graz wrote on 12/16/2009 at 04:41 PM
Re: How a giant battery may save the world (osmium & irw)
Link
|
|
![]()
How a giant battery may save the world
![]() look wrote on 12/16/2009 at 11:12 PM
Re: How a giant battery may save the world (osmium & irw) Great job, gentlemen. I appreciated the step-by-step explanation under Ian's questioning. I learned a lot. Looking forward to the next one.
Whatfur wrote on 12/17/2009 at 07:38 AM
Re: How a giant battery may save the world (osmium & irw) Interesting.
I may have mentioned that I exist off the grid for much of the winter months. Now I happen to do so in a tent, but that tent is set up a couple hundred yards from a buddy's log cabin. His cabin is what falls right into this discussion. Also off the grid, he has a system that utilizes wind power( 1, 6ft? turbine), solar power (4 3'x6' panels) , and a gas or diesel (dependant on which one is working) generator and a rack (a 12-20?) of lead/acid batteries.
I have not done a study of it but from him I know that although things are working, he is disappointed in much of it and the generators are running quite a bit. Personal observation has me being disappointed also as his needs are seemingly small yet he seems to have to be on constant vigilant watch...and I see that rack of batteries in the basement and it just seems like one should be able to run off them for a few days without any kind of regeneration...and that is just not the case. I will do a closer study this winter...usually I am already there by
graz wrote on 12/17/2009 at 10:08 AM
Re: How a giant battery may save the world (osmium & irw) Did I let everyone know that in the latter part of December I celebrate a festival that includes gift giving? So my nephew will be receiving lots of electronic toys and games that are sure to run out of "juice" or battery power sooner or later.Is it possible to have one huge battery that can run all the appliances via radio transfer of power? Will the effectiveness of the power-pack be affected by an increase in global or regional temperatures? If I were to live off the grid, does that mean that I won't post on the internet? Francoamerican wrote on 12/17/2009 at 01:55 PM
Re: How a giant battery may save the world (osmium & irw) The giant battery sounds like a good idea, at least to someone who knows nothing about chemistry. Keep up the good work, Osmium. I hope you succeed in devising the super-duper zinc battery before humanity runs out of juice. I invested in a company that manufactures zinc batteries to replace lithium batteries in hybrid cars. Not a great idea...so far at least. Few people want to buy hybrid cars.
Baltimoron wrote on 12/17/2009 at 07:31 PM
The Next Rare Earth Crisis After watching this report on rare earth extraction and processing for use in alternative energy technologies, I'm wondering if research isn't green enough. Are any of these rare earth elements a part of your research, Osmium?
Thank you for the diavlog.
JonIrenicus wrote on 12/18/2009 at 12:55 AM
Re: How a giant battery may save the world (osmium & irw) This seems to be the only way to make renewables work for 100% of our power generation. Even then though, it is still a good idea to have some base load power generation though that we can throttle up or down on demand right?
Do we ever want to get to a place where we are using nearly 100% renewables for power generation?
And if not, what base load options should we use?
The main ones seem to be coal natural gas nuclear And all but the last spew toxins into the atmosphere, and unfortunately, the last will always be prevented from the irrational, so what is left for base load power generation? cragger wrote on 12/18/2009 at 12:54 PM
Re: How a giant battery may save the world (osmium & irw) Good discussion. I particulaly appreciated the description of the problem as being one of grid level energy storage. The types of storage you considered - chemical energy in batteries or fuel cells and possibly storage in fields using capacitors aren't the only ways to store energy, though it's understandable you concentrated on batteries since that is what you work on.
A few initial thoughts spurred by the diavlog:
Considering the relative costs of renewable sources vs. the various fossil energy sources, the crossover point seems to be approaching. Solar costs per KWH have been coming down over time, and fuels increasing in cost, particularly for oil and gas-fired plants. These appear subject to steep cost increases in the near-term future, though it will likely be a while before coal costs go up steeply. Of course in comparing the costs per KWH one must also remember that the figures are very distorted by the externalization of considerable costs from the use of fossil fuels, costs now coming home to roost though not through market economics directly tied to the causes of those costs.
