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Primus Power

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Primus Power is a producer of low-cost, grid-scale electrical energy storage solutions

Hayward, United StatesFounded 2009Energy
Valuation $100–250M Last recorded · 2017
Headcount <100 Current team size
Total funding $50–100M Disclosed equity funding
Unlock exact values This page shows ranges. Dealroom has the exact numbers for Primus Power and the history behind them.

About Primus Power

Primus Power, established in 2009, operates in the grid-scale electrical energy storage sector. The company was co-founded by Tom Stepien, who also served as its CEO. Stepien brought over three decades of experience in engineering, operations, and general management from both small and large companies, including a significant tenure as a VP/GM at Applied Materials, where he managed a $500 million business. His background includes a BS and MS in Mechanical Engineering from MIT. The founding team also included Rick Winter and Dr. G.J. la O', who served as a technical advisor with extensive experience in battery design and a PhD in Material Science from MIT.

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The company focuses on providing long-duration, fade-free energy storage solutions designed for the smart grid. Its primary business involves manufacturing and selling zinc-bromide flow batteries. These batteries are targeted at commercial and industrial clients, data centers, microgrids, and utilities, both in the U.S. and internationally. Primus Power's business model is based on the sale of its modular energy storage systems, with revenue generated per system sold. The company's mission is to support the global transition to 100% renewable energy.

Primus Power's core product is the EnergyPod, a scalable zinc-bromide flow battery system. The second generation, EnergyPod 2, is a modular unit with a 25 kW power rating and 125 kWh of energy capacity, providing a five-hour discharge duration. A key feature is its projected 20-year lifespan with no capacity fade, a significant advantage over other battery technologies. The system's design is unique due to its single-tank, membrane-less architecture, which reduces maintenance costs associated with membrane degradation common in other flow batteries. These systems are scalable from 25kW to over 25MW, serving various applications such as peak shaving, renewable energy integration, frequency regulation, and providing backup power.

Throughout its history, Primus Power secured significant funding from a mix of venture capital, strategic investors, and government grants. The company raised approximately $92 million in equity over eight rounds, with its Series D round in 2017 raising $32 million. Investors included I2BF Global Ventures, Anglo American Platinum, DBL Partners, Matador Capital Partners, and Success Dragon. Additionally, it received over $20 million in grants from entities like the U.S. Department of Energy (DOE), the Advanced Research Projects Agency-Energy (ARPA-E), and the California Energy Commission (CEC). These funds supported the development and deployment of its technology, including a notable project to install a 25 MW/75 MWh EnergyFarm in the Modesto Irrigation District. Keywords: energy storage, flow battery, grid-scale storage, zinc-bromide battery, smart grid technology, renewable energy integration, long-duration storage, Primus Power, Tom Stepien, EnergyPod, peak shaving, microgrids, utility-scale battery, electricity storage, cleantech, energy infrastructure, stationary storage, power grid stability, battery technology, fade-free battery

Source: Dealroom company data

At a glance

Status
Operational
Founded
2009
Headquarters
Hayward, United States
Employees
17
Open positions
None listed
Dealroom signal
75.2/100
Sub-industry
Energy Efficiency, Energy Storage
Sector
Energy, Battery, Sustainable Development Goals, Climate Tech, Stationary Energy Storage, Alternative Battery Chemistry, Grid Technology, Hard Tech, Long Duration Energy Storage
Technology
Hardware, Deep Tech
Business model
Manufacturing
Client focus
b2b

Funding history

7 recorded events

Company financing events and reported valuations.

Deal typeDateAmountValuationInvestorsSource
GRANTOther financing Jun 2019 $4M — Undisclosed —
FundingOther financing Dec 2018 $0 — BIRD Foundation —
Showing the latest 2 of 7 recorded eventsBook a demo for the full funding history →

Growth signals

Primus Power website traffic

Latest recorded traffic for Primus Power is 670 monthly website visits, down 60.6% over the last three months. Primus Power's team declined 5.6% over the past year.

Latest monthly visits670 3-month web change-60.6% 1-year team growth-5.6%
Summary metrics are public; monthly history is available with a demoCompare with peers →

Investments and acquisitions

Capital deployed

Recent portfolio relationships for companies that also act as investors or acquirers.

Investors

11 investors on the cap table

From Dealroom's funding and investor records, grouped by the round each investor first entered.

Seed4 investors entered at this stage

  • US Department of Energy
  • Bonneville Power Administration
  • ARPA-E
  • California Energy Commission

Series A1 investor entered at this stage

Series B and later5 investors entered at this stage

  • Chrysalix Venture Capital
  • I2BF Global Ventures
  • DBL Partners
  • Anglo American
  • Matador Capital Partners

Other known investors1 additional known investor

  • BIRD Foundation
Team profiled 22 named & role-tagged
Founders Hidden — book a demo/100 quality score
Key operators 2 quality Hidden — book a demo/100
Potential founders Hidden — book a demo likely future founders
Startup mafia Hidden — book a demo alumni-founded startups
Talent movements Hidden — book a demo in · Hidden — book a demo out past 12 months

Source: Dealroom Talent Intelligence.

Global footprint

Workforce and web traffic by country
Workforce by country
4 countries with
team presence
🇺🇸 United States70%
🇪🇸 Spain10%
🇳🇬 Nigeria10%
🇬🇧 United Kingdom10%
4 countries shown

Market sentiment

Posts on X, past 7 days

An AI-synthesised read of the highest-engagement posts about Primus Power on X, ranked by likes and reposts, corporate channels excluded.

Reading the room on X — pulling top posts and synthesizing themes…

Source: X recent search ranked by engagement (likes + retweets) · Synthesis by Claude · Cached for 1 hour

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