Chemical storage of renewable energy
http://science.sciencemag.org/content/360/6390/707.full
Source: By Joel W Ager, Alexei A. Lapkin, Science.
Excerpt: The conversion of carbon dioxide (CO2) into fuels and chemicals using renewable energy is a potential pathway to mitigate increasing CO2 concentration in the atmosphere and acidification of the oceans.... In a process that is essentially the reverse of combustion and is analogous to photosynthesis, CO2 can be electrochemically reduced to hydrocarbons by using renewable power sources such as wind and solar.... This process would not compete with direct use of renewable energy as electricity, as the objective is to store excess energy for later use. On page 783 of this issue, Dinh et al. (3) show that ethylene can be generated selectively via electrochemical CO2 reduction at rates that could yield a technologically feasible process. The thermodynamics of reducing CO2 are similar to those of splitting water into hydrogen and oxygen, which has been done commercially with an energetic efficiency as high as 80% (4). However, CO2 reduction is considerably more challenging because of the unreactive nature of the CO2 molecule.... Copper catalysts bind carbon monoxide (CO) and other reaction intermediates in such a way as to produce two-carbon products such as ethylene and ethanol (5). However, it has been difficult to steer the reaction toward any one product....
Source: By Joel W Ager, Alexei A. Lapkin, Science.
Excerpt: The conversion of carbon dioxide (CO2) into fuels and chemicals using renewable energy is a potential pathway to mitigate increasing CO2 concentration in the atmosphere and acidification of the oceans.... In a process that is essentially the reverse of combustion and is analogous to photosynthesis, CO2 can be electrochemically reduced to hydrocarbons by using renewable power sources such as wind and solar.... This process would not compete with direct use of renewable energy as electricity, as the objective is to store excess energy for later use. On page 783 of this issue, Dinh et al. (3) show that ethylene can be generated selectively via electrochemical CO2 reduction at rates that could yield a technologically feasible process. The thermodynamics of reducing CO2 are similar to those of splitting water into hydrogen and oxygen, which has been done commercially with an energetic efficiency as high as 80% (4). However, CO2 reduction is considerably more challenging because of the unreactive nature of the CO2 molecule.... Copper catalysts bind carbon monoxide (CO) and other reaction intermediates in such a way as to produce two-carbon products such as ethylene and ethanol (5). However, it has been difficult to steer the reaction toward any one product....