Scientists from Australia’s University of New South Wales (UNSW) have examined the cost drivers for off-grid, solar-powered hydrogen electrolysis and found the fuel could be generated in one Queensland port for an average US$3.93/kg.
The researchers modeled costs using ‘Monte Carlo‘ algorithms typically deployed to assess unpredictable outcomes influenced by random variables, by reducing complex processes to a set of basic events and interactions.
The Techno-economic Analysis of Hydrogen Electrolysis from Off-Grid Stand-Alone Photovoltaics Incorporating Uncertainty Analysis paper, published in Cell Reports Physical Science, sets out how the scientists sought to determine the levelized cost of hydrogen (LCOH) by also considering historical weather data at specific locations.
Whilst harnessing off-grid solar limits the production capacity of an electrolyzer, the researchers said it “avoids the often-considerable expense of a grid connection and exposure to the risk of delays in both the physical connection and the approval process.”
The UNSW group used the Queensland port of Townsville as a base case before examining generation costs in other Australian locations. System size, capital cost and electrolyzer efficiency were highlighted as the most important factors for driving down the cost of off-grid, solar-powered electrolysis.
The researchers found off-grid green hydrogen from Townsville could be generated for US$2.89-4.67/kg, assuming electrolyzer capital expenditure of US$840/kW, conversion efficiency of 61 kWh/kg, a project capacity factor of 24% and a levelized cost of solar energy of US$0.0298-0.0412/kWh.
“In an Australian setting, the results highlight the potential feasibility of standalone [off-grid] PV electrolysis to meet target LCOH values from the Australian NHR [National Hydrogen Roadmap industry strategy document] [of] between [US]$3.26/kg and [US]$3.98/kg,” said the researchers.
The capital costs of the electrolyzer and solar plant modeled had little influence on the levelized cost of hydrogen, according to the researchers. The combination of such costs into a ‘total capital cost parameter’, however, could lead to a 20% variation in the hydrogen cost.
If electrolyzers follow the same learning rate-driven cost falls of around 18% demonstrated by PV technology of late, said the group, “we could expect a large reduction in the capital cost of electrolyzers as the industry grows and larger scale projects are implemented.”
With such technology cost falls in mind, the researchers predicted the cost of off-grid solar hydrogen electrolysis could fall to US$2.89-4.67 at some point, with Australia and Chile prime locations for bearing down on the figure. “It is possible to get even lower than this with proposed scenarios approaching [US]$2.50/kg, at which point green hydrogen starts to become competitive with fossil fuel production,” stated the group.
When forecasts made by other researchers about electrolyzer and PV costs were factored in, the University of New South Wales group said off-grid green hydrogen could cost as little as US$2.20/kg by 2030.
“One crucial way we could further decrease costs would be to use cheap transition metal-based catalysts in electrolyzers,” said research co-author Rahman Daiyan. “Not only are they cheaper but they can even outperform catalysts currently in commercial use.”