Consequences for a tenured person of not getting grants As far as I heard in (some of) the universities a person having a tenure track position who fails to get grants may not get tenure. 


  I am wondering what might be consequences of not getting grants for a tenured professor. (Say may he or she get more teaching load? more administrative load? What will happen if he or she will not agree for that?)


In your answers please indicate about what country are you talking about.
In the US, once you have tenure it is difficult to get fired other than for misconduct and hard even then. But, you don't need to get annual raises or further advances in rank unless you are seen as a contributor. What constitutes contribution depends on the institution. For some, grants are very important. For a few, they outweigh all else, partly because they fund students. But not all institutions are like that. For some, grants are nice but not essential. 

But, whatever the mission of the institution, not contributing will leave you in a bit of a dead end with little chance to choose courses or committees, etc. 

While it may be possible to have a 30+ year career without doing more than the minimum, you will likely still be earning at the end about what you were at the start. 

Moreover, department heads, have subtle ways to punish you, by assigning you things that you won't really like doing. And who knows where your office will be.