Ars Technica brings us a tale of renewable energy - Geothermal energy has success in Nevada, wants to spread to the rest of the west.
Geothermal energy advocates are quick to point out that when the Sun isn't shining and the wind isn't blowing, geothermal facilities can be brought online "in under an hour" as one worker explained to me. Coal-fired plants, on the other hand, have long and costly ramp-up times. Doug Hollett, a program director for the US Department of Energy (DOE) Geothermal Technologies Office, told a round table on Tuesday that the ramp-up issue can be seen in California. The state has been a leader in renewable energy, but it will have to deal with intermittency if it wants to incorporate more renewables into the grid.
In addition to Geothermal; this plant also uses Solar-Thermal to help heat the water into the range where they can get the most power from the generators.
- as Renewable energy goes, Geothermal is the one you can depend on for a base load; why is it that we don't see more of this?
(Score: 5, Interesting) by VLM on Tuesday August 12 2014, @01:11PM
"it’s made up of seven smaller plants that collectively generate 78 megawatts of power. A typical coal-fired power plant can generate around 660 megawatts of power, so Ormat’s 78 megawatts are not a lot by comparison."
Typical journalist filter in that 660 MW sounds "more correct" than the actually more factually correct "around half a GW or so"
Aside from that LOL its problem is the labor and capital cost is darn near the same as a coal plant although obviously the fuel cost is zero, so only generating about a 50th what a coal plant can generate is a slight financial problem.
Its like selecting a solar power site, building facilities for employees and equipment, running high voltage lines to connect it to the grid, adding all the SCADA for grid control, and then plonking down a solar calculator to actually generate power. Yes, yes, its a net gain of solar energy. But thats not enough to make it economically viable, or even worse, on a total lifetime system cost, it would probably make more financial / economic sense just to skip the geo-plant or my example solar-plant and just buy more coal for existing coal burners.
There are non cost related issues as the article discusses, like its very stable and reliable and is very dynamic and I'm guessing its about three orders of magnitude easier and cheaper to blackstart than a nuke and at least one order of magnitude easier to blackstart than a coal plant. Blackstarting this baby might be as trivial as manually opening a small intake valve and let nature take its course.
Something to think about is what if every nuke had a very small onsite geothermal plant, just enough to barely keep the scada and cooling system ticking over. Probably a good idea. Even if its not economically or geologically sensible to try to build a geothermal plant onsite, its probably an excellent safety idea.
Another peculiar idea would be a building code that requires all skyscrapers to be net electrically zero on long term average via cogeneration, a thermal plant in the basement and a solar plant on the roof might work out OK.
(Score: 2) by isostatic on Tuesday August 12 2014, @02:27PM
I thought that modern nuclear plants (i.e. ones built in the last 20 years) were of a design where they are unable to run without power, rather than liable to explode without power?
(Score: 3, Interesting) by VLM on Tuesday August 12 2014, @02:39PM
A complicated question.
You can always technically run a completely isolated reactor. Think of a submarine. For a land based plant that violates about one bazzilion lawyerly NRC regulations, like you will always have X number of standby power sources to keep the control systems and coolant pumps running at all times or you get a violation or whatever. So you've got multiple diesel generators on site (which need fuel...) but why not a geothermal, or a geothermal in addition. Seems like a wise decision in case something happens to the diesels. Considering nothing in the geothermal plant need be exposed to air other than the condensers, you could really harden a geothermal plant. Would have come in handy in Japan after that tidal wave destroyed the generators and their wiring.
You can always "blow something up" colloquially by a something carrying pressurized steam cracking or whatever. Just like I can "blow up" a soda can by dropping it off the roof. But for a variety of physics reasons plants can't blow up like an a-bomb.
(Score: 2) by bob_super on Tuesday August 12 2014, @10:23PM
The problem being that one of the most significant "somethings" which can happen to a properly protected nuke plant is excessive ground acceleration. That typically isn't highly friendly to Geothermal.
With regards to completely isolated generators, the submarine is not a great example, because it's surrounded by emergency coolant.