A couple of additional factors in solar's favor include
cragger wrote on 12/18/2009 at 12:55 PM
Re: How a giant battery may save the world (osmium & irw) Quoting JonIrenicus: Do we ever want to get to a place where we are using nearly 100% renewables for power generation?The answer is in the definition. If it isn't renewable it will eventually run out. osmium wrote on 12/18/2009 at 12:57 PM
Re: The Next Rare Earth Crisis Quoting Baltimoron: After watching this report on rare earth extraction and processing for use in alternative energy technologies, I'm wondering if research isn't green enough. Are any of these rare earth elements a part of your research, Osmium? Thank you for the diavlog.Thanks everyone--I know this was a snoozer unless you *really* want to know about big batteries. Natural selection and the big bang are much more interesting, but this is rubber meeting the road kind of science.
Baltimoron, I don't use any rare earths, but other odd elements do come up in my work. I used to use osmium (obvs) which is a tightly regulated "middle of the periodic table" element, although not technically a rare earth. These materials are useful, so the way I see, the mining and recycling operations have to be made cleaner over time. And once we can "tag" everything made, it'll be easier to recycle things like rare earth elements with no hassle to the general public.
osmium wrote on 12/18/2009 at 01:08 PM
Re: How a giant battery may save the world (osmium & irw) Quoting cragger: Good discussion. I particulaly appreciated the description of the problem as being one of grid level energy storage. The types of storage you considered - chemical energy in batteries or fuel cells and possibly storage in fields using capacitors aren't the only ways to store energy, though it's understandable you concentrated on batteries since that is what you work on. A few initial thoughts spurred by the diavlog: Considering the relative costs of renewable sources vs. the various fossil energy sources, the crossover point seems to be approaching. Solar costs per KWH have been coming down over time, and fuels increasing in cost, particularly for oil and gas-fired plants. These appear subject to steep cost increases in the near-term future, though it will likely be a while before coal costs go up steeply. Of course in comparing the costs per KWH one must also remember that the figures are very distorted by the externalization of considerable costs from the use of fossil fuels, costs now coming home to roost though not through market economics directly tied to the causes of those costs. A couple of additional factors in solar's favor include osmium wrote on 12/18/2009 at 01:12 PM
Re: How a giant battery may save the world (osmium & irw) Quoting Whatfur: Interesting. I may have mentioned that I exist off the grid for much of the winter months. Now I happen to do so in a tent, but that tent is set up a couple hundred yards from a buddy's log cabin. His cabin is what falls right into this discussion. Also off the grid, he has a system that utilizes wind power( 1, 6ft? turbine), solar power (4 3'x6' panels) , and a gas or diesel (dependant on which one is working) generator and a rack (a 12-20?) of lead/acid batteries. I have not done a study of it but from him I know that although things are working, he is disappointed in much of it and the generators are running quite a bit. Personal observation has me being disappointed also as his needs are seemingly small yet he seems to have to be on constant vigilant watch...and I see that rack of batteries in the basement and it just seems like one should be able to run off them for a few days without any kind of regeneration...and that is just not the case. I will do a closer study this winter...usually I am already there by osmium wrote on 12/18/2009 at 01:13 PM
Re: How a giant battery may save the world (osmium & irw) Ian, I think you got the cool masking technology colors. Dude, you look like an Avatar warrior something-or-other.
