
Cornell wants to drill 2-4mi underground for enhanced geothermal heating - shawndumas
http://arstechnica.com/science/2016/09/cornell-has-a-plan-to-prove-that-the-east-coast-can-have-geothermal-heat/
======
TeMPOraL
Almost everything we do that initially seems like a good idea stops being such
when we start doing it at scale. Burning fuels wasn't a problem at the eve of
the industrial revolution. I wonder what ecological issues will hit us
globally as we scale up geothermal energy use. E.g. I've read somewhere that
people putting too many ground-exchange heat pumps in a small area can cause
problematic cooling of the ground. Right now it's probably only a problem for
the energy efficiency of the pumps themselves, but as we scale up, I worry
about unintended environmental consequences.

Wikipedia seems to have only basic numbers up:

[https://en.wikipedia.org/wiki/Geothermal_energy#Renewability...](https://en.wikipedia.org/wiki/Geothermal_energy#Renewability_and_sustainability)

The first sentence of that section says that "geothermal power is considered
to be renewable because any projected heat extraction is small compared to the
Earth's heat content." I'd like to see some estimates on how much of that heat
content is available on the depths we're drilling down to (as opposed to the
contents of the whole planet); and again, trees were a renewable resource too,
before the industrial revolution.

~~~
dpark
> _The first sentence of that section says that "geothermal power is
> considered to be renewable because any projected heat extraction is small
> compared to the Earth's heat content." I'd like to see some estimates on how
> much of that heat content is available on the depths we're drilling down to
> (as opposed to the contents of the whole planet);_

Wikipedia links to an article with more detail. The crust alone is estimated
to hold enough heat to supply all of the Earth's electricity generation at
current levels for about 80 million years.

[https://web.archive.org/web/20100308014920/http://www.iea-
gi...](https://web.archive.org/web/20100308014920/http://www.iea-
gia.org/documents/FridleifssonetalIPCCGeothermalpaper2008FinalRybach20May08_000.pdf)

 _The total heat content of the Earth is of the order of 12.6 x 10^24 MJ, and
that of the crust the order of 5.4 x 10^21 MJ (Dickson and Fanelli, 2004).
This huge number should be compared to the world electricity generation in
2005, 6.6 x 10^13 MJ._

> _and again, trees were a renewable resource too, before the industrial
> revolution._

Trees are still a renewable resource, more so since we largely stopped using
them for fuel as a result of the industrial revolution.

~~~
dman
Keyword there is => "current levels"

~~~
incongruity
...and "80 million".

Fine, let's quadruple consumption – we're good for 20 million years. Ok, okay,
let's go to 100x consumption – we're good for 800,000 years. I think we're ok.

~~~
dsp1234
Since the magnetic field of the earth, which protects us from the solar winds
among other things, is generated by spinning of the molten outer core, do you
happen to know how much of that energy would be available before adverse
effects happen?

It's obvious that the answer is less than 100%, since a completely solid core
would provide no magnetic field. Is there some way to tell whether it's closer
to 0.1%, 1% or 10%?

~~~
dpark
Let's assume it's not just 0.1% but 0.001%. That still leaves us a comfortable
runway of 19 million years at our current levels.

But also let's hope it's not 0.001% because I'm pretty sure the core will cool
more than that on its own over a shorter timespan than 19 million years.

~~~
nitrogen
Won't thorium decay keep it warm for a good long while?

~~~
dpark
I'm honestly not sure. I don't know how much energy is being created inside
the Earth and how much is just residual. It's my understanding that the Earth
is slowly cooling, though, so radioactivity isn't replenishing heat as rapidly
as we're losing it.

------
baldfat
We already have geothermal cooling in the northeast. The very rich in New
England drill holes into the ground and send the house warm air into the
ground at one hole and then return air for another hole. Works unbelievably
well. I can't tell you why but it feels like cool mountain air and not just
A/C.

I really hope this works. It could be a huge answer to LARGE areas that
require heat.

