241–250 of 350 posts
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We should draw tidal power until there are exactly 360 days in a year, to make the arithmetic nice, and incidentally give us 24 minutes extra sleep.
The other way of doing this is just pushing the earth a bit off its orbit. Better to do it in the other direction though to stop global warming. Let's make it 400 days instead.
But don't the tides naturally dissipate a lot of that energy anyway? E.g. whenever you go to the beach and see waves crash upon the shore, that's tidal energy being dissipated as heat. If you stick a turbine in the mix to extract useful work before it turns into heat, isn't it still turned into heat regardless?
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Thanks so much. That feels much more in line with intuition. So maybe not technically renewable, but many orders of magnitude more renewable than e.g. fossil fuels...
Any useful interpretation of renewable energy has to do with purely human timeframes as thermodynamics doesn't allow for any energy source to be endlessly renewable. "If I use this source today will more of it naturally be there tomorrow" type consideration, otherwise you end up with a definition which either includes things like fossil fuels as renewable because you can wait millions of years or excludes things like…
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Constant percentage economic growth is possible indefinitely because the economy is made up. It’s like saying “you can’t imagine a bigger number than I can.” A person can always imagine a bigger number, and the marginal cost of doing so is merely what is necessary to store the larger number in a ledger.
If you want to define growth as cash, then sure. If you want to define it by tangible output, then not so much.
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This doesn't help much on the demand side but it will help if they go straight to clean energy.
The availability modern high tech items does help on the demand side. With LED lights a house, office, or school can be lit for a few tens of watts. Modern climate control can heat and cool buildings more efficiently than 40 years ago. Jumping to 3-5G cellular gets telecom for a fraction of the energy or resource investment of wired telecom while still providing high performance. Modern medicine reduces infant and ma…
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> The single most important assumption in this paper is that energy consumption will increase by 2% per year. […] How much energy will we consume in 1,000 years I keep posting this link here on HN but, once again, it seems very appropriate: > The upshot is that at a 2.3% growth rate (conveniently chosen to represent a 10× increase every century), we would reach boiling temperature in about 400 years. https://dothemat…
A global cooling system is easily conceivable. The ISS uses radiators to dissipate heat into outer space. We could do the same. We could concentrate heat with heat pumps and pump hot steam, molten salt, or plasma up a space elevator and radiate the heat away. Edit: The link points out that in 1,400 years we'd be using energy at the rate produced by the sun and in 2,500 years at the rate of the entire Milky Way. Even…
The sun radiates heat like a blackbody sphere with the surface area of the sun and a surface temperature of 5600K or so.
If the Earth were to have a fancy heat pump that radiated the same amount of heat into space, it would need the radiating area times the effective temperature to the fourth power equal to that of the sun. The real killer problem is that your heat pump is subject to the Carnot efficiency of pumping heat to that same temperature.
By the most straightforward Second Law calculation, entropy transferred to hot side >= entropy removed from cold side. So Q_hot / T_hot >= Q_cold / T_cold. Q_cold is the heat removed from the pleasant ~300K place where the humans are. At 5600K on the hot side, 18.6 times as much heat needs to be radiated out, so for every bit of useful work done on Earth, at least 17.6 times as much energy is consumed in cooling. If you want the radiator to be only half the surface area of the sun, multiply that by about 16.
What future humans really need is a Dyson sphere with absolutely enormous radiating area. :)
The single most important assumption in this paper is that energy consumption will increase by 2% per year. This kind of exponential growth leads to outlandish estimates for the amount of tidal energy that society will demand. Energy consumption has decoupled from population growth rates and economic growth. How much energy will we consume in 1,000 years? Most projections of the population have it stabilizing at arou…
[1] https://www.un.org/en/global-issues/population
[2] https://earth4all.life/news/press-release-global-population-...
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The problem with this, or any other hypothetical "decoupled growth" argument is that, well, it's purely hypothetical. There's no evidence whatsoever that economic growth can be decoupled from resource, and most especially energy, usage. There are instances of increased efficiencies , which thanks to the Jevons Paradox increase overall resource utilisation (economically, efficiency is equivalent to a reduced price, an…
Conversely the people who argue against growth never have any answers they want to elaborate on. They have "well we can't have endless growth" and that's where the conversation stops. They never want to examine the consequences of that thought (no growth means we're into a zero-sum game) or whether they think we're even plausibly close to the limit (instead they want to have a proxy argument about environmental damag…
But no.
War. War, real estate, and more pretend finance for finance sake. Either that or mass producing the tools of tyranny.
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> The single most important assumption in this paper is that energy consumption will increase by 2% per year. There's a 2nd big assumption: That tidal energy extracted is additional Earth's rotational energy loss above what Earth does by itself. According to the paper, tidal energy is dissipated through friction between ocean water & the seafloor. This dissipated energy subtracts from Earth's rotational energy. And s…
It's a bit absurd the idea that humans living on earth are going to produce more energy than the Sun. Maybe I'm naive and simple minded. But that just seems insane. If I'm doing the math right, at 2.3% growth = we produce more energy than the Sun in 4500 years. It doesn't matter how many years it is. It's never happening. Just look at how damn hot and inhospitable the sun is. We're not producing more energy here! It'…