Oort Energy, a UK hydrogen energy startup founded in 2021, manufactures Proton Exchange Membrane (PEM) electrolyzer systems to produce low-cost hydrogen by splitting water into hydrogen and oxygen. The PEM systems have superior performance, high durability and are competitively priced to provide a system giving the lowest levelized cost of ultrapure hydrogen on the market today.
Challenges: green hydrogen
Hydrogen fuel
Hydrogen (H₂), the most abundant element in the universe, is not just a fundamental building block of stars—it's also a vital ingredient in the synthesis of ammonia. Ammonia production is at the heart of creating a plethora of products that we rely on daily, from the fertilizers that nourish our crops to the plastics that are woven into the fabric of modern life.
Traditionally, the world has leaned heavily on steam methane reforming (SMR) to produce over 60 million tons of hydrogen annually. However, this method comes with a significant environmental cost. It's an energy-intensive process that contributes approximately 2% to the global carbon dioxide (CO₂) emissions, releasing between 5 and 9 tons of CO₂ for every ton of hydrogen it generates.
But there's a cleaner path forward: water electrolysis. This process splits water into hydrogen and oxygen using electric current and comes in various forms, including alkaline water electrolyzer, proton exchange membrane water electrolyzer, and solid oxide electrolysis cells. When these electrolyzers are powered by renewable energy sources—think nuclear, solar, and wind power—the result is "green hydrogen."
Green hydrogen is more than just an eco-friendly alternative; it's a beacon of hope for decarbonizing sectors that have traditionally been challenging to reform. Industries like steel manufacturing, long-distance transportation, and even aviation and shipping, which have long been tethered to fossil fuels, can now envision a greener horizon.
PEM electrolyzer
Proton Exchange Membrane (PEM) electrolyzers are particularly appealing for integrating with renewable energy sources to produce green hydrogen, contributing to the decarbonization of various sectors including transportation, industry, and energy storage.
PEM electrolyzers utilize a solid polymer electrolyte to conduct protons from the anode to the cathode while insulating the electrodes electrically. At the anode, water is oxidized to produce oxygen, protons, and electrons. The protons are conducted through the membrane to the cathode, where they combine with electrons to produce hydrogen gas. This process is driven by an external power source, typically from renewable energy sources to ensure the hydrogen produced is green.
PEM electrolyzer advantages and challenges
PEM electrolysis is beneficial over other types of electrolysis because the hydrogen produced is of high purity and high pressure. Moreover, the efficiency is greater in comparison with other forms of electrolysis. However, the resistance of the electrolyte membrane limits the efficiency, especially at high current densities. The inefficiencies are directly proportional to the resistance.
Most traditional PEM electrolyzers have an electrolyte membrane that is thick (above 125 um) and is made of perfluorosulfonic acid (PSFA) polymers, like Nation® or Aquivion®. The use of thick membranes can effectively reduce hydrogen diffusion through the membrane to the anode side. This significantly reduces the risk of forming a flammable or explosive mixture of hydrogen and oxygen, which occurs particularly when the hydrogen is produced at pressure.
However, the use of thick electrolyte membranes introduces significant ohmic resistance and consequently a lower efficiency of the electrolyser, especially at current densities above 1 A cm⁻².
Oort Energy Technology
Oort Energy has developed an advanced electrode/electrolyte membrane assembly for the PEM electrolyzers that can produce hydrogen directly at high pressure. The electrolyte membrane is less than 50 um. This significantly reduces the ohmic resistance and thereby increases the electrolyzer’s efficiency. Even though it uses a thin electrolyte membrane, the PEM electrolyzer can directly produce hydrogen at a minimum pressure of 30 bar without the risk of a flammable or explosive gas mixture forming.
Oort Energy PEM electrolyzer
The diagram below depicts the structure of the Oort Energy PEM electrolyzer cell with the innovative electrode/electrolyte membrane assembly.
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