|
Storing wind-generated energy as gravitational potential energy?
Not so great with wind-generated energy is the fact that you need a
battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John |
Storing wind-generated energy as gravitational potential energy?
John Nagelson wrote:
Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? They already use water as the large weight, is anything practical? Just over 1kWh from 4 tonnes lifted 100m (excluding losses). |
Storing wind-generated energy as gravitational potential energy?
John Nagelson wrote:
Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. a persistant myth http://www.wiki.diyfaq.org.uk/index....y_construction So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John how would you arrange gearing? Or would you have it only charge when half max windspeed were reached, and throw away any extra energy at higher speeds? Have you calculated what mass and height you'd use? NT |
Storing wind-generated energy as gravitational potential energy?
"John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John Umm do you have any idea on the weight required. I reckon my average consumption is around 2kW. Lets assume need to store energy for 24 hours supply. Lets assume maximum height available, practically, is 10m. PE = mgh 2kW for 24hrs is 48kWhr 48kWhr = 173MJ Solve for m in equation ----- err 1600 metric tonnes, and that assumes 100% efficiency in recovering the energy. Yep, sounds practical to me! |
Storing wind-generated energy as gravitational potential energy?
"John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John OK lets run with it. Suppose you could build a machine that could lift a 100 ton weight 10 metres with 100% efficiency. Suppose you could then recover that energy with 100% efficiency. The "potential energy" once it is fully lifted would be: m * g * h = approx 10 Megajoules = under 3 kilowatt hours. A typical home probably uses at least 3000 kwh per year. A 100 ton weight would mean about a 4.7 metre cube of concrete. Something in the back of my head says this is not practical. D |
Storing wind-generated energy as gravitational potential energy?
|
Storing wind-generated energy as gravitational potential energy?
On Dec 7, 3:41*pm, Andy Burns wrote:
John Nagelson wrote: Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? They already use water as the large weight, is anything practical? Just over 1kWh from 4 tonnes lifted 100m (excluding losses). True that (mass) x (g) x (height) = (required power) x (time) gives large figures for (mass) x (height). But maybe with concrete or old cars? Or maybe store some as elastic potential energy? I'm only thinking about at a domestic level. John |
Storing wind-generated energy as gravitational potential energy?
"John Nagelson" wrote in message ... On Dec 7, 3:41 pm, Andy Burns wrote: John Nagelson wrote: Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? They already use water as the large weight, is anything practical? Just over 1kWh from 4 tonnes lifted 100m (excluding losses). True that (mass) x (g) x (height) = (required power) x (time) gives large figures for (mass) x (height). But maybe with concrete or old cars? Or maybe store some as elastic potential energy? I'm only thinking about at a domestic level. John ____ Take a read of chapter 4 of Prof David Mackays fantastic book on sustainable energy: http://www.inference.phy.cam.ac.uk/s...ok/tex/cft.pdf (10 meg download) I think actually harvesting sufficient wind energy in the first place is problem zero. D |
Storing wind-generated energy as gravitational potential energy?
"Vortex3" wrote in message ... "John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John OK lets run with it. Suppose you could build a machine that could lift a 100 ton weight 10 metres with 100% efficiency. Suppose you could then recover that energy with 100% efficiency. The "potential energy" once it is fully lifted would be: m * g * h = approx 10 Megajoules = under 3 kilowatt hours. A typical home probably uses at least 3000 kwh per year. A 100 ton weight would mean about a 4.7 metre cube of concrete. Something in the back of my head says this is not practical. D You need two large ponds, one at a low level and one at a high one - the higher the better. See: http://www.fhc.co.uk/dinorwig.htm for an application. AWEM |
Storing wind-generated energy as gravitational potential energy?
"John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John How about opening a fitness centre and connecting all the machines to generators, you could also charge the users to generate electricity for you, However, I don't know what the pay back period on your capital would be? or even how many people you would need to generate an useful amount of power.? Don |
Storing wind-generated energy as gravitational potential energy?
