We often talk about the climate impact based on greenhouse gases, but extracting fuel from the ground and using it in exothermal processes of course also releases energy as heat.
This is mostly¹ in contrast with renewables, which make use of energy that’s not long-term contained to begin with, so would end up as heat in our atmosphere anyways.
So, my question is: Does the amount of energy released by non-renewables have any notable impact on our global temperature? Or would it easily radiate into space, if we solved the greenhouse gas problem?
¹) In the case of solar, putting up black surfaces does mean that less sunlight gets reflected, so more heat ultimately gets trapped in our atmosphere. There’s probably other such cases, too.
Given a radiative forcing coefficient of
ln(new ppm/old ppm)/ln(2)*3.7 W/m**2I have previously calculated that for every 1kWh of electricity generated from natural gas, an additional 2.2 kWh of heat is dumped into the atmosphere due to greenhouse effect in every year thereafter (for at least 1000 years that the resulting carbon dioxide remains in the air). So while the initial numbers are similar, you have to remember that the heat you generate is a one-time release (that dissipates into space as infrared radiation), but the greenhouse effect remains around in perpetuity, accumulating from year to year. If you are consuming 1kW of fossil electricity on average, after 100 years you are still only generating 1.67kW of heat (1kW from your devices and .67kW from 60% efficient power plant), but you also get an extra 220kW of heat from accumulated greenhouse gas.I have wondered this question myself, and it does appear that the heat from the fossil/nuclear power itself is negligible over long term compared to the greenhouse effect. At least until you reach a Kardashev type I civilization level and have so many nuclear/fusion reactors that they noticeably raise the global temperature and necessitate special radiators.