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Geothermal's path to relevance: cheap drilling

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Re: Geothermal's path to relevance: cheap drilling

#11

Post by Factorium »

Are ground-source heatpumps considered 'geothermal'?

Its much less sexy than a giant plant connected to a magma stream, but if we made these routine for all new suburban constructions, alongside passivhaus standards, we could eliminate residential fossil fuel connections for huge sections of the Western world.

Like another commenter mentioned, we could even have communal systems for individual streets, drilled beneath roads, to service townhouses and apartment blocks.

You can run the ground-source for heating and cooling, alongside a single wall-mounted air conditioner for dehumidification in the summer.

Re: Geothermal's path to relevance: cheap drilling

#12

Post by WarOnPrivacy »

Scoundreller wrote: post #9
WarOnPrivacy wrote: post #3

From the article: Traditional geothermal wells target rare hydrothermal resources Florida geothermal systems pull cool water from the aquifer, use it for A/C and return it via a 2nd well. They're about the only wells that water management districts will rubberstamp. Geothermal cooling (in FL) becomes cost efficient above 15k-20k sq ft (based on my 2010s exp). That led me to an idea that neighborhoods could be cooled…

What I always find dumb is when I see a swimming pool and an air conditioner without the two being one system. Do Floridians at least install heat-pump pool heater systems indoors so the cold goes indoors?

I've only seen winter water heating in geothermally cooled homes.

Re: Geothermal's path to relevance: cheap drilling

#13

Post by beerandt »

Scoundreller wrote: post #9
WarOnPrivacy wrote: post #3

From the article: Traditional geothermal wells target rare hydrothermal resources Florida geothermal systems pull cool water from the aquifer, use it for A/C and return it via a 2nd well. They're about the only wells that water management districts will rubberstamp. Geothermal cooling (in FL) becomes cost efficient above 15k-20k sq ft (based on my 2010s exp). That led me to an idea that neighborhoods could be cooled…

What I always find dumb is when I see a swimming pool and an air conditioner without the two being one system. Do Floridians at least install heat-pump pool heater systems indoors so the cold goes indoors?

Swimming pool temperatures in the south easily get over 85, and sometimes 90 degrees in the summer.

We always bought big blocks of ice to throw in the pool in the summer to cool it off.

Re: Geothermal's path to relevance: cheap drilling

#14

Post by uuddlrlr »

Factorium wrote: post #11

Are ground-source heatpumps considered 'geothermal'? Its much less sexy than a giant plant connected to a magma stream, but if we made these routine for all new suburban constructions, alongside passivhaus standards, we could eliminate residential fossil fuel connections for huge sections of the Western world. Like another commenter mentioned, we could even have communal systems for individual streets, drilled beneat…

There's a 52-home community in Alberta that provides ~all of their winter heating by storing heat in the ground throughout the summer:

https://www.dlsc.ca/borehole.htm

It gets up to nearly 80C, but took a few years of operation to get there.

The website covers it really well and I'd recommend checking it out.

Re: Geothermal's path to relevance: cheap drilling

#15

Post by phreeza »

Retric wrote: post #7
phreeza wrote: post #2

I am always a bit bearish on geothermal, because the energy flow through the earths crust is just so damn low. Per surface area, it is about 3 orders of magnitude less than solar irradiation, which means that the circumstances in which it really makes sense to exploit geothermal are those where you can effectively harvest flows from a much larger area, most likely due to convection of water or magma. My understanding…

It’s often less about the heat flow than simply the amount of heat contained in that volume of rock. For your example: A 1/2 acre home is 2023 m2, 1kg of rock is ~2000j/degrees Celsius, 1 cubic meter of rock is ~2500 kg, down 1k = ~2000 j * 2500 * 2023 * 1000 / 60 / 60 / 1000 ~= 2,800,000 kWh per degC. If you’re talking 1kw of heat on average from that rock you only drop 1 degree after 300 years. Of course 1km is a f…

Thanks that is a great point I hadn't considered. I suppose strictly speaking it is not renewable when you use it like that, but still pretty clean.