On Sun, 7 Dec 2008 07:31:41 -0800 (PST), John Nagelson
wrote: Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? The shear scale is the bugbear. It's Christmas so lets indulge ourselves and use real units. 1 horsepower is 746 watts. Lets anticipate some losses and call it a Kilowatt. 1 horsepower is also 550 foot pounds per second. So 1 kilowatt for 1 hour could lift 550 pounds a height of 3,600 feet. that's for about 12p's worth of electricity. Mix and match how you like (Eg. 5,500 lb's for 360 feet) it doesn't get any more workable. It would be expensive and wouldn't be safe. It would store about the same energy as a single 12 v 80 ah leisure battery. This is for your "Hut-Sut" in Sweden I take it ? Better maybe to cut timber for heating and cobble together a water, steam, or alcohol (FWIR the Swedes have already cracked the technology for that ! ) etc. powered generator to give a hundred or so watts of electricity. The Swedes have been living there quite a long time you know, and it's difficult to be a "child prodigy" in these matters. What do they do ? Parts would need replacing far less often than batteries. John Well good luck with it anyway. Derek |
Storing wind-generated energy as gravitational potential energy?
"Richard Head" wrote in message ... "John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John Umm do you have any idea on the weight required. I reckon my average consumption is around 2kW. Lets assume need to store energy for 24 hours supply. Lets assume maximum height available, practically, is 10m. PE = mgh 2kW for 24hrs is 48kWhr 48kWhr = 173MJ Solve for m in equation ----- err 1600 metric tonnes, and that assumes 100% efficiency in recovering the energy. Yep, sounds practical to me! I think the Germans experimented with energy storage systems in buses back in the early 1930s, they used a heavy flywheel system which absorbed energy when breaking and releasing it for accelerating, ideal for a stop and start vehicle but god knows how they arranged the pulley/ gear train to achieve the necessary power transfers. Interesting though!! Don |
Storing wind-generated energy as gravitational potential energy?
John Nagelson wrote:
Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? do the sums, and you will find the answers you want are pretty obvious. |
Storing wind-generated energy as gravitational potential energy?
Donwill wrote:
"John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John How about opening a fitness centre and connecting all the machines to generators, you could also charge the users to generate electricity for you, However, I don't know what the pay back period on your capital would be? or even how many people you would need to generate an useful amount of power.? Don I believe that an athlete running flat out generates about 300 watt. Can't do that for long either. That was the problem with man-powered flight. It was keeping up enough power to overcome the drag for long enough. So someone running at say 15 kph on a non-powered treadmill for an hour would generate no more than 0.3kWh of energy. Even if conversion was 100% that's only about 3p worth of electricity. Peter Scott |
Storing wind-generated energy as gravitational potential energy?
John Nagelson wrote:
On Dec 7, 3:41 pm, Andy Burns wrote: John Nagelson wrote: Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? They already use water as the large weight, is anything practical? Just over 1kWh from 4 tonnes lifted 100m (excluding losses). True that (mass) x (g) x (height) = (required power) x (time) gives large figures for (mass) x (height). But maybe with concrete or old cars? Or maybe store some as elastic potential energy? I'm only thinking about at a domestic level. When you look at energy density, for any form of storage of usable energy, you find a scale, and the lowest on the scale is mass times height systems. Much better is mass times velocity squared, and heat. Both of those can be large in small spaces and volumes. At moderate heats too. Then comes chemical energy, liquid fuels, batteries and the like. Things start to get pretty compact. Self contained portable power units of sensible dimensions become possible. At the top of the scale is nuclear energy. John |
Storing wind-generated energy as gravitational potential energy?
"Peter Scott" wrote in message om... Donwill wrote: "John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John How about opening a fitness centre and connecting all the machines to generators, you could also charge the users to generate electricity for you, However, I don't know what the pay back period on your capital would be? or even how many people you would need to generate an useful amount of power.? Don I believe that an athlete running flat out generates about 300 watt. Can't do that for long either. That was the problem with man-powered flight. It was keeping up enough power to overcome the drag for long enough. So someone running at say 15 kph on a non-powered treadmill for an hour would generate no more than 0.3kWh of energy. Even if conversion was 100% that's only about 3p worth of electricity. Peter Scott I don't think many people will work for 3p an hour these days, however people pay quite a lot to use these machines, personally I think they're bonkers they would be better off chopping logs to keep fit. Don |
Storing wind-generated energy as gravitational potential energy?