osmium wrote on 12/18/2009 at 01:15 PM
Re: How a giant battery may save the world (osmium & irw) Quoting graz: Did I let everyone know that in the latter part of December I celebrate a festival that includes gift giving? So my nephew will be receiving lots of electronic toys and games that are sure to run out of "juice" or battery power sooner or later.I am not afraid to admit I don't fully understand radio-transmission of power. I should become educated. osmium wrote on 12/18/2009 at 01:33 PM
Re: How a giant battery may save the world (osmium & irw) Quoting JonIrenicus: This seems to be the only way to make renewables work for 100% of our power generation. Even then though, it is still a good idea to have some base load power generation though that we can throttle up or down on demand right? Do we ever want to get to a place where we are using nearly 100% renewables for power generation? And if not, what base load options should we use?There probably has to be a long period where there's some fraction of renewables, for knowledge about them to get built up, and to prove they work. Work out the bugs, get people used to the idea. look wrote on 12/18/2009 at 07:16 PM
Re: The Next Rare Earth Crisis Quoting osmium: Thanks everyone--I know this was a snoozer unless you *really* want to know about big batteries. Natural selection and the big bang are much more interesting, but this is rubber meeting the road kind of science.I appreciated your no-nonsense, precise teaching style. I'll bet you've taught thousands of undergrads. look wrote on 12/18/2009 at 07:50 PM
Re: How a giant battery may save the world (osmium & irw) Quoting graz: Did I let everyone know that in the latter part of December I celebrate a festival that includes gift giving? So my nephew will be receiving lots of electronic toys and games that are sure to run out of "juice" or battery power sooner or later.Ah, yes, time to drag the Festivus pole out of the attic. Whatfur wrote on 12/18/2009 at 08:17 PM
Re: How a giant battery may save the world (osmium & irw) Quoting osmium: I am not afraid to admit I don't fully understand radio-transmission of power. I should become educated.Sorry osmium, but wherever I seem to travel I bring with me the possibility of attack by a rather small "Fur Troll". He is not as so much interested in any type of enlightening discussion as he is with attempting to insult me. You see, he has never quite gotten over past embarrassments nor has he been able to reciprocate, so he thinks that a constant harrassment of me is the next best thing. I feel kind of bad because there was a time when he attempted almost adult-like posts and I seem to have affected him so deeply that he now pretty much just Trolls for Fur. I had hoped when I saw he performed the public service of providing the link here that he was taking a step in the right direction and even finding some purpose in his life, but unfortunately it was just an aberration. But maybe we can take his post and turn it into something positive. First, it IS positive that he speaks of needing to provide gifts for his AemJeff wrote on 12/18/2009 at 10:05 PM
Re: The Next Rare Earth Crisis Quoting osmium: Thanks everyone--I know this was a snoozer unless you *really* want to know about big batteries. Natural selection and the big bang are much more interesting, but this is rubber meeting the road kind of science.This was really informative and just plain cool. I wonder about simply using gravity to for energy storage. Something like 10,000 or 100,000 gallon water tanks on stilts in a closed loop with a second tank on the ground. Use pumps to lift the water, and drive a turbine or something on the way down. Too inefficient? Whatfur wrote on 12/18/2009 at 11:03 PM
Re: The Next Rare Earth Crisis Quoting AemJeff: This was really informative and just plain cool. I wonder about simply using gravity to for energy storage. Something like 10,000 or 100,000 gallon water tanks on stilts in a closed loop with a second tank on the ground. Use pumps to lift the water, and drive a turbine or something on the way down. Too inefficient?Are you not kind of describing what is already being done tapping into hydro and tidal...yet they don't need the pumps? Personally, I have always felt that a full embrace to telecommuting by companies would have a huge impact. My company about 5 years ago moved in and took over 5 stories of a 7 story building for 400 employees or so. Probably 90% of those employees could do everything they do now from home. I am one of a small number who works about 60% from home...most drive in every day. I would say the average commute for most is at least 15 miles one way and that 15 miles on average probably takes people 25 minutes of driving. So just saying they work at least 200 days that equates to over 2 million miles traveled by people in this one company. There AemJeff wrote on 12/18/2009 at 11:15 PM
Re: The Next Rare Earth Crisis Quoting Whatfur: Are you not kind of describing what is already being done tapping into hydro and tidal...yet they don't need the pumps?Yeah, but this is about storage, not production; and doesn't require a river or an ocean as an energy source. And it doesn't necessarily have to be installed on an industrial scale. A single house, or a neighborhood, could use a system like this to bank whatever transient energy sources might be available to them. Btw, I've just been moved from 95% work at home to a mostly on site presence. Feugh. look wrote on 12/19/2009 at 08:47 AM
This is only a test Quoting Whatfur: Whatfur wrote on 12/19/2009 at 09:56 AM
Re: This is only a test Quoting look: You'll do anything to get away from the in-laws, won't you? Close though...I will do anything to get away...period. I was born in the wrong century. Actually there is a bread company around whose slogan is "100 years behind the times" that I have readily adopted.
