AWE	Anion exchange membranes
CAPEX	Capital expenditure
CCUS	Carbon Capture, Utilization, and Storage
DF	Dark fermentation
FP	Fast pyrolysis
GDP	Gross domestic product
GED	Global energy demand
GHG	Greenhouse gases
HER	Hydrogen evolution reaction
RS	Renewable sources
IEA	International Energy Agency
KOH	Potassium hydroxide
SOE	Solid oxide water electrolysis
SMR	Steam methane reforming
OER	Oxygen evolution reaction
PEMs	Proton exchange membranes
PNS	Purple non-sulfur
WGS	Water gas shift
$\Delta \mathrm{H}$	Heat of reaction
$\Delta \mathrm{Go}$	Free energy of the reaction