Industry survey reveals maturing market in which Levelized Cost of Storage (LCOS) calculations provide best insight to informed choice of long-duration battery technologies.

PORTLAND, OREGON - April 11, 2018 - ESS Inc., a leading manufacturer of safe, low-cost and long-duration energy storage systems, announced today the release of its "Further Beyond Four Hours" white paper on long-duration energy storage. The comprehensive report defines and evaluates the growth potential for long-duration storage in the maturing energy market, and confirms flow batteries as the most promising technology for long-duration storage applications.

Key highlights from the report include:
• Long-duration storage is now commonly viewed as having an energy delivery time of at least four hours, and the need for it is growing.
• Renewable energy self-consumption is seen as the most promising application for long-duration storage.
• A Levelized Cost of Storage (LCOS) calculation is considered the most reputable selection criterion in determining which long-duration storage technology to deploy.
• The most promising technology for long-duration storage is flow batteries and the key criterion for selecting a given asset is cost, particularly the capital expense required. 

"We believe there is a strong case to be made for long-duration storage solutions, especially for renewables integration - and that the market is looking for alternatives to lithium-ion," said Craig Evans, founder and CEO of ESS Inc. "The challenge is how to make an informed business decision when faced with an abundance of information and claims. As our survey showed, the highest percentage of decision-makers believe that Levelized Cost of Storage is the most reliable factor."
"Further Beyond Four Hours" combines in-depth survey results and research with insights from energy storage analysts, consultants, vendors and project developers, as well as engineering organizations and other industry groups.
Those interested in the free report can download "Further Beyond Four Hours" by visiting

About ESS Inc.
Established in 2011, ESS Inc. develops and manufactures the low-cost, long-duration Energy Warehouse (EW) flow battery for commercial and utility-scale energy storage applications requiring 4+ hours of flexible energy capacity and 20+ years of operating life with no capacity fade. The EW utilizes earth-abundant iron, salt, and water for the electrolyte, and delivers an environmentally safe, long-life energy storage solution for the worlds renewable energy infrastructure with the lowest levelized cost of storage per kWh. For more information, visit

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