cragger wrote on 12/19/2009 at 10:15 AM
Re: The Next Rare Earth Crisis Jeff,
I also think storage using water as a potential energy source is a good idea as indicated in my comment below. There is a question of how small this scales efficiently though. There are a couple aspects of that - technical and economic. Technically, the amount of energy depends on the height and larger installations typically operate more efficiently than small ones for other factors. Probably hydraulic flow issues related to the diameter of the pipes, etc. if nothing else.
Economically, you come up against the question of dollars per joule of storage per year over the life cycle of the system. At a small scale the cost of the installation may drive toward other storage methods, and water as potential energy may be better suited for large (e.g. dams) or medium scale, community applications. Many towns have water systems, using reserviors or water towers. Combining the provision of water with operation of an energy store might mean only that the system should use the highest practical storage rather than what is probably the lowest storage (in the case of water towers) that maintains the flow. Addition of a second tank
osmium wrote on 12/19/2009 at 10:45 AM
Re: The Next Rare Earth Crisis Quoting AemJeff: Yeah, but this is about storage, not production; and doesn't require a river or an ocean as an energy source. And it doesn't necessarily have to be installed on an industrial scale. A single house, or a neighborhood, could use a system like this to bank whatever transient energy sources might be available to them. Btw, I've just been moved from 95% work at home to a mostly on site presence. Feugh.Re: gravity and water as energy storage: Yes people do it, but I think it is necessarily a large project. Dinorwig power station's wikipedia entry is an interesting read. I'll look around for more examples. I remember a friend of mine telling me about this being done recently, but I don't remember the location. look wrote on 12/20/2009 at 12:47 AM
Re: This is only a test Quoting Whatfur:Me, too. Whatfur wrote on 12/20/2009 at 09:12 AM
Re: The Next Rare Earth Crisis Quoting osmium: Re: gravity and water as energy storage: Yes people do it, but I think it is necessarily a large project. Dinorwig power station's wikipedia entry is an interesting read. I'll look around for more examples. I remember a friend of mine telling me about this being done recently, but I don't remember the location.This IS cool and the use of the caverns inside the mountain to hide the workings is amazing...but it proved to validate my first feeling when I read Jeff's proposal...that it would take more energy to raise the water than it would produce by its lowering. Sure costs of such can be offset by time management but seems to still be a bit counter-productive to overall goals. I guess the same can be said about batteries right??...if it takes 10 mw to store/charge 8 mw which it turn becomes 6mw of usable energy we only gain something if the energy was going to be lost or shed in the first place. Unless we are talking $$$ where 6mw during the day may be >= 10mw at off-peak. (My numbers are guesses...osmium might have some actual) osmium wrote on 12/20/2009 at 11:08 AM
Re: The Next Rare Earth Crisis Quoting Whatfur: This IS cool and the use of the caverns inside the mountain to hide the workings is amazing...but it proved to validate my first feeling when I read Jeff's proposal...that it would take more energy to raise the water than it would produce by its lowering. Sure costs of such can be offset by time management but seems to still be a bit counter-productive to overall goals. I guess the same can be said about batteries right??...if it takes 10 mw to store/charge 8 mw which it turn becomes 6mw of usable energy we only gain something if the energy was going to be lost or shed in the first place. Unless we are talking $$$ where 6mw during the day may be >= 10mw at off-peak. (My numbers are guesses...osmium might have some actual)yeah, that's the general idea. You're always going to get less energy out than you put in, but the considerations are efficiencies and costs (both $$ and environmental, which in a perfectly operating market would be equivalent). Batteries can be 90% efficient, fuel cells can be 60% (reversible cycle with hydrogen), and turbines with fossil will be osmium wrote on 12/20/2009 at 11:10 AM
Re: The Next Rare Earth Crisis Quoting look: I appreciated your no-nonsense, precise teaching style. I'll bet you've taught thousands of undergrads.Thanks, that means a lot to me, because that's the way I want to be. Not thousands, no, but maybe a few hundred over the years. I'm a research associate, not a professor, so I haven't had much chance to develop my own classes yet. Maybe soon, who knows.