Donwill wrote:
"Peter Scott" wrote in message om... Donwill wrote: "John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John How about opening a fitness centre and connecting all the machines to generators, you could also charge the users to generate electricity for you, However, I don't know what the pay back period on your capital would be? or even how many people you would need to generate an useful amount of power.? Don I believe that an athlete running flat out generates about 300 watt. Can't do that for long either. That was the problem with man-powered flight. It was keeping up enough power to overcome the drag for long enough. So someone running at say 15 kph on a non-powered treadmill for an hour would generate no more than 0.3kWh of energy. Even if conversion was 100% that's only about 3p worth of electricity. Peter Scott I don't think many people will work for 3p an hour these days, however people pay quite a lot to use these machines, personally I think they're bonkers they would be better off chopping logs to keep fit. Its not about keeping fit. Its a fashionable way to preen, show off your body, get all sweaty watching the oppsite sex (or same sex..), and pick up a quick shag with your bulging pecs. Or slender tight ass, whichever. Utter narcissism. Clubbing for those too old to drop E's and stay up all night. Don |
Storing wind-generated energy as gravitational potential energy?
Richard Head wrote:
"John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John Umm do you have any idea on the weight required. I reckon my average consumption is around 2kW. Lets assume need to store energy for 24 hours supply. Lets assume maximum height available, practically, is 10m. PE = mgh 2kW for 24hrs is 48kWhr 48kWhr = 173MJ Solve for m in equation ----- err 1600 metric tonnes, and that assumes 100% efficiency in recovering the energy. Yep, sounds practical to me! Tsk! How are we going to achieve anything if people are so negative. Thats only 1.6 million 1 kg bags bags of flour. All you need to do is build such systems next to large bakeries and you have solved two problems in one e.g. energy & storage. -- Dave - The Medway Handyman www.medwayhandyman.co.uk |
Storing wind-generated energy as gravitational potential energy?
"Donwill" popple @diddle .dot wrote in message ... "John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John How about opening a fitness centre and connecting all the machines to generators, you could also charge the users to generate electricity for you, However, I don't know what the pay back period on your capital would be? or even how many people you would need to generate an useful amount of power.? Don As to the last question, we could ask for a reply from any Roman galley operators or Vikings perhaps? But you know, we have plenty of hardened criminals using exercise equipment in our prisons, (so they can get a "girlfiend" and not be someone else's). Then there is immigrant labor, maybe they would peddle a stationary bike for $0.03 a kw? Oops, that might be taken as Politically Incorrect. I, of course, meant no disrespect to any Vikings that may have read my post. Luck; Ken |
Storing wind-generated energy as gravitational potential energy?
On 7 Dec, 15:42, wrote:
John Nagelson wrote: Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. a persistant mythhttp://www.wiki.diyfaq.org.uk/index.php?title=Lead_acid_battery_const... This is crazy. I am far from an elfinsafetee fan. So, OK for a few-off cells by someone technically competent - but on a 'home-industrial" scale? That is idiotic. It is bulk H2SO4 you would be playing with. Have you ever had a sulphuric acid burn? Even a small spot stings like hell and it takes weeks for the scar to heal. Not to mention the mass of volatile ions being spurted into the air Could you be sure you could contain it safely? AND be sure no idiot tests the water with their finger.... Solve all those problems and you'd still have potential risks from lead contamination of the househild environment. Car batteries are surrounded by a rugged rubberised casing & sealed, but even so cases have been known to split. Have you calculated how much you need to store 10 to 20 KWhr (typical household daily elec requirements excluding space heating)? How much space it would take? And there is all the trouble of handling a DC supply. However running a wind generator to heat the domestic hot water directly might be feasible depending on the costs of suitable generator (s). That could store the generated energy quite nicely, but as with all such schemes you would have to accept lack of hot water when you need it most (eg during a run of windless mid-winter days with no cloud cover). It might be possible to extend such a scheme to space heating and to charging electric car batteries, but same objections apply. Even then you'd find extensive costs when it comes to implementation, Wind is popularly regarded as "free" energy. But it is no cheaper than the oil and coal lying free underground. Just like for coal and oil, spending starts when you start to build & run the infrastructure to extract the energy. Alas, an idiot's "don't try this at home" message needs appending to the wiki article: as if anyone could be so stupid... |
Storing wind-generated energy as gravitational potential energy?
