The impact of PV module orientation, water quality on hydrogen production

Scientists in Tunisia have investigated the impact of PV panel tilt and water quality on green hydrogen production and have found that, with a variable orientation PV panel, the hydrogen generator could reach an efficiency ranging from 32% to 62% using demineralized water and 45% to 65% with distilled water.

Scientists from Tunisia's Gabes University have designed a PV-powered green hydrogen (H2) production system and tested the impact of the water quality and the PV panel orientation on H2 production levels. Their findings suggest that the PV orientation is the most critical parameter, although water quality also plays a major role.

“Scientific literature clearly demonstrates that factors such as PV panel design, the materials used for electrolyzer electrodes, and the type of electrolyte significantly influence the efficiency of green hydrogen production systems,” the team explained. “Nevertheless, limited attention has been given to examining how water quality affects the production rate of green hydrogen.”

The academics' experimental rig used a polycrystalline solar panel with a power of 265 W and an efficiency of 16%. The maximum power and voltage needed by the electrolyzer were 85W and 9.3 V, so a voltage regulator was used. The hydrogen generator generated the gas with a proton exchange membrane (PEM) cell.

The impact was tested in four summer days in 2023 in the city of Gabès, located on the coast of Tunisia. To test the effects of the PV orientation, the team compared two setups. In one, the angle was based on the optimal solar panel positioning for Gabès, 34◦. The second configuration featured a manually adjustable PV panel capable of tracking the sun to maximize solar irradiation.

Both configurations were tested using demineralized and distilled water. The demineralized water had an ion content of 0–1 parts per million (ppm) and mineral salts in an amount smaller than 10 mg/L. The distilled water, on the other hand, has 1 ppm of ions and close to 0 mg/L of mineral salts.

“A variable orientation of the PV panel gave an increase in hydrogen production from distilled water, by >45%, compared to fixed PV panel,” the researchers emphasized. “Furthermore, the water quality plays a significant role in the green hydrogen production. Distilled water enhanced the hydrogen production rate by over 10% in the case of variable PV panel configuration, compared to demineralized water.”

They also found that, with a variable orientation PV panel, the hydrogen generator has an efficiency ranging from 32% to 62% using demineralized water and 45% to 65% with distilled water. Using the fixed PV panel, the efficiency ranges from 8% to about 55% with demineralized water and nearly 9% to 61% with distilled water.

“It is worth noting that distilled water, containing fewer residual contaminants, gives better hydrogen production compared to demineralized water. However, its environmental impact is worse since the distillation process can be energy-intensive, affecting the cost of production in large-scale and long-term application,” the academics highlighted.

The system was presented in “Experimental assessment of the effects of water quality and PV panel orientation on green hydrogen production,” published in the International Journal of Thermofluids.