This is a thread dedicated to posting news of "innovative" technologies and energy "solutions" that violate the laws of physics.
Here we will post links to articles that report on proposed projects that violate basic physical laws and mock the proposers and the public who take them seriously.
This project is actually being debated in Utah and seriously considered by Utah's governor. He rejected it "based on environmental concerns". Forget the environmental concerns -- its a perpetual motion machine. It will without any question consume more energy than it generates.
Posted by Artemisia Tridentata (Member # 8746) on :
You didn't read the whole thing. It would use power during off-peak times to pump the water up hill. Then it would run the water through the turbines during peak power usage hours to generate the additional power. Denver has a similar system that has been working well for at least a decade. I think it is called Wolf Creek dam. I was there two years ago looking at the system. That being said; it is still a stupid idea at Bear Lake for all the reasons the 400 vocal environmental obstructionists gave.
Posted by rivka (Member # 4859) on :
quote:Originally posted by Artemisia Tridentata: It would use power during off-peak times to pump the water up hill. Then it would run the water through the turbines during peak power usage hours to generate the additional power.
Potentially saving money, but definitely not with any net gain of energy.
Posted by The Rabbit (Member # 671) on :
Yes, I read the whole thing but the company has never reported this as an "energy storage" project. In fact, they call it renewable energy
quote: Symbiotics LLC, in arguing for the project, pointed to hydroelectricity's renewable energy potential and claimed the project could meet about 85 percent of Utah's current peak energy demands if used in concert with conservation efforts.
This is just energy storage. It can't meet any demand. All it can do is take electricity produced at one point in time and "save" part of it for use at a different point in time. Its not hydropower and its not renewable unless they are using a renewable source to pump the water into the damn.
Since I've talk classes in the stuff to none science majors, I KNOW that a good fraction of the public, in reading articles like this will not grasp the fact that this only energy storage and not energy production.
Posted by Artemisia Tridentata (Member # 8746) on :
OK, so I am getting old. It is Cabin Creek Dam. I don't know where the wolf came from. It is up the canyon from Georgetown on a very pretty alpine loop drive.
Posted by The Rabbit (Member # 671) on :
Here is another classic that pops up in news reports regularly.
I can't believe they are actually claiming he converts H2O to HHO which can then be burned as a fuel. They also gloss very quickly over the part that electricity is required to make this fuel from the water. A simple analysis of the first law will say if you start with water and end with water, you can't produce net energy.
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by Artemisia Tridentata: OK, so I am getting old. It is Cabin Creek Dam. I don't know where the wolf came from. It is up the canyon from Georgetown on a very pretty alpine loop drive.
I have no problems with the idea of pumping water uphill as a means to store energy. My problem is with the portrayal of this as "renewable energy" and the idea that this could meet "85% of Utah's peak energy needs". No it can't. It can't meet any energy needs.
Posted by Dan_raven (Member # 3383) on :
I had a highschool science teacher who went through an automotive parts catalog, and wrote down all the gas savings promised by the various devices.
His figures showed that if you got all the devices, and connected them up, and if they all worked as efficiently as advertised, then you would have to stop the car every 5 miles to empty out the extra gas before it overfilled the fuel tank.
Posted by Dagonee (Member # 5818) on :
quote:My problem is with the portrayal of this as "renewable energy" and the idea that this could meet "85% of Utah's peak energy needs". No it can't. It can't meet any energy needs.
I agree with you about the portrayal as renewable energy. I disagree that it can't meet peak energy needs. There are two ways to meet peak energy needs - one is to have facilities to produce more energy at peak demand, and one is to store energy produced at non-peak demand for use at peak demand. Since this can store energy, it could (I don't know if it will) meet peak energy needs.
I do agree that once the company adds the renewable energy claim, their claims as a whole do become misleading.
Posted by scifibum (Member # 7625) on :
My favorite crackpots. They had a big scandal a decade or so back when they promised revolutionary wireless communication tech and never delivered. Now they are promising ultra cheap solar electricity (and have been for at least 3 years) and...still waiting.
