Connect-VIServer <vcenter-fqdn>

Get-VM |
  Select-Object Name, PowerState,
    @{N='UsedGB';        E={[math]::Round($_.UsedSpaceGB,1)}},
    @{N='ProvisionedGB'; E={[math]::Round($_.ProvisionedSpaceGB,1)}},
    @{N='Datastores';    E={($_ | Get-Datastore).Name -join ','}} |
  Sort-Object UsedGB -Descending |
  Export-Csv vm-disk-usage.csv -NoTypeInformation