Low-Grade Waste Heat to Hydrogen

Industrial decarbonization via hydrogen: A critical and systematic review of developments, socio-technical systems and policy options

“…In this figure, the current status and forecast for hydrogen adoption in industrial sectors is presented in the context of favorable technological pathways and synergy with primary industrial processes. Both peerreviewed [41,45,55,75,104,109,112,152,155,156,[167][168][169][170][171][172][173][174][175][176][177][178][179][180][181][182] and grey literature [4,9,10,[183][184][185][186] were evaluated to provide a foundation for this snapshot. Major technological drivers for selection between the different pathways can be summarized as:…”

“…• For existing thermochemical production pathways, decarbonizing hydrogen production will rely on adoption of renewable and waste feedstocks [42,71,148,149,187], use of CCS technologies [162,171,[188][189][190], switch to renewable and nuclear energy [191], or a combination of these interventions [152,161,169,182,192]; • In case thermochemical production coupled with CCS technology does not meet regulatory criteria for classification as low-carbon hydrogen (further discussed in Section 6) or are unacceptable for other reasons, methane pyrolysis and hightemperature electrolysis may be suitable for hydrogen production with high heat processes [43,80,81,123,128,179,193,194]; • Electrolysis produces high-purity hydrogen and can be directly used for fuel cell applications (electric vehicles, electricity generators, distributed heat and power units) [120,[195][196][197]; • Biohydrogen pathways have much lower hydrogen production yields than other alternatives and will therefore have niche applications when coupled with the treatment of wastewater and industrial effluents, as well as the uptake of recalcitrant biomass feedstocks [86,93,102,138,172,[198][199][200][201]; • Renewable energy availability (in particular solar and wind energy) will impact technology adoption…”

“…By-product hydrogen production in main sectors is not covered. Diagram generated based on [4,9,10,41,45,55,75,104,109,112,152,155,156,[167][168][169][170][171][172][173][174][175][176][177][178][179][180][181][182][183][184][185][186]. Source: Authors…”

“…While energy losses are expected across the sociotechnical system elements, solutions and technology options that enable the recovery and re-use of such energy streams can indirectly improve the energy efficiency. At the overall hydrogen sociotechnical level, recovery of energy losses associated with hydrogen conversion into and regeneration from other intermediates is paramount to enable their use for storage and transmission applications [148,182,201,[643][644][645][646][647][648][649][650][651][652][653][654].…”

To decarbonize industry, we must decarbonize heat

“…For low-temperature heat, researchers have demonstrated a path to use low-grade heat to drive reverse electrodialysis cells to produce hydrogen, 113 which then can be stored and combusted again at flame temperature. However, like low-grade waste heat to electricity conversions the challenges of limited exergy, fluid handling volume, and heat exchanger cost remain.…”