Joker,
Thanks for your quick reply.
I am interested in using the Arduino to monitor home energy consumption with the aim of allowing users to save energy and save money.
Additionally, the Arduino with an ethernet shield is one of the cheapest solutions (< 30 Euros) to how you can serve real time data to the internet.
With many users sharing their home energy data, it then becomes a competition to use the least energy, and thus lower their domestic carbon footprint.
The Arduino could also be used to measure the output from renewable energy sources such as solar water heating, windpower and photovoltaic.
If many people shared their renewable energy generation data via the internet, it could be used to build up national statistics about the quantity and distribution of renewable energy installations.
If we are expected to reach 20% renewables by 2020, then we must find an effective way of monitoring our progress and logging the installations.
Already some people have solar water heating controllers, and electricity meters that output data - and perhaps the <30 Euro Arduino is a good low-cost way to publish this information to the internet.
G