They claim that a lens they make (or buy from a lens company, I think) is a "solar panel" and compare it to actual solar electricity panels. In actuality their product can merely focus sunlight to generate heat. A revolutionary product! They also have a heat driven turbine. Whoa!
Posted by The Rabbit (Member # 671) on :
quote:I disagree that it can't meet peak energy needs. There are two ways to meet peak energy needs - one is to have facilities to produce more energy at peak demand, and one is to store energy produced at non-peak demand for use at peak demand. Since this can store energy, it could (I don't know if it will) meet peak energy needs.
I know I'm being overly technical, but storage isn't a way to meet a demand. Their claim is like saying you could meet 85% of your food needs by saving leftovers. You can "reduce" the need to buy food by using leftovers effectively, you can't meet your food needs that way. Its like saying you could provide 85% of the fuel for your car by regenerative breaking. No, you can reduce your demand for fuel by regenerating breaking, it can't be used to meet the demand. The way this is worded it sounds like if we could simply reduce our peak demand by 15% through conservation, this project could meet all our demands.
Perhaps that's an overly technical way of looking at this considering this was a newspaper. If the company had said, "By using energy normally wasted during off peak periods, this project could meet 85% of the increased demand during peak periods, I'd find it acceptable. As it is, its highly misleading.
Also from a quantitative prospective, the 85% number is absurd. As an engineer, I normally would interpret "85% of peak demand" to mean that they could routinely provide 85% of the total energy required at peak periods. If for example it is reported that a coal fired power plant can provide for 85% of peak demand and peak demand was 1 GigaWatt, that would normally mean that the plant could provide a constant supply of 0.85 GigaWatts. I suspect what they actually mean is 85% of the increase in demand during peak periods. You may think I'm splitting hairs but % is a meaningless term without know what's in the denominator.
Posted by mr_porteiro_head (Member # 4644) on :
Storing non-peak power to be used later as peak power is an excellent idea. I have great hopes that we can find some way of doing that which makes sense, instead of just building more and bigger power plants.
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by mr_porteiro_head: Storing non-peak power to be used later as peak power is an excellent idea. I have great hopes that we can find some way of doing that which makes sense, instead of just building more and bigger power plants.
I agree absolutely, but its not a new source of energy. Its just more efficient usage of our current sources.
[ April 23, 2008, 02:07 PM: Message edited by: The Rabbit ]
Posted by Alcon (Member # 6645) on :
quote:I had a highschool science teacher who went through an automotive parts catalog, and wrote down all the gas savings promised by the various devices.
His figures showed that if you got all the devices, and connected them up, and if they all worked as efficiently as advertised, then you would have to stop the car every 5 miles to empty out the extra gas before it overfilled the fuel tank.
How did he do the math? Were they promising savings of percentages? And if they were, did he just add the percentages together?
Posted by Dagonee (Member # 5818) on :
quote:I know I'm being overly technical, but storage isn't a way to meet a demand. Their claim is like saying you could meet 85% of your food needs by saving leftovers.
But if you are having company next weekend, storing your leftovers from this week can help meet the extra demand next weekend.
quote:The way this is worded it sounds like if we could simply reduce our peak demand by 15% through conservation, this project could meet all our demands.
I agree, but only because of the "renewable energy" claim made in conjunction with it.
quote:I suspect what they actually mean is 85% of the increase in demand during peak periods.
That's what I think they mean as well.
quote: You may think I'm splitting hairs but % is a meaningless term without know what's in the denominator.
I agree with you on this one for sure.
Posted by mr_porteiro_head (Member # 4644) on :
quote:Originally posted by The Rabbit:
quote:Originally posted by mr_porteiro_head: Storing non-peak power to be used later as peak power is an excellent idea. I have great hopes that we can find some way of doing that which makes sense, instead of just building more and bigger power plants.
I agree absolutely, but its not a new source of energy. Its just more efficient usage of our current sources.
So? Using our current sources more efficiently is an excellent idea.
Posted by The Rabbit (Member # 671) on :
quote:So? Using our current sources more efficiently is an excellent idea.
And I agreed with that. That was never my objection to this article.
My problem is with presenting a technology that can improve the energy efficiency as though it is an energy source. And there is a big big difference.
