About me.

Hello, my name is Roberto, I’m 29 years old and I come from Madrid. I studied at the
University of Extremadura. I have a degree in industrial engineering and a masters degree in
project management. I have 5 years experience in the energy sector.
For the past several years I have been working for a condition monitoring company.
I’m an open minded and sociable person and I enjoy working in an international environment.
The reason I am here today is because I am looking for a new challenge.”

About me.

Certainly, my name is Roberto, I’m 29 years old and I come from Madrid. I studied at the
University of Extremadura. I have a degree in industrial engineer and a master degree in
project management. I have 5 years experience in the energy sector.
For the past years I have been working for a condition monitoring company.
I’m an open minded and sociable person and I enjoy working in an international environment.
The reason I am here today is because I am looking for a new challenge.”

(1) about me - a cover letter normally begins with 'Dear X', where X is the name of the company you are applying for.  Or, better yet, have X be the name of the person you are talking to.  So if you are emailing Bob, the district manager, you would say, "Dear Bob",

(2) certainly, my name is Roberto- This is not needed here at all.  And, in fact, your name should be on your resume and/or at the bottom of the cover letter.  So having it here is just redundant. Regarding your age, unless they asked for that specifically or unless it is very important for the position you are trying to get, I'd leave it out. 

(3) degree - what type of 'degree' did you obtain?  A BA? BS? you might also type the whole word out, but I couldn't for the life of me spell it myself, so I just write BA or BS.  So for this sentence, a better thing to write would be 'I have a BA in industrial engineering' (or BS if that's what you got instead).

(4) engineer should be changed to 'engineering'.  you have a degree in 'industrial engineering'.

(5) "for the past years' - how many years?  1?  5?  20?  This should read, 'for the past X years, I have been working...' where X is the number of years you were working for a condition monitoring company.

(6) "I'm an open minded person and sociable person and I enjoy working in an international environment.  You can probably sum all these things up by saying, 'I am flexible and work well with a globally diverse team."

NOTE: Try and avoid saying the things YOU like.  Most employers don't really care about this and don't really want to see this kind of stuff.  They are mostly interested in what you do for their company.

(7) Regarding your last sentence, again--your employer wants to know what you can do for them.  Not what they can do for you.  Try and put an end note to how you can benefit their company. 

FINALLY, #6 may not even be the best thing to say.  You might want to get a second opinion on how to word that.  I have no idea how you would tell an employer you work well with people with many backgrounds.  'globally diverse' was the best I could come up with.