AemJeff wrote on 12/20/2009 at 01:34 PM
Re: The Next Rare Earth Crisis Quoting osmium: yeah, that's the general idea. You're always going to get less energy out than you put in, but the considerations are efficiencies and costs (both $$ and environmental, which in a perfectly operating market would be equivalent). Batteries can be 90% efficient, fuel cells can be 60% (reversible cycle with hydrogen), and turbines with fossil will be something less than 40%. But fossil fuel stuff is cheapest due to 100 years of optimization and the relative ease that you just take it out of the ground. For pumped hydro storage (I am not an expert, but this is my impression), it won't scale down very far in size. I think you need a lot of gravity behind water to get that kind of power back out of it, so you essentially need a mountain. (But if you happen to own a mountain already, I bet it's pretty cheap.) Batteries, fuel cells, and turbines can all probably work on a scale small enough to distribute them fairly evenly through a city, and if one breaks, then the others can bring up the slack, much like the internet. I don't know the numbers either, Whatfur, but those ones you give in your last sentence Flaw wrote on 12/20/2009 at 10:22 PM
Re: How a giant battery may save the world (osmium & irw) I'm a fan of osmium and irw.
JonIrenicus wrote on 12/20/2009 at 10:37 PM
Re: How a giant battery may save the world (osmium & irw) Here is an old article from 1990 that seems to talk about some of the issues with zinc batteries.
http://www.lbl.gov/Science-Articles/...nt-at-lbl.html
I wonder what mentioned there has been solved, and what has not. I guess the dendrites are still a big issue, is that the only big hurdle left? osmium wrote on 12/20/2009 at 11:34 PM
Re: How a giant battery may save the world (osmium & irw) Quoting JonIrenicus: Here is an old article from 1990 that seems to talk about some of the issues with zinc batteries. http://www.lbl.gov/Science-Articles/...nt-at-lbl.htmlThat's a pretty awesome article. You know, I work with a couple people from the Cairns lab, and there is a huge review paper on zinc batteries by Cairns and McLarnon that I used to learn my head from my ass when I started working on Zn batteries. I allude to it in the diavlog briefly, but I think a major shift in funding priorities effectively ended their research in the early 90s, and we are one of the first labs to pick up Zn batteries again after all those years. It's deep in the weeds, but our design is a flow battery that's a bit different than theirs. A friend of mine says if I want to ask Cairns any questions I can, but I'm holding off till I feel like I've taught myself as much as I can and made a couple advances myself. Dendrites are still the issue! But not Whatfur wrote on 12/21/2009 at 04:08 PM
Re: How a giant battery may save the world (osmium & irw) One thing lithium seems to have an advantage with is ability to keep its charge in cold weather.
How does Zinc do?
graz wrote on 12/31/2009 at 09:01 PM
Re: How a giant battery may save the world (osmium & irw) Quoting Whatfur: How does Zinc do?Very well, thank you. Starwatcher162536 wrote on 01/02/2010 at 06:44 PM
Quick question. I don't have a problem with co-generation, but if the emissions are cooled to near ambient levels, convection won't occur and the emissions could become a local nuisance.