Re: Geothermal's path to relevance: cheap drilling

#16

Post by api »

phreeza wrote: post #2

I am always a bit bearish on geothermal, because the energy flow through the earths crust is just so damn low. Per surface area, it is about 3 orders of magnitude less than solar irradiation, which means that the circumstances in which it really makes sense to exploit geothermal are those where you can effectively harvest flows from a much larger area, most likely due to convection of water or magma. My understanding…

The great thing about geothermal is that it's 24/7 dispatchable without expensive added storage. That would make it a great companion to solar and wind energy in place of natural gas. Even 5-10% of total power on an absolute basis from geothermal could be more valuable than it appears by adding stability to the grid without fossil fuels. Drilling into geothermal would make sense if it were cheaper than adding grid-scale battery storage for nighttime use.

The energy flow from the Earth's core is small in a percentage sense, but keep in mind that humanity's energy use is actually tiny when measured on planetary or cosmic scales. Here's the total solar surface area we'd need, for scale:

https://www.axionpower.com/knowledge/power-world-with-solar/

Cover much of New Mexico with solar PV and you could power all of global industrial civilization (ignoring storage).

Re: Geothermal's path to relevance: cheap drilling

#17

Post by Freak_NL »

Factorium wrote: post #11

Are ground-source heatpumps considered 'geothermal'? Its much less sexy than a giant plant connected to a magma stream, but if we made these routine for all new suburban constructions, alongside passivhaus standards, we could eliminate residential fossil fuel connections for huge sections of the Western world. Like another commenter mentioned, we could even have communal systems for individual streets, drilled beneat…

This is already being done in some countries (e.g., the Netherlands), but it is just a (necessary) part of the puzzle.

The existing housing stock needs solutions too, and installing heat pumps in older terrace housing is far from ideal due to noise pollution, cost, lack of space, and a limit to what can be done in terms of insulation. Geothermal plants can be used to provide district heating, which is a much better fit for certain types of houses.

Re: Geothermal's path to relevance: cheap drilling

#18

Post by goldenshale »

phreeza wrote: post #2

I am always a bit bearish on geothermal, because the energy flow through the earths crust is just so damn low. Per surface area, it is about 3 orders of magnitude less than solar irradiation, which means that the circumstances in which it really makes sense to exploit geothermal are those where you can effectively harvest flows from a much larger area, most likely due to convection of water or magma. My understanding…

Yeah, per-house is probably never going to make sense, but larger scale operations where they can use hydraulic fracturing techniques to expand the surface area could be the solution. They call these Enhanced Geothermal Systems, and basically they frack the rock between two well bores to try to maximize connectivity and surface area.

Re: Geothermal's path to relevance: cheap drilling

#19

Post by turtlebits »

Factorium wrote: post #11

Are ground-source heatpumps considered 'geothermal'? Its much less sexy than a giant plant connected to a magma stream, but if we made these routine for all new suburban constructions, alongside passivhaus standards, we could eliminate residential fossil fuel connections for huge sections of the Western world. Like another commenter mentioned, we could even have communal systems for individual streets, drilled beneat…

Yes, ground source/loop is considered geothermal.

The problem is that you need to a dig up a large area of possible natural vegetation to do it.

Re: Geothermal's path to relevance: cheap drilling

#20

Post by rudedogg »

turtlebits wrote: post #19
Factorium wrote: post #11

Are ground-source heatpumps considered 'geothermal'? Its much less sexy than a giant plant connected to a magma stream, but if we made these routine for all new suburban constructions, alongside passivhaus standards, we could eliminate residential fossil fuel connections for huge sections of the Western world. Like another commenter mentioned, we could even have communal systems for individual streets, drilled beneat…

Yes, ground source/loop is considered geothermal. The problem is that you need to a dig up a large area of possible natural vegetation to do it.

You can go vertical instead of horizontal
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