Add vertical space in moderncv

You can for example use command patchcmd from etoolbox package to get what you want.

Write in your preamble:

%usepackage{etoolbox} % already loaded by moderncv!
patchcmd{maketitle}{%search <===============================
    [2.5em]%
  }{%replace
    [4em]% <================================================
  }{%success
  }{%failure
  }

to change the value from 2.5em to 4em. Change the value 4em for your needs ...

With an complete MWE

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% "ModernCV" CV and Cover Letter
% LaTeX Template
% Version 1.2 (25/3/16)
%
% This template has been downloaded from:
% http://www.LaTeXTemplates.com
%
% Original author:
% Xavier Danaux ([email protected]) with modifications by:
% Vel ([email protected])
%
% License:
% CC BY-NC-SA 3.0 (http://creativecommons.org/licenses/by-nc-sa/3.0/)
%
% Important note:
% This template requires the moderncv.cls and .sty files to be in the same 
% directory as this .tex file. These files provide the resume style and themes 
% used for structuring the document.
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%----------------------------------------------------------------------------------------
%   PACKAGES AND OTHER DOCUMENT CONFIGURATIONS
%----------------------------------------------------------------------------------------

documentclass[11pt,a4paper,sans]{moderncv} % Font sizes: 10, 11, or 12; paper sizes: a4paper, letterpaper, a5paper, legalpaper, executivepaper or landscape; font families: sans or roman

moderncvstyle{casual} % CV theme - options include: 'casual' (default), 'classic', 'oldstyle' and 'banking'
moderncvcolor{blue} % CV color - options include: 'blue' (default), 'orange', 'green', 'red', 'purple', 'grey' and 'black'

usepackage[scale=0.75]{geometry} % Reduce document margins
%setlength{hintscolumnwidth}{3cm} % Uncomment to change the width of the dates column
%setlength{makecvtitlenamewidth}{10cm} % For the 'classic' style, uncomment to adjust the width of the space allocated to your name

%----------------------------------------------------------------------------------------
%   NAME AND CONTACT INFORMATION SECTION
%----------------------------------------------------------------------------------------

firstname{John} % Your first name
familyname{Smith} % Your last name

% All information in this block is optional, comment out any lines you don't need
title{Curriculum Vitae}
%address{123 Broadway}{City, State 12345}
%mobile{(000) 111 1111}
%phone{(000) 111 1112}
%fax{(000) 111 1113}
%email{[email protected]}
%homepage{staff.org.edu/~jsmith}{staff.org.edu/$sim$jsmith} % The first argument is the url for the clickable link, the second argument is the url displayed in the template - this allows special characters to be displayed such as the tilde in this example
%extrainfo{additional information}
%photo[70pt][0.4pt]{pictures/picture} % The first bracket is the picture height, the second is the thickness of the frame around the picture (0pt for no frame)
%quote{"A witty and playful quotation" - John Smith}

%----------------------------------------------------------------------------------------

%usepackage{etoolbox} % already loaded by moderncv! <==================
patchcmd{maketitle}{%search
    [2.5em]%
  }{%replace
    [4em]%
  }{%success
  }{%failure
  }
% <=====================================================================

begin{document}



%----------------------------------------------------------------------------------------
%   COVER LETTER
%----------------------------------------------------------------------------------------

% To remove the cover letter, comment out this entire block

%clearpage
%
%recipient{HR Department}{Corporation123 Pleasant Lane12345 City, State} % Letter recipient
%date{today} % Letter date
%opening{Dear Sir or Madam,} % Opening greeting
%closing{Sincerely yours,} % Closing phrase
%enclosure[Attached]{curriculum vitae{}} % List of enclosed documents
%
%makelettertitle % Print letter title
%
%lipsum[1-3] % Dummy text
%
%makeletterclosing % Print letter signature
%
%newpage

