Periodic Reporting for period 2 - NEPTUNE (Next Generation PEM Electrolyser under New Extremes)
Reporting period: 2019-08-01 to 2021-01-31
Solvay and CNR have produced journal papers and presented the project at external events, and when there are more results, it is expected that other partners will be able to present these and share the achievements of the project as they are realised.
The operating temperature is planned to be 90 degrees for base-load operation and up to 140 degrees for peak load operation of at least one hour under pressurised conditions.
The hydrogen output pressure will be 100bar for current densities ranging between 0.2 and 4-8 A⋅cm-2
The prototype will be validated with 398 cm-2 active area cells achieving TRL5.
The gas crossover targets are extremely ambitious with the planned maximum hydrogen content in the oxygen stream being under 0.5% across the entire load curve and the loss of faradic efficiency being under 1% with hydrogen purity over 5N.
The electrolyser efficiency will be over 80% against HHV of hydrogen at 4 A⋅cm-2 current density with energy consumption lower than 50 kWh/kg H2.
The prototype will be tested for at least 4,000 hours (cumulative) with targeted degradation rate lower than 5 µV/h at a current density of 4 A⋅cm-2 and less than 10 µV/h at higher current densities (6-8 A⋅cm-2)
Cost reduction is a key part of Neptune and material use will focus on minimisation by use of thin cost-effective short-side chain membranes, low precious metal catalysis and low cost coated titanium cell components and flow-field free bipolar plates designed for cost-effective stack hardware.
The CAPEX is planned to be <1.5 M€/ (t/d H2) achieved by quadrupling operating current density, system simplification and materials use minimisation.
The stack will also be capable of rapid start up (warm <1 s) and (cold <10 s) and partial load behaviour (load range 5%-200% corresponding to 0.2 A⋅cm-2 and 8 A⋅cm-2 operating current densities)