On Sun, 7 Dec 2008 16:13:52 -0000, "Donwill" popple @diddle .dot
wrote: I think the Germans experimented with energy storage systems in buses back in the early 1930s, they used a heavy flywheel system which absorbed energy when breaking and releasing it for accelerating, ideal for a stop and start vehicle I once saw a BBC Christmas lecture by Prof Eric Laithwaite which explored the idea. The biggest issue was safety, the energy stored in the flywheel would have been tremendous and if a failure occured and the flywheel escaped it would have carved "A neat slot" through buildings for miles across the city. That and Gyroscopic precession. If the flywheel was horizontal the bus could turn left or right, but if ever one side of the bus ran into a gutter and the bus tried to rotate the flywheel in the horizontal axis once again absolutely tremendous forces would impinge on the bearings / mountings of the flywheel. but god knows how they arranged the pulley/ gear train to achieve the necessary power transfers. Intuitively I feel sure that could be done magnetically / electrically Derek |
Storing wind-generated energy as gravitational potential energy?
On Sun, 7 Dec 2008 07:31:41 -0800 (PST), John Nagelson wrote:
So why not store the energy as gravitational potential energy? If you have the space pumped storage might get you a bit of energy but you'd probably get 50% back. Probably best just to dump any electricity you have no immediate need for into a heat store/bank via emersion heaters, once the store is up to temperature sell the excess to the grid. -- Cheers Dave. |
Storing wind-generated energy as gravitational potential energy?
John Nagelson wrote:
On Dec 7, 3:41 pm, Andy Burns wrote: John Nagelson wrote: Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? They already use water as the large weight, is anything practical? Just over 1kWh from 4 tonnes lifted 100m (excluding losses). True that (mass) x (g) x (height) = (required power) x (time) gives large figures for (mass) x (height). But maybe with concrete or old cars? Or maybe store some as elastic potential energy? I'm only thinking about at a domestic level. John Getting four tonnes of material isn't a problem. But what mechanism have you got that would raise that four tonnes 100 metres straight up? Or 40 tonnes 10 metres? Or 400 tonnes one metre? The raising and lowering has to be a) safe; b) controlled; c) connected to some sort of generator. And all that for a measly 1 kWh. Maybe if you had an arrangement which used your whole house as the weight? But the cost of making it (in financial and resources terms) would be prohibitive. -- Rod Hypothyroidism is a seriously debilitating condition with an insidious onset. Although common it frequently goes undiagnosed. www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org |
Storing wind-generated energy as gravitational potential energy?
On Sun, 7 Dec 2008 07:31:41 -0800 (PST), John Nagelson
wrote: Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energ Ahhhh, another liberal arts major :-) OK, smart-assed mode off. E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? there are two answers to this question: A) we already are. It's called hydroelectric power. More specifically pumped storage power. Unfortunately it takes a whole lot of water to make a little bit of electricity. Research TVA's Raccoon Mountain pumped storage facility to see just how much water has to be pumped how high to store just a partial day's worth of output of the nearby Sequoyah nuclear plant. B) gravity is very weak force and therefore it's very ineffective for storing energy. Back in the summer there was a scandal at Purdue University when some kid announced that he'd invented a gravity powered lamp. Supposedly a person could lift up the built-in weight and its gradual drop to the ground would power the lamp the rest of the day. Their public relations department failed to do even the most basic fact checking before stumbling over themselves and releasing a press release. We ripped it apart pretty well in this group. I calculated that his specified weight would have to be raised to approximately the height of the Empire State Building to produce the amount of light he claimed. In response, Purdue public relations department issued yet another press release in which they admitted that the kid had not actually built the lamp, but only simulated it, but they still had confidence in his work. This was sad testimony to just how bad the current educational system is. Not only did he make a huge mistake in his simulation, but he knew so little physics of the real world that he didn't recognize the magnitude of his mistake. Many orders of magnitude, actually. There was egg on a lot of faces. I should add that the amount of light that he claimed his lamb produced wasn't all that much, certainly not as much is a good hundred watt equivalent compact fluorescent lamp. I don't recall whether his weight was 20 pounds or 20 kg but in either case it demonstrates just how little energy is stored by raising a weight to a reasonable height. His first claim was that the weight only had to be lifted to chest level to operate the light all day. John -- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com -- best little blog on the net! Tellico Plains, Occupied TN There is much pleasure in useless knowledge. —Bertrand Russell |
Storing wind-generated energy as gravitational potential energy?
