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Iceland Seeking 'Supercritical Steam' For Power Source (bbc.com)
New submitter FatdogHaiku writes: Already getting over 25% of its electrical power from geothermal sources, Iceland hopes to break new ground using "supercritical steam" from a 5 km deep borehole. Is it just me, or does this sound like the start of a movie where everything that can go wrong does in fact go wrong? It's not like they are new to the tech, but working with geologic sources at 450C to ~600C is a new ball game for anyone. It should be noted that Iceland also uses direct geothermal for most of its space heating. "In this area at Reykjanes, we typically drill to 2km or 3km depth to harness the steam, to run power plants and produce clean, renewable electricity," explained Asgeir Margeirsson, CEO of the Iceland Deep Drilling Project (IDDP). "We want to see if the resources go deeper than that." The "supercritical steam" holds more energy than a liquid or a gas. The team wants to bring it up to the surface to convert into electricity, as they believe it could produce up to 10 times as much energy as the steam from conventional geothermal wells.
what kind of pipe they use for this kinda thing, im thinking some kind of ceramic metal hybrid?? Temps and sulfer corrosion must be a major PITA to deal with.
release some prehistoric mutant monster, or hit a pocket of zombie creating virus
You've obviously never watched the History Channel. It reports accurate and verified claims about this sort of stuff daily.
Or not.
"supercritical steam" just means steam at above the boiling point of water at whatever pressure applies. More specific heat than "saturated steam" (steam at the boiling point of water at the applicable pressure), but otherwise pretty much the same as any other steam....
"I do not agree with what you say, but I will defend to the death your right to say it"
We've hit magma before (drilling at Krafla) - only the second time in the world that it happened. Totally by accident. The magma backed a couple dozen meters up the borehole, then stopped.
The first time anyone ever accidentally drilled into a magma chamber was in Hawaii; they immediately sealed up the borehole as a result. Here they just decided "what the heck..." and started pumping water down it to see if they could turn it into a production well. And the performance turned out to be superb.
Sometimes I doubt your commitment to Sparkle Motion.
Most power plants (natural gas, oil or coal) run on supercritical steam anyways, at least in their designed power level. The technology is neither new nor rare. The need to run on "dry" steam for efficiency is known at least from steam locomotives. The only modern power-generating subcritical steam systems I know of are some nuclear power plants where the reactor expects some of the cooling water in it to stay liquid (read: dense) because it serves as neutron moderator as well.
Why do people insist on calling those thing renewable? How exactly do you renew sun or earh?
The sun should probably be called reusable as nothing we do on earth can affect the output of the sun. We can block it from reaching the surface with pollution but we can't change it's output. Many of the other "green" technologies I wonder about. Wind power is a good example. How much energy can we take out of the air with windmills before we start seeing an effect on the weather? Is it really completely free? Massive geothermal is another example. How much energy is down there and are we going to screw things up by depleting it? Even if there is plenty of energy down there we are still releasing extra heat into the system so we are still adding to the global warming problem. I wonder if 100 years from now if we find out that some of our free and green energy sources are not as free and green as we originally thought.
Also, even the most hardcore anti-nuclear people wouldn't generally have a problem knowing that there's a ,ulti-kilometer thick radiation shield in place.
Even if they did object it's not going to stop the process, no matter how much they protest.
Did you know your decaf latte probably used supercritical CO2 to decaffeinate the beans? Supercritical CO2, also at very high pressures, is a very good solvent and used in many industries.
Have some fun videos about the latter.
https://www.youtube.com/watch?...
https://www.youtube.com/watch?v=-gCTKteN5Y4
Silence is a state of mime.
Or not.
"supercritical steam" just means steam at above the boiling point of water at whatever pressure applies. More specific heat than "saturated steam" (steam at the boiling point of water at the applicable pressure), but otherwise pretty much the same as any other steam....
That would be superheated steam as opposed to saturated steam. Supercritical steam would be steam that is at pressure higher than water can exist as a vapor and temperature higher than water can exist as a liquid. For water this is above 3200 psia and above 705F.
I assume you mean wind turbines? Here you go.
The higher you go, the higher the figure you can harvest. Effects at the surface are generally rather minimal, although there are some small effects. It's a shame, honestly, as I think most people in windy areas (at least speaking for myself) would like more of a reduction on surface wind speeds.
