Comment by Communitivity | Hacker News Reader

Comment by Communitivity | Hacker News Reader

TANSTAAFL... If we tap the energy from the molten core, part of the system that both drives/stabilizes the rotation of the planet, and provides the magnet generating our solar radiation shield (van allen belts), then I think we can expect eventually to face rotation/stabilization degradation.

Of course, eventually might be a million years from now. I remember climate change deniers saying that climate change might produce a visible effect by 2400, and by then we could fix it. Now look where we are with that.

There's also fracking. To tap the core we probably need to do deep drilling, with a lot of the problems that drilling for oil or fracking cause, except possibly magnified because of the depths we're talking about.

It is much easier, and safer, to tap solar energy. If we pour research into solar efficiency and house-scale batteries, we could provide all of the electricity needed for U.S. homes and have enough to sell to Canada and Mexico with only 16k sq miles (the size of Nellis AFB).

"A square mile, 5,280 feet times 5,280 feet equals 27,878,400 square feet. Divided by 15 sq.ft. per module, we can fit 1,858,560 modules per square mile. At 0.6266 kilowatt-hours per module per day, our square mile will deliver 1,164,574 kWh per day on average, or 425,069,510 kWh per year. Back to our goal of 4,000,000,000,000 kWh, divided by 425,069,510 kWh per year per square mile, it looks like we need about 9,410 square miles of surface to meet the electrical needs of the U.S. That’s a square area a bit less than 100 miles on a side. This is a bit over half of the approximate 16,000 square miles currently occupied by the Nevada Test Site and the surrounding Nellis Air Force Range." [1]

[1] https://www.terrawatts.com/PV-production.html

Just a nit: fracking problems aren't from the depth of the drilling. In fracking (hydraulic fracturing) they drill a hole then push high pressure fluid into the hole in such a way as to cause large volumes of rock to break apart. For something like this, you'd want the hole to be stable and not tear apart all the rock around it, like in a traditional well.

But if we convert a lot of solar energy into electricity instead of letting it turn into heat that could usher a new ice age.

That's about as reasonable as your point about tapping enough heat from Earth's core to disturb the magnetic field.

The electricity will eventually be turned into heat too. Since PV panels are pretty dark, in most places where you put them they will increase the amount of heat generated, because less light is reflected back to space.

It all gets turned into heat anyway. Whether at the solar panel or in the electrical transmission process, inverters, or the actual devices being powered.

Tell that to an air conditioning heat pump!

Solar is much more limited by resources and manufacturing ability, likely would cost a lot more than this just in finished product, will take up a ton of land (very expensive), works much better in certain areas than others, plus the still unsolved problem of grid-scale storage for at night. You also need to still build the equipment to hook it up to power lines; if you can retrofit existing power plants into something that works 24/7, then that is a much better alternative.

I think the reality is we need a “yes and” approach, not a “no but”.

There is no possible way for humans to ever extract enough geothermal energy in any of our lifetimes, expanded out to 100,000 lifetimes, to ever affect the geothermal reserves of the earth. You are making things up to fit you argument that solar is better.

There was this idea going around that solar power would cause global warming, since a solar panel is typically warmer than whatever was there before it was installed. But the idea turns out to be bullshit, the warming effect is tiny compared to what the equivalent co2 from fossil fuels would cause.

The lesson is: Always. Do. The. Math. First.

You can't really do the math until you have an idea of what you want to calculate.

Pumping the energy out of the Yellowstone supervolcano was proposed to lower the risk of an eruption. That seems like a win-win to me.

Just as long as the math is correct and it doesn't turn out to have the opposite effect..

> It is much easier, and safer, to tap solar energy. If we pour research into solar efficiency and house-scale batteries, we could provide all of the electricity needed for U.S. homes and have enough to sell to Canada and Mexico with only 16k sq miles (the size of Nellis AFB).

A million times this.

We have solutions at our hands, but we're not willing enough to use them

Hm. Annual PV module production in 2020 was ~180 GW [0]; peak power per 1m² is on the order of 200W, meaning roughly the equivalent of 1000 km² or ~386 sq. miles or thereabouts of PV modules.

Covering 16,000 sq. miles would take about 40 years of the entire global PV module production - a few years less if adjusted for production increase.

Doesn't sound very realistic to me, especially considering infrastructure, storage solutions(!!!), and maintenance/replacement have to be added on top of that.

I'm all for clean and sustainable power generation, but a little diversity (wind, nuclear, geothermal, biomass, tidal power, hydropower, etc.) seems to be more realistic and actually achievable.