Rod wrote:
But what mechanism have you got that would raise that four tonnes 100 metres straight up? I haven't got one, I was just pointing out the scale of the problem And all that for a measly 1 kWh. Exactly. |
Storing wind-generated energy as gravitational potential energy?
You need two large ponds, one at a low level and one at a high one - the higher the better. See: http://www.fhc.co.uk/dinorwig.htm for an application. Yes, and the next stage is to do it at sea. See http://www.kema.com/corporate/news/corporate/2007/Q3/energie-eiland.asp |
Storing wind-generated energy as gravitational potential energy?
"Donwill" popple @diddle .dot wrote in
: "John Nagelson" wrote in message . .. Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John How about opening a fitness centre and connecting all the machines to generators, you could also charge the users to generate electricity for you, However, I don't know what the pay back period on your capital would be? or even how many people you would need to generate an useful amount of power.? Don I actually half assed presented that idea to an investment group one time -- It wouldn't actually generate that much power, but the marketing for green minded folk is where you'd make the money .. making people feel good about running on a tread mill like they are combating global warming or nonsense like that. Also i'd install my (pat. pending) **** turbines in all the urinals |
Storing wind-generated energy as gravitational potential energy?
On Sun, 7 Dec 2008 15:47:04 -0000, "Vortex3"
wrote: OK lets run with it. Suppose you could build a machine that could lift a 100 ton weight 10 metres with 100% efficiency. Suppose you could then recover that energy with 100% efficiency. The "potential energy" once it is fully lifted would be: m * g * h = approx 10 Megajoules = under 3 kilowatt hours. A typical home probably uses at least 3000 kwh per year. A 100 ton weight would mean about a 4.7 metre cube of concrete. Something in the back of my head says this is not practical. to further put this in perspective consider this. A typical nuclear reactor vessel weighs about 300 tons (American tons). It's not hard to look around the net and find pictures of reactor vessels being set. Find one of those pictures and take a look at the hardware involved. I participated in the vessel setting at the Sequoyah nuclear plant. We had four of Manotowok's largest cranes plus a 13 shiv block and tackle pulled by a Caterpillar D9 bulldozer (the largest made at the time. The four cranes lifted the vessel in the air, a Gantry was rolled under it, a cable attached, and the bulldozer pulled it horizontally into place. Then, after uprighting, the dozer lowered the vessel into place using the block and tackle. The whole operation took about two days. The drop was about 30 feet so that corresponds fairly well with the 10 m in the above calculation. At 300 tons, the dozer dissipated about 9 kWh during the lowering. A typical middle-class house uses something on the order of 20 kWh a day. Now I think it would be pretty cool to have something that big going up and down in my backyard every day but I just don't think it's practical, if for no other reason than the neighbors would bitch. John -- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com -- best little blog on the net! Tellico Plains, Occupied TN What do you call a blonde's dildo? Pneumatic tool. |
Storing wind-generated energy as gravitational potential energy?
On Sun, 7 Dec 2008 07:31:41 -0800 (PST) someone who may be John
Nagelson wrote this:- Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. Whether one needs a battery depends on whether the wind generator is connected to an external system or not. If it is connected to an external system then the easiest thing is to export the electricity. If it is not connected to an external system then at a house scale a battery is just about it. There have been developments with capacitors and flywheels are possible, though both run for relatively short periods. Compressing air or producing hydrogen are other alternatives. Of course the way to improve all these storage methods is to reduce electricity consumption. -- David Hansen, Edinburgh I will *always* explain revoked encryption keys, unless RIP prevents me http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54 |
Storing wind-generated energy as gravitational potential energy?