(Score: 4, Informative) by aclarke on Tuesday August 12 2014, @01:24PM
Here in Ontario (Canada) where I live, geothermal installations are very common. They're not used for producing electricity, but for heating (and cooling) houses. Our house has a geothermal system installed. It uses a pond beside the house as the heat sink, and will heat the house in the winter and cool it in the summer.
I hadn't really given much thought to why we aren't using geothermal around here to produce electricity, given the push the Ontario government has authorized towards alternative energy. We also have a 10kW solar installation where the power is sold back into the grid. Apparently geothermal installations don't qualify [powerauthority.on.ca] for that program though. According to the linked source, "[e]xperience with geothermal projects for electricity production is limited in the province."
(Score: 3, Interesting) by paulej72 on Tuesday August 12 2014, @01:35PM
Unless you are doing geothermal near active volcanic sources (Iceland) you do not get high enough delta T to be able to generate electricity on a large scale. This system seems to be built just to make the tree huggers happy. I really do not see it being a viable alternative. Also with a 1 hour startup time, it still is not fast enough to make up for loss of wind or solar. You need to make that up within seconds. This just puts more a variable load on the base load coal plants and requires more frequent switching of temp load gas turbine plants.
Team Leader for SN Development
(Score: 1, Informative) by Anonymous Coward on Tuesday August 12 2014, @01:40PM
"peaker plants" (used during peak demand times) are generally hydro/pumped-storage or gas turbine (there are plants that even use ex-aircraft engines for reduced ramp up times due to their lightweight design)
(Score: 5, Informative) by VLM on Tuesday August 12 2014, @02:56PM
There's black start time, and there's spinning reserve. Given the cost of fuel and the legendary inefficiency of idling turbine engines I don't think you'd keep a natgas peak plant in spinning reserve. Yet given the cost of fuel of a geothermal plant (zero) there seems little point in not keeping it in permanent instant available spinning reserve.
I guess the best SN car analogy is there's two time intervals when driving away in a car. First you have to boot the thing up to idle. At which point it uses fuel continuously (and slowly wears out). Next you have the time it takes to floor the engine to actually move. Nukes take forever to do both. Coal also takes forever to start and get to idle, then they're not that pitiful once you floor it but its still tens of seconds maybe a minute till full blast. Natgas is like 10 seconds from motionless to full blast but the fuel is expensive and capital cost is expensive and maintenance is expensive. Geothermal takes about an hour to power up and run at idle, but flooring it from idle to full power is very likely as fast as a natgas plant. How fast can you spin up a circulation pump from idle to full blast... probably seconds to at most a minute?
Given that the fuel is free, you could just heat up a 10 MW resistor bank when you don't need power, and then flick a geothermal online in a couple milliseconds. Given a smart enough power control system you could keep it in synch with the grid 24x7 and deliver power during only portions of individual waves if the peak is sagging due to brownouts or whatever. You'd need something smart enough to understand the power factor and how it changes locally when you slam the plant on and off line (current and voltage waveforms are not necessarily zero phase offset although ideally they are). Probably it would be a whole hell of a lot simpler to dump a constant 10 MW into the grid all day long, and play with a local resistor bank to eat whats not needed. That can be slammed on and off the grid very quickly and easily indeed. So if the grid as a whole needs 5 MW like right now, you have 5 of 10 one MW loads slam off at the next current wave zero crossing.
You could do something useful with your excess waste energy rather than just making heat. Warm greenhouses for higher aggregate productivity. Distill ethanol. Power grow lights in a greenhouse. Domestic hot water heater. Things like that. In the biz this is called a sheddable load. Much better price, but reliability is very low compared to "real" power.
(Score: 2, Flamebait) by Hairyfeet on Tuesday August 12 2014, @04:12PM
Question...why not simply store any unneeded energy in flywheel storage [wikipedia.org] instead of wasting it? And wouldn't this solve the "coming up to speed" problem as well, since you could use the flywheel energy to provide power until the system was at peak and then just recharge the flywheels? Of course since we are talking geothermal another possibility would be using molten salt storage [wikipedia.org] which from the looks of Wikipedia can reach 99% efficiency.
