Great work!  I've been playing around with trying to do more of the data/graphing locally.  This really helps me get started.
 Here are some thoughts.

You might want to update your first post when you update this.  I was running off that for the latest instructions and they weren't up to date.  It's a convention thing to help "updates" not get lost in longer threads.

There are some issues with your walk through and user permissions.  Also I can see that you've edited out the create sql user in the create_db.sql, but your walk through does not indicate that you need to create the user.  It also does't setup permissions quite right for your script (grafana only needs SELECT but your script needs a lot more than that).  Not hard to fix, but just something to point out.  

I'm a bit confused by all the local storage of data in CSVs.  Aren't you using the database as well?

The rest of the bugs and issues I'll open on github, unless you'd prefer I put them here.

I use smartthings for HA and electricity monitoring.  I'll probably write something that either works with your script or just writes to the DB directly.  I believe I can get that data from their API.  ST is pretty popular here in the US so others might like to use that as well.