Exhibit 10.120



SECOND AMENDMENT TO EMPLOYMENT AGREEMENT



This Second Amendment
to Employment Agreement (the “2nd Amendment”) is made and entered into by and between QS Energy, Inc. (the
“Company”) and Greggory M. Bigger (“Executive”), effective as of March 10, 2016 (the “2nd
Amendment Effective Date”), with reference to the following:



RECITALS



| | A. | Effective as of February 1, 2012, the Company and Executive entered into that certain Employment
Agreement (the “Employment Agreement”);
| | -- | ----------------------------------------------------------------------------------------------------------------------------------------



| | B. | Effective as of September 1, 2013, the Company and Executive entered into that certain First Amendment
to Employment Agreement (the “1st Amendment”);
| | -- | -----------------------------------------------------------------------------------------------------------------------------------------------------



| | C. | It is the desire of the Company and Executive to amend the Employment Agreement again, pursuant
to the terms and conditions of this 2nd Amendment, effective as of the 2nd Amendment Effective Date.
| | -- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



NOW, THEREFORE, the
parties hereto agree further to amend the Employment Agreement, as follows: (All capitalized terms used herein shall have the meanings
ascribed to such terms in the Employment Agreement.)



I.	Section 1 of
the Employment Agreement is hereby amended and restated as follows:



Effective Date and
Term. Unless sooner terminated as provided in this Agreement, including as a result of the Company’s early termination
of this Agreement as provided in Section 4 below, the Company shall continue to employ Executive for an initial term commencing
on March 10, 2016 (the “Effective Date”), and continuing thereafter until the close of business on the day immediately
preceding the third anniversary of the Effective date (the “Expiration Date”). This Agreement shall in all respects
terminate on the Expiration Date, except for those obligations of either party that are expressly stated to continue after such
time or by nature will continue after such time. The period beginning on the Effective Date and ending on the earlier of the Expiration
Date or the date Executive's employment under this Agreement actually terminates is referred to as the “Term.” No less
than ninety (90) days prior to the Expiration Date, the Company and the Executive hereby undertake to meet and negotiate a mutually
acceptable extension of the Expiration Date.



II.	If there are
any inconsistencies between the Employment Agreement and the 1st Amendment and the terms and conditions of this 2nd
Amendment, the terms and conditions of this 2nd Amendment shall control.











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III.	Except for
the changes set forth in this 2nd Amendment, all terms and conditions in the Employment Agreement and 1st
Amendment shall remain unchanged and in full force and effect.



Executed effective
as of the 2nd Amendment Effective Date.







| | QS ENERGY, INC. |                                                                                  
| | --------------- | ---------------------------------------------------------------------------------
| |                 |                                                                                  
| |                 |                                                                                  
| | By:             | /s/ MARK STUBBS                                                                  
| |                 | Mark Stubbs,                                                                     
| |                 | Director and Chairman of the
Audit Committee, on behalf of the Board of Directors
| |                 |                                                                                  
| |                 | /s/
GREGGORY M. BIGGER                                                           
| |                 | Greggory M.
Bigger                                                               

















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