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How solar inverters and storage work together

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q  This webinar will be available afterwards at solarpowerworldonline.com & email

q  Q&A at the end of the presentation q  Hashtag for this webinar: #SolarWebinar

Before We Start

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Kathie Zipp Solar Power World

Moderator

Elise Murphy System Designer

Fire Mountain Solar

Mara White Product Manager OutBack Power

How solar inverters and storage work together

Meet your presenters…

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How solar inverters and storage work together

Presented by Mara White, OutBack Power & Elise Murphy, Fire Mountain Solar

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•  A look at the solar PV industry o  Growth Indicators o  Industry projections

•  A look at the energy storage market o  Growth indicators o  Industry projections o  Drivers

•  A look at the customer •  A look at the system

o  How inverters work o  Types of systems

•  System Design o  Best practices for solar storage system installation o  Considerations for choosing an inverter and battery o  Training

•  Real world examples

Agenda

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Introductions

OutBack Power Technologies

•  OutBack’s field is electrical power conversion and storage o  FIRST: Early development of the “true sine-wave” inverter o  FIRST: First multi-voltage MPPT charge controllers - The de facto industry standard o  Today: Leader in Grid/Hybrid technology, products and solutions

Fire Mountain Solar

•  Premier full-service solar solutions company in Washington State o  Grid-tied and battery back up experts o  Design consults for DIY worldwide

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Growth Indicators 1.  Currently PV a $14 billion business

in the US •  PV+ES $8.2B in 2018

2.  More solar installed in the US in the past 18 months than in 30 years prior

•  One system now installed in the US every 4 minutes

•  In 2006 it was one every 80 minutes

•  Now 13,000 mW cumulative solar capacity

•  Enough for 2.2 million homes •  Residential up 68% last year

Sources: various, including SEIA, IHS/IMS Research, US DOE, Forbes, Wall Street Journal, Bloomberg Business, Solar Foundation

Source:  Solar  Power  World,  January  2015  

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Global Market Projections

IHS forecasts global PV installations will exceed 70 GWPV in 2018. •  Growth of the global PV market in next

five years will largely be driven by the Americas and Asia

•  All PV includes:

•  Grid connected Residential •  Grid connected – Commercial •  Grid connected- Utility •  Off Grid – Residential •  Off Grid Remote •  Off Grid Micro Grid

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PV installations vs. PV +ES uptake The development of storage for PV is essential to increase the ability of PV systems to replace existing energy sources. •  Storage to grid-connected applications

is new, storage has been used in off-grid PV systems for some time.

•  New products & less expensive storage solutions, will lead to the increased use of energy storage in the PV industry.

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Today’s market opportunity

•  The off-grid PV market is currently very small; however, most installations will require an ESS.

•  The grid-connected residential market consists of small systems which provide power to a house connected to the grid.

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IHS global outlook for PV with energy storage (2014)

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PV+ES by Market

•  It is assumed that any PV installation in the off-grid market will be installed with energy storage.

•  Energy storage can be installed with commercial PV systems to manage energy usage, reduce electricity bills, and provide back up.

•  Energy storage can be added to utility-scale PV systems to help smooth the output of the system and overcome challenges with grid integration.

•  Energy storage will be used in grid-connected residential PV systems to increase self-consumption.

•  Energy storage solutions today can be deployed in most PV markets.

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Economics: price trends in storage

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Disruptive Technology

10. Artificial intelligence 9. Biometrics 8. Flexible displays 7. Sensors 6. Advanced user interfaces 5. Graphene 4. Energy storage and advanced battery technologies 3. 3-D printing 2. Cloud computing and big data 1. The Internet of everything

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#4 Energy Storage

4. Energy storage and advanced battery technologies Energy storage will be critical to maintain reliable electricity grids and enable renewables to make an even more significant contribution to the energy mix. IHS predicts that global installations of new solar storage systems in the residential, commercial and utility-scale segments will rise by a factor of 18.

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All up •  New installations are forecast to account for a growing share of the market over the

next five years.

o  IHS defines a ‘new’ ESS as one added at the same time as the PV system is installed. A ‘retrofit’ system is an ESS that is added at a later date.

