This table summarizes the U.S. Department of Energy (DOE) technical targets for liquid alkaline electrolysis. There are many combinations of performance, efficiency, lifetime, and cost targets that can achieve the central goal of low-cost hydrogen production of $2/kg H2 by 2026 and $1/kg H2 by 2031. The combination of targets listed here were developed with input from experts from industry and national laboratories; they can be considered a starting guidepost for technology developers.
Technical Targets for Liquid Alkaline Electrolyzer Stacks and Systems a,b
| Characteristic | Units | 2022 Statusc | 2026 Targets | Ultimate Targets |
|---|---|---|---|---|
| Stack | ||||
| Performance | 0.5 A/cm2 @ 1.9 V/cell | 1.0 A/cm2 @ 1.8 V/cell | 2.0 A/cm2 @ 1.7 V/cell | |
| Electrical Efficiency d | kWh/kg H2 (% LHV) |
51 (65%) |
48 (69%) |
45 (74%) |
| Average Degradation Rate e | mV/kh (%/1,000 h) |
3.2 (0.17) |
2.3 (0.13) |
2.1 (0.13) |
| Lifetime f | Operation h | 60,000 | 80,000 | 80,000 |
| Capital Cost g | $/kW | 250 | 100 | 50 |
| System | ||||
| Energy Efficiency | kWh/kg H2 (% LHV) |
55 (61%) |
52 (64%) |
48 (70%) |
| Uninstalled Capital Cost g | $/kW | 500 | 250 | 150 |
| H2 Production Cost h | $/kg H2 | >2 | 2.00 | 1.00 |
a This target table has been developed specifically for low-temperature liquid alkaline electrolyzers; separate tables have been developed for other electrolyzer technologies. There are many combinations of performance, efficiency, lifetime, and capital cost targets that can achieve the central goal of low-cost hydrogen production. The targets listed here can be considered a starting guidepost for technology developers.
b All performance, durability, and capital cost targets must be met simultaneously on the same stack or system for achieving the levelized cost of hydrogen cost targets. Ultimately, the goal is to demonstrate these targets in stacks and systems at relevant commercial scales.
c Status is based on traditional liquid alkaline electrolyzer technology in commercial products that have been available for many years.
d Includes 2.5% efficiency loss due to H2 crossover (2.5% is included as an upper limit to allow for safety margins).
e Status and targets are consistent with an end-of-life performance loss of 10%. While the status value is based on continuous operation, evaluation of degradation rate with respect to targets must include operation near the stack’s nominal operating point as well as consider dynamic operation (e.g., to meet duty cycle requirements) and on-off cycling if applications/end uses require.
f End-of-life is based on 10% voltage loss from beginning-of-life operations (following any break-in/conditioning period), measured at the same current density. Lifetime is calculated based on average degradation rate from beginning-of-life to end-of-life voltage (e.g., for 2022 Status: [(1.9 V * 1.1) – 1.9 V] / [0.0032 V/kh*kh/1,000 h]).
g Assumes economies of scale have been achieved with high-volume manufacturing. Installation costs, such as engineering, procurement, construction, and permitting costs, are not included in system cost values.
h Values (including the lower bound of $2/kg H2 for status) assume utilization of low-cost, clean electricity (e.g., ≤$0.03/kWh) with high availability (e.g., >90%); however, other scenarios utilizing lower-cost, clean electricity at lower capacity factors (e.g., from wind or solar) could also be considered to meet production cost targets.