Utility computing is a service provisioning model which will provide adaptive, flexible and simple access to computing resources, enabling a pay-per-use model for computing similar to traditional utilities such as water, gas or electricity. On the other hand, grid technology provides standard functionality for flexible integration of diverse distributed resources. This paper describes and evaluates an innovative solution for utility computing, based on grid federation, which can be easily deployed on any infrastructure based on the Globus Toolkit. This solution exhibits many advantages in terms of security, scalability and site autonomy, and achieves good performance, as shown by results, mainly with computeintensive applications.