# How can I convert cathodic energy efficiency to overall energy efficiency?

Im working on calculation which involve the energy efficiency of producing formate by CO2 electroreduction.

I wonder how to convert the reported cathodic energy efficiency (71%) of papers e.g (1) this paper or (2) this paper into an overall energy efficiency.

I want to assume that water is oxidized at an anode. If needed we can plug in an assumed efficiency for the anode reaction.

I am relatively new to electrochemistry, and trying to learn so forgive me if this is trivial, but I can barely find the term "cathodic energy efficiency" online for me to learn this.

• If the efficiency is not $100$%, it means that the rest of the electric energy is lost in heat by the Joule effect. Mar 22, 2021 at 16:01
• Thank you. Is there a way to estimate what is the loss of energy on the anode side for these kind of papers? Mar 22, 2021 at 16:20
• @Maurice I think the <100% cathode energy efficiency they report of producing the desired product (formate) is also result of the competing HER reaction, and not just heat. Mar 22, 2021 at 16:51
• You may be right, after all. Why not ? Mar 22, 2021 at 17:54