Geo is generally locally, temporarily depletable. Over broad regions or over long periods of time, it's renewable. Nuclear decay inside the earth yields an average of 0.06W per square meter heat input. While that's far less than solar (even accounting for night, angles, inefficiencies, etc), it's particularly useful because it concentrates and stores. So if you drill a well into a particular hot water reservoir, you're harnessing the heat that flows up through that entire reservoir, not just immediately at the point of the borehole. And even if you're depleting it faster than it's being added (which is generally anticipated to be the case by significant margins, although these things are surprisingly difficult to assess), there's always other areas to move into; over somewhere between dozens and thousands of years (depending on the reservoir), the old site will reheat.
Note that this isn't always the case; sometimes you have "fossil heat". For example, in some places we tap heat from old lava flows or dikes. They're hot because they represent heat from another location (deep magma sources). They're hotter than their surrounding rock, and if you take the heat from them, they're never again going to be hotter than their surrounding rock.
Climate does not work that way. Planet surfaces very rapidly equalize to their equilibrium temperature, as radiation increases relative to the fourth power of temperature. The only way to have a meaningful difference in the surface temperature is to change the radiation balance (which can happen in a wide range of factors, affecting both incoming and outgoing radiation), and thus the equilibrium. Simply having "something hot at points on the surface" is virtually meaningless.
Sometimes I doubt your commitment to Sparkle Motion.
We mainly just get quakes when doing water injection for enhanced recovery. Quakes don't propagate well here, and the plants aren't exactly in the middle of major cities.
Sometimes I doubt your commitment to Sparkle Motion.
Tapping geothermal energy is a great idea, but it's not precisely renewable.
The process, whether using natural (in place) water or by water injection, is removing paleolithic heat from a piece of solidified rock. That rock only has so much heat in it and the process of tapping that heat cools it. There are already geothermal fields in Northern California (The Geysers) that are producing reduced power output due to local cooling.
The upside with deep geothermal is that there is a whole lot of crust to drill into and depleted wells can be deepened. With better grid technology more remote geothermal sources can be tapped including shallow magma.
There is a lot of energy available but technically speaking it is neither infinite nor renewable any more than anthracite coal fields were renewable. At the turn of the 20th century mining companies were looking forward to mining these vast fields of coal forever.
Don't take life too seriously; it isn't permanent.
You appear to think that most of the heat at the earth's core is residual, in which case presumably tapping this heat would "let it out" and we would eventually run out. This is not the case. The vast majority of the heat (90% or more) is from the decay of radioactive elements. Thus, the heat is being produced continually and is renewable until the radioactive elements decay (should be a good source of heat for at least a few billion years, probably much more). This means that tapping into the earth's core is not going to ruin the insulation of our crust and cause all the stored up heat to get out, because the core isn't really hot because of residual heat – regardless of what people are taught in grade school.
Saying geothermal heat like this is not renewable is ultimately like saying that hydropower is not renewable because at some point the sun will expand and the earth will get so hot that all the water in all the rivers evaporates – which
Of course we haven't figured it out. Too many goddamn hippies tell us that we need to preserve the pristine nature of the area... so we made it a park and forbid any serious effort to try to poke around at it and make any useful headway.
Then you have morons like the guy on scienceforums.net that says "The idea is like trying to put a pin into a balloon to let just a bit of the air out." Idiot doesn't realize that there is a way to do just that. Put a piece of tape on the balloon; poke a hollow needle coupled with a valve into balloon through the tape; have as much control as the valve allows to let the air out slowly without bursting the balloon. Using science it'd be easy enough to figure out a method to tap the volcano and bring it under control for man's usage in much the same way.
There's all this talk of making America great again as a leader in business and scientific innovation, but it just isn't going to happen until we get over this fear of death and killing thing going on right now. You can't make a damn omelette without breaking a few eggs. Likewise you can't make meaningful progress without killing a few people in experimental ways. Case in point, how many test pilots died as we tried to figure out how to get into space? How many people died from the effects of radiation exposure and gave us a better understanding of nuclear technology from it? How many people died in the construction of the various skyscrapers that dot the oldest American cities? True progress can't happen without the deaths to learn from.
Precisely. Engineering has been handling stuff that puny meat-sacks find terrifying since forever. Have you any idea how unutterably mindbogglingly insane the inside of the jet engine that takes you on holiday is? School perhaps should be teaching the science of exotic man-made technology rather than avoiding goto loops
I've found that the level of ignorance of engineering technology is completely astounding. Even the basic premise of this story is silly. Who knew that we have worked with supercritical steam for years, and it's not a BFD?
The benefits are many, and use of supercritical steam has it all over saturated steam. While everyone is aghast over the temperatures, I'm pretty certain that all of the equipment will actually last longer in addidion to generating more power. Only in modern America is technology so evil that a story of an obvious engineering step is somehow going to doom the earth.
