Mining Nontraditional Water Sources for a Distributed Hydrogen Economy

Abstract

Securing decarbonized economies for energy and commodities will require abundant and widely available green H 2 . Ubiquitous wastewaters and nontraditional water sources could potentially feed water electrolyzers to produce this green hydrogen without competing with drinking water sources. Herein, we show that the energy and costs of treating nontraditional water sources such as municipal wastewater, industrial and resource extraction wastewater, and seawater are negligible with respect to those for water electrolysis. We also illustrate that the potential hydrogen energy that could be mined from these sources is vast. Based on these findings, we evaluate the implications of small-scale, distributed water electrolysis using disperse nontraditional water sources. Techno-economic analysis and life cycle analysis reveal that the significant contribution of H 2 transportation to costs and CO 2 emissions results in an optimal levelized cost of hydrogen at small- to moderate-scale water electrolyzer size. The implications of utilizing nontraditional water sources and decentralized or stranded renewable energy for distributed water electrolysis are highlighted for several hydrogen energy storage and chemical feedstock applications. Finally, we discuss challenges and opportunities for mining H 2 from nontraditional water sources to achieve resilient and sustainable economies for water and energy.

Pathways to a Green Ammonia Future

“…Industrially synthesized ammonia (NH 3 ) is essential to support the world population because approximately 85% of global NH 3 production is used as agricultural fertilizer . Recently, NH 3 has also been considered as a promising carbon-free H 2 carrier for energy storage and transportation. , Ammonia’s relatively high boiling point of −33.4 °C (at atmospheric pressure) enables facile liquefaction for compatibility with existing liquid fuel infrastructure . Further, NH 3 has a higher volumetric energy density (12.92–14.4 MJ L –1 ) than compressed H 2 (4.5 MJ L –1 ) and liquefied H 2 (8.49 MJ L –1 ) .…”

Enabling Unprecedented Ultra‐Efficient Practical Direct Seawater Splitting by Finely‐Tuned Catalyst Environment via Thermo‐Hydrodynamic Modulation

“…The topic of direct seawater splitting is represented as debatable in the literature, especially with reports demonstrating a small contribution in the overall cost reduction upon direct seawater splitting in comparison to a two-step scenario with the current technologies (water desalination and then current water splitting). [60,61] However, it is very important to realize that the state-of-the-art cost estimations for seawater splitting are based on conventional alkaline electrolyzer where high-cost precious electrocatalysts, highly alkaline condition stable electrolyser materials, and expensive specialized alkali stable membranes are required. Apart from this, the cost of reverse osmosis system for chloride removal, a purification unit for ultra-pure water, and the cost of an alkaline additive is also included.…”

Global land and water limits to electrolytic hydrogen production using wind and solar resources

“…Desalination is already widely used in coastal regions at high renewable potential as a technology to feed electrolyzers with high-quality deionized water based on reverse osmosis 42 . In land-locked countries, the purification of nontraditional water resources, i.e., municipal and industrial wastewater or brackish water, can represent an option to avoid competition with other water uses 43 . In this study, solar and wind potential were considered separately.…”