A N O V E R V I E W O N

BATTERY ENERGY STORAGE

Pictures taken from Google Images

RAMON L. ASAÑA JR.Head, Network Technology Strategy and Architecture

Manila Electric Company

Outline

1. Energy Storage Overview

2. Energy Storage in the Philippines

3. Battery Energy Storage Technologies

a. Lead-acid

b. Redox Flow

c. Sodium Sulfur

d. Lithium-ion

4. Battery Energy Storage Applications in MERALCO

WHAT IS ENERGY STORAGE?

ENERGY STORAGEdevices or physical media that stores energy to perform useful processes at a later time

Pumped Hydro Storage

Battery Energy Storage (grid scale and distributed)Thermal Energy Storage

Compressed Air Energy Storage (CAES)

Classification of Electrical Energy Storage Systems

Global Energy Storage Deployments*

*As of July 24, 2017; based on DOE Global Energy Storage Database (https://www.energystorageexchange.org)

95%

2%2%1%

Energy Storage Capacity (in MW)

Pumped Hydro Electro-Chemical Electro-Mechanical Thermal Storage Hydrogen Storage

Total Capacity: 171.08 GWNo. of Projects: 1,267

Energy Storage in the Philippines

Kalayaan Pumped StoragePower Plant (KPSPP)

Commissioning Year: 1982

Location: Kalayaan, Laguna

Capacity: 720 MW (4 x 180 MW)

AES-Masinloc Battery Energy Storage System

Commissioning Year: 2016

Location: Masinloc, Zambales

Capacity: 10 MW

Energy Storage Applications across the Electric Power Industry

• Energy Time Shift (Arbitrage)

• Supply Capacity

• Ancillary Services• Frequency Regulation• Reserve Capacity• Voltage Support• Black Start

• Transmission Upgrade Deferral

• Transmission Congestion Relief

• Peak Shaving

• Voltage Support/Power Quality

• Renewable Integration

• Distribution Upgrade Deferral

• Microgrids

• Energy Management

• Energy Time Shift

• Service Reliability

• Power Quality

Generation

Energy Storage Technologies

Battery Energy Storage System

Battery Energy Storage System (BESS) consists of an array of batteries, charge controllers, and inverters

On-grid or off-grid solutions

Wide range of sizes: from residential to grid-scale use

Modular installation; scalable

Mobile systems available(batteries stacked in a container van together with its control system)

Provides high degree of availability, reliability and built-in flexibility

LEAD-ACID BATTERIES

GENERAL DESCRIPTION:

• Mature battery technology

• Widely used in cars and UPS but limited on utility scale deployment

• Improved depth of discharge from ordinary Lead Acid resulting to longer cycle time

• Low energy density – requires larger footprint

• Electrode corrosion limits useful life

BATTERY OPERATION:

During Discharge • Chemical reactions coat both plates in Lead sulfate

(Sulfation)• This can be removed by prompt charging• Chemical reaction allowed to proceed

During Charge • Chemical reactions driven in reverse direction• If left for too long uncharged, crystallization of lead

sulfate cannot be reversed by connection to power supply

Advance Lead Acid Battery

LEAD-ACID BATTERIES

1.32 MWh Lead-acid Batteries from Hitachi installed at the TappiWind Park (2001)

REDOX FLOW BATTERIES

GENERAL DESCRIPTION:

• Most of the technologies are still in the demonstration phase

• High number of discharge cycles and relatively longer battery life; ~20 years

• Low energy density – requires larger footprint

• Largest operational system is 0.6MW

BATTERY OPERATION:

• The positive half cell electrolyte contains V4+ and V5+ ions

• The negative half cell contains V3+ and V2+ ions

• Electrons lost from the positive terminal and gained by the negative terminal turn V5+ into V4+ and V3+ into V2+ respectively

• This then flows through a membrane which separates the anolyte and the catolyte solutions

• All vanadium – existence in 4 oxidation states allows the battery to only require that as an electroactive material, removing the problem of cross contamination

REDOX FLOW BATTERIES

Gildemeister’s Vanadium Redox Flow Battery (VRFB) CellCubeinstalled in a solar plant in Pellworm, Germany

SODIUM SULFUR BATTERIES

GENERAL CHARACTERISTICS

• Longer discharge periods (~6 hours)

• NGK Insulators Ltd. and TEPCO jointly developed the technology for 25 years

• 316 MW deployed at 221 sites mostly in Japan and the US

• Normal operating temperature in the range of 300 – 350 oC

BATTERY OPERATION

• Consists of liquid Sodium as anode, liquid Sulfur as cathode and a solid electrolyte – Beta Alumina

• During discharging, Sodium gives off ions , then it passes through the electrolyte, then the ion is combined with sulfur to form sodium polysulfide Na2S4

• Reversal of the process occurs with every recharging

• Heat is generated in both process

SODIUM SULFUR BATTERIES

The NaS battery installation provided by NGK Insulators, Ltd., deployed at Xcel in Lucerne, Minnesota, in 2008 to supplement wind turbine generation contains 20 50-kW

modules with 7.2 MWh of storage capacity and a charge/discharge capacity of 1 MW.

