Nel Hydrogen switches to mass flow meters for more accurate flow verification on high-tech PEM electrolysers

Hydrogen, the most abundant, energy-dense element in our universe, is a highly desirable energy source. Unfortunately, most hydrogen production utilizes natural gas and releases harmful greenhouse gases into the atmosphere. In an effort to improve the sustainability of hydrogen, many researchers have been hard at work developing electolyser technology. Electrolysers are a promising way to produce green energy – and to accomplish the UN’s goal of reaching net zero emissions by 2050. While the high cost of renewable energy and technology has previously been a barrier to green hydrogen, extensive research and development is breaking down that barrier.


Nel Hydrogen: Changing the hydrogen market

Nel is a global hydrogen company, delivering optimal solutions to produce, store, and distribute hydrogen from renewable energy. Their roots date back to 1927, and since then, they have had a proud history of development and continuous improvement of hydrogen technologies. Today, their solutions cover the entire value chain: from hydrogen production technologies to hydrogen fueling stations, enabling industries to transition to green hydrogen, and providing fuel cell electric vehicles with the same fast fueling and long range as fossil-fueled vehicles – without the emissions. Nel Hydrogen, an industry leader in both Alkaline and PEM electrolysers, sees hydrogen as the future of energy.

Here, Nel explains how their PEM electrolysers produce green hydrogen:

“PEM water electrolysis simply splits deionized water (H2O) into its constituent parts, hydrogen (H2) and oxygen (O2), on either side of a solid polymer electrolyte membrane. When a DC voltage is applied to the electrolyser, water fed to the anode (or oxygen electrode) is oxidized to oxygen and protons, while electrons are released. The protons (H+ ions) pass through the PEM to the cathode (or hydrogen electrode), where they meet electrons from the other side of the circuit, and are reduced to hydrogen gas.”

– Nel Hydrogen

Challenge: Verifying a Nel PEM device with Alicat

Before Nel Hydrogen installs a PEM device, their team verifies that it produces the proper quantity of hydrogen. This process verification is performed by measuring the flow rate of hydrogen.

Historically, Nel has used traditional ball-type rotameters to take these measurements. While this got the job done, rotameter technology proved difficult to use and the measurements were not precise enough. They therefore began their search for an easy-to-use, high-precision flow measurement device.


Solution: Mass flow meters to replace rotameters

Nel switched out their rotameters with Alicat mass flow meters to test their S, H, and C PEM electrolysers.

“This has helped us simplify our test setups, increase reading accuracy/reduce variability, [and] is much easier for our technicians performing the test.”

 Philep Levesque, Nel Hydrogen manufacturing engineer

Nel Hydrogen setup with mass flow meter


Depending on the model, Nel reads either the instantaneous flow rate or the average flow rate over a period of time. Averaging is performed directly by the Alicat, using totalizer flow averaging technology. This enabled Nel’s team to compensate for any oscillation in flow. Switching to Alicats improved the accuracy of measurements and decreased the time it took to verify that a device is working properly.

Nel’s future plans

If green hydrogen is to become a viable energy solution, the cost must continue to decrease to compete with fossil-based fuels. Nel is working to scale hydrogen production solutions like PEM electrolysers and produce even larger electrolysis stacks. Meanwhile, the cost of renewable energy continues to decrease, boding well for the hydrogen market overall. Nel hopes that one day, with the help of decreasing costs, they can provide generators to every household so that anyone can produce and store their own clean energy.

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