This is the old my kid was two feet tall a year ago and three feet tall this year, so by the time she's an adult she's going to be as tall as a house!
Tidal energy is not renewable
181–190 of 350 posts
Re: Tidal energy is not renewable
#182Earlier quoted context omitted.
> gets us to about 150 trillion humans in 1,000 years I realize the big issue is settled here but just to scope this detail: the total land area of earth is coincidentally approximately 150 million km^2 At 150 trillion humans each human would get just about a square meter. Many of those square meters are uninhabitable.
That’s about the density of Kowloon walled city. And ignores the available space in the ocean.
Did they grow any food, produce electricity, or had any manufacturing at all in Kowloon?
Re: Tidal energy is not renewable
#183Earlier quoted context omitted.
A lot. Look up Hadley cells. https://groups.seas.harvard.edu/climate/eli/research/equable... Warm air rises near the tropics, rotating with the Earth. It then goes towards the temperate zone, still rotating with the Earth to form the jet stream. It then falls, creating the trade winds as it slows down. It then is sucked back towards the tropics, creating a reverse trade wind because it is only going as fast as the te…
Hadley cells determine wind patterns but not the energy content of the wind, to any appreciable degree, which comes from solar flux. Wind energy is solar energy once removed. Wave energy is solar energy twice removed (solar -> wind -> waves).
Yes, the energy driving the entire system comes from the Sun. But the fact that it takes the form of wind rather than rising/falling columns of air has to do with the rotation of the Earth.
Ditto for hurricanes. Hurricanes turn rising/falling air into cycling air into hurricane force winds because the Earth rotates. But the energy for it came from the Sun. Often removed by another factor, Sun warms ocean, ocean drives the storm.
Re: Tidal energy is not renewable
#184Earlier quoted context omitted.
Developing countries will increase their energy usage but have the benefit of buying things from developed countries. As we've seen developing countries today have been able to jump right to modern technology for infrastructure. They didn't need to build massive lines of analog telecommunications, they just jumped right to cellular and satellite technology. They can jump right to solar and other renewables as they el…
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 maternal mortality and leads to lower birth rates.
Re: Tidal energy is not renewable
#185Earlier quoted context omitted.
The lesson that constant percentage (that is, exponential) growth cannot continue endlessly is the fundamental message behind the concept of Limits to Growth. That is, there exist intractable limits to growth , and that no matter how convenient it may be to pretend otherwise, humans ignore this fact at their extreme peril. Long-term ongoing economic growth, expressed as a constant percentage, is baked in to most curr…
I think there is one escape from this, basically confining more and more "growth" to artificial numbers on paper (or in a DB). Cryptocurrencies are kind of going in that direction, where the "value" that is reported as economic growth doesn't correspond to any kind of real-world matter or activity, but is simply assigned to some specific group of bits. I can kind of believe that this virtual kind of growth could cont…
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, and hence induces greater demand). And there are instances of outsourced resource utilisation (both in terms of inputs and of waste sinks), most notably that of China which has committed tremendous domestic resources and incurred immense environmental insult in providing "cheap goods" (that is: goods lacking fully-costed externality impacts) to developed countries.
But there's nary a trace of actual empirical evidence of substantive decoupling in the real world. Much handwaving and could-be's, however.
Re: Tidal energy is not renewable
#186Earlier quoted context omitted.
Hadley cells determine wind patterns but not the energy content of the wind, to any appreciable degree, which comes from solar flux. Wind energy is solar energy once removed. Wave energy is solar energy twice removed (solar -> wind -> waves).
Yes, the energy driving the entire system comes from the Sun. But the fact that it takes the form of wind rather than rising/falling columns of air has to do with the rotation of the Earth. Ditto for hurricanes. Hurricanes turn rising/falling air into cycling air into hurricane force winds because the Earth rotates. But the energy for it came from the Sun. Often removed by another factor, Sun warms ocean, ocean drive…
Wind is due to Earth's rotation much in the same way that airflow through ducts is due to the ducts.
Earth's rotation directs the energy imbued by the Sun, much as ductwork directs airflow through a structure imbued by blower motors.
But neither wind, nor ducted airflow, originate from, are driven by, or otherwise exhaust the Earth's rotation, or the containing ductwork, respectively.