%----------------------------------------------------------------------------------------
%   CURRICULUM VITAE
%----------------------------------------------------------------------------------------

makecvtitle % Print the CV title

%----------------------------------------------------------------------------------------
%   EDUCATION SECTION
%----------------------------------------------------------------------------------------

section{Education}

cventry{2011--2012}{Masters of Commerce}{The University of California}{Berkeley}{textit{GPA -- 8.0}}{First Class Honours}  % Arguments not required can be left empty
cventry{2007--2010}{Bachelor of Business Studies}{The University of California}{Berkeley}{textit{GPA -- 7.5}}{Specialized in Commerce}

section{Masters Thesis}

cvitem{Title}{emph{Money Is The Root Of All Evil -- Or Is It?}}
cvitem{Supervisors}{Professor James Smith & Associate Professor Jane Smith}
cvitem{Description}{This thesis explored the idea that money has been the cause of untold anguish and suffering in the world. I found that it has, in fact, not.}

%----------------------------------------------------------------------------------------
%   WORK EXPERIENCE SECTION
%----------------------------------------------------------------------------------------

section{Experience}

subsection{Vocational}

cventry{2012--Present}{1textsuperscript{st} Year Analyst}{textsc{Lehman Brothers}}{Los Angeles}{}{Developed spreadsheets for risk analysis on exotic derivatives on a wide array of commodities (ags, oils, precious and base metals), managed blotter and secondary trades on structured notes, liaised with Middle Office, Sales and Structuring for bookkeeping.
newline{}newline{}
Detailed achievements:
begin{itemize}
item Learned how to make amazing coffee
item Finally determined the reason for textsc{PC LOAD LETTER}:
begin{itemize}
item Paper jam
item Software issues:
begin{itemize}
item Word not sending the correct data to printer
item Windows trying to print in letter format
end{itemize}
item Coffee spilled inside printer
end{itemize}
item Broke the office record for number of kitten pictures in cubicle
end{itemize}}

%------------------------------------------------

cventry{2010--2011}{Summer Intern}{textsc{Lehman Brothers}}{Los Angeles}{}{Rated "truly distinctive" for Analytical Skills and Teamwork.}

%------------------------------------------------

subsection{Miscellaneous}

cventry{2008--2009}{Computer Repair Specialist}{Buy More}{Burbank}{}{Worked in the Nerd Herd and helped to solve computer problems by asking customers to turn their computers off and on again.}

%----------------------------------------------------------------------------------------
%   AWARDS SECTION
%----------------------------------------------------------------------------------------

section{Awards}

cvitem{2011}{School of Business Postgraduate Scholarship}
cvitem{2010}{Top Achiever Award -- Commerce}

%----------------------------------------------------------------------------------------
%   COMPUTER SKILLS SECTION
%----------------------------------------------------------------------------------------

section{Computer skills}

cvitem{Basic}{textsc{java}, Adobe Illustrator}
cvitem{Intermediate}{textsc{python}, textsc{html}, LaTeX, OpenOffice, Linux, Microsoft Windows}
cvitem{Advanced}{Computer Hardware and Support}

%----------------------------------------------------------------------------------------
%   COMMUNICATION SKILLS SECTION
%----------------------------------------------------------------------------------------

section{Communication Skills}

cvitem{2010}{Oral Presentation at the California Business Conference}
cvitem{2009}{Poster at the Annual Business Conference in Oregon}

%----------------------------------------------------------------------------------------
%   LANGUAGES SECTION
%----------------------------------------------------------------------------------------

section{Languages}

cvitemwithcomment{English}{Mothertongue}{}
cvitemwithcomment{Spanish}{Intermediate}{Conversationally fluent}
cvitemwithcomment{Dutch}{Basic}{Basic words and phrases only}

%----------------------------------------------------------------------------------------
%   INTERESTS SECTION
%----------------------------------------------------------------------------------------

section{Interests}

renewcommand{listitemsymbol}{-~} % Changes the symbol used for lists

cvlistdoubleitem{Piano}{Chess}
cvlistdoubleitem{Cooking}{Dancing}
cvlistitem{Running}

%----------------------------------------------------------------------------------------

end{document}

you get the wished result: