Wow, this EPA guy (Joseph Goffman, EPA Associate Assistant Administrator & Senior Counsel) thinks that renewables are going to make up 30% of the power grid by 2030. That may be, but the big hidden gotcha in that is that 30% is not power on demand. It is at the whims of wind and clouds. By replacing that much of the power grid with transient energy, look for brown-outs and black-outs in our future. What happens in a major heat wave (which they predict will be more frequent) and the wind does not blow? Watch the video:
youtube=http://www.youtube.com/embed/AcNTGX_d8mY
See also this report: Renewable Energy Poses Security Risk, New Paper Warns
The reality today:
![fig_if7-1[1]](https://wattsupwiththat.files.wordpress.com/2014/06/fig_if7-11.png?quality=75)
Source: http://www.eia.gov/forecasts/aeo/elec_proj.cfm
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Offshore pumped storage hydro provides unlimited energy storage
That means we can get trillions of GW days of storage? At what cost? BTW how many of these devices are currently delivering power to the grid? What is their long term record for reliability? What is their long term cost?
Stephen Rasey says:
June 2, 2014 at 11:48 am
You HAD to bring up logistics and materials science. Dang. 😉
Let me remind you that Roger has a degree in Chemistry. What more proof do you need?
BTW 2000psi? That is nuclear plant pressure. And I can assure you that they don’t use concrete pipes. BTW if the spheres are built by the lowest bidder a slump test needs to be performed on every load of concrete made or delivered. Some people will cheat.
Since concrete will not be used for pipes (concrete is near useless in tension) how will the air be delivered 1000ft or more below the surface?
First, a quote (or paraphrase) from Confucius: “I show a dull man one corner of a room, and he sits in the corner grinning. I show a wise man one corner of a room, and he shows me the other corners, plus the entire house.” There are quite a number of people grinning in the corner, based on some of the comments above.
Now, as to the basics of how PSH (pumped storage hydroelectric) works, and then how the MIT spheres work. There are numerous PSH sites in the US (more than 22,000 MW at last count by EIA – Energy Information Agency). One of the largest sites is on the eastern shore of Lake Michigan, the Ludington Plant. Like all PSH plants, there is an upper reservoir and a lower reservoir. The lower reservoir is Lake Michigan. The upper reservoir is man-made, about 360 feet above the lake, and on a sandy cliff-like edge of the lake. At night, six turbine/pumps run in pump mode by drawing power from the grid to pump water from Lake Michigan into the upper lake. The next day, the flow is reversed so that water flows from the upper lake through the turbine/pumps into Lake Michigan, this time generating power as needed. The upper reservoir and land occupy 1,000 acres. The generators produce 1,872 MW of power at maximum flow. The penstocks (six of them) or pipes, are 1,300 feet long and 28 feet diameter. These connect the upper and lower reservoirs. The plant was built between 1969 and 1973. As PSH plants go, it is large but has a low elevation change.
In contrast, the Castaic PSH in Southern California, near Los Angeles, has an elevation change of 1,060 feet and produces 1,247 MW for up to 10 hours in generating mode. Castaic PSH also draws power from the grid at night to pump water uphill from Castaic Lake into Pyramid Lake, the upper reservoir. The tunnel connecting the two lakes is 7.2 miles long and is 30 feet in diameter. Castaic PSH has six pump/turbines and one standard turbine generator. Because the elevation difference is greater, Castaic has much lower water flow than does Ludington.
These two examples show a low-head and a high-head PSH plant (Ludington is low-head, and Castaic is high-head). In this context, head is the elevation difference in feet between the upper and lower reservoirs.
The MIT spheres will do exactly the same function: draw power from the grid at night to pump water out of the spheres. The spheres are not closed as one commenter above assumes. Instead, they are vented by a pipe to the atmosphere. The sphere acts exactly like the lower reservoir. It is at atmospheric pressure at all times. A turbine/pump connected to a motor/generator draws power at night (or whenever the wind blows) and runs in pumping mode to send water out of the sphere into the surrounding ocean. Air flows from the atmosphere through the vent pipe into the sphere. The ocean, at that depth, has considerable pressure. One can estimate the water pressure by dividing the water depth by two. Thus, 1,000 feet of water will exert approximately 500 pounds of pressure. (Engineers will know that the exact relationship is 32.2 divided by 14.696, but for estimating purposes, two will suffice.)
During the day, when peak power is required, seawater is allowed to flow by natural pressure from the ocean through the turbine/pump into the sphere, turning the generator and producing power to the grid. Water flowing in forces air out of the sphere through the vent line into the atmosphere. With proper design, about 80 MW will be produced into the grid for each 100 MW consumed from the grid.
As to the servicing and maintenance issues someone asked above, this is trivial. Proper design will have the entire turbine/pump and generator/motor equipment in the atmospheric pressure zone above the sphere. Simply put, that building will also be vented to the atmosphere. Likely, an elevator will convey workers and materials to the submerged sphere, much like in a mine shaft on land. There is no need to contemplate high-pressure underwater activities. Purists will say, at this point, yes but what about screens to keep fish and other marine life out of the turbines? Those screens or similar devices may require periodic cleaning, but that can be done remotely with ROVs. (remote operated vehicles, think unmanned submarines).
As to the MIT paper indicating 6 hours of storage, and the naysayers objecting that this is far too little. It should be pointed out that Castaic PSH has only 10 hours of generating capacity, and about 11 hours for Ludington. However, these spheres would be storing offshore wind-energy and could require operation for several days. There are three salient points about PSH generating time: one need only change the generating time by 1) increasing the diameter, 2) adding more spheres, or 3) increasing the head. Put simply, if the sphere volume is the same and only one sphere is used, one can obtain double the generating time by setting the sphere twice as deep into the water – this increases the head. Similarly, if one maintains the head constant, one can obtain 8 times the generating time by doubling the sphere’s radius. Or, one could maintain the head constant and add more spheres of constant radius to obtain the increased generating time.
Note that it is not required to have a turbine/pump with motor/generator on each sphere. The spheres can be connected one to another by suitable high-pressure pipes. Very likely, the most economic choice for increased generating time is simply to increase the spheres’ size. Spheres have a nice property for that, as materials required go up with the square of the radius, but volume increases with the cube of the radius. One may also excavate out a hollow in the ocean floor and set the larger sphere in place, if water depth is an issue with a larger sphere.
Now, as to the testing and prototyping as asked above: yes, the MIT publications state the system has been built, has been tested, and measurements taken on an actual sphere.
The economics are much criticized in the comments above. It was overlooked, apparently, by the naysayers that MIT stated the cost per sphere will decrease as more are deployed. This is the economy of mass production. Henry Ford recognized this with automobiles; it still applies today. Another cost-reduction will occur as spheres are made larger, this is the economy of scale for unit production. Yet another cost reduction will occur as spheres are installed along trunk power lines laid on the ocean floor. It will not be necessary to build the electrical infrastructure again for each sphere.
Another word about economics: with a suitable number of spheres in place, there will be no need for land-based fossil-fuel power plants to be built in excessive numbers. Instead of the 1,000 GW currently installed, the US could have only 600 GW installed, and let the spheres do the peak load work. The savings from not installing 400 GW of on-shore fossil-fuel power is indeed large. That will offset much of the cost of installing the spheres.
As to the land-locked cities, spheres can be installed in the larger Great Lakes, with a power grid designed to send power from wind-farms in the Great Plains to those storage systems, then back out the next day. Even shallow Lake Erie can have storage spheres, they would simply be buried in a suitable hole in the lake bottom.
This wraps up the MIT sphere grid-scale storage technology. It works. It has zero energy cost. It has very low environmental impact. It can be constructed now, without waiting for offshore wind-turbines. It reduces the cost of on-shore generating plants – fewer plants will be required. Power from the spheres is almost instantaneous and can be at full power in less than 30 minutes. It quite easily follows the load. Economy of scale and mass production will decrease the costs. There is a huge coastline with shallow continental shelf along most of the Eastern seaboard and Gulf of Mexico, so placing numerous spheres is quite possible. It makes intermittent wind energy very reliable, available on demand.
M Simon
“Let me remind you that Roger has a degree in Chemistry.”
Wrong. My B.S is in Chemical Engineering – a big difference between that and Chemistry.
If you are going to snipe with snarc, at least get your facts straight.
Go sit in the corner and commence grinning.
To Mods… It says “watch the video.”
What video? Got a link?
[Added. .mod]
Where’s the video link? I couldn’t find it. One second…Found this online that I assume is the video link referenced:
Please update post to include it.
[Done ..Thank you! .mod]
Roger Sowell says:
For the terminally stupid, like davidmhoffer, there is truly no hope. He clearly thinks he “thrashed” me, whatever that means in his feeble mind.
>>>>>>>>>>>>>>>>
Oh I made some good points, but it wasn’t me that thrashed you it was others. And they did so soundly. But never mind that:
Are you going to invest your personal money in this technology or aren’t you?
davidmhoffer,
You are indeed a dullard. And have no manners, either. My investment portfolio is none of your damn-d business. An educated man would know not to ask such personal questions. You, however, are a boor and a Neanderthal.
If you can refute anything, anything at all I write, please give it your best shot. I’m sure it will be quite entertaining for all to observe.
Go back to your corner and continue grinning.
Ah, link found, here’s the thread:
http://wattsupwiththat.com/2014/03/01/renewable-energy-in-decline/
If anyone doubts that Mr Sowell got thoroughly trashed in this thread, I invite them to read through the thread and make their own judgment. You can search for comments by me to Mr Sowell, or you can look through some comments by A. Scott and others. I’ve reproduced a couple from A. Scott below. Not carefully that the pattern is identical. When confronted with facts that he cannot refute, when challenged on his assertions, he stoops to ad hominem attacks. Long after rational people have abandoned the thread, he continues to throw spin after spin at the thread. He’s just not worth debating on the facts. Which is why I renew my question to him.
Mr Sowell, are you going to invest your own money in this technology?
A. Scott says:
March 6, 2014 at 5:33 pm
Roger has stooped to ad hominem attack and a complete refusal to address detailed, sourced comments from me and others … a sure mark that he is unable to substantiate his positions (which are exceeding short on documentation and sources) nor able to defend against the claims I and otherz have made.
Ridicule and denigration are the marks of someone who is unable to intelligently discuss and support their positions Roger.
It makes you look juvenile and ignorant in your response:
“futile arguments”
“low-information commenters”
“religious-style belief”
“bleating sheep”
“religious-style”
Then, you make broad, specious statements, mostly devoid of ANY sources or supporting proof – claiming them as fact – that are anything but, as I have repeatedly shown. A single example is your statements about the Mass/RI Offshore wind lease – that YOU brought up:
To all my detractors, fellas, you just cannot win. Wind power will be installed offshore… Storage will be provided either as MIT described, or possibly by more economic means. Operating experience will drive down the costs. The benefits to all will be enormous. I posted a link earlier to the Maryland offshore wind program. Other coastal states (MA and RI) have similar programs.
I posted the details of the wind lease you noted …. that the winner of that lease, Deep Wind, will someday install appx 200 turbines with 1,000 MW name plate capacity. In the entire 165,000 acre lease area they will only install 1,000 MW – not the 3,400 MW claimed available. And theirs was the BEST of 8 bidders.
I also noted your claim about “MIT storage” being installed were ridiculous – 100% completely unsupported by the facts. The MIT storage spheres operate at depths of 400-750 meters, 1200 to 2,300 feet. The waters across the entire lease area are from 90 to 130 FEET, 30 to 40 meters. Not only WON’T the MIT spheres work in this shallow water, they would stick OUT of the water in many areas.
You lecture about engineering, and looking at facts … yet despite all your self proclaimed expertise, in your rush to denigrate others you show you are literally clueless about your own claims. I understand the engineering very well. And I actually researched the real facts Roger, including reading the MIT paper on the sphere technology. I went and obtained the Nautical charts along with copies of the leases and maps of lease areas.