Wind Turbines, for example, can be considered a legitimate energy source because you can get a lot more usable energy out of a wind turbine than it takes to build one. So it is conceivable that we could meet all our energy needs, including building the wind turbines, with energy produced by wind turbines.
In contrast, hydrogen fuel can't ever be considered an energy source because it takes more energy to make it than you could ever recover by by oxidizing it. Similarly, this reservoir could never be a source of energy because it will take more energy to pump water into the reservoir than they could ever get out of the reservoir
I suppose that I should have acknowledge in starting this thread that there are two ways people in the news "violate the laws of physics" . The most common way is by making misleading statements about a workable technology. Less common, but still too common are proposals for technologies that could never work.
Posted by mr_porteiro_head (Member # 4644) on :
Ah. I see. I thought you were replying to what I said.
Posted by Shigosei (Member # 3831) on :
Perhaps it would be better if we started to refer to things like this as "batteries." Hydrogen, for example, is more a battery than an energy source.
Posted by mr_porteiro_head (Member # 4644) on :
Until Joe flies up to the sun and scoops up a lot of hydrogen and brings it back here for us.
I just need to tweak the wings a little bit...
Posted by Kwea (Member # 2199) on :
...his wax runith over.
Posted by Dan_raven (Member # 3383) on :
quote: I had a highschool science teacher who went through an automotive parts catalog, and wrote down all the gas savings promised by the various devices.
His figures showed that if you got all the devices, and connected them up, and if they all worked as efficiently as advertised, then you would have to stop the car every 5 miles to empty out the extra gas before it overfilled the fuel tank.
How did he do the math? Were they promising savings of percentages? And if they were, did he just add the percentages together?
First, this was many many years ago, so my memory isn't perfect.
Second, it was a combination of % Savings and phrases like, "Add 10 Miles to the gallon" and "Like adding 3 gallons to every tank of gas."
Posted by ricree101 (Member # 7749) on :
I do agree with Rabbit that this is a really terrible article:
quote:The Article But others argued the project actually would have resulted in a net loss of electricity because it would take more energy to pump the water to the storage reservoir than the falling water could produce.
They say that as though this is something up for debate, or that there is a legitimate difference of opinion here, and completely miss the fact that this cannot be an energy source.
That said, I do think the idea of pumping water as a means of storage is interesting, especially in the context of longer term storage to average out fluctuations in renewable sources such as solar power.
Posted by Alcon (Member # 6645) on :
quote:First, this was many many years ago, so my memory isn't perfect.
Fair enough, I won't nit pick. Posted by King of Men (Member # 6684) on :
I seem to recall I posted a thread on precisely this subject a while ago, suggesting it as a money-saving measure for individual households.
Posted by Icarus (Member # 3162) on :
*blink*
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by King of Men: I seem to recall I posted a thread on precisely this subject a while ago, suggesting it as a money-saving measure for individual households.
And I would have found that a potentially good suggestion, so long as you didn't claim it was a renewable energy source and you didn't discuss conservation of energy as though it was a controversial idea.
Posted by mr_porteiro_head (Member # 4644) on :
I think that it's a potentially good idea, even if you do claim that it will cause Santa Clause to visit your house every single night.
Overblown claims don't invalidate a good idea.
Posted by Tatiana (Member # 6776) on :
It is a good idea, and it's not creating energy from nothing. But if you think about it, the power company has to build enough power plants to provide the PEAK energy levels, even though most times of the day and night, and most seasons of the year, the peak isn't demanded. The power company generates, moment by moment, exactly the electricity demanded by the customers at that moment. So of course, as Rabbit obviously knows, it makes very good sense and efficient use of the capital invested in power plants to generate extra power at non-peak times that can be stored in the form of the potential energy of water. It's about the most efficient storage method we have. Certainly far better than batteries, and with less environmental impact.
It's just not creating extra energy from nothing. You still use the fuel and such that it takes to generate it. However, the extra capacity that the power plant can't put to good use during off-peak times is an inefficiency that this storage method helps to lower.
