This is taken from this page:
http://technet.microsoft.com/en-us/library/hh403394.aspx > Security: > Permissions By default, only members of the local administrators group can start, stop, pause, resume or restart a service. To grant non-administrators the ability to manage services, see How to grant users rights to manage services in Windows Server 2003. (The process is similar on other versions of Windows.) > Stopping the Database Engine by using the Transact-SQL SHUTDOWN command requires membership in the sysadmin or serveradmin fixed server roles, and is not transferable.