Clearly you did NONE of this simple basic research – you read an MIT April 2013 press release which says:
The concept is detailed in a paper published in IEEE Transactions and co-authored by Alexander Slocum, the Pappalardo Professor of Mechanical Engineering at MIT; Brian Hodder, a researcher at the MIT Energy Initiative; and three MIT alumni and a former high school student who worked on the project.
This was not even their work. They basically stole it from graduate student Gregory Fennel’s Master’s thesis dated May 2011. Slocum was the Thesis Supervisor – who certified Fennel’s highly detailed thesis paper.
This “sphere storage” is in no way proven – its a mere pipe dream idea at present – nothing more. Yet you have it providing the solution to wind power intermittency problems – despite that even the appear notes it can at best provide “several” hours of back up despite its huge costs. And that is assuming it actually works.
Just like you ignored the depth issue in the lease area (a lack of necessary depth) … so too did you completely ignore the fact that any wind turbine installed in an area where the MIT sphere storage would work (1200-2300 feet deep) would require a floating platform … and that I showed there a total of TWO deep water floating platforms (in 45-100 meter depths only) in the WORLD … 0.1% of all off shore wind is on a floating platform.
And finally, wind turbines are claimed to be too unreliable. I first entered this thread with an account of proven energy storage that overcomes the unreliability issue.
So neither the sphere or any other storage technology exists today at all, And floating deep water turbine platforms are all but non-existent as well. A floating platform for the massive 5 MW turbines Deep Wind plans for the MA/RI lease area is a huge technological challenge.
So much for your “proven storage technology” and your claims the Mass/RI leases were some massive savior.
A. Scott says:
March 6, 2014 at 5:58 pm
Then there is your denigrating juvenile and completely unsourced attack on my comments regarding Germany’s actual emissions experience.
You posted a link to an NREL “study” that attempted to model different scenarios in Iowa. I posted a link to the Bloomberg story with direct quotes from officials in Germany’s Environmental Ministry – those responsible for energy in Germany, and their shift to solar.
Germany emitted the equivalent of 931 million metric tons of CO2 equivalents last year, which was up from 917 million tons the year before, the Environment Ministry said in February. “We’re tracking this development with great concern,” Juergen Maass, a spokesman for the Environment Ministry, said July 26 by phone, declining to comment further.
Merkel in 2011 ordered the country’s eight oldest atomic reactors that provided near CO2-free power to be unplugged. She wants to shut the remaining nine by 2022.
http://www.bloomberg.com/news/2013-07-28/merkel-s-green-shift-backfires-as-german-pollution-jumps.html
And 2012 saw similar increases according to the Environmental Administrator:
Federal Environment Minister Peter Altmaier (CDU) …said … in 2012 there was an increase in greenhouse gas emissions by about 1.5 percentage the German Press Agency reported, citing experts. [Total] carbon dioxide emissions in 2012 may be increased by up to two percent – final figures are [not available yet] because of the complexity of the acquisition …just under a year ago.
http://www.focus.de/wissen/klima/erfuellung-der-klimaziele-gefaehrdet-co2-emissionen-in-deutschland-steigen-wieder_aid_923133.html
Hard quotes and facts … not a “study”.
Same thing with my levelized construction costs data. I presented data directly from the US Energy Information Agency. I included a direct link to the documents from them. I aslo provided a seprate link to an earlier WUWT article than looked at Maryland offshore wind which confirmed the EIA costs numbers.
Roger blathers about some alleged California “CEC” numbers yet never posts a link to the data. All too typical.
I hate people who refuse to engage and support their claims. I hate people like that even more, who denigrate and demean anyone who disagrees with them, and who ignore documented research and facts when they don’t conform to their position or world view.
I do detailed research on my positions and claims. I support everything with documented sources and references so people can confirm for themselves. I expect those like Roger to at least make a minimal effort to support their claims. And to engage in the discussion when rebutted – and support their claims.
Roger Sowell says:
June 2, 2014 at 6:56 pm
davidmhoffer,
You are indeed a dullard. And have no manners, either. My investment portfolio is none of your damn-d business. An educated man would know not to ask such personal questions. You, however, are a boor and a Neanderthal.
>>>>>>>>>>>>>>>>
I shall take that as a resounding “No”.
You lecture me about bad manners? ROFLMAO.