What I really wish is that I could think of a good way to use the 60% or so of the energy released by my plants as waste heat. Surely there are many fortunes to be made there. Right now it's acting as a very awesome bird elevator. A worthy cause, no doubt. But it seems to me as though it could be put to some better use.
Posted by King of Men (Member # 6684) on :
Some places in Norway use it to heat housing. Not a very scalable method, though.
Posted by The Rabbit (Member # 671) on :
quote:What I really wish is that I could think of a good way to use the 60% or so of the energy released by my plants as waste heat. Surely there are many fortunes to be made there. Right now it's acting as a very awesome bird elevator. A worthy cause, no doubt. But it seems to me as though it could be put to some better use.
The second law of thermodynamics sucks!!
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by King of Men: Some places in Norway use it to heat housing. Not a very scalable method, though.
Its also not terribly practical in Alabama where a good fraction of the electricity is used for air conditioning in the summer months.
Posted by King of Men (Member # 6684) on :
Yes, true. Air conditioning is rarely an issue in Norway. Posted by Mucus (Member # 9735) on :
quote:Originally posted by Tatiana: ... But if you think about it, the power company has to build enough power plants to provide the PEAK energy levels, even though most times of the day and night, and most seasons of the year, the peak isn't demanded.
I may point out that in many jurisdictions, you can't really just measure from the peak. For example in Ontario, the power plants in use include a large portion of nuclear, hydroelectric, and thermo (coal, natural gas). The standard operating procedure is that the nuclear power plants go 24 hours and the hydroelectric is used as needed first and the thermo is used as needed second.
Of course, you probably shouldn't use this method to store electricity from thermo, not only would you lose a lot in the energy conversion loss, but it would somewhat kill the environmental advantage. Hydroelectric usually already can store power in this fashion on its own via the reservoirs, for example at Niagara Falls the flow is greatly reduced at night in order to store up the water. So all these dedicated reservoirs could store at off-peak times would be any surplus energy from nuclear.
Working through the numbers in Ontario (36.6% nuclear, 25% hydro, 37% thermo) you'd only be able to conserve roughly (36.6% - off-peak use) which is probably pretty minor after the energy loss entailed in pumping water.
IIRC, it would even be less for the United States since the United States uses something like 50% coal, 20% nuclear, natural gas 20%, and 7% hydro. So something like (20% - off-peak use).
Still potentially useful granted, but far from saving right from the peak.
Posted by Kwea (Member # 2199) on :
Except for the fact that coal plants can take days to heat up to full power, and days to cool off as well, so it is uaully more cost-effective to keep them running at (or close to) full power rather than shut down their productions.
This is one way to store energy that has been used for years, and it is fairly effective.
Posted by The Rabbit (Member # 671) on :
The same holds for nuclear power. With the exception of hydro-electric, most power plants run close to full power round the clock. They really can't easily ramp up and down with diurnal demand cycles. Seasonal changes can be made but not rapid changes.
Still the greatest potential for energy storage is for wind power. Winds tend to be not only intermittent but they also tend to peak at night when demand is lower. So hydro storage is a great companion for wind power. Wind could be used at night when demand is low to pump water into the reservoir. Then at midday when demand peaks, water could be released from the reservoir.
Hydrostorage is also a much better idea if you can pump the water into an existing reservoir. Reservoir construction is an environmental disaster.
Flywheels are probably a better bet for dealing with diurnal variations in energy demand.
Posted by Mucus (Member # 9735) on :
quote:Originally posted by Kwea: ... it is uaully more cost-effective to keep them running at (or close to) full power rather than shut down their productions.
I'm fairly certain that this is not the case, at least in Ontario. Here is one example:
quote:Ontario’s existing coal-fired generation capacity is used intermittently. In contrast, because of their capital-intensiveness, nuclear plants are best operated continuously. We show that replacing Ontario’s existing coal-fired plants with new nuclear plants operated continuously would easily create enough off-peak electricity to supply electricity for over one-third of the Ontario light-vehicle fleet if these were PHEVs or EVs in 2015. Annual CO2 emissions would be reduced by over 6 million tonnes.
The Rabbit: Thats pretty much what I said when I noted "nuclear power plants go 24 hours" and why both sets of my statistics for the power that can potentially be saved is using the nuclear power as a base.