"Neon John" wrote in message ... On Sun, 7 Dec 2008 07:31:41 -0800 (PST), John Nagelson wrote: Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energ Ahhhh, another liberal arts major :-) OK, smart-assed mode off. E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? there are two answers to this question: A) we already are. It's called hydroelectric power. More specifically pumped storage power. Unfortunately it takes a whole lot of water to make a little bit of electricity. Research TVA's Raccoon Mountain pumped storage facility to see just how much water has to be pumped how high to store just a partial day's worth of output of the nearby Sequoyah nuclear plant. B) gravity is very weak force and therefore it's very ineffective for storing energy. Back in the summer there was a scandal at Purdue University when some kid announced that he'd invented a gravity powered lamp. Supposedly a person could lift up the built-in weight and its gradual drop to the ground would power the lamp the rest of the day. Their public relations department failed to do even the most basic fact checking before stumbling over themselves and releasing a press release. We ripped it apart pretty well in this group. I calculated that his specified weight would have to be raised to approximately the height of the Empire State Building to produce the amount of light he claimed. In response, Purdue public relations department issued yet another press release in which they admitted that the kid had not actually built the lamp, but only simulated it, but they still had confidence in his work. This was sad testimony to just how bad the current educational system is. Not only did he make a huge mistake in his simulation, but he knew so little physics of the real world that he didn't recognize the magnitude of his mistake. Many orders of magnitude, actually. There was egg on a lot of faces. I should add that the amount of light that he claimed his lamb produced wasn't all that much, certainly not as much is a good hundred watt equivalent compact fluorescent lamp. I don't recall whether his weight was 20 pounds or 20 kg but in either case it demonstrates just how little energy is stored by raising a weight to a reasonable height. His first claim was that the weight only had to be lifted to chest level to operate the light all day. John -- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com -- best little blog on the net! Tellico Plains, Occupied TN There is much pleasure in useless knowledge. -Bertrand Russell The hydraulic accumulators in Tower Bridge are interesting. http://www.london-sightseeing.co.uk/tower_bridge7.php |
Storing wind-generated energy as gravitational potential energy?
"John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John Ha Ha Ha Ha Ha Ha Ha Ha Ha Ha Ha Ha Ha !!!!!!! You are kidding on, aren't you? The energy used to lift the weight would exceed the energy given back, unless you had some way of storing the energy given. To lift a 1kg weight takes 1.3kg of force just to make it move against the effects of gravity and friction through air. So you use 0.3kg more of the potential on every lift cycle, unless you had some way of storing the energy used to lift the weight. If you can think of a way to lift a lighter weight to the height you need, then make the weight heavier when it reaches the top, you might be on to a winner. But, until then, stick to just directly spinning a magnet in a coil and store the generated potential energy in an accumulator. Believe me. The perpetual motion motor will never exist in our lifetimes, combined. Point one. You lift your weight to the maximum height and do not use any power. The weight stays at the top. But the lifting mechanism is still able to use the source that it used to lift the weight, because the source of energy is still there. The power source has not stopped at the top like the weight has. That's wasted potential energy right at the start. Point two. You begin to use power and the weight begins to drop. It is limited in its possibility to provide energy by the height. You are still using the power it is giving, then the weight hits the ground and stops. Your power source stops and you have to begin lifting the weight again. That is a waste of energy in having to stop using the power and start off lifting the weight again. Point three. You have a perfectly good source of renewable energy spinning the pulley system used to lift the weight, which could possibly be used to spin a generator to provide an unlimited amount of power directly to the system which will use it. Why waste all that potential energy source trying to do something that is not going to provide anywhere near the same unlimited amount of power. It a waste of time and brain power even thinking about it. Would you like to be directed to a cheaper source of rechargeable batteries? :-) LOL It was a good thought, but stop it. |
Storing wind-generated energy as gravitational potential energy?
On Sun, 07 Dec 2008 16:48:40 +0000 (GMT) someone who may be "Dave
Liquorice" wrote this:- If you have the space pumped storage might get you a bit of energy but you'd probably get 50% back. http://www.fhc.co.uk/dinorwig.htm has figures. For each unit the pump input is 275 * 7 = 1925MWH The respective generator output is 288 * 5 = 1440MWH This is for a full fill and then depletion of the top reservoir. In other words just under 75% of the energy put in is got back out again. This does ignore station loads, but these are relatively small. -- David Hansen, Edinburgh I will *always* explain revoked encryption keys, unless RIP prevents me http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54 |
Storing wind-generated energy as gravitational potential energy?
