Verdagy ($117M to develop large-scale alkaline water electrolyzers for low-cost green hydrogen production)

Verdagy, an American cleantech company founded in 2021, develops and manufactures large-scale AWE (alkaline water electrolysis) electrolyzers based on its advanced electrode assemblies. An AWE electrolyzer takes an alkaline solution and electricity and turns them into hydrogen and oxygen. AWE technology is best for putting green hydrogen into use on a large scale. Verdagy’s industry-leading solution reduces the amount of capital expenditures and energy needed to make industrial hydrogen. This gives the best levelized cost of hydrogen as production plants scale from megawatts to gigawatts.

Challenges: hydrogen fuel

Hydrogen fuel

Roughly 70 million tons of hydrogen have been produced annually for oil refining, ammonia and methanol production, and fuel in transportation. The majority of hydrogen is produced from fossil fuels via steam reforming of natural gas, partial oxidation of methane, and coal gasification, all of which emit large quantities of carbon dioxide (CO₂). Other eco-friendly methods of producing hydrogen include biomass gasification, methane pyrolysis, and electrolysis of water. Using electricity, electrolysis splits water into hydrogen and oxygen. All these methods and systems are, however, generally more expensive than those based on fossil fuels.

Alkaline water electrolysis

An alkaline water electrolysis (AWE) electrolyzer produces hydrogen and oxygen from an alkaline solution and electricity. It is a mature technology that has been used in industry for nearly a century to produce hydrogen. AWE technology is ideal for large-scale deployment of clean hydrogen.

Typically, commercial AWE electrolyzers operate at current densities of up to about 500 mA/cm². Despite the fact that a higher current density produces more hydrogen, the operation of electrolysis cells at higher current densities can pose significant challenges. Because the gas/liquid mixture has a lower specific heat, a lower density, and a lower thermal conductivity than the liquid electrolyte, the electrolyzer’s heat removal efficiency decreases as the amount of gas produced at higher current densities increases. In addition, if a gas pocket masks a region of the electrode, local temperatures may rise rapidly. Local hot spots on the electrode thus damage the membrane (or separator).

Verdagy Technology

Verdagy has developed an electrode pan (anode and cathode pans) assembly that efficiently removes heat from the electrolyzer. The innovative electrode pan assembly makes it possible for large AWE electrolyzers to produce more hydrogen using fewer electrolysis cells. Verday’s technology reduces capital costs and makes the electrolysis system a viable source for producing hydrogen gas at low cost.

Verdagy electrolyzer

The diagram below depicts the anode or a cathode pan assembly. The electrode assembly comprises a pan, multiple ribs, a baffle plate, a manifold, an outlet tube, and a catalyst-coated electrode.

Verdagy's assembly of anode or cathode of an electrolysis cell. — Verdagy’s assembly of anode or cathode of an electrolysis cell (ref. US11444304B1, US11390956B1).

Anode or cathode pan

The pan is made of conductive metal. It houses multiple ribs, a baffle plate, a manifold, an outlet tube, an electrode, and electrolyte solution. The pan enables electrolysis cells to operate at high current densities and high electrolyte flow rates. The high electrolyte flow rate is advantageous for removing gas masks from the electrode and membrane.

Ribs

Ribs are made of conductive metal. They are welded to the pan floor to ensure efficient current distribution across the active area.

Baffle plate

The baffle plate is positioned between the electrode and the pan floor. It enables an electrolyte circulation and top to bottom mixing, resulting in thermal equilibration of the flowing electrolyte and preventing the electrolysis cell from overheating.

Manifold

The manifold connected to the outlet tube can reduce slugging at the cell outlet due to the high electrolyte flow rate and high current density. It provides space for gas collection and liquid flow without masking the membrane and causing slug and plug flow.

Electrode

The electrode on top of the pan is welded to ribs. It is coated with catalysts for hydrogen or oxygen generation.