Posted by Sergeant (Member # 8749) on :
I didn't read the article so I may be missing the point but as was mentioned, the best candidate for energy storage is wind power I think Bear Lake may be a good place to start. I've stood on USU's campus at night and the wind that blows is significant.
Of course all of the arguments against the project probably outweigh benefits
Sergeant
Posted by Mucus (Member # 9735) on :
Here's a better reference that includes both coal and natural gas:
quote: Natural gas and coal-fired generation stations have the advantage of being able to manage demand shifts very well. During peak demand more units are turned on and during off peak hours the generators remain inactive. This allows the supply curve to closely match the demand curve throughout the day. The province will need a better means of controlling the supply-demand curve throughout the day.
Edit to add: I would also add that the previous link shows the Ontario generation data for 2005. During the year nuclear power was utilized at 90% of capacity, hydro at 52%, gas at 23% and coal at 45%. Meaning that coal-fired plants were actually off on average more than half of the the time and even less for gas.
[ April 23, 2008, 10:37 PM: Message edited by: Mucus ]
Posted by Kwea (Member # 2199) on :
Coal plants are a little bit more efficient at it than nuclear plants, for sure, but I know engineers at coal plants and they are not great at shutting off and turning on power. Hydro-storage is a FAR more efficient tool than shutting off generators.
It takes 2-3 days fro a plant to warm up after being shut down for maintenance, but that is a complete shutdown.
[ April 23, 2008, 11:19 PM: Message edited by: Kwea ]
Posted by The Rabbit (Member # 671) on :
Coal plants and gas plants can't actually turn on and off like as Mucus' link suggests but they do go into a sort of standby mode where they are kept hot but the generators are not spinning under load. That way they can be ramped up quickly. The efficiency is lower when the plant is in standby mode than when its operating at peak, but its not nearly as bad as it would be is they were running at full power and wasting half the electricity.
Posted by Kwea (Member # 2199) on :
I know that...I was wondering who else did as well.
They burn coal at almost the same rate, but produce less electricity because not all their generators are engaged, so it decreases efficiency. By using the generators, which run of the heat that is already being generated to keep the plant active, efficiency is raised even if all that electricity does is pump water....storing the potential energy.
Although, as Rabbit mentioned earlier, than only stores the energy rather than creating it in the first place.
Posted by Mucus (Member # 9735) on :
quote:Originally posted by Kwea: They burn coal at almost the same rate...
This seems especially dubious to me. Can you maybe source this? Perhaps your area just has a particularly bad coal-fired plant design?
Consider this debate:
quote:... Steve Erwin, a spokesman for Energy Minister Dwight Duncan, said the sources are mixed for the power that Ontario exports. Very little of it likely comes from coal, he said, because that power generation is only used on days when demand is at its peak.
He said if Ontario reduced the amount of power it exports, it would just mean the United States would step up production at their coal plants sending more dirty air across the border.
link This seems to indicate that emissions (and thus coal consumption) are proportional to energy production. If it were true that coal consumption was pretty much uniform regardless of electricity consumption, then the debate would be moot.
Posted by Lyrhawn (Member # 7039) on :
Interesting. The two main storage methods I'm seeing when reading Green news are compressed air and salt. For compressed air, the excess power is used to compress air, which is released on demand to power a generator. For the salt, it works with solar power, and they heat the salt during the day, which stays hot during part of the night to provide power on demand while the sun isn't shining. I've seen a few other ideas being batted around too.
There's also a theory that once LION batteries become standard in cars, there will be a huge market for used batteries in energy storage at power plants. The batteries will lose their usefulness for cars when they fall below 80% capacity, but that still leaves a lot of capacity for commercial scale power, and purchasing these batteries in the cheap in bulk keeps them out of landfills, makes them cheaper, and makes energy cheaper. Thousands of megawatt hours of power are wasted at night every year. I've read a report that says that excess offpeak night power could power enough EVs to replace 84% of small trucks, cars of all kinds and minivans, the LDV fleet of he US, without ANY excess power generation, it's just using the stuff we don't use currently. It wouldn't require any extra technology on the part of the power companies, it would just require people to charge their cars at night, which could probably be done through two-mode pricing (make power cheaper at night and people will charge their cars at night).
