Does computer interfacing electric energy meters exist? With possibilities to get/log current power usage and monthly used kilowatt hours. With ethernet/rs232 etc interface. I am looking for this for European current 3phase, 230V. Looking for affordable options.
It's also possible to DIY. For 3 phase power, you'd need 3 current transformers, and then something to interface them to (an arduino may fit the bill). Note, be sure you actually have 3-phase: most residential buildings use split-phase (in which case you only need 2 transformers). On top of the hardware, you'd have to write all the software for logging and viewing the data, or interface into the Google Powermeter API.
There's several projects to look at as well:
You should check KWh meters that support the S0 interface that provides a pulse output. I have something like this http://www.produktinfo.conrad.com/datenblaetter/125000-149999/125363-an-01-ml-WechselstrZaeh_Geco32_230V32A_LCD_de_en_fr.pdf
i think this one is as well able to do it http://www.iskra-mis.si/catalogue/20071212152244/20071212153441/2008041510314899/
after that you should just follow these steps with arduino http://www.arduino.cc/playground/Main/EEM12L-32AKWhMonitoring
I did it using a data logger shield and then exporting it to excel.