Geothermal Power Plant in Iceland [image credit: Wikipedia]
Tapping into geothermal energy always seems like one of those ideas that maybe works in a few local areas, but won’t make a massive difference on the global scale. There’s also its earthquake problem to dent the enthusiasm of climate-obsessed ‘green’ ideologists.
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Drilling holes into an extinct volcano might sound like an unusual start to an energy project, says BBC News.
But that’s what J Michael Palin, a senior lecturer at the University of Otago in New Zealand, is planning to do.
His project involves drilling two boreholes to a depth of 500m (1,600ft) and monitoring the rock to see if it is suitable to provide geothermal energy.
“It has been known for some time that the Dunedin region has surface heat flow about 30% higher than expected based on previous measurements,” says Dr Palin.
It is that free heat that Dr Palin is hoping to tap into.
Temperatures in Earth’s core, which starts at 2,890km (1,800 miles) below the surface, can reach 5,400°C, about the same temperature as the surface of the Sun. This heat moves upward over time and molten rock known as magma creeps toward the surface, carrying enormous heat.
Geothermal energy companies drill wells and as hot water rises through the well, the heat is extracted and used to make electricity or to heat homes nearby.
Many researchers have long been excited about geothermal’s potential to bring about a greener heating system. It is not a new market – Italy’s Prince Piero Ginori Conti tested the first geothermal power generator in 1904.
And it is not just New Zealand. There is renewed interest in this energy source as countries set themselves renewable energy targets, including net zero projects – commitment by dozens of nations to decarbonize their economies by 2050.
Full article here.
Tallbloke's Talkshop 
Very niche idea.
Watch. Some nitwits will start a crusade over geothermal energy extraction cooling the planet’s core down too much, causing you know what…
I just want to know how they handle the blowback from below.
Enhanced geothermal system
From Wikipedia, the free encyclopedia
An enhanced geothermal system (EGS) generates geothermal electricity without the need for natural convective hydrothermal resources. Until recently, geothermal power systems have exploited only resources where naturally occurring heat, water, and rock permeability are sufficient to allow energy extraction. However, by far most of geothermal energy within reach of conventional techniques is in dry and impermeable rock. EGS technologies enhance and/or create geothermal resources in this hot dry rock (HDR) through a variety of stimulation methods, including ‘hydraulic stimulation’.
[bold added]
https://en.wikipedia.org/wiki/Enhanced_geothermal_system
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EGS may or may not be a ‘closed loop’ system.
Why Deep Closed-Loop Geothermal Is Guaranteed To Fail
February 21, 2021
by Mark McClure
The concept of closed-loop geothermal is to circulate fluid through a wellbore that is 1000s or even 10,000s of ft deep and then back up to the surface. No fluid ever leaves the well.
. . .
The problem is that heat conduction through rock is very slow.
. . .
Before I discuss deep closed-loop geothermal, I should state that I am a believer in the potential of Enhanced Geothermal Systems (EGS). The concept of EGS is to use hydraulic fracturing to increase production rates for geothermal energy production.
[bold added]
https://www.resfrac.com/blog/why-deep-closed-loop-geothermal-guaranteed-fail
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Will the no-fracking brigade give this a pass?
Two things, what will they be using as a heat transfer mechanism,and what are they goung to do if magma comes out of the hole?
Much of where the rocks are hot enough to provide the necessary driving force for a turbine requires fracking to get enough heating area and since that is a no-no in a lot of places because of the fear of earthquakes, therefore geothermal generating plants are usually away from where the power is needed creating extra expense for long transmission lines.
Only cost effective in a small number of regions.
The more common way to use geothermal is not to generate electricity, but as a heat source of low grade for “Ground source heat pumps”.
Running your heat pump off of a ground loop at 60 F a dozen feet down is a lot more effective than in the air at 0 F…
That actually works fairly well.
Near me at the other end of the San Francisco Bay Area is a geothermal plant. One of the first in the USA. Early on they had corrosion problems from the gasses dissolved in the ground water making it acidic. Eventually they seem to have solved that.
They can work OK, but tend to be rather small. There’s also a couple in Hawaii where one of them lost out to a lava flow 😉
‘It is that free heat that Dr Palin is hoping to tap into.’
Variable cost approaches zero. Fixed cost high. The heat is free AFTER you drill deep holes . . . which cost money. And buy equipment to use it . . . which cost money.
It’s all free, once you have spent a lot of money.
From what I’ve read drilling a geothermal mine is in effect a form of fracking — fracturing rocks to allow water to circulate through the fractures and accumulate geothermal heat.
Click to access NEGATIVE%20ASPECTS%20OF%20GEOTHERMAL%20POWER%20GENERATION.pdf
Effects of drilling and exploration.