It might not be renewable energy, but I think it'd be fair to call it recycled energy.
Posted by Mucus (Member # 9735) on :
quote:Originally posted by Lyrhawn: ... I've read a report that says that excess offpeak night power could power enough EVs to replace 84% of small trucks, cars of all kinds and minivans, the LDV fleet of he US, without ANY excess power generation, it's just using the stuff we don't use currently.
I may point out that the first link that I posted focuses on this very topic Posted by Kwea (Member # 2199) on :
Yep.
I talked to ma friend after posting, and he said that of course it costs more to run a plant at full power than it does overnight, but not by as much as most people think.
He said the fuel consumption drops by about 30% if the plant is run at 70-75%, but that his plants (he works at 3) rarely run at lower than 70% power because it isn't cost effective to do so. His plants produce a lot of power than isn't used at night....which is why storage plans like this are still worth while.
Posted by Lyrhawn (Member # 7039) on :
I missed that link sorry. The report I read was a comprehensive study about the whole United States, based on our current electric grid and power plants in place.
It's an interesting idea, and the thing is, it's still a good 20 years off before EVs really saturate the market enough to really make use of that energy, and by that time, we'll likely have a much more diverse generation capacity, which could include even more nuclear, making the idea look even more attractive.
Posted by Mucus (Member # 9735) on :
Kwea: Hmmm, I appreciate that you did take the effort to talk to your friend. But when I said source, I meant something that I can get to and more independently verifiable than hearsay, if only because I AM interested in the subject and would like a more comprehensive source Posted by Morbo (Member # 5309) on :
Yeah, Mucus, this isn't the AAAS, this is an internet fora. If Kwea, a long time member, says he talked to a friend in the coal-powered electricity generation biz (presumably an engineer, tell me I'm not sticking my neck out for some PR flack Kwea), that works for me. Especially as it corresponds to previous info I've seen.
Counter the (presumptively good) post yourself, with a more comprehensive source, if you can Mucus. Posted by The Rabbit (Member # 671) on :
I think some of the discrepancy between Mucus' source and what Kwea and I are claiming is because there are two kinds of peaks, diurnal and seasonal. There are a lot of smaller older coal and gas fired electric plants that may only run during the hottest summer months when demand for air conditioning peaks. Additional, larger facilities will typically have multiple lines of boilers and generators so they can totally shut down a portion of the plant in the off season. Between plants that are shut down 75% of the year and those that drop down by 30% at night, you might end up with the same answer.
The real problem is that Mucus' data is designed to address a slightly different question. That data addresses the question of how to build a more efficient electric system presuming that you can't store electricity from off-peak times for use at peak times. The answer to that question is that you need to be able to increase and decrease production rapidly. So even if your coal fire plant is 30% less efficient running at half power than it is running full power, there is a big savings from dropping to half power.
The question we are asking is how much improvement in efficiency you could get by storing electricity generated in the off peak. In this case, the most efficient solution could be to shutdown half the coal and gas fired power plants entirely, run the other half at full power 24/7. Store the excess generated at night and in the winter by pumping water into a reservoir and then use hydropower to meet the peaks. Its impossible to tell from Mucus' data how much more efficient such a system would be than it is to ramp the coal and gas plants up and down on a diurnal cycle.
Posted by Scott R (Member # 567) on :
I think the Laws of Physics are really just suggestions.
I refuse to be held down. I refuse to relinquish my momentum merely because of some arbritrary limit discovered by some rich, dead, white guy.
Posted by aspectre (Member # 2222) on :
Go ahead, make my day -- Harry Callahan, practical physicist -- A man's gotta know his own limitations.
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by aspectre: Go ahead, make my day
I saw that earlier today. I guess we've identified someone else who is lurking at hatrack and stealing our best ideas.
Posted by Mucus (Member # 9735) on :
Morbo: While I would disagree that the standards of an academic journal are not something to aspire to especially on a academic topic like this, I fully recognize that kwea is hardly obligated to provide a link, which is part of why I asked nicely.
