2018 UC Solar Research Symposiumcast.ucmerced.edu/sites/cast.ucmerced.edu/files/public... ·...

Demonstration of Flow Batteries for the Prevention of Minimum Import

Violations

October 19, 2018

University of California, Riverside

Southern California Research Initiative for Solar Energy (SC-RISE)

www.scrise.ucr.edu

Center for Environmental Research and Technology (CERT)

www.cert.ucr.edu

Presented by:

Alfredo A. Martinez-Morales, Ph.D.

2018 UC Solar Research Symposium

U.S. Renewables Status

2

In 2016, U.S. renewable electricity accounted for 18.3% of total installed

capacity and 15.6% of total electricity generation.

Source: 2016 Renewable Energy Data Book

California Solar PV Status

3

In 2016, California continued to lead with the most installed renewable electricity

capacity of any state (nearly 35 GW). California had the largest amounts of

cumulative installed solar capacity.

Source: Renewable Energy Data Book Department of Energy

Electro-chemical Storage

Status

4

According to IRENA 2016 report, during the last 20 years, global installations of

electrochemical storage deployment grew exponentially.

Source: ELECTRICITY STORAGE AND RENEWABLES: COSTS AND MARKETS TO 2030, IRENA

ZBFB is at a pre-commercial stage. Currently, installation costs are higher than

other types of battery. IRENA forecasts that by 2030, ZBFB costs are expected to

decrease to one third of current costs.

Source: ELECTRICITY STORAGE AND RENEWABLES: COSTS AND MARKETS TO 2030, IRENA

Zinc Bromine Flow Battery

(ZBFB)

5

6

Source: Self-Sufficient, High Resilience Microgrids, Primus Power

Conventional ZBFB EnergyPod ZBFB

EnergyPod ZBFB

Victor Valley Wastewater Reclamation Authority (VVWRA) Facility 7

8

Project Summary:

• Deployment, demonstration, and validation of a ZBFB at the VVWRA

Facility;

• Objective is to demonstrate the potential for minimizing (preventing) the

minimum import violations at the VVWRA facility by optimizing the utilization

of the ZBFB;

• System is composed of two on-site 800 kW biogas generators, 200 kW/

1 MWh ZBFB, SCADA system, and controller;

• System optimization is achieved by a heuristic control framework;

• Minimize the operational power buffer;

• Increase on-site renewable energy; and,

• Reduce the amount of water (in treatment) being discarded.

VVWRA Project

9

March 2016 Week 4

Minimum Import

Violation

Minimal Import

Violation

Generators

decoupled

VVWRA receives

energy from two

sources:

• on-site biogas

generators

• Southern California

Edison (SCE) grid.

• Minimum Import

Violation

• Power Import

< 80 kW

• Lasts for > 2 s

VVWRA System Layout

10

VVWRA Control

11

12

• Energy management goals are changed from reducing peak demand by

discharging battery to maintaining net load above 80 kW by charging

battery.

• The BESS acts as the net load regulator to trigger the onsite generators to

produce more/less power.

• The frequency (less than 2 second) to operate the battery is much faster

than the previous battery control methods.

The BESS will smooth the facility load and maintain a load margin above the

minimum import threshold.

VVWRA Control Requirements

13

States Conditions SCE Generator

Actions

0: Steady State SOClower < 𝑆𝑂𝐶< 𝑆𝑂𝐶𝑢𝑝𝑝𝑒𝑟

Steady No Output

Change

1: Charge Initiate SOC ≤ SOClower Increase Increase

Output

2: Charge Maintain SOC ≤ SOC𝑚𝑖𝑑 Steady No Output

Change

3: Discharge Initiate SOC ≥ SOCupper Decrease Decrease

Output

4. Discharge Maintain SOC ≥ SOCmid Steady No Output

Change

VVWRA Control States

14

State 1:

Charge

Initiate

State 2:

Charge

Maintain

State 0:

Steady

StateSOC ≥ SOCupper

SOC ≤ SOClower

SOC ≥ SOC𝑚𝑖𝑑

State 3:

Discharge

Initiate

State 4:

Discharge

Maintain

SOC ≤ SOC𝑚𝑖𝑑

State 0:

Steady

State

VVWRA Simulation Results

VVWRA LabVIEW Simulator

15

VVWRA LabVIEW Simulator

16

Simulation Results

17

18

Simulation Results

19

Reducing the Occurrence of Minimum Import

Violations

Under certain conditions the simulation is unable to prevent the

minimum import violation. There are two main reasons :

1) The facility load drops sharply

2) The battery is engaged in a “refresh cycle”

20

Minimum Import Violation:

Load Drops Sharply

21

Minimum Import Violation:

ZBFB is in ‘Refresh Cycle’

Decreasing Occurrence of Minimum Import

Violation

To improve the prevention of minimum import

violations, optimization is needed to:

1. Determine what is the most appropriate

steady range

2. Determine what is the most optimal

threshold value

22

23

Decreasing Occurrence of

Minimum Import Violation

Steady Range (130 kW ~ 150 kW), trigger 100 kW, set 110 kW

24

Decreasing Occurrence of Minimum

Import Violation

Steady Range (100 kW ~ 120 kW), trigger 90 kW, set 95 kW

Steady Range (130 kW ~ 150 kW), trigger 100 kW, set 110 kW

25

Conclusions

• New technologies have a lot of potential, but demonstration and validation is

needed for de-risking investment and adoption;

• Operational constraints are critical for properly managing and utilizing new

technologies;

• Performing use case studies and application-based projects will validate the

limitations and constraints of new technologies for validating the applicability

of new technologies; and,

Thank you

For more information please visit

www.cert.ucr.edu

or email me at

alfmart@cert.ucr.edu