[0] https://www.statista.com/statistics/668764/annual-solar-modu...

I think geothermal can be part of a solution, as can solar, and nuclear, and wind, etc. We need all hands on deck here. I think you're not wrong to worry about cooling the interior of the Earth too much, but that's a much slower problem we would have plenty of time to adapt to. Millions of years is longer than humans have been a species. Given all the other very viable energy options out there, I don't see us overdoing it on the geothermal front. Global warming on the other hand is going to fuck us up over the next century.

One thing I would like to see happen is tap the energy at Yellowstone in a big way. We want to cool that down before it blows up in our faces.

For every few miles you drill the temperature rises by 370F. The closest we've ever come to drilling was with the Japanese scientific drilling ship Chikyu [1]. It had to stop because of extreme pressure collapsing the walls of the drilling hole after just 7km. Just putting it into perspective, the amount of heat trapped inside Earth is immense.

[1] https://en.wikipedia.org/wiki/Chiky%C5%AB

I'd expect we'd use this energy source for only 50-100 years, before tech & science developments makes it obsolete.

So it's the wrong time to worry about effects after that.

I've wondered as well about the effect of pumping all of that heat - energy - out of the core and into (effectively) space.

Best case, our use falls in the .003% mentioned in another thread of heat that contributes to warming the Earth's crust, and the surface is that .003% cooler.

The worst case, though, is we start slowing (maybe even stopping) the flows of molten rock as it's cooled down. I don't even have the beginnings of a background to comment - does anybody?

Global energy usage is 15TW. The earth's core currently dissipates 47TW through passive cooling. The core has a mass 528,000 times that of the atmosphere.

I don't think I even need to do the math on this, to demonstrate that our total energy usage is many orders of magnitude smaller than what would be required to cause the problem you're discussing.

Solar is great, and growing fast, but for fairly obvious reasons works better as part of a multifaceted solution than as a single source.

AFAIK they aren't planning to do any fracking, and it's not obvious that it is even possible at these depths. And the drilling is far less disruptive as it is given that it is done at atmospheric pressure (no drilling fluid).

As for your second point, batteries are not cheap. Nowhere near cheap. We need solutions not pipe dreams.

TANSTAAFL applies to batteries. There is no viable path known to produce multi-day batteries to cover everyone on the planet. Solar & wind is great. But we're not solving the climate crisis without baseload power generation and distribution. All hands on deck.

Just use hydrogen if you can't build enough batteries. Make it into methane or ammonia if you have trouble storing it.

Firstly, the energy from geothermal is NOT from the core or even remotely that deep of an energy source. It is from potassium and other elements doing radioactive decay in the crust and upper mantle.

Nonetheless, it is worth putting some numbers to gain perspective:

1. World electricity demand was 24K terawatt hours in 2019 [1]

2. Mt St Helens volcano released 24 megatons of energy when it erupted [2]. That is 28 terawatt hours.

3. Thus, you would be adding 824 equivalent Mt St Helen eruptions a year in terms of additional energy extraction from the earth. Which sounds like a lot, but it really isn't for several reasons.

4. In particular, the earth is already radiating substantially than this amount of energy to the surface. "Because of the internal heat, the Earth's surface heat flow averages 82 mW/m2 which amounts to a total heat of about 42 million megawatts."[3]. That is 42 terawatts of continual energy loss from the crust/upper mantle to the surface. That is 16 times as much electricity as humanity uses -- and it is already be radiated to the surface.

My guess is that if we started extracting this from 20KM down and bringing that heat to the surface, then it would cause some increase in energy radiated to the surface, but it would also be concentrating that energy radiated to the surface at the location of the plant and potentially decreasing that energy from its slow radiation path to the surface through the rock above it.

Either way that potassium and uranium is going to decay. Either way, that heat will eventually make it to the surface and eventually be lost to space. The question is whether we can stand in the middle of that process and capture it for use. Our using of that heat and turning it into electricity -- ultimately still turns into heat and is radiated to space. It just is turned into heat when it is loses on the electricity transmission grid, when it is used to heat a house, when it is used to move a car, etc.

TANSTAAFL really doesn't intersect with the reality that stars burn and the earth decays whether we use the energy or not. Entropy comes for us all. We are just trying to be a step in the ultimate transition of all this energy to the heat death of the universe.

[1] https://www.statista.com/statistics/280704/world-power-consu... [2] https://science.howstuffworks.com/environmental/energy/energ.... [3] https://www.worldenergy.org/assets/images/imported/2013/10/W...

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