I've bought a flukso v2b, a device meant to monitor the usage of electricity and gas. I simply hooked it up to the P1-port of the Smart Meter, and it worked. It came with the right cable, it just had to be connected in reverse. I love the device, the graphs I can see on the website (http://www.flukso.net) are fine, but of course I had to tinker. I aimed for a way to see the current power-usage, the consumption per day and per month. The website offers almost just that, but there's no way to see your month's usage. And I love to tinker, so here we go !

flukso device 
Because I'm already running a Linux webserver, I just had to create my own graphs, and to do that i did the following:
1) create a script that retrieves the data from flukso.net and stores it in a mysql table (one value per minute for gas and electricity)
2) create some scripts that create graphs and show a web-page from my own data and live from the flukso device
3) add the data also to the Cacti data I already had.

and now I've got some graphs, showing me the usage now, last days and a view for the month. The rest will follow soon, after I collected more than a few weeks data.

today and yesterday (sample):

Power consumption today and yesterday

Live, the last minute (sample):

Live power consumption

the last month (31 days) (sample):

Power consumption per day

The live graph that is provided by flukso.net almost always fails when I use my pc (You are probably not in the same local network as the FLM) (later I found that it's a security problem in the browser concerning mixed content), and it always works when I use the Ipad. My own live graph (created with some Jquery auto-refresh) works just fine, probably because it has no auto-discovery using Bonjour for the flukso device. It just uses curl to retrieve the sensor-page, and create a graph. (from here, link in first comment)
I've used the Flukso PHP API-class to retrieve the data from flukso.net, I only added "resolution" (download here rename to .php). I've used pChart to create most of the graphs.

I've tried the MQTT protocol, but that seems to be aimed at continuously receiving data, and not just some for a web-page. I've used php-mqtt to make a web-page with it, didn't like it, perhaps it's coming back sometime.

Targets for now:
- because I can
- provide a clear view of power and gas usage
- search for easy savings

Two years later, the gas usage has gone down by more than 50% and the power consumption has gone down by 30%. Not by measuring, but by taking measures based mainly on these measurements.