You can use the following script to add a new module path to the PSModulePath environmental variable. Adding modules to this path will allow you to use them in your own scripts and if you have Powershell 3.0+ these modules will be automatically loaded when you call one of the custom CMDLET’s.

Notes:
Please replace the $ModulePath variable with the path that you would like to use.

$ModulePath = "YOUR PATH HERE"
$Path = (Get-ItemProperty -Path "HKLM:\SYSTEM\ControlSet001\Control\Session Manager\Environment").PSModulePath
$NewPath = "$ModulePath" + ";" + $Path

If($Path -notlike "*$ModulePath*") {
    Set-ItemProperty -Path "HKLM:\SYSTEM\ControlSet001\Control\Session Manager\Environment" -Name PSModulePath -Type String -Value "$NewPath"
}