Noise caused by geothermal plants is considerable. During drilling it can reach above the pain threshold of 120dB and once in operation reaches 90dB. In the open landscape such noise can be heard for some
distance and reduces the value of tourist sites and local recreation. (Kristmannsdóttir,2003).
Surface disturbance of wilderness has high impact as active sites tend to be in rare landscape types of
very high scenic and toursitic (economic) value including ‘colourful striking landscapes, hot springs, lavas
and glaciers’. (Thórhallsdóttir, 2007). Disturbance includes roads, powerlines, factories, heavy lorries and
drilling equipment.
Also the use of geothermal energy for electrical generation and a variety of other purposes can require the handling and disposal of large volumes of geothermal fluids. These fluids can contain constituents such as CO2, methane, radon, dissolved ammonia, hydrogen sulfide gas, and trace elements such as mercury, arsenic, boric acid, etc.
Boron and arsenic and other heavy metal contamination has, in some parts of the world, proved to be quite a problem at some geothermal plants.
Also see https://core.ac.uk/download/pdf/194547239.pdf ‘Environmental impact of geothermal power plants in Aydın,Turkey’
Ersel Yilmaz 1, *, and Mustafa Ali Kaptan 2
1 Department of Biosystems Engineering, Adnan Menderes University, Aydın, Turkey
2 Department of Soil Science and Plant Nutrition, Adnan Menderes University, Aydın, Turkey
And finally this old document still hold a lot of good information —
Health and Environmental Effects Document on Geothermal Energy-1981
by David W. Layton, Lynn R. Anspaugh, Kerry D. O’Banion
available at https://geothermalcommunities.eu/assets/elearning/8.17.www.osti.pdf
From what I’ve read (and I’m no expert in this) closed systems have major problems with both metallic and non-metal contamination, and the requirement to quickly deal with any hot gasses that have been released from the fractured rocks.
But with a good understanding of the underlying rock strata and chemistry, and a proper understanding of all the engineering requirements, geothermal energy should still be a very worthy addition to any nation’s energy mix. 🙂
Just don’t think it will come either very cheaply or easy.
The geothermal plant near Rotorua has been going for years, but has problems with dissolved solids clogging pipes. They got around this by drilling new holes which restored steam flow.
However they ran into another problem as the nearby volcanic tourist area (boiling mud pools, geyzers, coloured rocks from mineral waters) had a drop-off in activity. As the tourist trade was more valuable than the steam power, the plant has been reduced in output
My last message seems to have gone to the spam bin?
[mod] yes, retrieved
All of the above, but add in: grit sand stones acid that disintegrates steam turbine blades in hours. I know this from two sites we did in Mexico. Best stick with good old reliable clean coal that will last long enough for the World to have viable sustainable low polluting energy sources. Why not coal fuelled CHP district heating – something the CEGB unwittingly pioneered in the 1950’s with Battersea and Pimlico. Can the green brigade image smoke free chimneys and a nett system efficiency >130% from burning a fuel that’s under our feet? Obviously Bojo needs to be educated to understand that CO2 does not and cannot make the atmosphere hotter than what the Sun does.
Michael Owen – you are conflating a lot of geothermal fields into one. NZ currently gets about 1000MW of baseload power from geothermal stations, about 10 in total. There has been reinjection issues with silica deposition but they are solved with better management. You don’t use those wells for production. The production area usually several km from reinjection and in a different formation.
Rotorua has never had geothermal power – the fluid was always too cold. No power station was backed off for Rotorua.
Plenty of hot rock here…
FEBRUARY 23, 2021
Mt Etna’s latest eruptions awe even those who study volcanos
https://phys.org/news/2021-02-mt-etna-latest-eruptions-awe.html
Big Oil Invests In Geothermal Energy Breakthrough
By Felicity Bradstock – Feb 18, 2021
The new technology, named ‘loop’, provides a closed-loop network of pipes which is installed between 3 to 4 km underground, linked to an aboveground facility.
https://oilprice.com/Alternative-Energy/Geothermal-Energy/Big-Oil-Invests-In-Geothermal-Energy-Breakthrough.html
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But as noted earlier, it’s unlikely to work as hoped.
Why Deep Closed-Loop Geothermal Is Guaranteed To Fail
February 21, 2021
by Mark McClure
The concept of closed-loop geothermal is to circulate fluid through a wellbore that is 1000s or even 10,000s of ft deep and then back up to the surface. No fluid ever leaves the well.
. . .
The problem is that heat conduction through rock is very slow.
https://www.resfrac.com/blog/why-deep-closed-loop-geothermal-guaranteed-fail