Final answer:
Solar energy to produce hydrogen gas is expensive due to the high up-front cost of solar energy systems, the intermittency of solar energy, and the efficiency of electrolysis.
Step-by-step explanation:
Solar energy to produce hydrogen gas is expensive in comparison to other energy sources due to several factors.
The high up-front cost of solar energy systems, including the cost of solar panels and equipment, installation, and maintenance.
The intermittency of solar energy, which requires the use of battery storage to overcome the variation in sunlight availability. Battery storage can double the cost of the solar energy system and requires regular maintenance and replacement.
The efficiency of electrolysis in capturing input energy to produce hydrogen is typically around 65-80%, resulting in a lower overall efficiency compared to other energy storage options like batteries.
These factors contribute to the higher cost of producing hydrogen gas using solar energy compared to other energy sources.