The bitch is we could probably toss the coal plants if we were to build some new reactors with a smaller reprocessing reactor built beside it to deal with waste and backed those up with green tech like molten salt solar, wind, and geothermal but between the NIMBYs screaming, the dumbasses screaming "zomfg Chernobyl!" when you say anything about reactors (not to mention old stupid rules preventing reprocessing), and general bribery from the coal industry means that just getting the shit done would be more difficult than building a fricking space elevator.
ACs are never seen so don't bother. Always ready to show SJWs for the racists they are.
(Score: 5, Informative) by evilviper on Tuesday August 12 2014, @04:29PM
Flywheels are gigantic capacitors, with very high self-discharge rates. They do NOT store energy for any length of time. The WP article you cited, specifically says "15 mins".
Flywheel developers keep promising the long-term storage versions, but they've never gotten those magnetic bearings to work, so it's a non-starter anywhere you have gravity and an atmosphere.
Hydrogen cyanide is a delicious and necessary part of the human diet.
(Score: 2) by Hairyfeet on Tuesday August 12 2014, @06:20PM
Uhhh...that is why I also included molten salt storage which IS long term, but since any info on both I could find is seriously short on hard data I can't tell you how short is short or long is long, for all i know you could store energy in the flywheel for weeks and then transfer it to the salt for longer lengths. I figured (unless there is something I am missing) you could use the flywheel for the short term (again defining length is difficult, can't find any hard numbers) ramp up problem (since again zero cost of fuel) while storing excess long term in the molten salt. the previous poster was talking about the ramp up problem and since the flywheels can be kept at high RPM for a decent amount of time? (and one could always have more than one) this would allow covering both long AND short term.
The reason i posted the molten salt as an addendum is that I don't know enough about it to know how well it would work for the ramp up problem, I know its designed to store the energy as heat but i don't know how quickly one could convert heat to power, if it would be faster or slower than ramping up the geothermal. thinking about it further IF one can turn the heat into energy quickly this would solve both the long AND short term problem, but again don't know enough about the speed of molten salt for power creation but I DO know that you can turn rotational energy into power pretty damned easily hence why I suggested flywheel for the front line storage, although i have no idea exactly HOW short flywheel storage would be so maybe you can answer that...days? Weeks? I tried looking up more info on both but with all green tech the promoters seem to have "speaking without saying shit" down to an artform.
So sorry if I should have just went with salt but with all the green tech they have "pretty sounding bullshit" in Oscar grade by the tonnage. In any case since we are talking about free power here even with transfer losses a combination of flywheel and salt (or just salt if you can convert fast enough) should alow them to have all the advantages of a fast fire NG plant without the high cost of fuel.
ACs are never seen so don't bother. Always ready to show SJWs for the racists they are.
(Score: 3, Insightful) by evilviper on Tuesday August 12 2014, @09:16PM
Flywheels only do a few minutes. Friction causes quick and substantial energy loss. It's an ultra-short-term battery, but it's lousy for energy storage.
The best molten salt power storage only holds its temperature for about a week. That's better than flywheels, but still not long-term.
You'd know this if you just read the WP articles on both, including the one you linked-to.
Hydrogen cyanide is a delicious and necessary part of the human diet.
(Score: 2) by evilviper on Tuesday August 12 2014, @02:54PM
That's a bit like saying hydro is very common in Canada, because lots of people have electric water pumps...
The two types of "geothermal" are drastically and almost completely different.
Hydrogen cyanide is a delicious and necessary part of the human diet.
(Score: 2, Informative) by aclarke on Tuesday August 12 2014, @03:51PM
Yes I am completely aware of the difference. It's a valid point to say that geothermal energy is regularly harnessed, although not to produce electricity. If we had lava flowing under the ground here maybe we'd use it to create electricity, but in most cases here, using it with a heat pump for heating and cooling makes more sense.
(Score: 2, Informative) by evilviper on Tuesday August 12 2014, @09:33PM
No. Actually, you aren't harnessing geothermal energy at all, except in the loosest sense of the term... You're just using the earth as a large thermal-mass heat-sink by another name. Ground-source heat-pumps don't go down far enough to tap into the heat generated by the decay of radioactive elements in the earth.
