Photo-electrochemical cells vs. PV electrolysis

Aug 12, 2020 12:48 PM ET
  • Dutch researchers have evaluated the two most promising solar-assisted technologies to generate environment-friendly hydrogen, based upon the levelized cost of hydrogen. They found that PV-powered hydrogen manufacturing uses the lowest expenses, at $6.22/ kg, with a solar-to-hydrogen effectiveness ratio of 10.9%
Photo-electrochemical cells vs. PV electrolysis
Image: U.S. Army Environmental Command

A research study team from Utrecht University in the Netherlands has contrasted both most promising solar-assisted hydrogen production technologies: the photo-electrochemical (PEC) systems that directly convert solar radiation to hydrogen, as well as off-grid, PV-powered electrolyzers (PV-E).

They offered their research in "Renewable hydrogen production: A techno-economic comparison of photo-electrochemical cells and photovoltaic-electrolysis," which was just recently published in the International Journal of Hydrogen Energy. They concluded that the prospective techno-economic advantages of PEC over PV-E doubt as well as limited.

The researchers computed the levelized expense of hydrogen (LCOH) for both technologies by taking into consideration basic PV-E styles as well as predicted PEC styles for future large-scale applications.

" Despite intense as well as encouraging research study during the last years on PEC technology, no system is yet readily available," the scientists claimed. "The present paper will examine if, and also under what problems, PEC tools can outcompete solar hydrogen production with PV-electrolysis."

Levelized costs

The team determined the LCOH of the innovations based upon financial investment costs, incomes, and also prices throughout a plant's lifetime, discounted to a referral day. The manufacturing rate of both systems was set at 10 loads each day, while the time frame for hydrogen generation was 20 years.

They conducted the demonstration in Daggett, California, as it is an area with daily irradiance of 6.19 kilowatt-hours per square meter. Setups costs are thought to be 20% of the capital prices for both systems.

" The installation of the PV-E systems calls for even more cabling and also the setup of the electrolyzers," the academics said. "The PEC system, on the other hand, needs more piping and on top of that the installment of the compressors."

The PV-E system was developed for the high costs of the electrolyzer via the optimization between the scale of the photovoltaic unit which of the electrolyzer. The shown electrolyzer had an overall efficiency of 10.9%.

For the PCE system, the researchers chose a non-concentrated panel with a performance of 10%. It was based upon a one liquid-solid-junction design, with one side of the photo-electrode being submersed into the electrolyte. "One part of the solar panel have to endure electrochemical reactions as well as rust, while the opposite is in contact with ambient air," the researchers claimed.


The scientists revealed that the PV-E system can accomplish an LCOH of $6.22/ kg. They concluded that balance-of-system (BoS) costs for the electrolyzer can drop once again in the future, because of economies of range.

" The costs for the electrolyzer are more than the costs for the PV system," they said. "This gap is even bigger without maximizing the scale of these 2 plant elements."

They likewise claimed that an LCOH of $3.76/ kg could be attained in the future, if tough BoS prices as well as PV component prices fall by one more 50%. The LCOH of the PCE system was greater than $2 higher, at $8.43/ kg, with the PEC component bookkeeping for practically half of the whole system costs.

" This is followed by the soft BoS costs, where the contingency prices have the largest impact considering that the uncertainties are still rather high within this new technology," the academics stated. "The membrane as well as the photoactive material have by far the largest impact on the costs, with $1.50/ kg and also $1.35/ kg, specifically."

They wrapped up that the PEC system would possibly not cause reduced hydrogen generation costs contrasted to the PV-E system.

"Even under generous presumptions, PEC gadgets are costlier as well as much less versatile in their application," they said.

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