

Decentralize the developing world: If Crane were to start his career over, “I’d be bringing solar to every country in East Africa,” he said. “The opportunities are immense.” The market for off-grid solar is expanding quickly, with record-level commitments coming from local governments and investors in this sector. Crane suggested that emerging economies should avoid building out centralized power systems with large centralized fossil-fuel plants (which NRG owns a lot of).

Connecting Renewable Generation to the Distribution Grid (US)

Using the Grid as “virtual storage”

Participate in the Energy Market (ISO)

California “Rule 21” Smart InvertersIEEE 1547 UL/ ANSI 1741

Net Metering / Net Energy Metering

Micro grids:

On Customer Side of theMeter

Micro Grid

MUD

Campus

Building Complex

Apartment Complex

Commercial Building

Farm

Home

Why Micro Grids?

Island operation (no grid to serve)

Rural areas

Electrical power availability

Grid outage

storms

instability

terrorism

Outages

Large areas

Longer time to restoration

Power System Restoration

M.M. Adibi (editor)

ISBN: 978-0-7803-5397-8

690 pages

June 2000, Wiley-IEEE Press

Power System Restoration

“At a time when bulk power systems operate close to their design limits, the restructuring of the electric power industry has created vulnerability to potential blackouts. Prompt and effective power system restoration is essential for the minimization of downtime and costs to the utility and its customers, which mount rapidly after a system blackout.”

Resiliency

“ability to recover from or adjust easily to misfortune or change”

Micro Grid Management

Research Project

Utility “smart meter” data is inadequate

Employ low-cost instrumentation on customer side of utility meter

Smart Electrical Distribution Grids

What one consumer can imagine smart meters / smart grid

could facilitate

Smart Grid ??

The term “Smart Grid” refers to a modernization of the electricity delivery system so it monitors, protects and automatically optimizes the operation of its interconnected elements – from the central and distributed generator through the high-voltage network and distribution system, to industrial users and building automation systems, to energy storage installations and to end-use consumers and their thermostats, electric vehicles, appliances and other household devices.

The Smart Grid will be characterized by a two-way flow of electricity and information to create an automated, widely distributed energy delivery network. It incorporates into the grid the benefits of distributed computing and communications to deliver real-time information and enable the near-instantaneous balance of supply and demand at the device level.

Energy Independence and Security Act of 2007.

IEEE Smart Grid

http://smartgrid.ieee.org/nist-smartgrid-framework/distribution

“Smarts” of Distribution

Silver Spring Networks View

http://www.silverspringnet.com/pdfs/SilverSpring-Datasheet-GE_kV2c.pdf

TOU Electric Rate

http://www.gosolarnow.com/pdf%20files/PGE%20E7%20Rate%20Schedule.pdf

http://www.gepower.com/prod_serv/products/metering/en/downloads/kv2ci_oi.pdf

[GEH-7285, kV2c Encompass Electronic Meter pg.1-10]http://www.gepower.com/prod_serv/products/metering/en/downloads/kv2ci_oi.pdf

MicrogridGrid

FossilGeneration

Wind Turbine

SolarGeneration

Load

Storage

Microgrid

Instrumentation Overview

Develop and apply – a cost/effective system including: monitoring of disaggregated energy use Load control (shedding / adding) Fossil fuel minimization Management of storage

Control/Operate “small” micro grid (nano-grid?)

Transform / integrate data into “intelligence”“Non-Intrusive Load Monitoring”

Micro grid Challenges

Control Challenge does not scale

Small micro grids not easier than large ones

Maintaining voltage, frequency

Renewable Generation volatility

Loads Constraints

Limited Storage

Minimize use of fossil fuel

Energy Forensics

Use “AI” pattern recognition on sensor data to extract (“decompile”) aggregate energy consumption

Provide use input to user for retrospective on use

Obtain user preferences on costs/timing

“Smart Agent” implements user preferences vs. TOU, CPP

Distribution System

Use of Smart Meter Data

System State Estimation

System Identification

System Restoration Speed-up

Data Architecture for Distribution System

Micro-Grids

Renewables now intermixed in distribution system

Increased variability: difficulty forecasting demand

Effects (locally and regionally) of weather

Customer choices

Electric vehicles

Microgrid Perspective

Garage

House

Neighborhood

Facility

Campus

PG &E

Smart Grid

Renewable Energy Sensor Network for the Santa Cruz Wharf

Wind

Generators

Solar

Power

Wind, Imaging &

Solar Sensors

Sensor

Node

Roof Top Pallet

Experiment

Internet

Interface

Wave

Power

Pili

ng

Wave

Sensor

Wharf

Power

Users

User

Sensor

Suites

Interpretive

Center

Research

Wharf Power

Design

Wharf Power

Operations

ClassesAMES

µ Grid

JFV 2-7-10

??

