[sai_c]

Could someone please enlighten a physics noob?

As i understand it, nuclear fusion could (as soon as really achieved, i.e. there exist commercial plants) provide more energy than we are currently producing by all other methods. And if we can produce it, I have no doubt we would use more and more energy.

Which would mean that all this energy must end up somewhere somehow. What I would like to know is, don' we then (just in another form) contribute to the heating of the planet again? Are there any studies/theories about that? What would the impact of the ever increasing energy release/production be?

[twic]

> 'Don't blame me,' said Poole, fighting back gamely after one round of criticism. 'Anyway, see what a mess the twenty-first century made.'

> There was a chorus of 'What do you mean?'s around the table.

> 'Well, as soon as the so-called Age of Infinite Power got under way, and everyone had thousands of kilowatts of cheap, clean energy to play with - you know what happened!'

> 'Oh, you mean the Thermal Crisis. But that was fixed.'

> 'Eventually - after you'd covered half the Earth with reflectors to bounce the Sun's heat back into space. Otherwise it would have been as parboiled as Venus by now.'

-- 3001: The final Odyssey, Arthur C. Clarke

Accuracy not guaranteed!

[sai_c]

Made my day :-).

[lambdatronics]

Yeah. This blog post [0] has a nice graph showing that at continued exponential growth of energy consumption, we have less than a few hundred years until the planet would become uninhabitable simply due to the amount of additional heat. In particular, in about 400 years, the energy demand would equal the total solar energy flux hitting the planet.

[0] https://dothemath.ucsd.edu/2011/07/galactic-scale-energy/

[TaylorAlexander]

It’s a good question. I recall someone saying that the amount of direct heat produced by energy generation is very small compared to the heat captured from the sun by the greenhouse effect.

Also I don’t think it’s true that commercial fusion power plants would in the near term produce extraordinarily high energy levels compared to a large hydroelectric or fission nuclear power plant. The thing that’s great about fusion is that it requires very little fuel and doesn’t produce nuclear waste.

[sai_c]

I hope i did not understand you wrong, but what I meant was the following. We create electric energy from source X. The electric energy is mutated to heat, or mechanical energy or what not (computers produce heat, electric cars mutate it into kinetic energy and so on). Energy is never destroyed, it just changes its form. So if we produce/consume more energy than now (yes that's just theoretical) would that contribute to climate change in a significant manner?

[DennisP]

Eventually, yes. Right now waste heat is a tiny fraction of excess greenhouse heating, but if we kept multiplying our energy usage by a couple percent per year, we'd boil the oceans in four centuries.

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

If we invent fusion, I think we could grow exponentially for quite a while, but it'll mostly happen in space. Controlled fusion makes a really great rocket.