Researchers from Japan’s NIMS (National Institute for Materials Science), the University of Tokyo and Hiroshima University have jointly conducted a techno-economic analysis for hydrogen production from photovoltaic power generation (PV) utilizing a battery-assisted electrolyzer.
The results from this study suggested a cost of hydrogen as low as ¥17 to ¥27/Nm3 (US$0.16 - $0.25) using a combination of technologies and the achievement of ambitious individual cost targets for batteries, PV, and electrolyzers. This approximately converts to US$1.92 to US$3.00/kg of hydrogen, with 1 kg H2 equal to about 12 Nm3 of hydrogen. For comparison, the US DOE’s 2020 target for the levelized cost of hydrogen (production only) is $2.30/kg. The findings are published in a paper in the International Journal of Hydrogen Energy.
The joint research team designed an integrated system capable of adjusting the amount of battery charge/discharge and the amount of electrolysis hydrogen production in relation to the amount of solar power generated. The team then evaluated the economic feasibility of the system.
System capable of adjusting the amount of battery charge/discharge and the amount of electrolysis hydrogen production in relation to the amount of solar power generated. Comprehensive analysis of various factors, including rechargeable battery and electrolyzer capacities, enables the estimation of technology levels required for low-cost hydrogen production. Credit: NIMS
The team identified technology levels necessary for the system to produce hydrogen at low cost through a comprehensive analysis of various factors such as rechargeable battery and electrolyzer capacities, considering the future technological advancements. For the study, the researchers optimized the installed capacity of each component technology for the wide range of unit costs of electricity from the PV, battery, and proton-exchange membrane electrolyzer.
For example, rechargeable batteries that can discharge only at a low rate but can be produced economically are expected to become available by around 2030.
Broadly, they found that with the leveling of PV electricity output through the use of the battery, the required capacity of electrolyzer is lowered and the operating ratio of electrolyzer increases.
The battery-assist will result in a lower hydrogen production cost when the benefit associated with the smaller capacity and higher operation ratio of the electrolyzer exceeds the necessary investment for battery installation.
In future studies, the team plans to determine component technology levels required for proposed systems and set R&D target values to achieve these levels.
The team will also investigate the system feasibility of renewable power generation systems even under output suppression control or restriction to electricity power grid connection in order to demonstrate a proto-type system of the proposed system.
Yasunori Kikuchi, Takayuki Ichikawa, Masakazu Sugiyama, Michihisa Koyama (2019) “Battery-assisted low-cost hydrogen production from solar energy: Rational target setting for future technology systems” International Journal of Hydrogen Energy doi: 10.1016/j.ijhydene.2018.11.119)