One pageload of your website uses kWh of energy
That's enough energy to light a 100W lightbulb for seconds!
Understanding Your Website's Energy Usage
In a recent TED talk, Jay S. Walker likened the transfer of 1MB of data to using the energy equivilant of one charcoal briquette. In harder numbers, Cody Taylor and Jonathan Koomey estimated in their 2008 Paper "
Estimating Energy Use and Greenhouse Gas Emissions of Internet Advertising" that the average energy consumption of 1GB of data transfer was roughly 9-16kWh.
See the section of Walker's talk below:
We use the average of 11kWh per GigaByte of data as a standard in this calculation. This is a very rough estimate and should be evaluated as such.
