Charging your iPad every other day requires less than 12 kilowatt-hours per year (costing a mere $1.36 in total), according to a new analysis by the Electric Power Research Institute (EPRI).
To date, 67 million iPads have been purchased worldwide. EPRI suggests that if the number of iPads tripled over the next two years, the energy required would be equivalent to the output of one medium-sized power plant operating at full capacity.
Perhaps even more surprising: charging the Apple iPhone 3G consumes just 2.2 kWh of electricity each year, adding $0.25 to your annual electricity bill.
For further perspective on how gadgets and electronics have affected home energy consumption over the past few decades, check out this report from the US Energy Information Administration.