~~~
dougb
My sister has a [http://www.waterfurnace.com](http://www.waterfurnace.com)
with a about 1500 feet of plastic tubing buried in her yard. Works really
well.

~~~
giarc
I did the savings calculator on that site and it said it will cost me more
than my current system? I thought there would be cost savings from this? Does
it assume I have an AC unit already?

~~~
baldfat
I would save $1700 in PA. half is from A/C and half from heat.

------
cossatot
EGS is a very promising technology. Currently, geothermal energy is better
considered _hydrothermal_ energy as hot water in abundance is required to turn
the turbines in generators, or by heating fluids w/ lower boiling points to
turn the turbines. However, there are a lot more regions with sufficient heat
but insufficient groundwater circulation (because they tend to be in
relatively impermeable igneous rock, and often in arid regions) that EGS will
unlock if it becomes competitively priced (which it should with more
technological refinement).

One of the most advanced test sites is happening now by a joint
DOE/University/private collaboration at Newberry Volcano west of Bend, OR
[http://www.newberrygeothermal.com/](http://www.newberrygeothermal.com/)

I think there is a lot of room for investment here. Geothermal is, in general,
a relatively safe, secure and environmentally friendly method of power
generation (the biggest concerns are in dewatering hot springs, which are
beloved if not held sacred by locals). EGS may potentially have some similar
wastewater issues as fracking, although not to the same scale both due to
smaller volume and the lack of a need for nasty surfactants to get organics to
desorb from rock. But it's generally not viewed as a viable large-scale
technology in the press or more superficial energy analyses.

~~~
briffle
A hundred miles south of Newberry is OIT, a state tech school. The whole
campus has been heated/cooled by Geothermal for decades (including outside
sidewalks) and in the last decade, they built a 2MW geothermal power plant,
and 2MW solar plant. They sell excess electricity (and hot water for heating)
to the hospital next door. [http://www.oit.edu/sustainability/clean-
energy](http://www.oit.edu/sustainability/clean-energy)

[http://www.oit.edu/orec/geo-heat-center](http://www.oit.edu/orec/geo-heat-
center)

~~~
freehunter
Kind of off-topic from the subject of renewables but on-topic for the subject
of what to do with waste heat from power generation: a city near me has a
power plant on the shore of Lake Michigan. They draw in water from the lake
for steam generation and then have to dispose of the hot water somehow.
Instead of dumping it straight back into the lake and disrupting the ecosystem
with extra hot water, they run it under the sidewalks in the city. 762 gallons
of really hot water runs under the sidewalks of the city every minute, keeping
the northern-latitude tourist town ice-free, salt-free, snowplow-free no
matter how cold it gets.

There are really interesting ways to deal with all kinds of byproduct from
industry that are non-obvious. Like heating a hospital with waste heat from a
power plant.

------
jgamman
NZ does a lot of geothermal so i know a little more about it than most but i'm
no geologist. couple points - first, don't confuse depleting the ground water
with depleting the heat. a lot of geothermal taps the heated groundwater and
yes, you can screw that up by extracting more than is re-plenished.
luck/geology is your guide for what the ratio is though. binary systems fare
better as you pull the water out, suck off the heat and then inject the liquid
back in. secondly, the big problem with geothermal is that the wells cost 10s
of millions of dollars. the financial decisions far outway the technical ie,
you have to spend $30-40M to get a well that's active upfront but it may take
decades to get it paid back. hot dry wells are like throwing money into a pit
and then paying someone else to burn it. if you're relatively small then you
can eliminate this risk by running your own fluid up and down but remember
these wells are only 20-30 cm in diameter. oh - and don't forget that if you
mess it up, presurised ground water or mud will use your well to get through
an impermeable rock layer and into an aquifer. there's some well head in
Indonesia that's been pumping out cubic km's of hot mud for the last 20
years...

~~~
cossatot
This is what enhanced geothermal systems (EGS) are all about: Pumping external
water into hot, dry systems. Most of the work is focused on either opening
natural fractures or creating new ones between an injection well and an
extraction well, so the volume of rock in which heat is extracted is much
larger.

------
sfifs
Asimov in his novels had Trantor, the planet girding capital city largely
extracted it's energy from geo thermal sources. In his novels, they would bury
heat exchange rods to tap this power.

Interesting to see this potentially close to fruition. Now if only all roofs,
roads and windows could extract solar power...

