Simple Concept: PowerShell: The local farm is not accessible.

[Question]: What permissions should I have to run PowerShell against SharePoint 2010?
How can I fix following issues:
 - The local farm is not accessible. Cmdlets with FeatureDepedencyId are not registered
 - Cannot access the local farm
 - Object reference not set to an instance of an object?

[Answer]:
Remember, when using the SharePoint 2010 Management Shell and its Windows PowerShell cmdlets, you need both:


  the rights  granted via the Add-SPShellAdmin cmdlet and 


 local administrator rights on the server on which you’re running the management shell


(From Hey, Scripting Guy! Tell Me About Permissions and Using Windows PowerShell 2.0 Cmdlets with SharePoint 2010)

P.S. Do you need a fast tour on PowerShell And SharePoint 2010?

PowerShell and SharePoint: What, Why and How - gives you an overview what's PowerShell and how to use it for SharePoint 2010

SharePoint 2010: PowerShell and Stsadm - explains why you want to use PowerShell instead of stsadm in SharePoint 2010

Simple concept: How to use SharePoint cmdlets in PowerShell ISE - shows you how to user PowerShell in SharePoint 2010

PowerShell: Add-SPSolution -force when wsp is already deployed - a PowerShell replacement for stsadm -o addsolution and deploysolution