Is ABAP knowledge necessary in an SAP BW career?

Is it necessary to have ABAP knowledge to excel in SAPBW career?

It depends on the type of role you wish to have. If you are a developer it definitely helps to have ABAP knowledge since you can perform better without relying on the assistance of other developers. If you are a functional consultant and if your responsibilities are towards FrontEnd and reporting areas, it is not necessary to have ABAP knowledge. However, if your intention is to become an expert BW consultant, knowing all areas including ABAP is important.