But on the other hand, you have to recognize that especially on the Internet, one always has to take hearsay from people you don't personally know with a grain of salt. It doesn't matter if its a newbie or a long-time poster, and its nothing personal either which is why I do hold myself to the same standard when presenting information, providing sources when possible.
The Rabbit: I think your explanation seems to more sense, especially in the Ontario context where we use coal to a much smaller extent than the US as a whole. Being able to shut down a section of the plant pending seasonal demand makes more sense than being forced to run the whole thing at 70% always.
I also agree that it is not possible to tell from the data which is more efficient. However, my guess is that between the energy conversion loss of two conversions (electricity->water potential NRG->electricity), the cost of the reservoir, and the increased emissions of generating full power from coal at any time, it might be cheaper and better for emissions to take the money for the dam (assuming that the dam is purely for storage and cannot generate power without pumping) and simply build more natural-gas fired plants and shutdown as much coal totally as possible, especially when we combine that with the potential of soaking-up off-peak electricity with PHEVs as they become available "anyways".
Posted by Qaz (Member # 10298) on :
Our local hydro dam does something similar: pumps water back into the lack during the night, so there'll be more power during the day.
Posted by The Rabbit (Member # 671) on :
quote:However, my guess is that between the energy conversion loss of two conversions (electricity->water potential NRG->electricity)
Pumping and hydroelectricity generation are extremely efficient processes. It turns out that this is probably the most energy efficient way to store electricity. I'll go hunt my references to try to find and exact number.
quote:the cost of the reservoir, and the increased emissions of generating full power from coal at any time
This one has been worked out in detail. I'll talk about the cost of the reservoir later but the combination of the low efficiency of ramping power plants up and down, low efficiency when operating at less than full power and the electricity that's currently thrown away far out way the inefficiency of pumped water storage. This one definitely results in a net decrease in emissions.
quote:It might be cheaper and better for emissions to take the money for the dam (assuming that the dam is purely for storage and cannot generate power without pumping) and simply build more natural-gas fired plants and shutdown as much coal totally as possible, especially when we combine that with the potential of soaking-up off-peak electricity with PHEVs as they become available "anyways".
As I mentioned before the economics of this have been fully worked out and your assertion is wrong. At least its wrong if you don't consider the externalities. Combined capital and operating costs for new hydroelectric power are much lower than the combined capital and operating costs for new coal and gas. There are already operational systems like this out there. It works and its economical.
Unfortunately the picture changes when you look at the externalities. Large hydroelectric dams have possibly the highest adverse environmental impact of any technology including greenhouse impact. Studies of the large damns recently built in China show that destruction of vegetation and the release of methane gas from land flooded by the new reservoirs is extremely high.
When you consider the external costs, pumped water storage only makes sense if you can pump into an existing reservoir.
Posted by Mucus (Member # 9735) on :
Qaz: Big difference between using an existing reservoir attached to an existing hydro dam that normally generates power and pumping water (possibly using nuclear power) and building a new dedicated reservoir just to store water that is pumped using thermo plants. As I mentioned, we already do the former in Ontario. AKAIK, we do not do the latter.
quote:Originally posted by The Rabbit: ... the low efficiency of ramping power plants up and down, low efficiency when operating at less than full power ...
As I noted earlier, this is an assumption which is still under debate. If we accept it, I admit that the equation would be different. But for now, it is unresolved as far as I am concerned.
Also, I do appreciate the reference hunting re: efficiency
quote: Combined capital and operating costs for new hydroelectric power are much lower than the combined capital and operating costs for new coal and gas. There are already operational systems like this out there. It works and its economical.
That may be true, but its the wrong comparison. We're comparing the operating costs of operating coal plants at full off-peak + capital and operating cost of a new reservoir) vs. (combined capital and operating costs for new coal or gas).
That combined with the long build time of a reservoir and the short build time of gas, plus the fact that the province has already committed to build more nuclear power anyways leads me to believe that the equation would be very different for different jurisdictions.
quote: When you consider the external costs, pumped water storage only makes sense if you can pump into an existing reservoir.
This we can agree on.
