If you charge your iPad every other day, it will cost you approximately $1.36 in electricity per year, according to a report by the Electric Power Research Institute (EPRI). The report also found that it costs about $.25 to charge an iPhone 3 all year.
According to the report, an iPad uses less than 12 kWh of electricity over the course of a year if it’s charged every other day, much less than a 42″ plasma TV which uses about 358 kWh of electricity a year.
Check it out: “EPRI calculations show that the average energy used by all iPads in the market is approximately 590 gigawatt hours (GWh). In a scenario where the number of iPads tripled over the next two years, the energy required would be nearly equivalent to two 250-megawatt (MW) power plants operating at a 50 percent utilization rate. A quadrupling of sales in two years would require energy generated by three 250-MW power plants.”