On Sun, 07 Dec 2008 16:16:29 +0000, Peter Scott
wrote: How about opening a fitness centre and connecting all the machines to generators, you could also charge the users to generate electricity for you, However, I don't know what the pay back period on your capital would be? or even how many people you would need to generate an useful amount of power.? Don I believe that an athlete running flat out generates about 300 watt. Can't do that for long either. That was the problem with man-powered flight. It was keeping up enough power to overcome the drag for long enough. So someone running at say 15 kph on a non-powered treadmill for an hour would generate no more than 0.3kWh of energy. Even if conversion was 100% that's only about 3p worth of electricity. good analysis, Peter. this whole thread illustrates the problem we nukes face. People just don't understand the magnitude of the energy problem. A nuclear plant isn't that large - many factories are larger. It can't make that much power, can it? Well, as a matter of fact, it can. A typical unit generates 1,000 megawatts. A few less, a few more and many are being uprated during outage and retrofit but 1000 is a good number. Day in, day out, 24/7 for 18 months or more at a time between refuelings. Now consider Hoover Dam http://www.usbr.gov/lc/hooverdam/faqs/powerfaq.html It's nameplate rating is 2,080 megawatts but with a hydro plant, that's deceptive. It can make that much power only when a specified amount of water is available. It usually isn't. I couldn't conveniently find the AVERAGE yearly output of Hoover dam but even if we assume that it can make its nameplate rating all year long, that's equivalent to roughly one single two unit nuclear plant. There's only one Hoover dam. We can plop down nukes pretty much wherever we want 'em. Since this is alt.energy.home-power, let's look at one of the more often mentioned alternatives - wind power. A typical utility wind turbine has a nameplate rating of from 1 to 5 megawatts. That means that with everything optimum - wind blowing at the design speed, etc, it would take from 200 to 1000 such turbines to equal ONE NUCLEAR UNIT. Remember that most plants have two units in the US and at least one (Browns Ferry) has three. According to the utility trade magazines I get, the availability factor for wind farms is lousy - typically around 50%. That is, the farm is making, on average, only half its nameplate rating. The causes are a combination of (mostly) not enough wind and (partially) low equipment reliability. Lowest bidder and all that. The money wasted on wind and solar "alternatives" amount to little more than a sad joke to us nukes. And to tax- and rate-payers who have a clue. John -- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com -- best little blog on the net! Tellico Plains, Occupied TN The secret to creativity is knowing how to hide your sources -Albert Einstein |
Storing wind-generated energy as gravitational potential energy?
John wrote:
The hydraulic accumulators in Tower Bridge are interesting. http://www.london-sightseeing.co.uk/tower_bridge7.php They are, but did you know that the hydraulic service ring main around the City of London of which this was originally a part, and which sat unused for 100 years or so, got recycled in the '90s as comms fibre ducts for the financial institutions? Tim Jackson |
Storing wind-generated energy as gravitational potential energy?
On Sun, 07 Dec 2008 12:40:28 -0500 someone who may be Neon John
wrote this:- People just don't understand the magnitude of the energy problem. Don't assume that anyone who disagrees with you, "just don't understand the magnitude of the energy problem." No form of electricity generation produces electricity continuously at full output. It is necessary to understand their individual foibles to understand the issues. "Different types of generators operate at a range of capacity factors - during 2004, gas power stations had a capacity factor of around 60 per cent, nuclear 71 per cent, hydro 37 per cent, pumped hydro 10 per cent, and coal 62 per cent. Meanwhile, the overall average capacity factor (or load factor) for the UK electricity network is around 55 per cent. "Clearly this does not mean that the UK electricity network only operates for 55 per cent of the time, and that the remaining 45 per cent of the time no electricity is generated! What this figure means is that all the generators connected to the network produce in a year a little over one-half of their theoretical maximum output. "Why does this occur? The main reasons are that electricity generators must be switched off for planned maintenance, that mechanical failure forces generators to be switched off at times, but also that generators will only be run if there if there is a demand for the electricity they are producing. "As a result, it is not possible for any generator to achieve a 100 per cent capacity factor - to do so would mean a perfect operational record, without a single hour of down-time due to maintenance or mechanical failure, and an electricity demand level that never varied. This has never been achieved on the UK (or any other) electricity network." http://www.shetland-news.co.uk/opinion/energy/response_1_confusion_over_wind_capacity.htm and it was written by someone who knows a little about electrical systems. Pumped storage systems were and are expensive to build. They were built because when nuclear stations conk out, because of their size, they leave a large hole in the electricity supply. Because they are very slow to react, other nuclear stations cannot cover this hole. Because of the magnitude of the hole, coal fired plants cannot cover it in the short term. What is needed is something which will start almost instantly and cover the hole for long enough for coal fired plants to be wound up. That is a hydro plant. By making it a pumped storage plant the excess electricity produced by nuclear plants can be absorbed overnight and it can have a far higher power output than a "simple" hydro plant would have for an equivalent volume of water. A good example of such a plant is Dinorwig, which can produce as much electricity as a nuclear power station within seconds, using just four of its six units http://www.fhc.co.uk/dinorwig.htm. In order to perform this trick the turbines must be spinning in air, synchronised with the external system. When doing this they either take a little electricity from the external system, or they take a little of the output of another turbine. From a standing start it may take as long as a minute to produce full output, though I guess 45 seconds is more typical. -- David Hansen, Edinburgh I will *always* explain revoked encryption keys, unless RIP prevents me http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54 |
Storing wind-generated energy as gravitational potential energy?
