CO₂ Reduction to Substitute Natural Gas: Toward a Global Low Carbon Energy System

Abstract

Methane has proven to be an outstanding energy carrier and is the main component of natural gas and substitute natural gas (SNG). SNG may be synthesized from the CO2 and hydrogen available from various sources and may be introduced into the existing infrastructure used by the natural gas sector for transport and distribution to power plants, industry, and households. Renewable SNG may be generated when H2 is produced from renewable energy sources, such as solar, wind, and hydro. In parallel, the use of CO2‐containing feed streams from fossil origin or preferably, from biomass, permits the avoidance of CO2 emissions. In particular, the biomass‐to‐SNG conversion, combined with the use of renewable H2 obtained by electrolysis, appears a promising way to reduce CO2 emissions considerably, while avoiding energy intensive CO2 separation from the bio feed streams. The existing technologies for the production of SNG are described in this short review, along with the need for renewed research and development efforts to improve the energy efficiency of the renewables‐to‐SNG conversion chain. Innovative technologies aiming at a more efficient management of the heat delivered in the exothermic methanation process are therefore highly desirable. The production of renewable SNG through the Sabatier process is a key process to the transition towards a global sustainable energy system, and is complementary to other renewable energy carriers such as methanol, dimethyl ether, formic acid, and Fischer‐Tropsch fuels.

Production of Methanol from Aqueous CO2 by Using Co3O4 Nanostructures as Photocatalysts

“…Almost all the excess of this gas in the atmosphere is produced by the combustion of mineral fuels, like gasoline or coal. Many efforts have been done in the last years aiming to reduce CO 2 emissions to the atmosphere: imposition of taxes for CO 2 emissions, CO 2 sequestration using different methods [10][11][12][13][14][15][16][17][18][19][20], or the conversion of this gas using different techniques to obtain value added products, e.g., fuels [21][22][23][24][25][26][27][28][29][30][31][32][33]. In order to reduce CO 2 quantity in the atmosphere and produce fuels using this gas and water, different materials and methods have been applied: metal complexes [21], microalgae [28,33], syngas procedure [24], polymers [31], electrochemical transformations [26,32], photothermal and thermochemical conversions [23,25], semiconductors [27,30], and several others.…”

Renewable Methane Generation from Carbon Dioxide and Sunlight

“…than, for example, hydrogen, the other well investigated power to gas product. So far, the combination of hydrogen generation by electrolysis and the Sabatier process (hydrogenation of CO 2 to CH 4 ) already demonstrates the general feasibility of an energy storage cycle (Figure a). An alternative way to generate methane from renewable sources is based on the production of biogas from biomass .…”

Spinel Mixed Oxides for Chemical-Loop Reforming: From Solid State to Potential Application

“…In the near future, the possibility to produce hydrogen in a sustainable manner on the larger scale will boost research landmarks to search for new technological platforms for direct transformation of captured CO 2 to its hydrogenated C1-counterparts: formic acid (HCOOH), formaldehyde (H 2 CO), methanol (CH 3 OH), and methane (CH 4 ) [27]. Highly reduced methanol is indeed the key molecule for the methanol economy and remains obviously a target molecule of choice in terms of its further use in MTHprocesses, as well as H 2 -storage and carriers in fuel cells.…”

“…Methane, the totally reduced product from CO 2 , is still considered as a potent molecule in a power-to-gas concept [29], in which superfluously produced energy by nuclear sources or irregularly produced wind, water, and wolar (WWS) electricity may be converted and stored in the chemical bonds of the methane molecule. The advantage of this concept is that methane can be fed in the already available natural gas infrastructure [27,30]. p0030 In conclusion, there is a fast-growing need for increased hydrogen production, because H 2 itself may become an important "energy vector" with key applications as a carbon-free fuel and as a fuel for hydrogen-driven fuel cells for automotive uses.…”