~~~
astrodust
We literally live on a ball of molten iron and we've barely tapped this
potential. If anyone wants free energy it's down there, bubbling away, just
waiting to be harnessed.

------
fencepost
This sounds great, my biggest concern would be that it's basically the same
mechanism as "fracking," but likely minus some of the more esoteric chemicals
and the sand.

What are the chances of this having similar seismic impacts with the injection
of water at those depths - is there already a significant amount of water down
there so the net effect would be replacement of the increased volume of the
system's interior? Is the nature of the area involved such that adding water
is going to lubricate existing fault lines?

Part of the concern with this is whether we're going to start seeing a
significant volume of earthquakes in areas where building codes don't and
haven't traditionally required the kind of safety features found in more
seismically active areas.

------
gtvwill
Man I wonder what drill rig they are using for the holes!? 2 to 4 mile is
roughly what? 3 to 6.4 km or so. That's a mighty deep hole! I have worked as
an offsider on a prototype deep hole surface core rig and our deepest were
1600 metres and they took ages to drill!(I heard stories of the rig drilling
2.5+ holes earlier in its life) The complications you start getting down hole
at those depths are pretty weird,the ground can chew bits in 10 metres. Which
then take 24 hours to change.

Also wonder what gauge the holes will be, I assume they will leave them cased
with the rod string but christ they can't be planning to drill HQ that deep
could they? Maybe even 8 inch for the first leg? Anyone seen anymore hardware
details?

Edit :fix phones autocorrect.

------
tn13
This might be an incredible way to generate cheap energy. I lived in a remote
location called Manikaran in Himalayas in India. It is a small town with
limited resources but has an incredibly hot water spring. The locals have
built pipelines that connect all major establishment with this boiling hot
water which is then used to cook, soak and simply bath or heat up rooms.

The motel like place I stayed in had created an exposed pipe network in the
room which emitted heat from this water. Don't want heat ? Just close the tap.
Less heat turn the tap a little bit :D

~~~
rm_-rf_slash
You may have missed the point of this article. The northeastern United States
is very geologically stable, so any geothermal energy would have to come by
going very, very deep underground. We don't have any hot springs around here.
So even if this project works out and eliminates a lot of future carbon
emissions, it will hardly be considered cheap.

~~~
iaw
Normally I agree with your assessments but I don't think you're right on this
one. Presuming geothermal wells would have a >100 year lifespan with minimal
upkeep the upfront costs may be very large but the long-term cost per/MW
extracted would go close to zero because of the virtually non-existent
marginal costs for operating geothermal wells.

Ignoring externalities created by using fossil fuels for heating (pollution,
corruption, etc.), if this technique is sound it could be a more financially
sensible decision than any alternative.

~~~
Spooky23
The problem is that the capital cost is very high and since you're not really
capturing a cash flow, its hard to finance.

------
dirtyaura
Very interesting! I just read about a Finnish geothermal project in which they
are drilling two 7km (4.35 miles) deep holes to test feasibility of geothermal
energy in areas which do not have naturally occurring geothermal sources close
to ground level. It is a serious attempt to produce geothermal energy, and
made possible by recent advantages in drilling techniques. They have now
reached a depth of roughly 3.5 km.

There's not that much about the project in English, though. Here is a short
video interview
[https://www.youtube.com/watch?v=n853GBQocC4](https://www.youtube.com/watch?v=n853GBQocC4)
and a short article [http://www.thinkgeoenergy.com/finnish-40-mw-district-
heating...](http://www.thinkgeoenergy.com/finnish-40-mw-district-heating-
project-to-be-operational-in-2017/)

------
WalterBright
The ground below about 6 feet remains at a constant 55 degrees year round. If
you make use of that as a heat source/sink, you can cut about 30% off of your
HVAC bills. I wonder why more people don't do that, especially with new
construction, when it can be installed cheaply.

------
realkitkat
There are similar (research) projects going on in Europe as well. One in
Finland is also drilling to get about 4 miles deep[1]. I believe some recent
news (that I couldn't find) have said that the project has been progressing
ok.

URL: [http://www.st1.eu/news/st1s-geothermal-heating-project-
appro...](http://www.st1.eu/news/st1s-geothermal-heating-project-approaching-
pilot-plant-stage)

------
mrfusion
I predict once we have lasers powerful enough to do laser drilling then This
will really take off. You'd just be paying the cost of electricity to drill
and if the laser is in orbit you could quickly drill power plants all over the
earth.

I'd be curious how much power is required to vaporize soil and rock.

