Bryan Walsh, writing for Time about the largely hidden energy footprint behind digital devices:
Beyond the amount of wireless data being streamed, total energy consumption also depends on estimates of how much energy is consumed per GB of data. The top example assumes that every GB burns through 19 kW of electricity. That would be close to a worst-case model. The Centre for Energy-Efficient Communications (CEET) in Melbourne assumes a much lower estimate of 2 kWh per GB of wireless data, which would lead to a much lower electricity consumption estimate as well—as little as 4.6 kWh a year with the low T-Mobile data use.