Are there industry standards for minimum heat levels for various emission types to make sure the emissions meet minimum dispersion requirements?
Starwatcher162536 wrote on 01/02/2010 at 06:45 PM
Can't view diavlog...... Is this diavlog still up? Whenever I click on the orange "View Diavlog" link, I just get a blank page with:
{/exp:weblog:entries} bjkeefe wrote on 01/02/2010 at 06:58 PM
Re: Can't view diavlog...... Quoting Starwatcher162536: Is this diavlog still up? Whenever I click on the orange "View Diavlog" link, I just get a blank page with:That's a bug with all Apollo diavlogs. For this one specifically, go here. In general, the way to get to a given Apollo diavlog from its associated thread page is to added apollo. to the URL; e.g., in this case, you want to visit http://apollo.bloggingheads.tv/diavlogs/24630 while the "View Dialog" link points to http://bloggingheads.tv/diavlogs/24630 So, the kludgy way to get to the Apollo diavlog is to click the "View Diavlog" link and then modify the URL in your browser's location bar. P.S. All Apollo diavlogs are listed and linked to in the sidebar of the page at http://apollo.bloggingheads.tv/diavlogs/. Whatfur wrote on 01/04/2010 at 09:57 PM
Re: How a giant battery may save the world (osmium & irw) Quoting graz: Very well, thank you.That was funny...but shouldn't you have been out with your friends at the time you posted it? popcorn_karate wrote on 01/05/2010 at 04:17 PM
Re: The Next Rare Earth Crisis Quoting AemJeff: I haven't totally given up the idea that smaller scales might be workable. The 75% efficiency achieved at Dinorwig surprised me. I have no idea how to quantify the amount of power that could be generated by a water tower size pair of tanks - but, if you powered the pumps with combination of solar and wind, e.g., the cost of storage seems pretty reasonable. If it's possible to generate useful power on that scale, then there might be the germ of a workable idea here. That said, I hear what you're saying.i loved this idea for a while (water battery) but i do think you would need some good topography to make it work. 15 feet of head 10,000 gallon tank of water 5 cfs = 3.5 kw for 5 minutes head(ft) * cfs * efficiency (0.55 for a good system) * 0.085 = kw 1cfs = 448 gallons/minute the only way to make it really work is to have something closer to 200 feet of head. cragger wrote on 01/06/2010 at 02:39 PM
Re: The Next Rare Earth Crisis The energy is dependant on the head, but that is not the only variable. There are many dams, including one near me, that don't have anywhere near 200 feet of head. More is good, but not necessary. Note that in your example, a 10k gallon tank is only about a 10 foot cube. It's not a lot of water for this application, though your figures do support your overall point, with which I agree, that the technique doesn't scale well down to individual home use.
On the other hand, playing with the numbers a bit you can see the merits of the approach. Even on a home level,
3.5 kW x (1/12 hr) x 30 (days/month) ~ 8.75 kWh.
