[mmwako]

Someone more knowledgable than me, please correct me... if they are drilling a hole in the ground and making steam come up from said hole, doesn't that heat up the Earth's crust and atmosphere more than the previous condition without the hole, therefore contributing to higher temperatures (and climate change), making it not that "clean" after all? Maybe cleaner than carbon/petrol, but not ideal for the current context.

[cowboysauce]

>doesn't that heat up the Earth's crust and atmosphere more than the previous condition without the hole, therefore contributing to higher temperatures (and climate change)

It's irrelevant when compared to the amount of energy from the sun. World energy consumption is roughly 5.4 * 10^20 Joules per year. This is 86% of the total energy from the sun that hits the Earth in an hour.

It's like worrying over putting a single drop of poison into the ocean.

[jedimastert]

> It's irrelevant when compared to the amount of energy from the sun. World energy consumption is roughly 5.4 * 10^20 Joules per year. This is 86% of the total energy from the sun that hits the Earth in an hour.

Man, every once in a while you remember the scale of energy when you're talking about the sun. Good lord.

[IanCal]

And that's just what hits us, a tiny spec 8 light minutes away.

It outputs our yearly energy usage in about a microsecond, and converts 4 million tons of mass to energy per second.

However, per unit volume, it's putting out energy about the same as a compost heap.

[deeviant]

Global warming isn't really about heat per se, it's about heat retention. It's the green house gasses reflecting back the latent infrared energy preventing it from escaping to space.

Adding more heat doesn't change the equation, it's how much we retain.

[ljf]

And mostly, it is heat retention of solar radiation rather than heat caused by consuming fuel on earth.

[devrandomguy]

I'm probably no more knowledgeable than you in this area, but I have a free morning, and this is interesting. My hypothesis, is that the heat that we produce or release to generate usable energy, is an insignificant factor in global warming, compared to the solar heat that we trap with greenhouse gases. Let's find some quick simple stats and do some arithmetic, to figure out how much we are directly heating the surface of the Earth.

According to Wikipedia, the global energy production for 2012 was about 5.616e+20 joules, or 156 petawatt-hours. The Earth has about 1.386e+21 liters of water on it, and I will assume that that water represents the bulk of the relevant thermal mass, when considering weather patterns and sea level.

Now, let's estimate the heating caused by that energy. According to www.bickfordscience.com/03-05_State_Changes/PDF/Specific_Heat.pdf, 4,184 Joules of energy applied to 1 KG of water will raise its temperature by 1 degree Celsius, and this scales linearly with mass. Assuming that Earth-water averages out a density of 1 KG per liter, our 5.616e+20 joules, applied over a year to our 1.386e+21 liter water mass, would heat that water by 1.036e-38 degrees Celcius.

It has been a while since I've done a dimensional analysis, and the scale here are so extreme that I can't tell if my result is sensible. However, if my assumptions are reasonable and my math is correct, and the processes that I have chosen to ignore are insignificant (i.e. radiation into space over one year), then all of the heat that we release in the generation of the global energy supply, has a negligible impact on the temperature of the planet.

[ajnin]

You multiplied instead of dividing somewhere, the result should be : dT = 5.616e+20 / 1.386e+21 / 4,184 = 9.684e-5, or about 1 ten thousandth of a Kelvin. So still insignificant.

[mmwako]

Thanks for doing the math!

[ant6n]

Overall, the warming effect of greenhouse gases is 100x the warming effect of waste heat: http://www.cgd.ucar.edu/tss/ahf/

[EGreg]

It doesn't matter what they use. There is a lot of heat byproduct. Read this:

https://dothemath.ucsd.edu/2012/04/economist-meets-physicist...

[giarc]

I imagine any pipes down into the hole will be insulated however there was some work looking at the changes in bacterial make up of soil surrounding these access lines. I can't find reference, but it was mentioned last time this idea was brought up on HN.

[StavrosK]

I don't know if it's a matter of absolute temperature, as much as one of rate, ie that we need more rays to be reflected than are now.

Relatedly, though, won't this cool the core?