An Telraam consumption is about 3-4 Watt (http://www.pidramble.com/wiki/benchmarks/power-consumption). To give you an idea, that is about 3 times less than the stealth consumption of a digicorder.
Monitoring shows that an active Telraam sensor consumes about 3.2W during the day and about 0.5W at night. Over the 31-day period, that was 1.56kWh
(credits: Andy Openshaw)
Approx. 15MB download
Approx. 4 MB upload