An Italian company wants to use carbon dioxide to store renewable power on the grid

Smells like a boondoggle! Or is it a little bit of dolce vita (loosely translated: to good to be true 😄)?

The idea is to compress and store CO2 as a liquid and the use the stored energy to drive a turbine for energy production. Well, sounds almost like the holy grail of a or elusive perpetuum mobile? Year, right!

How much energy does it take to compress CO2 to liquefy it?
How much energy does it produce by e.g. driving a turbine when expanding (quite possibly releasing the CO2 into the atmosphere again)?

What is the net energy output?

This company wants to use carbon dioxide to store renewable power on the grid | MIT Technology Review Energy Dome is starting up a trial plant to store energy in compressed gas, but the engineering challenges might not be so simple to tackle.

Energy Dome: Our technology