~~~
cossatot
You don't need a laser, just a projectile:
[http://www.hypersciences.com/](http://www.hypersciences.com/)

~~~
mrfusion
Wow that's amazing! It seems like this could revolutionize several industries
and create several new ones! I guess there's got to be some kind of catch? Too
expensive?

------
dimino
Do you have to get permission when you do things to the planet as a whole? Who
would grant that permission?

For example, what if I wanted to modify the atmosphere for an experiment I'm
running, who do I talk to about that?

~~~
amaranth
If you're in the US I imagine you'd talk to the EPA. Anything you might do
that could potentially harm others or their property has to get approved by
one government agency or another. Heck, most things that wouldn't have to be
too.

------
test_pilot
There are living ecosystems underground too. Worms have been found at 1.4 km
depth and microbes down to 3 km underground. We are probably destroying
ecosystems we don't yet understand.

------
ufmace
For a little background on geothermal, keep in mind that while the amount of
energy stored in heat within the Earth is indeed vast, it's also extremely
hard to make use of generally.

One of the things that I find interesting about physical science is how many
similarities there are between things that flow of very different types. In
this way, making power from heat is very much like making power from water. We
cannot make power from water just sitting around somewhere, no matter how high
or low; we can only make power by allowing it to flow from somewhere high to
somewhere low and tapping that flow. And for practical purposes, we need flow
that has a certain minimum pressure and volume to be able to convert it
electrical power in a cost-effective way.

Heat works the same way. There may be a tremendous amount of energy in
something very hot, but the only way to use it, convert it into power, is to
allow it to flow to somewhere cooler, and tap that flow in a way similar in
concept to a water turbine. And just like the water turbine, the heat flow
must have a certain temperature difference and rate of flow to be converted
into electrical power in a cost-effective way.

Unfortunately, geothermal is terrible at this over most of the Earth's
surface. The heat gradient between the hot lower levels of the crust and the
surface is so long and gradual that it's effectively impossible to make
electrical power from it. It's kind of like trying to extract energy from a
flowing stream that's thousands of miles wide, but only a centimeter deep and
flowing at barely a trickle. The total amount of energy associated with that
flow is enormous, but it's so diffuse that it's difficult to tap.

Note that these guys are planning to use it for heating buildings. That's much
easier, as water coming out at 120-150 degrees F is perfectly fine for that.
It could potentially save a bunch of energy versus electrical or gas heating,
assuming they can pipe it around without losing too much heat. But making
electricity effectively requires getting the water hot enough at moderately
high pressure to make steam to turn a turbine with. You can play games with
exotic working fluids and such to try and get something from lower temperature
differences, but it's probably impossible to run a plant at market electricity
rates like that.

If we ever want to make really big amounts of energy from geothermal, I
haven't really run the numbers on it, but I suspect we'd need to tap into heat
below the actual crust, just to get the heat replenishment rate from the
mantle high enough. We'd definitely need to be able to drill and maintain
holes that deep, and then run some sort of working fluid down to the bottom,
let it pick up heat at a multi-gigawatt rate, then pipe it back up to the
surface without losing too much of the heat. If we ever figure out how to do
that, then we'll have essentially all the power we could ever use in about the
safest and least-interfering way I can imagine.

------
csense
What happens if they delve too greedily and too deep?

~~~
truth_sentinell
They'll awake old things that should be better keep sleeping...

~~~
DougWebb
Good for heating in the winter, though.

