France

Hydrogen’s increasing potential as an alternative fuel for heavy-duty transport has led to the conversion of conventional diesel compression-ignition engines to spark-ignition hydrogen operation. Hydrogen’s broad flammability range enables leaner operation achieving both higher engine efficiency and near-zero emissions. In particular direct injection hydrogen combustion improves volumetric efficiency and reduces problems including pre-ignition and knock related to hydrogen port-fuel injection. In the present work we performed an optical investigation of direct injection (DI) hydrogen combustion under leaner mixture conditions. The study was conducted using a heavy-duty optical diesel engine modified for spark-ignition operation. Bottom-view natural flame luminosity and OH-PLIF imaging were conducted along with in-cylinder pressure measurements. Experiments were conducted at three air-excess ratios (3 3.4 and 3.8) with spark timings (ST) varied from − 15 ◦CA aTDC to − 30 ◦CA aTDC. Hydrogen injection ended at − 30 ◦CA aTDC with the start of injection adjusted accordingly to achieve the desired lambda conditions. The maximum IMEPg corresponded to the lowest COV of the IMEPg indicating optimal spark timing for lean DI hydrogen combustion. The optimized spark timing for λ = 3 λ = 3.4 and λ = 3.8 were occurred at − 25 ◦CA aTDC − 25 ◦CA aTDC and − 30 ◦CA aTDC respectively. The corresponding COV of IMEPg values were below 5 % indicating stable combustion. The flame kernel first initiates at the spark plug and then propagates toward the piston’s outer boundary however the flame propagation does not remain as a continuous front unlike port-fuel injected hydrogen combustion. The effect of fuel stratification is evident in combustion luminosity and OH-PLIF images showing pockets of varying intensity within the combustion chamber. Natural flame luminosity images reveal incomplete flame coverage and asymmetric combustion emphasizing the need for metal engine experiments to further quantify the unburned hydrogen and associated combustion losses.

This study evaluates the techno-economic performance of hybrid renewable microgrids integrating hydrogen storage and fuel cells in two Moroccan pilot farms: a grid-connected site (BLFARM) and an off-grid site (RIMSAR). Real meteorological and load data were analyzed in HOMER Pro to assess feasibility. In 2024 BLFARM achieved a Levelized Cost of Energy (LCOE) of e1.63/kWh and a Renewable Fraction (Ren Frac) of 83.9% while RIMSAR reached e4.32/kWh with 100% renewable contribution. Hydrogen use remained limited due to low demand and high costs. Assuming 2050 hydrogen-technology reductions LCOE decreased to e0.160/kWh (BLFARM) and e0.425/kWh (RIMSAR) while hydrogen components were still underutilized. Aggregating demand from 5-80 farms reduced LCOE by over 50% from e0.093 to e0.045/kWh (BLFARM) and from e0.142 to e0.074/kWh (RIMSAR) while increasing electrolyzer and fuelcell operation. Community-networked hydrogen microgrids thus enhance component utilization energy resilience and cost effectiveness in rural Moroccan agriculture.