But I guess that's what happens when we get our science education from Kim Kardashian and Politicians.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
Have they done anything to address the issue of the earthquakes this can produce? Earthquakes (especially large numbers of microearthquakes) are why geothermal energy is off the table because it damages all of your buildings and infrastructure. To make things worse, the effects of lots of earthquakes on wildlife isn't well understood.
It's Iceland, They have volcanoes and lava and new islands forming, and earthquakes all the time anyway. You could shoot every evil hoomin, appoint some pond algae prime minister, and they'd still have all of the above.
Perhaps a lawsuit against the Mid-Atlantic Ridge is in order.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
Wind power is a good example. How much energy can we take out of the air with windmills before we start seeing an effect on the weather? Is it really completely free?
The short answer is yes. Trees also slow down wind and we are short on those, literally — old growth is taller. We can see a minor localized heating effect downwind of a turbine (due to turbulence and a reduction in wind speeds) which is rapidly lost in the chaotic noise.
Massive geothermal is another example. How much energy is down there and are we going to screw things up by depleting it?
So far the only problems we're actually seeing (or even imagining) with geothermal are increased seismicity and pollution. Radioactives come out of those vents with the water. These are both real problems, though. It would be interesting to do the math and figure out how much of humanity's energy needs would have to come from geothermal before the delta would be significant. Well, it would be interesting for someone else to do it, since they might do it correctly, and then report back.
I wonder if 100 years from now if we find out that some of our free and green energy sources are not as free and green as we originally thought.
We already know geothermal to fall into that category, but we have no reason to suspect it of wind. Solar, of course, can involve toxic manufacturing processes, but barring those it's not going to cause any substantial problems until it dramatically changes albedo. Mostly they don't change it much because of where they are located, and anyway a solar panel with a white back (as most of them have) is going to reradiate most of the unused energy back into space (or at least the atmosphere) through the usual mechanism.
There's no good reason to believe that wind or solar have a negative environmental impact. There is exceptionally good reason to be concerned about the implementation details when it comes to geothermal.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Because on human time scales, the resource renews itself. Suck heat out the ground with a geothermal plant, and the ground will heat up again from deeper sources. Collect solar and wind energy, and there will be more tomorrow. This is unlike coal or oil, where the resource does not renew itself on human time scales.
Strictly speaking, all energy sources are finite. The Sun's fuel will eventually run out, and the Earth's interior heat will run out. But that will take billions of years, and energy projects are measured in decades to centuries.
> How much energy can we take out of the air with windmills before we start seeing an effect on the weather?
As much as three trillion trees do. Trees are pretty effective at slowing wind, which is why areas like the Southeast aren't so good for wind power. We have lots of trees, the midwest not so much. It's also why offshore wind is generally better than land, in terms of available power - no trees.
In real world units around 375 degC and 220 Bar.
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This is not correct. Combustion temperatures can reach these temperatures, but boiler water circulates by convection fast enough that the heat is conducted away before the boiler tubes reach those temperatures. The superheater tube bundles must be carefully designed since they are cooled only by steam (less heat carrying capacity than water) and are often exposed directly to the radiant heat. Typical properties for high temperature steam for coal or natural gas plants is 1000F-1050F (538-566C) at 2400psi (measured at the turbine inlet). Plants do exist at up to 1100F steam with some designs using up to 4200psi steam, but these designs are less common due to extra costs of using thicker pipes and pressure vessels, requirement for superalloys and more frequent maintenance.
Even those who arrange and design shrubberies are under considerable economic stress at this period in history.
If my calculations are correct, 5km down is right around where the balrogs live...
And if the Earth were a ball of compressed gasses held together by an airtight skin, that would be a valid worry.
Fortunately the Earth is actually a ball of liquid and semi-liquid rock held together by its own gravity, with an incredibly thin and broken crust floating on the outer surface. Absolute worst case scenario, a borehole is creating a pinprick hole through one of the floating pieces of broken crust that, if conditions are just right, may end up spewing magma on the surface - i.e. creating a new volcano. Could be a really bad day for anyone directly downstream, but it isn't going to threaten the planet.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
Also the sun's, though if I recall correctly it's only about half as strong.
More to the point though, even an extraordinarily deep 6km borehole, you'd only be reaching 1/1000th of the way to the Earth's center. We're not appreciably cooling the liquid core, or even the outer semi-liquid mantle, we're just cooling some of the hot spots in the solid crust floating on the surface.
In the extreme long term, or if human energy consumption increased radically, that might indeed be a problem. As it is though, the Earth's core is already cooling at about 100*C per billion years. We could double that and the magnetosphere would still be going strong by the time our slowly heating sun boils off the oceans.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
It would be crazy to use the geothermal steam directly and not use a secondary boiler.
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