On Sun, 7 Dec 2008 07:31:41 -0800 (PST), John Nagelson
wrote: Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John Already done in some places. Two big holes one deeper than the other. Pump water into one and let it out into the other through a turbine. |
Storing wind-generated energy as gravitational potential energy?
On Sun, 7 Dec 2008 16:13:52 -0000, "Donwill" popple @diddle .dot
wrote: "Richard Head" wrote in message ... "John Nagelson" wrote in message ... Not so great with wind-generated energy is the fact that you need a battery bank, and batteries are expensive. So why not store the energy as gravitational potential energy? E.g. make the generated energy lift a large weight, controlled in such a way that it falls when you need it to, yielding just the amount of electrical power you need? ?? Parts would need replacing far less often than batteries. John Umm do you have any idea on the weight required. I reckon my average consumption is around 2kW. Lets assume need to store energy for 24 hours supply. Lets assume maximum height available, practically, is 10m. PE = mgh 2kW for 24hrs is 48kWhr 48kWhr = 173MJ Solve for m in equation ----- err 1600 metric tonnes, and that assumes 100% efficiency in recovering the energy. Yep, sounds practical to me! I think the Germans experimented with energy storage systems in buses back in the early 1930s, they used a heavy flywheel system which absorbed energy when breaking and releasing it for accelerating, ideal for a stop and start vehicle but god knows how they arranged the pulley/ gear train to achieve the necessary power transfers. Interesting though!! Don Swiss http://www.newscientist.com/article/...l-firsts-.html |
Storing wind-generated energy as gravitational potential energy?
On Sun, 07 Dec 2008 18:03:59 +0000 someone who may be Tim Jackson
wrote this:- John wrote: The hydraulic accumulators in Tower Bridge are interesting. http://www.london-sightseeing.co.uk/tower_bridge7.php They are, but did you know that the hydraulic service ring main around the City of London of which this was originally a part, The hydraulic supply was firstly installed around the (older) docks, where it was used to operate bridges, cranes, capstans, lock gates and so on. It was also used in railway goods depots in the area to operate lifts, cranes, capstans and so on. Obviously these docks are fairly close to the City. As well as the accumulators there were the pumping stations. It was then extended much further, covering much of what we would now call central London, it was used to operate lifts in hotels as well as other machinery. http://www.subbrit.org.uk/sb-sites/sites/h/hydraulic_power_in_london/index.shtml has a short history. and which sat unused for 100 years or so, got recycled in the '90s as comms fibre ducts for the financial institutions? The tunnels run through the older docks, which were being converted to memorials to the Mad Woman of Finchley at the time, so they were ideal for conversion. Some culverted rivers, combined sewers and storm water pipes were also used for fibre cabling. -- David Hansen, Edinburgh I will *always* explain revoked encryption keys, unless RIP prevents me http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54 |
Storing wind-generated energy as gravitational potential energy?
Alang wrote:
http://home.clara.net/darvill/altenerg/pumped.htm If only Carole Vorderman had stuck to the day job eh? Instead of flogging consolidation loans to Countdown viewers who think she's good at maths... |
| All times are GMT +1. The time now is 10:19 PM. |
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 DIYbanter