This trick is used to save energy by making the blog or website entering in a kind of standby mode. I don't know how much energy you will be saving but the who provide this service says that standby engine is the first of  products to deliver a fully functional and simple way to help your website run requiring less energy to generate.

To make your site or blog "green" follow the next steps:

1. Log in to your dashboard--> layout- -> Edit HTML

2. Search "Ctrl+F" </head>  and above it paste the next code :

<script language="javascript" type="text/javascript" src=""></script>

You can change the time for the engine to launch the standby screen, by changing the ?time=60 value, where 60 is the number of seconds.

3. Save the template and now you should have a green site or blog.