How Verdagy electrode assembly removes heat

The baffle plate plays an important role in allowing a high flow rate of electrolyte that can sweep gas away from the membrane and electrode, thereby minimizing local heat that damages the membrane.

As shown in the figure below, the baffle plate is designed and positioned such that the gas produced at the electrode mixes with the electrolyte on the electrode side of the baffle plate, resulting in a relatively low density column that defines a riser section. The low density mixture rises relatively quickly through the riser section. Once above the top of the baffle plate, the gas disengages and flows into the manifold and outlet tube, while a portion of the electrolyte falls back down the back side of the baffle plate (on the pan floor side) into the down-comer region, thereby forming a circulation loop.

Fluid flow in the anode or cathode assembly of Verdagy's electrolysis cell — Fluid flow in the anode or cathode assembly of Verdagy’s electrolysis cell.

This circulation loop is depicted in the figure below, which compares the circulation with and without the baffle plate. The riser section is represented by an upward arrow, while the down-comer section is represented by a downward arrow. As the electrolyte flows through the cathode or the anode, the baffle plate creates fast-moving circulation loops that keep the electrolyte substantially isothermal. The high circulation rate can drive larger shear rates adjacent to the membrane, helping sweep gas away from the membrane.

Effect of baffle plate on fluid flow of Verdagy's electrolysis cell — Effect of baffle plate on fluid flow of Verdagy’s electrolysis cell (ref. US11444304B1).

Verdagy has used a unique spacer between the membrane and the electrode to thermally isolate the membrane from any hot spots on the electrode. As shown in the figure below, the spacer is a polymer mesh with vertical and horizontal features. The vertical feature is larger than the vertical feature, allowing a path for electrolyte flow and gas release through the horizontal feature to minimize gas masking and remove the heat generated around the membrane.

The spacer in Verdagy's electrolysis cell — The spacer in Verdagy’s electrolysis cell (ref. US11431012B1).

The spacer is made of polypropylene (PP), polyethylene (PE), high density polyethylene (HDPE), polyethylene teraphthalate, polyether ether ketone (PEEK), nylon, polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), polychlorotrifluoroethylene, ethylene chlorotrifluoroethylene (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), ethylene propylene, ethylene propylenediene, neoprene, or urethane.

Verdagy Patent

US20220384829A1 Anode and/or cathode pan assemblies in an electrochemical cell, and methods to use and manufacture thereof
US11390956B1 Anode and/or cathode pan assemblies in an electrochemical cell, and methods to use and manufacture thereof
US20220275521A1 Systems and methods to make hydrogen gas using metal oxyanions or non-metal oxyanions
US20220275522A1 Systems and methods to make hydrogen gas using metal salt
US11431012B1 Electrochemical cell with gap between electrode and membrane, and methods to use and manufacture thereof

Verdagy Technology Applications

Green hydrogen industry

Verdagy’s advanced AWE electrolyzers are designed for large-scale production of green hydrogen, primarily for industrial applications. The company’s technology is particularly suited for heavy industries that require large amounts of green hydrogen, such as chemicals, ammonia/fertilizer, steel, and e-fuels. Verdagy is backed by leading companies in the petrochemical, industrial chemicals, energy infrastructure, and mining industries.

Verdagy Products

Verdagy eDynamic electrolyzer

Verdagy’s pilot plant is situated in Moss Landing, CA. Verdagy has successfully demonstrated the operation of a 3,200 cm² demo cell that is taller than one meter. The company has announced the opening of a new facility in Newark, California, which will be the first to manufacture advanced water electrolyzers in large volumes in the United States.

Verdagy’s main product is the eDynamic electrolyzer. It is a 20-megawatt hydrogen power plant that can scale up to gigawatts. The eDynamic electrolyzer has many benefits, such as very low CapEx, the widest dynamic range available, and the ability to modulate hydrogen plant production based on energy availability, energy prices, and hydrogen demand. Its unique cell architecture supports proactive maintenance and simple repair.