Re:The impact of direct air carbon capture on climate change
by gwbas1c on Thursday November 21, 2019 @10:21PM
(#21602143)
Honestly, I suspect that long-term storage will be inefficient for a long time.
For example, batteries exceed 90% efficiency for storage, but they are only cost effective for day-to-day storage. (Charge when the sun is out, discharge at night.)
In contrast, charge during long summer days, and discharge during shorter winter days will probably be lower efficiency at first. For example, generating hydrogen by electrolysis is about 75% efficient (https://en.wikipedia.org/wiki/Hydrogen_production#Electrolys...), and then pressurizing it will also consume energy.
This means it may be more cost efficient to extract CO2 from the atmosphere as "storage" and then burn natural gas... At least until we find a better way to store energy than hydrogen!
For example, batteries exceed 90% efficiency for storage, but they are only cost effective for day-to-day storage. (Charge when the sun is out, discharge at night.)
In contrast, charge during long summer days, and discharge during shorter winter days will probably be lower efficiency at first. For example, generating hydrogen by electrolysis is about 75% efficient (https://en.wikipedia.org/wiki/Hydrogen_production#Electrolys...), and then pressurizing it will also consume energy.
This means it may be more cost efficient to extract CO2 from the atmosphere as "storage" and then burn natural gas... At least until we find a better way to store energy than hydrogen!