[ solar coupling ]
Fig. 4. Monthly usable energy for green hydrogen production using modular versus conventional electrolyzer systems. The modular setup includes 120 × 10 kW pairs; the conventional system uses a single 1 MW stack with a 365 kW( 30 %) threshold. Both are assessed under DC / DC and AC / DC coupling. Curtailment losses from power electronics are shown separately. Data from TMY PVGIS for Tarragona.¹¹
It is evident from Fig. 4b that incorporating power electronics and a conventional electrolyzer stack of larger rated power negatively impacts the amount of available energy used for green hydrogen production. For this location, losses due to power electronics inefficiencies and curtailment amount to approximately 12 %. Including the electrolyzer’ s threshold limit, the total loss of usable solar energy increases to around 25 %.
To better assess how location influences losses, 38 locations across southern, western, central, eastern, and northern Europe are analyzed similarly. Instead of presenting individual plots, the total loss from curtailment and threshold effects is calculated for each location and presented as percentages of total solar energy production in the color map shown in Fig. 5.
irradiance. In northern areas, systems experience higher average threshold losses. These can be mitigated by using electrolyzer systems composed of small modular units, significantly lowering the effective threshold limits.
It should be noted that although southern European locations are energetically more favorable for solar-based green hydrogen production, the 25 % electrical loss shown in Fig. 5 remains significant. This loss can be greatly reduced by using method 3: a modular system with very low threshold limits and no curtailment loss due to the absence of power electronics.
Based on the map, solar losses range from about 25 % in southern Europe to nearly 50 % in northern regions. The screening consistently shows smaller solar losses in southern regions compared to northern and western Europe. The analysis reveals that power electronics losses are fairly consistent between 12 – 14 % across all locations and are less dependent on geography. However, when including electrolyzer threshold effects, the losses become more sensitive to geographical location and solar
Fig. 5. Geographic distribution of energy losses from curtailment and threshold effects across Europe. Curtailment losses( ca. 12 – 14 %) are fairly consistent, driven by power electronics. Total losses, including threshold losses below 30 % of nominal capacity, vary with solar irradiance – from 25 % in southern to 43 % in northern regions – highlighting the impact of location on system performance.
Hydrogen Tech World | Issue 22 | June 2025 19