•  IHS believes that by 2018, almost all customers who want an ESS will install it at the

same time as a system PV. By 2018, 84% of residential PVESS installations will be new.

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World Electricity Generation by Percentage of Source

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U.S. Installed Cost of Solar Power ($/kilowatt)

•  Average panel price has declined 60% in the past 2 years

•  Battery prices expected to decline 35% over the next 3 years

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Energy anxiety •  Grid challenges, instability, and

unreliability o  Seems like lot’s more “once a century”

storms o  Life-altering events such as tsunamis,

earthquakes •  Grid collapse

o  Solar activity impact unknown o  Geopolitical and other crises o  Cyber-warfare against smarter and

consequently more vulnerable grids •  Policy and incentives in flux •  Supply and pricing uncertainty

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The need for grid stability – world wide

•  Germany gets 5% of its gross electricity production from solar… …but depends on that source for an “astounding” 30% of peak-delivery demand.

•  Grid architecture simulations show potential for instability and even “system collapse”

under certain conditions

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The need for grid stability – domestic

•  California is among the leading renewable energy countries (California is now 55% of the US solar market)

•  California gets 15% of its electricity from renewables… •  And California currently has 40% more renewable energy capacity than it can handle •  The more renewable energy added, the less stable the grid

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Hurricane Sandy’s tough solar lesson

“Here’s a $70,000 system sitting idle,” said Ed Antonio, who watched his 42 panels as well as those on several other houses in the area go unused since the power went out Oct. 29. “That’s a lot of power sitting…just sitting.”

Solar  panels  didn'ʹt  help  Sandy-­‐‑stricken  

homeowners

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AC DC

How solar inverter/chargers work

•  Converts stored DC to AC with a pure sine wave output •  Charges DC batteries from AC source •  Can sell excess energy to the grid •  Provides back-up power •  Handles load surges •  Load Management and peak shaving

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PV System Types: Overview

Off-Grid with energy storage

Grid-Direct AKA Grid-Tied

Grid-Interactive AKA Grid/Hybrid with energy storage

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Simple Grid-Tied Systems Pros

•  System qualifies for state and federal incentives

•  The simplest, least expensive and most efficient solar energy systems available

•  Designed to lower your utility bill

Cons

•  Systems automatically disconnect from the grid during a power outage for safety reasons

•  Cannot provide power during an outage or emergency

•  Cannot store energy for use during emergencies

•  Cannot store energy for use during peak demand times

o  Potential solution – add battery backup later with an AC coupled system

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Simple Grid-Tied System

Utility Grid Meter

PV Array Grid Tie Inverter

Main Service Panel AC Loads

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Grid-Interactive System with Battery Backup - (Grid/Hybrid Systems) Pros •  Lower your utility bill •  Provides power during an outage or emergency •  Stores energy for use during emergencies our outages •  Stores energy for use during peak demand times •  Backs up essential loads such as lighting, appliances and furnace •  System qualifies for federal and state incentives same as simple

grid-tied Cons •  Less efficient, higher initial cost •  More components •  More complex system design

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Grid-Interactive System with Battery Backup - (Grid/Hybrid Systems)

PV Array

Main Service Panel Meter

Utility Grid

Charge Controller

Grid Tied Inverter/Charger

Battery

Non backed-up loads

Backed-up loads

Backed-up Sub-panel

Generator

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Off-Grid System Pros •  Provides energy independence and self sufficiency for applications

in remote areas •  Fixed energy cost •  Systems are modular and can be increased in capacity if your

needs grow •  Often contain additional charging sources such as wind or

generators to provide energy in all conditions

Cons •  Systems may not qualify for state incentive programs •  Must be designed to fit 100% of load-- not budget or roof

size •  More components, higher expense •  May require a generator

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Off-Grid System

PV  Array

Main  Service  Panel Charge  

Controller Ba?ery-­‐‑based  Inverter Ba?ery

DC  Load  Panel

DC  Loads

AC  Loads

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Steps to designing a system - 1. How to size a system?

