The following PowerCLI script will report the spaces for all VM's in datacenter "New York" and write the output to a file called VMSpaces.csv:
Get-Datacenter -Name "New York" | Get-VM |
Select-Object -Property Name,ProvisionedSpaceGB,UsedSpaceGB,@{N='FreeSpaceGB';E={$_.ProvisionedSpaceGB-$_.UsedSpaceGB}} |
Export-CSV -Path VMSpaces.csv -NoTypeInformation -UseCulture