Screenshot of price info as incorporated in home automation system (not live!)
historic price of kWh. Price is updated upon page visit and may fluctuate more than is visible in graph.
Peak shaving is an important means to reduce carbon emission as it avoids use of costly and CO2 emitting gas electricity plants. Recently an unnamed electricity company introduced hour-by-hour kWh rates.
As an excercise, the home automation system was coupled with their rate display (in the green bar) to light a green LED when the enegy price (static example) drops under a limit an a red LED when the price rises above another limit.
Appliances can be switched off based on the price limits and the device status. The freezer for instance, can be switched off until it reaches a certain temperature at which you DO want to switch it on, despite the high price.
The difference between this approach and the one that the company offered, namely switching off your appliances by them, is that the company only minds the production side of it, and they don't take into account your needs, such as a thawed freezer or an overheated office.
Check for yourself that the price below is indeed the realtime price:
RRTP price for 2012 02 06 18:00 is 03.5¢
Current price 2012 02 06 18:45 is $03.6¢
Download the brief howto with source code (AppleScript en PHP).