LITHIUM-ION BATTERIES

GENERAL DESCRIPTION:

• Mature battery technology

• Largest commercial deployment ~30GWhr

• High energy densities – requiring less footprint

• High charge/discharge efficiency

• Good cycle life

• Widely used in EVs, consumer electronics and utility applications

BATTERY OPERATION:

• Consists of an anode and a cathode, as well as an electrolyte salt solution with lithium ions

• During discharging, positively charged lithium ions go towards the cathode, when the cathode is positively charged, this attracts electrons which flow through the connected device towards the cathode

• Reversal of direction occurs with every recharging, allowing this process to start over

LITHIUM-ION BATTERIES

AES’ 20MW Lithium Battery Energy Storage System in Moraine, Ohio

18From Samsung SDI Energy System

Quick Comparison of BATTERY Technologies

LITHIUM-ION BATTERIES

19

Energy Storage Applications in Meralco

BEHIND-THE-METER GRID SUPPORT ISLAND ELECTRIFICATION

Images taken from:• https://www.atarlife.com/wp-content/uploads/2016/10/house-with-battery-and-panels.jpg• http://www.energystorageexchange.org/projects• http://www.hitachi.com/New/cnews/month/2015/02/150226a.html

APPLICATION: BEHIND-THE-METER

Solar-plus-Battery Pilot Project

PROJECT OBJECTIVES:

To gather “real world”

understanding of how Energy

Storage Systems (ESS) interact

with the electricity network

and how they can benefit

customers

APPLICATION: BEHIND-THE-METER

System Connection Diagram (Actual Installation)

ROOFTOP SOLAR PV

DISTRIBUTION

UTILITY

MAIN PANEL

BOARD

LOADS

HYBRID

INVERTER

12.8 kWh

BATTERY

STORAGE

CRITICAL LOADS

ATSAutomatic

Transfer

Switch

AC

DC

LEGEND:

COMMUNICATIONS

Monitoring

PortalNET METER

(Smart Meter)

Examples:

• Lighting

• Power Outlets (for fans,

phone chargers, TV, etc.)

• Refrigerator

• Small Aircons

6 kWp

CT

APPLICATION: BEHIND-THE-METER

Use Cases

SELF-CONSUMPTION ENERGY TIME SHIFT BACK-UP POWER SUPPLY

BESS is used to decrease the

user’s dependency from the

grid by storing excess solar

PV output and consuming it

later when it is needed.

BESS is used to store energy during

off-peak hours and discharge

during peak hours in order to take

advantage of the electricity price

difference under Time-of-Use

(TOU).

BESS is used as back-up

power supply, similar to a

diesel gen-set, to critical

loads during outages

APPLICATION: BEHIND-THE-METER

System Connection Diagram (Actual Installation)

ROOFTOP SOLAR PV

DISTRIBUTION

UTILITY

MAIN PANEL

BOARD

LOADS

HYBRID

INVERTER

12.8 kWh

BATTERY

STORAGE

CRITICAL LOADS

ATSAutomatic

Transfer

Switch

AC

DC

LEGEND:

COMMUNICATIONS

Monitoring

Portal

NET METER

(Smart Meter)

Examples:

• Lighting

• Power Outlets (for fans,

phone chargers, TV, etc.)

• Refrigerator

• Small Aircons

6 kWp

CT

Daytime

Nightime

SELF-CONSUMPTION

APPLICATION: BEHIND-THE-METER

System Connection Diagram (Actual Installation)

DISTRIBUTION

UTILITY

MAIN PANEL

BOARD

LOADS

HYBRID

INVERTER

12.8 kWh

BATTERY

STORAGE

CRITICAL LOADS

ATSAutomatic

Transfer

Switch

AC

DC

LEGEND:

COMMUNICATIONS

Monitoring

Portal

NET METER

(Smart Meter)

Examples:

• Lighting

• Power Outlets (for fans,

phone chargers, TV, etc.)

• Refrigerator

• Small Aircons

CT

Off Peak

Peak

ENERGY TIME SHIFT

APPLICATION: BEHIND-THE-METER

System Connection Diagram (Actual Installation)

ROOFTOP SOLAR PV

DISTRIBUTION

UTILITY

MAIN PANEL

BOARD

LOADS

HYBRID

INVERTER

12.8 kWh

BATTERY

STORAGE

CRITICAL LOADS

ATSAutomatic

Transfer

Switch

AC

DC

LEGEND:

COMMUNICATIONS

Monitoring

Portal

NET METER

(Smart Meter)

Examples:

• Lighting

• Power Outlets (for fans,

phone chargers, TV, etc.)

