I've got one at my place in WA, they put it in when I had a solar system installed.
I believe it measures power in, and out, every 15 minutes or so, and when they come round to read it then they download all the data.
Our bills have been slashed by installing the solar, and replacing halogen downlights with LED, updating the fridge and changing the hot water unit to a solar system as well.
Obviously this takes money, and you need your own place to be able to install the systems.
