This question comes up quite often. What permissions does a user need to execute a command in the SharePoint 2010 Shell?
Short answer is you will need published here http://misspippilotta.com/knitting-summer-jo-sharp-patons-kim-hargreaves/ SharePoint_Shell_Access access.
To give user SharePoint_Shell_Access access run the following command
Add-SPShellAdmin -UserName [USERNAME] -Database [DBNAME]
-Database switch is optional and if the database is not specified the configuration database is used.