Stable oxide electrolyzers (SOECs) are rising to be a scorching matter on this planet of vitality. They use a strong ceramic materials to separate water into hydrogen and oxygen at extraordinarily excessive temperatures (600°C to 850°C). Because of the excessive working temperature, they’re additionally extremely environment friendly, hitting vitality effectivity ranges between 80-100%. These ranges are considerably increased than different dominant electrolyzers out there comparable to Alkaline (AEL), Proton Alternate Membrane (PEM), and Anion Alternate Membrane (AEM), which often have effectivity ranges of 58-75%.
Nonetheless, while SOEC effectivity is unparalleled, the excessive prices and technical challenges related to SOECs make them appropriate just for particular, high-value use instances.
Be aware: LHV 33.3 refers back to the decrease heating worth of hydrogen (33.3 kWh/kg), used to calculate SOEC effectivity by measuring the vitality content material of the hydrogen produced. It represents the usable vitality with out accounting for water vaporization.
The Promise of SOECs
SOECs are distinguished by their excessive effectivity, usually attaining Larger Warmth Worth (HHV) effectivity above 100%. Because of this the vitality output of the method can exceed the vitality enter, a uncommon and worthwhile trait in vitality manufacturing applied sciences. This excessive effectivity ends in the manufacturing of high-purity hydrogen, which is essential for industries that require stringent high quality requirements, such because the artificial fuels sector.
Moreover, SOECs can use waste warmth and steam from industrial processes, making them much more environment friendly and cheaper to run. This can be a win for each price financial savings and sustainability in numerous industries.
The place SOECs Actually Shine
- Artificial Fuels: SOECs are significantly appropriate for producing syngas (a mixture of hydrogen and carbon monoxide) for artificial fuels. The excessive purity of hydrogen means much less refining is required, making the entire course of cheaper and extra environment friendly. That is promising for the Sustainable Aviation Gas (SAF) business, which additionally has rising regulatory and manufacturing help. Offtake agreements comparable to Norsk e-fuels with Sunfire, and Airbus with Genvia, are already in place.
- Steelmaking: The metal business can minimize CO2 emissions by 80-90% utilizing SOECs, as hydrogen can change carbon within the iron ore discount course of. The high-temperature setting and the provision of waste warmth in metal crops align nicely with the operational wants of SOECs, additional rising effectivity. Tasks like GrinHy with Sunfire and Salzgitter, and Ceres’ SteelCell improvement with Doosan, are key in demonstrating the viability of this use case.
- Nuclear Energy Vegetation: SOECs might be built-in into nuclear crops to supply hydrogen extra effectively utilizing the surplus warmth from the crops. This not solely boosts plant effectivity but additionally enhances security by lowering the necessity for exterior hydrogen provides. The combination of hydrogen manufacturing inside nuclear crops may also assist in balancing the vitality grid, offering a versatile and dependable vitality supply. Corporations like FuelCell Vitality and Bloom Vitality are exploring this potential.
Company engagement via pilot demonstration crops and offtake agreements is essential for scaling up manufacturing from kilowatts (kW) to megawatts (MW). Such initiatives are already underway, indicating a rising curiosity and funding on this know-how.
The Roadblocks
Regardless of their advantages, the promise of SOECs comes at a excessive price—two to 3 instances costlier than different electrolyzers. Additionally they face technical challenges because of their excessive working temperatures, which may result in sooner wear-and-tear and better upfront prices. Whereas excessive working temperatures may also help mitigate efficiency loss, in addition they induce thermal stress, rising the chance of stack failure via electrolyte cracking or seal breakage. SOECs can run at full load for about 2.5 years, whereas different electrolyzers can final 4-8 instances longer.
Moreover, SOEC know-how depends closely on electrical energy prices as a result of it wants lots of vitality to run the high-temperature electrolysis course of. It’s cheaper in locations the place electrical energy is affordable or there’s loads of inexpensive renewable vitality. Then again, it struggles in areas with excessive electrical energy prices, unstable energy, or small-scale setups. SOECs want regular excessive temperatures and secure energy to work nicely, so areas with unreliable renewable vitality sources like photo voltaic or wind can have points except they use vitality storage options or good grid administration to easy out the ability provide.
Scaling manufacturing from kW to MW would drastically cut back manufacturing and materials prices and financial savings in whole stack price might be 67% to 77% when evaluating kW to MW scaled applied sciences. Nonetheless, only some innovators comparable to Bloom Vitality and Topsoe have stacks at massive scales, that are important to exhibit technical maturity and long-term viability to buyers.
Innovating for the Future
Wanting forward, the main focus for SOEC know-how is on technical innovation and value discount. ‘Subsequent-generation’ SOEC know-how goals to deal with the present limitations by enhancing the sturdiness of supplies, optimizing design, and enhancing manufacturing processes. Some examples are:
Manufacturing Innovation:
- Mitsubishi Heavy Industries: Makes use of tubes as a substitute of sheets for stack manufacturing – simplifies gasoline sealing and movement administration, resulting in improved efficiency reliability
- FuelCell Vitality: Makes use of disc-shaped stacks to chop prices by repurposing DVD manufacturing equipment; stacks are 95% recyclable
- Elcogen: Automating stack meeting to hurry up manufacturing and decrease prices
Materials and Design Innovation:
- Ceres: Makes use of a Gadolinium-doped ceria electrolyte, which permits for decrease temperature operation, and stack makes use of much less nickel – improves sturdiness and reduces prices
- Elcogen: Operates at a decrease temperature, permitting the usage of cheaper elements comparable to stainless-steel as a substitute of specialised alloys
- Bloom Vitality: Reducing out deoxygenation items to simplify system design – reduces prices and upkeep wants
Integration Innovation:
- Topsoe: Integration of electrolyzer know-how with ammonia and methanol manufacturing, leveraging experience via their catalyst enterprise
- Sunfire: Vegetation operating on a mix of alkaline and SOEC electrolyzers, offering a powerful benefit for the power-to-liquid and e-fuels markets
These developments are paving the best way for SOECs to scale up and turn out to be extra inexpensive. Because the vitality panorama shifts, SOECs may play a vital position in a sustainable and environment friendly hydrogen financial system. Nonetheless, realizing this potential will rely on continued innovation and company partnerships.
