Researchers at the National University of Singapore have developed an innovative optimization model for PV-powered green hydrogen facilities, offering a comprehensive evaluation of different technology options.
Their work, published in the journal Energy Conversion Management, aims to determine the cost-effectiveness of green hydrogen production from solar power, a key aspect in making it competitive with other types of hydrogen.
The model developed by the scientists takes into account crucial factors such as solar irradiance, physical hydrogen storage, land footprint, power grid carbon intensity, project specifications, capital and operating costs, efficiencies, and lifespans. By incorporating detailed data and considering intra-day and inter-day variations in renewable electricity generation, the model enables a fine-grained analysis of the system’s performance. It also provides the flexibility to incorporate battery storage for managing renewable energy fluctuations and hydrogen molecule storage to meet hydrogen demand.
The researchers focused on a green hydrogen facility consisting of a PV plant, electrolyzer, battery storage, buffer tanks, and a hydrogen pumping station. The facility can trade power with the grid as needed, allowing for import and export of electricity. The main challenge lies in optimizing the utilization of transient and uncertain solar irradiance to meet hydrogen demand at the lowest cost. The model assists in obtaining the optimal facility design, considering different geographical and techno-economic conditions, to achieve the most affordable green hydrogen production.
The study explores four scenarios: a fully grid-disconnected plant (Islanded Facility – ILF) generating exclusively green hydrogen, a facility with grid import (FGI), a facility with grid export (FGE), and a facility with both grid import and export (FGIE). The researchers found that grid connectivity in any configuration significantly reduces the levelized cost of hydrogen (LCOH) compared to the fully grid-disconnected plant. LCOH values varied across countries due to solar radiation levels and cost estimations.
In Singapore, for example, the LCOH for different project types was identified as $11.78/kg for FGI, $12.55/kg for FGE, and $10.44/kg for FGIE. The researchers also observed that stronger solar irradiance resulted in lower LCOH and a smaller solar PV farm.
To achieve a significant cost reduction in green hydrogen production, the analysis suggests a combination of advancements in solar PV, storage, and battery technologies. The researchers projected that an LCOH range of $3.29/kg to $4.15/kg could be achieved through a 60% reduction in solar PV capital expenditure (Capex), a 20% increase in electrolyzer performance, a 75% reduction in battery Capex, and a discount factor of 0.01%.
While green hydrogen holds promise for deep decarbonization, the researchers emphasized the need for continuous advancements in solar PV, storage, and battery technologies to make it a more cost-effective solution.