How would / should a microgrid smoothly and cost-effectively

Disconnect and Reconnect

to the grid?

Key Assumptions

Grid Connection

Price of energy from the grid depends on “time of use” (TOU) and /or “critical peak pricing” (CPP) “Demand Response” (DR)

DR complicates situations where focus is on minimum cost of energy (vs. minimal use of non-renewable sources)

Context

Local generation

Renewable (solar, wind)

Fossil fuel generator (standby?)

Storage

Hybrid vehicle

Grid connection

Key Assumptions

Local Generation (Renewables and ..)

Local loads not (all) essential at all times

Battery Storage -Example

Tesla “Power Wall”7-10 KWH Energy Storage for a Sustainable Home

“Powerwall is a home battery that charges using electricity generated from solar panels, or when utility rates are low, and powers your home in the evening. It also fortifies your home against power outages by providing a backup electricity supply. Automated, compact and simple to install, Powerwall offers independence from the utility grid and the security of an emergency backup.”

Battery Storage -ExampleDeeya Energy “L-Cell” technology

Energy Storage Platform (ESPTM) ESP 24KTM.

Modular energy storage

* 6+ hours of storage capacity

* Super fast charging time

* Rugged, outdoor design: -5C to +50C

* Clean, green & non-toxic materials

* 10,000+ charge/discharge cycles

Local Generation (?)

Microgrid Control: Load Matches Generation

Generation Load

HVAC

Electric Car

Solar Generation

Wind Generation

Microgrid : Load Exceeds Generation(Grid Connected)

Generation Load

HVAC

Washer & Dryer

Electric Car

Solar Generation

Wind Generation

Grid

Microgrid : Load Exceeds Generation(Grid Connected)

Generation Load

HVAC

Washer & Dryer

Electric Car

Solar Generation

Wind Generation

$$Grid $$

Microgrid: Generation Exceeds Loads (Island)

Generation Load

Microgrid Control: Generation Matches Loads(Island)

Generation Load

HVAC

Electric Car

Storage as load

Solar Generation

Wind Generation

Solar Generation

Microgrid : Load Exceeds Generation (Island)

Generation Load

MicrogridGrid

FossilGeneration

Wind Turbine

SolarGeneration

Load

Storage

Microgrid

MicrogridMonitorin

gAnd

Control

LM

LM

LM

LM=Load Monitor

Do we need a control room for Microgrid?

Control /Synchronization

Ideal – smooth transitions from grid-connected to operation isolated from grid and back to grid connection.

Today

Going off grid – e.g. conventional backup

Grid connection failure initiates local generation

With adequate backup storage and local renewable, may not be disruptive

Otherwise, delay to bring up local generation

Grid to Microgrid

Going off grid requires matching local load to generation

Generation excess – problem of back feed of generator(s)

Generation deficiency – won’t carry load

Local energy storage critical for smooth transition

Need automated load management to match loads to available power when off-grid

Implies good instrumentation and remote control of loads –power on / off, and possibly varying load

Control /Synchronization

Ideal – smooth transitions from isolated micro grid back to grid connected operation

Reconnection to the grid requires synchronization

Today

Reconnecting to grid –synchronization

Requires local generation disconnected

May need to reduce load before reconnect

Load brought back slowly

Reconnect Renewable Generation

(solar, wind) via inverter”

“Power System Restoration”

Micro-Grids and Power Distribution Research

Micro Grid Instrumentation and Control

Renewable Generation (major energy source)

Operation Grid Connected or as “Island”

Storage (technology, size, management)

Load Identification, Monitoring / Intelligent Agents for Demand /Response Economical Instrumentation for EMS, ToU Pricing

Smoothing Impacts of Renewable Generation on the Grid

VAR Compensation, Distribution Voltage Profile Management

Distribution System Monitoring, Fault Identification and Location to Improve Safety and Service Restoration

Conclusion

Micro grids present challenges

Micro grids have value to both

Consumers

Utilities