•  Load calculations •  Oversize and factor for worst-

case scenarios •  Days of autonomy

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Typical home electricity use Load Analysis

LOADS QTY

x WATTS = Total

WATTS x HRS/ DAY = AVG WH/DAY

CF lights 15 x 20 = 300 x 3 = 900

Refrigerator 1 x 416 = 416 x = 1500

Freezer 1 x 600 = 600 x = 1750

TV/cable box 1 x 200 = 200 x 2 = 400

Stereo 1 x 50 = 50 x 4 = 200

PC/network 2 x 150 = 300 x 5 = 1500

Copy machine 1 x 250 = 250 x 1 = 250

Septic pump 1 x 600 = 600 x 0.5 = 300

AC TOTAL WATTS 2716 W AC AVG DAILY LOAD 6800 Wh

Used for Battery and Array Sizing

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Steps to designing a system - 2. Select your components

•  Quality vs price •  Need for reliability •  Features Save time with pre-

wired systems •  Programming – GridZero and

FLEXtime •  Battery options

FLEXpower Radian FLEXpower ONE

FLEXpower FOUR

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Pick your chemistry/technology/design

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Energy Storage Technologies

Ba?ery  Type Optimal  Application General  Maintenance Best  Practices  for  Safety

Cycling Ability

Costs

 Flooded  Lead  Acid

Off-­‐‑grid,  medium  to  high  capacity  

Electrolyte  refreshing  required  by  automatic  or  manual  watering  systems

Equalization  cycle  can  be  periodically  required

Hazardous  

Installed  vertically  only  with  basic  racking  solution

Must  be  in  well-­‐‑ventilated  space

High  cycle  life

Low  initial  cost  of  ownership Higher  maintenance  and  accessory  costs

VRLA Lead  Acid

 Grid-­‐‑interactive,  off-­‐‑grid,  UPS  and  backup  power,  emergency  vehicles,

Maintenance-­‐‑Free

Superior  shelf  life

Electrolyte  does  not  need  to  be  replaced

Does  not  require  equalization

Usually  rated  non-­‐‑spillable  for  transportation.  Sealed  VRLA  requires  very  minor  ventilation  with  99%  recombination  efficiency

High  to  moderate  cycle  life  

Low  initial  cost  of  ownership  with  reduced  maintenance  and  accessory  costs

Lithium-­‐‑ion Hybrid  EV’s  or  high  ambient  temperature  with  high  cycle  required

Maintenance-­‐‑Free

Must  be  used  with  an  onboard  ba?ery  management  system  to  prevent  over-­‐‑charge  /    over-­‐‑discharge  /  thermal  runaway

Superior  cycling  ability

Very  high  initial  cost  of  ownership.  Dependent  on  application

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Steps to designing a system - 3. Installing the system

•  Training o  NABCEP Certification o  Solar Energy International (SEI) o  Learn from professionals in the industry

•  Assembly and Design

o  Line diagrams o  Layout

•  Code compliance o  Check with your AHJ (Authority Having

Jurisdiction) and local code

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Case Study: Grid-tied with energy storage

Owners: Tim and Alana Nelson, of Fire Mountain Solar •  5.5kW system •  Initial system was off-grid

o  no grid power on property, would have cost $60,000 - $80,000 to bring the grid in

•  In 2013, the neighborhood pooled resources and brought the grid in o  Tim and Alana upgraded their system to a

battery-based inverter •  Now their family has battery backup when the grid

goes down and save on their utility costs through their local utility’s net metering program

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Case Study: Grid-tie with battery back up system

•  Customer originally had a grid-tied PV system without battery backup o  Customer lived in area that experienced

frequent power outages and wanted a PV system to remain powered

o  During first power outage, the grid-tied system shut down

•  System was upgraded to battery-based inverters with battery backup

•  Customer’s critical loads remained powered during outages

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Case Study: AC-coupled system

•  Original system – 9kW with 3 SMA string inverters with generator for backup o  Customer wanted to reduce his electricity

bill •  System upgraded to battery backup through an

AC-coupled system o  Battery-based inverter and battery bank

added onto the existing system, powers critical loads at night and during outages

o  Generator did not have to be used as often §  Used now to top off the batteries

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Kathie Zipp Solar Power World Moderator kzipp@wtwhmedia.com

Elise Murphy System Designer Fire Mountain Solar elise@fmsolar.com

Mara White Product Manager OutBack Power mwhite@outbackpower.com

How solar inverters and storage work together

Questions?

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