Why do Spanish TV channels have 15 minute averts breaks?

I'm in my sofa right now watching the TV, and as usual the adverts has started, so I will go to have a shower I will have lunch and then probably when I get back to the sofa the program could start. 

I didn't understand yet, why the adverts are so long, it's horrible to have to wait 15 minutes for a program, watching ridiculous adverts, because the Spanish's adverts are so ridiculous, well, not only in adverts, in another fields too.

 I know that this wouldn't change because it's a business and the companies have to sale their products, eventhought my opinion is that this has to change quickly because is excessive their duration. 

Sometimes apart from that adverts, in some programs of Tele5, a Spanish TV, they do adverts while they are doing the programs. That's the worst because you are concentrated with the program and suddenly they put and advert totally different to the programme.