so if one had for example a slightly bigger tank, 15' cube ~25k gallons, you would get nearly 22 kWh/month. Still obviously not a lot of energy, but for certain isolated applications that might be enough to say, keep the refrigerator and freezer running overnight and allow for some nightime lighting if one used solar/wind to fill the tank and did energy demanding activities during the daytime (assuming solar generation). Scaling up a bit more by considering a water store the size of a backyard swimming pool, and
popcorn_karate wrote on 01/06/2010 at 05:11 PM
Re: The Next Rare Earth Crisis Quoting cragger: The energy is dependant on the head, but that is not the only variable. There are many dams, including one near me, that don't have anywhere near 200 feet of head. More is good, but not necessary. Note that in your example, a 10k gallon tank is only about a 10 foot cube. It's not a lot of water for this application,here's a 10k tank you can buy - check out the dimensions and price. Part Number: T10000IW Capacity: 10000 Gallons Size: 141"D x 160"H Weight: 1803 lbs. Ships From: CA, AL (oops - $2400.00 is the price) so, you would be elevating 82,000 pounds. by the time you build something to support that amount of weight and buy the tank - you are already deep in a financial hole that will probably never be filled. Quoting cragger:given the assumptions in the original calculation, you would need a 180,000 gallon tank - the cost of the tank would price you out before you tried to elevate it. Quoting cragger: All a somewhat long winded way that while one doesn't want to dismiss this out of hand as an option for some users, the method seems better suited in general for larger scale applications at the community level and above.or someone with cragger wrote on 01/06/2010 at 06:21 PM
Re: The Next Rare Earth Crisis You miss the point of the "x 30 days" in the calculation. Using the example of solar generation, you would re-fill the upper water store every day using solar power. You need to store enough energy to get you through to the next generation period, not build up a month's-long store at once. Looking at things on a month long scale just seemed to be useful since we typically get electric bills on a monthly basis, so there is a little "feel" to that sort of timescale.
This neglects extended periods of bad weather/no wind or whatever of course, just back-of-the-envelope stuff that shows theoretical potential, though not necessarily at a $/kWh cost that is attractive. On the other hand, a large energy store using current deep discharge batteries isn't what you would call cheap either.
This leads to the point Osmium was alluding to in looking at this as a grid-level question. Like many things, a cooperative approach is likely the most efficient. I favor a hybrid system, with millions of small points of power generation going down to the home level, combined with large generation sources on the grid
popcorn_karate wrote on 01/07/2010 at 05:04 PM
Re: The Next Rare Earth Crisis Quoting cragger: You miss the point of the "x 30 days" in the calculation.or perhaps you missed that you would need a 180,000 gallon tank to run it for 1.5 hours each day of the month as you suggested? Quoting cragger: Using the example of solar generation, you would re-fill the upper water store every day using solar power. You need to store enough energy to get you through to the next generation period, not build up a month's-long store at once. Looking at things on a month long scale just seemed to be useful since we typically get electric bills on a monthly basis, so there is a little "feel" to that sort of timescale. This neglects extended periods of bad weather/no wind or whatever of course, just back-of-the-envelope stuff that shows theoretical potential, though not necessarily at a $/kWh cost that is attractive. On the other hand, a large energy store using current deep discharge batteries isn't what you would call cheap either. This leads to the point Osmium was alluding to in looking at this as a grid-level question. Like many things, a cooperative approach is likely the most efficient. I favor cragger wrote on 01/07/2010 at 08:27 PM
Re: The Next Rare Earth Crisis Quoting popcorn_karate: or perhaps you missed that you would need a 180,000 gallon tank to run it for 1.5 hours each day of the month as you suggested?Perhaps. From your BOE calculations, the 10k gallon tank delivers: 3.5 kW for 5 min - close enough for BOE for sure 3.5 kW x 5 min /60 min/hr = .2916667 kWh/day reflecting the energy recovered each time you run the upper tank through the generator. .291666. kWh/day x 30 d/mo = 8.75 kWh/mo for the 10k gallon tank you suggested. Perhaps you are referring to my suggestion that with a slightly greater head, and a larger water store one could easily envision a home system with a storage capacity in the neighborhood of 100 kWh/mo? 100/8.75 ~ 11.4 suggesting you need a bit more than an order of magnitude increase in head, gallons of storage, or some combination thereof. i.e gallons x N and head x P with N x P ~ 11.4 < the factor of 18 as you suggest. (i.e. 1.5 hours/day = 90 min at 5 cfs = 18 x 5 min) , presumably how you got to the 180k gallons figure). As I recall I suggested that a combination of a modest increase in head (20' vs. 15' gives a factor of 4/3, and a larger water store such as swimming pool size: 11.4 x 3/4 x 10k gallons ~ 85.5k gallons for example). Or |
|
![]()
|
||||||||||||||||||