Hydrogen cyanide is a delicious and necessary part of the human diet.
(Score: 1) by aclarke on Wednesday August 13 2014, @11:02AM
OK, I'll give you that. Very little of the energy extracted by most heat pumps around here is actually "geothermal", despite the use of the name.
(Score: 1) by evilviper on Thursday August 14 2014, @04:35AM
...which is actually a good-thing, because ground-source heat-pumps are very efficient for *cooling* as well. If you were tapping into a lava tube, it would be heating-only.
Hydrogen cyanide is a delicious and necessary part of the human diet.
(Score: 0) by Anonymous Coward on Tuesday August 12 2014, @07:21PM
That is not geothermal. Those are ground-source heat pumps. There's an enormous difference.
The ground-source heat pump industry has used the term "geothermal" because it's trendy, ignoring the fact that it is _wrong_.
Ground source heat pumps are not a source of energy, they are an energy sink. Geothermal is a source of energy. Ontario is not Iceland.
(Score: 2, Informative) by Anonymous Coward on Tuesday August 12 2014, @01:28PM
Hellisheidi Power Station (largest geothermal): 303 MW
Taichung Power Plant (largest coal): 5,500 MW
With a ready supply of fuel, a coal power power plant might not look so bad compared to a geothermal plant of equivalent output.
Long ramp up times are possibly more related to the size of the steam turbine than the source of the heat to create the steam. Coal furnaces do take time to start creating enough heat to pressurize boiler tubes, but geothermal heat would take a while too. Big turbines must be heated in a controlled manner to allow for metal expansion and graduate thermal loads. Prevention of creep failure is critical to their longevity.
"The high pressure used in steam turbines is the reason for a thick casing. Steam turbines experience large thermal inertia. Turbines must be warmed up and cooled down to minimize differential expansion between the rotating blades and stationary parts. Large turbines can take over ten hours to heat up while smaller units have rapid start up times." - http://cset.mnsu.edu/engagethermo/components_steamturbine.html [mnsu.edu]
(Score: 5, Informative) by evilviper on Tuesday August 12 2014, @02:51PM
Large hydro is the one you can depend on for base load, and it takes SECONDS to bring massive amounts of capacity online, not an hour. It also doubles as efficient grid-scale energy storage once a pump is installed.
In 2012, California's electrical generation consisted of:
Large Hydro 23,202GWH 11.7%
Geothermal 12,733GWH 6.4%
That's a significant amount, and a hell of a lot more than the 78 megawatts TFA talks about. How much "more" are they supposed to have? What is the proper amount?
The reasons why are stupidly obvious... Geothermal isn't free. There are limited sites available, and it's expensive to develop, so other power sources remain cheaper and more convenient.
So what? California barely uses any coal, instead depending on natural gas, which has much, much faster ramp-up times.
Coal 1,580GWH 0.8%
NatGas 121,716GWH 61.1%
Not at all. There have been hybrid plants with various power sources for a long time. Solar-thermal is most-often combined with natural gas, giving the turbine something to do over-night when it would be idling. But combining the high up-front prices and siting requirements of geothermal with the high up-front costs and siting requirements of solar, sounds like it'll most often be a loser all-around.
Hydrogen cyanide is a delicious and necessary part of the human diet.
(Score: 0) by Anonymous Coward on Tuesday August 12 2014, @03:30PM
Not an engineer here, but geothermals biggest technical hurdle is probably the corrosiveness of the source.
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on the economic side, geothermal faces the same hurdles as wind, solar, tidal.
because these are "free" (as in sunshine not "free" as in prison) some thinkers consider these energy sources as not productive. it means that money cannot be made, because it has no cost, because it is free and UNLIMITED!
only by inserting artificial hurdles in form of paper (legislation and laws) can the "tide of lose" be stemmed.
also many of the non-free source players probably went to the bank and said: "give me a billion dollars. my collateral is rising oil, gas and coal costs and my powerplant. and anyways your banks busy-ness depends on me anways".
they probably never intended to pay back the billion anyways, but now that free sources are popping up, their calculation on monthly payment on a billion dollar loan is probably starting to look bad.
