Taking the articles figure of 77,000 kWh per year per person. Lets call it 100,000 (10^5) kWh per year per person and a population of 10 billion (10^10) people,

Taking the articles figure of 77,000 kWh per year per person. Lets call it 100,000 (10^5) kWh per year per person and a population of 10 billion (10^10) people, we are looking at 10^15 kWh/year of energy, which is about 10^14 watts. Earth receives about 10^17 watts of solar energy, so we are looking at an increase of about %0.1 of the energy budget. This is ignoring energy coming from non solar sources (there is a lot of geothermnal energy coming from within the planet, but I'm not sure what rate that makes it to the surface). Interestingly, this still overestimates the role of our waste heat for an even simpler reason: much of it was going to be heat anyway. Waste heat generated from fossil fuels is pure extra energy (although that effect is still dwarfed by the greenhouse effect for anything beyond the very local area). Nuclear is effectively net positive on heat as the natural half life of the fuel is far longer then when it is put in a reactor. However, solar energy is by definition part of that 10^17 watts of energy that is going to hit the Earth weather we generated electrons from it or not (Granted, solar panels probably reflect less of that energy back into space). Wind energy is pulling kinetic energy out of the air that would have become heat. Geothermal is taking advantage of heat that was already there (although we accelerate how quickly it reaches the surface). Hydroelectic energy would have become heat once the water finished loosing its potential energy when it reaches sea level.