[ April 24, 2008, 11:20 AM: Message edited by: Mucus ]
Posted by The Rabbit (Member # 671) on :
quote:Originally posted by Mucus: As I noted earlier, this is an assumption which is still under debate. If we accept it, I admit that the equation would be different. But for now, it is unresolved as far as I am concerned.
Also, I do appreciate the reference hunting re: efficiency
As far as I'm concerned, its neither an assumption nor debatable. Its an established fact. I am engineering prof., I've taught courses in this. You aren't required to believe me on any of those points but its not worth my time or effort to keep argue.
You are speculating in an area where there is no need to speculate.
quote:That may be true, but its the wrong comparison. We're comparing the operating costs of operating coal plants at full off-peak + capital and operating cost of a new reservoir) vs. (combined capital and operating costs for new coal or gas).
That's not the correct comparison either. Whether you believe it or not, a significant amount of the electricity produced is wasted.
Posted by Mucus (Member # 9735) on :
quote:Originally posted by The Rabbit: As far as I'm concerned, its neither an assumption nor debatable. Its an established fact. I am engineering prof., I've taught courses in this. You aren't required to believe me on any of those points but its not worth my time or effort to keep argue.
Honestly, I think you're being unfair. Seriously, hearsay and "because I said so" are reasonable techniques for establishing the truth to you?
Consider if our positions were reversed, if I was presenting an unintuitive result from my field and in response to your questions I was only able to present A) not only an appeal to credentials, but my own credentials to boot B) hearsay from another poster who heard it from a friend, then I would fully expect you to be skeptical and it would be warranted too. This skepticism would only be enhanced if you do have access to several actual sources that seem to indicate otherwise.
Present me with evidence, math, actual numbers and then I'll fully consider them. I have no personal stake in this debate. Try to shut down the discussion with rhetorical tricks and I will remain skeptical. If our positions were reversed, I doubt you would do very differently.
As someone noted, this is the *Internet* after all.
Posted by Tatiana (Member # 6776) on :
quote:Originally posted by King of Men: Some places in Norway use it to heat housing. Not a very scalable method, though.
The idea of combined heat and power generation does have a lot of possibilities. Though there aren't enough potential uses of hot water in rural Georgia to make this worthwhile at my plant, it works well for smaller distributed generation plants.
For example, a hotel or office building in a big city will have need for hot water for heating guest-room water, room heating, laundry water, etc. Plus they can have an absorption chiller which takes hot water in as a power source and uses it to chill cold water. The cold water can be used for air-conditioning and refrigeration. The electricity generated can be used to lower the hotel's power bill, particularly if it decreases the peak demand the hotel needs during the month, which lowers the price per kilowatt hour of all electricity used in the month. (Power companies charge their largest customers a rate according to their peak demand, to help cover the capital costs of providing Megawatts only needed during peak times.) That's a good use for the 60% of the energy of generation that would otherwise be lost as waste heat.
For nuclear plants, though, it's best to put them in places with low population density, so emergency planning is made easier. And there just aren't any uses of hot water there that I can think of that pay for themselves. Oh well, I guess the birds are glad of it.
During the recent outage one day I saw about 20 birds perched on the top of the unit 1 tower as though waiting for the elevator to start back up. =)
Posted by scifibum (Member # 7625) on :
I wonder how the efficiency of capturing cheap off-peak electricity in the form of hydrogen via electrolysis might compare to the efficiency of pumping water uphill to run it through a turbine. It'd have to be quite a bit better to win on efficiency, I suppose, because converting the chemical energy of hydrogen back to electricity wouldn't be very efficient. However, hydrogen storage tanks might have a lot less impact on the environment. (Storing hydrogen couldn't be that much more dangerous than storing large quantities of oil or gasoline, could it?)
Posted by mr_porteiro_head (Member # 4644) on :
It doesn't have to be all that efficient to be useful. In some of the solar power plants being built, they're talking about storing energy (so that some electricity can continue to be produced when the sun isn't shining) in the form of heated water, which has got to be terribly inefficient.
![[Wink]](wink.gif)
![[Big Grin]](biggrin.gif)
![[Smile]](smile.gif)