When Bigger Is Not Greener: Ensuring the Sustainability of Power-to-Gas Hydrogen on a National Scale

Boris Brigljević, Manhee Byun, Hyunjun Lee, Ayeon Kim, Boreum Lee, Changhwan Moon, Jae Hyung Choi, Hyung Chul Yoon, Chang Won Yoon, Yong Sik Ok, Dong Ha Lim, Chang Hee Kim, Sangbong Moon, Hankwon Lim

Research output: Contribution to journalArticlepeer-review

Abstract

As the prices of photovoltaics and wind turbines continue to decrease, more renewable electricity-generating capacity is installed globally. While this is considered an integral part of a sustainable energy future by many nations, it also poses a significant strain on current electricity grids due to the inherent output variability of renewable electricity. This work addresses the challenge of renewable electricity surplus (RES) utilization with target-scaling of centralized power-to-gas (PtG) hydrogen production. Using the Republic of Korea as a case study, due to its ambitious plan of 2030 green hydrogen production capacity of 0.97 million tons year-1, we combine predictions of future, season-averaged RES with a detailed conceptual process simulation for green H2 production via polymer electrolyte membrane (PEM) electrolysis combined with a desalination plant in six distinct scale cases (0.5-8.5 GW). It is demonstrated that at scales of 0.5 to 1.75 GW the RES is optimally utilized, and PtG hydrogen can therefore outperform conventional hydrogen production both environmentally (650-2210 Mton CO2 not emitted per year) and economically (16-30% levelized cost reduction). Beyond these scales, the PtG benefits sharply drop, and thus it is answered how much of the planned green hydrogen target can realistically be "green"if produced domestically on an industrial scale.

Original languageEnglish
Pages (from-to)12828-12837
Number of pages10
JournalEnvironmental Science and Technology
Volume56
Issue number18
DOIs
Publication statusPublished - 2022 Sep 20

Keywords

  • PEM electrolysis
  • green H
  • power-to-gas
  • renewable electricity surplus
  • target scaling

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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