• Refrigerator

• Small Aircons

6 kWp

CT

BACK-UP POWER SUPPLY

APPLICATION: GRID SUPPORT

Grid-scale Battery Energy Storage Project

Installation of 2MW Battery Energy Storage System

(BESS) for various grid applications such as peak

shaving and renewables integration

DESCRIPTION PROJECT DETAILS

• To demonstrate and evaluate the potential of Battery Energy

Storage System (BESS) to manage peak demand and energy,

improve service reliability and power quality, and compensate

for the intermittency of renewable generation

• Gain actual learning experience on grid-scale BESS

OBJECTIVES

INSTALLATION SITESan Rafael Bulacan

APPLICATIONS

• Peak Shaving for Network Upgrade Deferral (76% Peak Loading for 2016)

• Voltage Support

• Renewables Integration (SPARC 3.82 MW Solar)

PARTNERSHIP WITH: GRID CONNECTION13.8kV Circuit

APPLICATION: ISLAND ELECTRIFICATION

Cagbalete Island Microgrid Pilot Project

CAGBALETE ISLAND PROFILE

• Situated in Mauban, Quezon

• 1,795 hectares total land area

• Total of 887 households; 758 in Brgy. CagbaleteI and 129 in Brgy. Cagbalete II

• Approximately 13 km from Mauban port (1-hour boat ride)

• A booming tourist attraction because of its beautiful beach (with at least 18 resorts)

A pilot project on Microgrids for the electrification of households located in

remote islands and far-flung areas.

DESCRIPTION PROJECT SITE

• Evaluate the feasibility and sustainability of using Microgrids for island electrification in providing reliable, affordable, sustainable, and clean 24/7 electric service

• Gain actual learning experience from planning to operations and maintenance of Microgrids

• Prepare Meralco for future Microgrid installations

OBJECTIVES

Diesel Generator Solar PV Battery Storage

Battery Storage Basics

CELL, MODULES, AND PACKSA cell is the smallest, packaged form a battery can take and is generally on the order

of one to six volts. A module consists of several cells generally connected in either

series or parallel. A battery pack is then assembled by connecting modules together,

again either in series or parallel.

C-RATEIn describing batteries, discharge current is often expressed as a C-rate in order to

normalize against battery capacity, which is often very different between batteries. A

C-rate is a measure of the rate at which a battery is discharged relative to its

maximum capacity. A 1C rate means that the discharge current will discharge the

entire battery in 1 hour. For a battery with a capacity of 100 Amp-hrs., this equates to

a discharge current of 100 Amps. A 5C rate for this battery would be 500 Amps, and

a C/2 rate would be 50 Amps.

CAPACITY OR NOMINAL CAPACITY (Ah for a specific C-rate)The coulometric capacity, the total Amp-hours available when the battery is

discharged at a certain discharge current (specified as a C-rate) from 100 percent

state-of-charge to the cut-off voltage.

ENERGY OR NOMINAL ENERGY (Wh for a specific C-rate)The “energy capacity” of the battery, the total Watt-hours available when the battery

is discharged at a certain discharge current (specified as a C-rate) from 100 percent

state-of-charge to the cut-off voltage.

Battery Storage Basics

NOMINAL VOLTAGE (V)

The reported or reference voltage of the battery.

OPEN-CIRCUIT VOLTAGE (V)

The voltage between the battery terminals with no load applied. The open-circuit

voltage depends on the battery state of charge, increasing with state of charge.

TERMINAL VOLTAGE (V)

The voltage between the battery terminals with load applied. Terminal voltage

varies with SOC and discharge/charge current.

CUT-OFF VOLTAGE

The minimum allowable voltage. It is this voltage that generally defines the

“empty” state of the battery.

INTERNAL RESISTANCE

The resistance within the battery, generally different for charging and discharging,

also dependent on the battery state of charge. As internal resistance increases,

the battery efficiency decreases and thermal stability is reduced as more of the

charging energy is converted into heat.

Battery Storage Basics

STATE OF CHARGE (SOC)(%)

An expression of the present battery capacity as a percentage of maximum capacity.

SOC is generally calculated using current integration to determine the change in

battery capacity over time.

DEPTH OF DISCHARGE (DOD) (%)

The percentage of battery capacity that has been discharged expressed as a

percentage of maximum capacity. A discharge to at least 80% DOD is referred to as a

deep discharge.

CYCLE LIFE (NUMBER FOR A SPECIFIC DOD)

The number of discharge-charge cycles the battery can experience before it fails to

meet specific performance criteria. Cycle life is estimated for specific charge and

discharge conditions. The actual operating life of the battery is affected by the rate and

depth of cycles and by other conditions such as temperature and humidity. The higher

the DOD, the lower the cycle life.

End of Presentation1 August 2017