The World’s Largest and Most Efficient Solid Oxide Electrolyzer

Bloom Energy has begun generating hydrogen from the world’s largest solid oxide electrolyzer installation at NASA’s Ames Research Center, the historic Moffett Field research facility in Mountain View, Calif. This high-temperature, high-efficiency unit produces 20-25% more hydrogen per megawatt (MW) than commercially demonstrated lower temperature electrolyzers such as proton electrolyte membrane (PEM) or alkaline.

This electrolyzer demonstration showcases the maturity, efficiency and commercial readiness of Bloom’s solid oxide technology for large-scale, clean hydrogen production. The 4 MW Bloom Electrolyzer™, delivering the equivalent of over 2.4 metric tonnes per day of hydrogen output, was built, installed and operationalized in a span of two months to demonstrate the speed and ease of deployment.

Hydrogen Electrolyzers for a Clean Energy Future

Hydrogen is critically important to decarbonize the energy economy. Solid oxide electrolysis reduces the cost to produce hydrogen fuel.

Efficiency is Critical to Achieve Decarbonization Targets

The cost to produce hydrogen fuel via electrolysis is driven primarily by a single variable: the cost of electricity. Because electricity costs have the biggest impact on the financial viability of clean hydrogen, it is imperative that hydrogen electrolyzers consume as little electricity as possible. Researchers at Idaho National Laboratory (INL) have been conducting a variety of tests on Bloom Energy’s solid oxide electrolyzer at the Dynamic Energy Testing and Integration Laboratory.

Running at high temperatures and high availability, the pilot results reveal the Bloom Electrolyzer is producing hydrogen at 37.5 kWh per kilogram of hydrogen at the system level. Alternative electrolyzer technologies, such as PEM or Alkaline, consume as much as 52 – 54 kWh per kilogram of hydrogen produced.

Learn more about the impact of efficiency on system economics by contacting us.

Electricity Required to Generate 1kg of Hydrogen

Meet Bloom’s Hydrogen Electrolyzer

Our solid oxide electrolyzer technology can be paired with renewable energy sources to create clean, low-cost hydrogen with industry-leading efficiency.

Our solid oxide electrolyzer is built on the same platform as our Energy Server. The scale, experience, reliability and manufacturing capabilities that went into deploying over 1 GW of solid oxide fuel cells directly translate to our solid oxide electrolyzer.

Video: The Bloom Electrolyzer

How Solid Oxide Electrolysis Works

Electrolysis is a process that uses electrical energy to break water molecules into hydrogen and oxygen.

A solid oxide electrolysis cell (SOEC) consists of an anode, a cathode, and an electrolyte.

The electrolyte itself is a solid ceramic material and the anode and cathode are made from special inks that coat the electrolyte and facilitate an electrochemical pathway to produce hydrogen from renewable electricity.

High operating temperatures of solid oxide cells provide a greater overall efficiency than alternative technologies, thus requiring far less electricity to facilitate the reaction.

Bloom Electrolyzer - How it works

Benefits of Bloom’s Hydrogen Electrolyzer



  • Lowest energy needed to convert water to Hydrogen
  • More efficient than alternative technologies like PEM and alkaline fuel cells




  • Modular design with redundancy
  • 99% Availability
  • Concurrent maintainability




  • Decades of experience in the solid oxide platform
  • 2 GW of SOEC equivalent deployed
  • 2+ GW of MGH capacity


Lowest Cost

Lowest Cost

  • Fastest learning rate with a 28% cost reduction for doubling of capacity
  • Lowest levelized cost of Hydrogen


Technology Comparison

The Solid Oxide Electrolysis Advantage

  PEM Electrolysis Alkaline Electrolysis Solid Oxide Electrolysis
Description Based on polymer membrane on a plate under high voltage and high current Production reaction occurring in liquid alkaline solution Solid ceramic material as electrolyte operating at high heat to reduce electrical needs
​Materials Availability Limited
High High
(Robust supply chain)
​Efficiency (kWh/kg) 52 54 37-44
​Estimated learning rate 13% 9% 28%
  Developing Mature Mature

Unlock the Hydrogen Economy

Hydrogen is the clear answer for our changing energy needs. See why solid oxide technology is the most effective way to produce hydrogen and how Bloom Energy is leading decarbonization efforts across industries.

Unlocking the power of heat to maximize clean hydrogen production through electrolysis

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Bloom Energy Unveils Electrolyzer to Supercharge the Path to Low-Cost, Net-Zero Hydrogen

Bloom Energy Unveils Electrolyzer to Supercharge the Path to Low-Cost, Net-Zero Hydrogen

SAN JOSE, Calif., July 14, 2021 – Bloom Energy (NYSE: BE) today unveiled the Bloom Electrolyzer; the most energy-efficient electrolyzer to produce clean hydrogen to date and 15 to 45 percent more efficient than any other product on the market today.

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