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and off-topic (sort off) i would just like to point out the brain-washing/propaganda pitting solar and wind against base-load (gas, coal, nuke, hydro, gas aaaaannnd geothermal) plants.
get this through your head: the sun doesn't shine at night! period. stop wasting your time arguing about this.
however it is a fact that if you have a PV solar generator at your house and the sun shines, you will use LESS from the "in-debt" base-load powerplants! this is the REAL BENEFIT of solar!
for the too brain-washed: you can buy a new fridge that uses 200 Watt less then the old one -or- keep the old one and install 200 Watt of PV. both are the same!
have a sunny day!
(Score: 0) by Anonymous Coward on Tuesday August 12 2014, @03:49PM
oh forgot to mention: when solar power output is peaking (or good) then from the point-of-view of base load powerplant it looks like everybody has just turned of all their devices.
so assume there is no solar connected to the grid but everybody turns off all their devices
-or-
everybody has solar (and using their devices like normal) and the sun is shining.
for the baseload powerplant both situation look the same!
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so if a cloud passes thru, solar output falls (hopefully all the panels aren't concentrated in one spot *greedy farmers*) and this looks to the baseload powerplant like people all plug-in their mobile chargers at the same time, or turned on their washing machine at the same time or started drying their hair ...
(Score: 0) by Anonymous Coward on Tuesday August 12 2014, @07:58PM
whatever is used to create a electricity flow can be put into two groups:
1) unlimited
2) finite
as it stands, we are very dependent on electricity for the producing economy.
furthermore we are still firmly rooted in the "finite source" group.
thus if we liken "cost of some project" to "friction", then we could define 3 layers:
1) aquatic
2) gaseous
3) vacuum
using 100% finite sources puts us firmly in the aquatic layer. lots of friction
100% unlimited sources would thus be in the gaseous layer.
now since we are trying to create/manufacture/develop the unlimited source in a aquatic environment it seems to look costly, thus we have much friction.
once a certain amount of gaseous projects have reached fruition we leave the aquatic zone and move to the gaseous zone where there is less friction -aka- cost.
in the long run we NEED to harness the unlimited sources, no matter the "cost". if we cannot reach the gaseous layer before we run out of limited sources, that is we stay submerged too long in the aquatic layer, we could reach a point were we don't have the means anymore to leave and just sink dead to the bottom.
to put it in simple terms: if the price of oil and gas and coal goes up (friction of the aquatic layer) so does the cost to acquire (for example) devices to produce electricity from the great ball of fusion in the sky (devices of the gaseous layer).
people that manufacture these solar-eating devices need to travel to and from work, the raw materials need to be dug out (or recycled), they need food to eat,etc.etc. all this is part of the friction of being in the aquatic layer to produce a device for the gaseous layer.
once a certain amount of gaseous devices have been created then we lose a lot of friction and further gaseous devices will become much cheaper. remember cost = friction.
as for vacuum devices ... we will see : ) and so the cost is relative!
(Score: 2) by khallow on Wednesday August 13 2014, @12:19AM
I recall a recent argument where I was arguing with someone over why we obsess over baseload. It's not because baseload is particularly important - he had that part right, but because historically, baseload was the cheapest power available. If you're an electricity generator with numerous power plants at your disposal, you don't run the most expensive power first. Further, you can sometimes, as in the case of historically cheap coal power, optimize the plant so that it is always running at optimal efficiency making the power even cheaper (there's modest synergy between the cost of power and infrastructure, and the baseload role for some power sources).
Now, if wind or solar power becomes vastly cheaper, then these electricity providers will orient their power generation strategy around wind or solar, not around baseload. They won't be asking "How can we incorporate an expensive power generation source into our network so we can have baseload". Instead, they'll be asking "What do we need to do to address the flaws of our cheap power?" They'll go for power smoothing, electricity transmission, and energy storage long before they'll add an expensive baseload option. My view is that a load-following coal plant or some more peaking load natural gas plants may even be greener than the geothermal option for most regions since such infrastructure would allow for more intermittent cheap, relatively green power sources to be deployed. Depends on the tradeoffs of the situation, I suppose.