E n e r g y S t o r a g e S y s t e m s

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OUR MARKET

We defi ne our initial market as behind-the-meter commercial and industrial facilities that will realize signifi cant energy savings by enabling higher use of renewables, the smart management of demand and time-of-use rate structures, and participation in other grid services.

Customers are typically located in sun & wind-rich locations where renewable energy can saturate the grid. Storage can be used to smooth the generation from intermittent renewables. In particular, California, Hawaii, the Northeastern U.S., and Pacifi c Islands will be key regions for early success. Our initial entry points are applications which require 30kW-1.0MW of power and more than 4 hours of storage capacity.

In the long-term, ESS believes the IFB will provide needed fl exibility for grid-scale use by utilities to smooth and shift renewables, while providing ancillary services to support short-term grid resiliency.

OUR COMPETITION

We compete directly with other long-duration energy storage systems and alternatives to our product include vanadium, zinc/bromine and iron/zinc fl ow batteries. Our product is superior because we incorporate earth-abundant, non-corrosive materials that enable lower upfront installed costs. Our durable design and long cycle life drives a lower 20 year levelized cost of energy (LCOE).

THE COMPANY

Founded in 2011, ESS Inc. manufactures a cost-effective, reliable, and environmentally friendly All-Iron Flow Battery (IFB) that expands the use of renewables. By incorporating abundant, low cost and non-toxic materials into our system design, ESS offers one of the lowest installed cost/kWh storage systems on the market. ESS has a primary market focus on the need for time shifting bulk amounts of renewable energy for use at other times of the day. The expected growth in the use of 4+ hour duration storage over the next fi ve years is signifi cant. The management team consists of seasoned veterans in cleantech and distributed generation. Having closed a Series A funding and moved into its new 23,000 sq. ft. production facility in Portland, Ore. in 2015, ESS is positioned to ramp production in 2016.

OUR PRODUCT

The company makes an extremely cost effective energy storage and management system. Presently, our fl agship product is the 125 kW / 1.0 MWh All-Iron Redox (reduction-oxidation) Flow Battery. These systems can be combined to achieve multiple MWh of energy storage capacity. Housed in a rugged container, the system is turnkey, with an AC disconnect for ease of installation. ESS also provides the following services: customized containers, on-site electrolyte hydration and turnkey installation, remote communications and monitoring, a continuing bumper-to-bumper warranty tied to an annual service agreement.

Executive Summary

Customized ‘A’ shipping container and electrolyte tanks.

MECHANICAL STORAGE ELECTROCHEMICAL STORAGEPumped Hydro CAES Flywheels Super Caps Trad. Batteries Flow Batteries ESS

FOR TIME OF USE ENERGY MANAGEMENT

CostSizeDurationInstallationCycle LifeResponse

GOOD MEDIUM POOR

Environment

The IFB leads competitive technologies in low cost per kWh and unlimited deep cycles, as well as with an environmentally friendly electrolyte,

20-plus year system life, turnkey installation and fast electrical response time.

E n e r g y S t o r a g e S y s t e m s

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Copyright © 2015 ESS Inc. All rights reserved. IFB-1000-ES-111315

ESS Inc.17898 SW Boones Ferry RoadPortland, Oregon 97224

Tel: (855) 423-9920Email: info@essinc.com

www.essinc.com

For more information, contact:

Neg

ativ

e Positivemem

bran

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FeCl2,FeCl3

FeCl2

Negative side - plating side Positive side - redox side

AC/AC round-trip efficiency > 70%Depth of discharge > 90%Cycleability > 5000 cycles

Coulombic EfficiencyEnergy Efficiency

ESS ALL IRON REDOX FLOW BATTERY CYCLE PERFORMANCEDEPTH OF DISCHARGE 25% - 95% SOC

0 500 1000 1500 2000 2500

NUMBER OF CYCLES

100%

80%

60%

40%

20%

0%

EFFI

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CY (%

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Coulombic EfficiencyEnergy Efficiency

ESS ALL IRON REDOX FLOW BATTERY CYCLE PERFORMANCEDEPTH OF DISCHARGE 25% - 95% SOC

0 500 1000 1500 2000 2500

NUMBER OF CYCLES

100%

80%

60%

40%

20%

0%

EFFI

CIEN

CY (%

)

THE TECHNOLOGY

ESS’ IFB utilizes earth abundant iron, dissolved in salt water as its energy storage medium. By combining this low cost iron-based electrolyte with ESS’ proprietary high power density design, ESS’ IFB technology has demonstrated thousands of 90% deep charge/discharge cycles at 70% AC round trip efficiency with immeasurable performance degradation. The low cost materials in the IFB design will support a complete AC system cost of <$300/kWh.

The technology is based on the simple and elegant electrochemistry of Iron – the ferrous/ferric redox reaction on the battery’s positive side and the ferrous/iron plating reaction on the negative side.

ESS has cracked the secret to keep traditional iron chemistry stable for thousands of deep charge and discharge cycles with no degradation. ESS’ patent-pending electrodes’ design allows us to operate at high flow battery efficiency levels.

OUR TEAM

The team at ESS boasts decades of experience in cleantech, distributed power generation and energy storage technologies. We understandard how the economics of renewables is evolving and how the grid has to change to accommodate deeper penetrations. We are motivated to enable this transition with cost effective, reliable and flexible energy storage solutions that match the project lives of wind and solar.

MANAGEMENTCraig E. Evans, CEO/FounderJulia Song, CTO/FounderBill Sproull, VP Business Development

INVESTORSPangaea VenturesVarious Angel groupsFounders

GRANTS ARPA-E, ONAMI, Oregon BEST, Wells Fargo IN2

Using earth-abundant materials, the system contains no hazardous materials, corrosive acids or noxious fumes.

Each IFB, along with its AC electronic components, is housed in a shipping container for transportability and protection from the elements.