(Yes, there are frictional forces of the atmosphere against the Earth's surface. On balance these probably net out, as atmospheric flows at large scale are balanced, else we'd end up with a zone of vacuum and one of infinite pressure on the Earth's surface.)
The original question was "How much [wind] is due to earth's rotation?", in the context of whether or not wind is a renewable energy resource. Given that wind is fundamentally driven by solar flux, wind is renewable, and it is not driven (vs. directed or influenced) in any meaningful way by Earth's rotation.
Re: Tidal energy is not renewable
#187Earlier quoted context omitted.
This boiling temperature conclusion makes the assumption that we continue using thermal power (steam engines, etc...), where waste heat is around 60%. However photovoltaic and wind does not produce much waste heat. Arguably solar and wind cannot scale 1000x but then you could have non thermal fusion like Helion's https://www.helionenergy.com/technology/ . Btw, thermal power is already showing limits (rivers overheati…
Where does the energy go then? EM radiation leaving the planet?
Chemical energy. Like the plants, they take sun energy and store it as chemical energy.
We could do the same, take CO2 and water and make CH4 and oxygen (electrolysis + Sabatier reaction) and make plastic. Or take ore, aluminum oxide and iron oxide, and "unburn" them releasing again oxygen (we already do that) etc...
We mostly use energy to manufacture things.
Life takes energy and lowers the entropy of the planet. Why shouldn't humans able to do the same? Any technical reason?
Re: Tidal energy is not renewable
#188Earlier quoted context omitted.
> 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…
This boiling temperature conclusion makes the assumption that we continue using thermal power (steam engines, etc...), where waste heat is around 60%. However photovoltaic and wind does not produce much waste heat. Arguably solar and wind cannot scale 1000x but then you could have non thermal fusion like Helion's https://www.helionenergy.com/technology/ . Btw, thermal power is already showing limits (rivers overheati…
> This boiling temperature conclusion makes the assumption that we continue using thermal power (steam engines, etc...), where waste heat is around 60%.
No, it doesn't. The waste heat, at the very end of the day, is always rather close to 100%. I.e. we use all that electric energy we generate to power computer, fridges, and many other machines, all of which – sooner or later – convert that electric energy to heat. (And, well, maybe a bit of chemical binding energy, depending on the application. But then, a few decades later, those products of our work will usually fall apart and/or are being burnt or torn down.)
> you could have non thermal fusion like Helion's
No, you can't. As the author says:
> this statement is independent of technology. Even if we don’t have a name for the energy source yet, as long as it obeys thermodynamics, we cook ourselves with perpetual energy increase.
Free free to have a look at his other article (the one he links in the paragraph above) for some more details -> https://dothemath.ucsd.edu/2011/07/galactic-scale-energy/
Re: Tidal energy is not renewable
#189Earlier quoted context omitted.
This boiling temperature conclusion makes the assumption that we continue using thermal power (steam engines, etc...), where waste heat is around 60%. However photovoltaic and wind does not produce much waste heat. Arguably solar and wind cannot scale 1000x but then you could have non thermal fusion like Helion's https://www.helionenergy.com/technology/ . Btw, thermal power is already showing limits (rivers overheati…
> This boiling temperature conclusion makes the assumption that we continue using thermal power (steam engines, etc...), where waste heat is around 60%. No, it doesn't. The waste heat, at the very end of the day, is always rather close to 100%. I.e. we use all that electric energy we generate to power computer, fridges, and many other machines, all of which – sooner or later – convert that electric energy to heat. (A…
100% of the heat we get from the sun is currently lost as waste heat, by one means or another. So you're not boiling the oceans by any reasonable projection of energy usage increase of solar energy.
(yes yes some of it is reflected back into space as non-IR light, but you can also lose IR-emissions back into space without heating the Earth as well).
Re: Tidal energy is not renewable
#190Earlier quoted context omitted.
I think there is one escape from this, basically confining more and more "growth" to artificial numbers on paper (or in a DB). Cryptocurrencies are kind of going in that direction, where the "value" that is reported as economic growth doesn't correspond to any kind of real-world matter or activity, but is simply assigned to some specific group of bits. I can kind of believe that this virtual kind of growth could cont…
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 damage or global warming, and are very uninterested in any specific solutions to their go to examples - i.e. "we can't possibly stop emitting CO2 from power generation, we must simply use less power!").