Shut down all Coal power plants tomorrow morning and shut the lights off in America and you will see America throw the bums and environmental wackos out by the weekend. We must declare war on them today, not tomorrow as they want to destroy America and you know it.
TURN OUT THE LIGHTS………………………. We are done talking, the war has started…………………….
Huffer,
[trimmed. Address the criticisms, not the person. In turn, they should do the same. .mod]
“Now, as to the testing and prototyping as asked above: yes, the MIT publications state the system has been built, has been tested, and measurements taken on an actual sphere.”
Perhaps I was not clear with my request before. Yes, I have look at the MIT publications. There is some hand-waving in the air about MIT Spheres for energy storage, and a very brief statement that something was built, somewhere, sometime, and it worked out well. Very good, I will simply accept that on faith. But where is the data from that? Where was it tested, at what depth, and how much energy was created, and how much energy was expended to create that energy? What difference of psi had to be used to force the water out of the sphere, compared to the psi at whatever depth this was done at? What type and size of air pump was used to push the water out? This is all simple laboratory notebook information, and should be readily available somewhere on the web, or available in a published paper. I have also noted that grid power was going to be used to pump air into the sphere, displacing the water. If this is to be hooked to a windmill, why would grid power be used?
This is not a project that is ready to be deployed, as the prototypes have never even been built (except for possibly one), and nothing has been published (along with data) so that the engineering calculations can be checked. At this point it appears to be hand-waving and salesmanship.
Each pumped storage design I have analyzed and checked has had the power immediately available. On the east coast of the US, the continental shelf – the basic depth you have to go out to get get to 1000 meters deeps is 100 km out (up near Boston and off of Maine), then as far as 400 km further south. that is a very, very long way to run wires underwater to get power out, and power back.
true, a spherical pumped storage system is the best theoretical energy storage design so far. that does not mean it will work as expected!
i am pumping the stored water out up, not 50 feet as at Niagara against air pressure. I am pumping it against sea water 5000 feet underwater.
Now, let’s see one operate for a few years.
Windmills too are a wonderful idea. In theory. But they are only 16% efficient, while requiring 100% money be paid to the political backers of the required scheme, who are being paid by taxpayer subsidies and tax credits to the net price of 500.00/Mwatt-hr..
OK, read back through. Is the water being removed from the sphere by pumping it up to the surface of the ocean? I had been thinking that air was pumped to force the water out, down at the level of the sphere. If indeed you are pumping the water out of the sphere, up to the surface of the ocean, why don’t you just take all of that concrete and build a bunch of concrete water tanks on top of hills overlooking the ocean. Especially on the west coast, there are bluffs that drop directly down to the ocean, and are probably several hundred of meters, or more, tall. And if you are using windmills, the wind on those bluffs is going to be better than what you get out away from the shore. Why put anything other than a hose with a pump attached into the water (and fairly shallow water), and just pump the water up to the top of the bluff, and then let it flow down, with the turbines down at the bottom of the cliff? As romantic a notion as huge concrete spheres are, that is just silly to do it that way. Everything needs maintenance of some sort, and the last thing anyone wants is to do it in deep water where there is no heat or light. The sea water is going to corrode everything eventually, too.
Roger scribbles:
The MIT spheres will do exactly the same function: draw power from the grid at night to pump water out of the spheres. The spheres are not closed as one commenter above assumes. Instead, they are vented by a pipe to the atmosphere. The sphere acts exactly like the lower reservoir. It is at atmospheric pressure at all times.
False.
The sphere is below sea level, it is at the ambient water pressure at all times.
If left open at the surface, the column will fill with water to equal the local sea level.
If you want to replace the seawater with air, you have to compress the air in the entire column of pipe and the sphere volume, and as you add pressure the level drops to where the external pressure is equalized.
Oil rigs get around this by having metal walled pipes – as was stated earlier, this must be some really special concrete to avoid outgassing from overpressure, requiring additional energy to keep the pressure up until it’s time to run the turbines in power output mode.
This scheme is nowhere near ready to deploy today as you stated – otherwise why is this a recent patent filing?
If the sphere were at -1500 meters (5000 feet) below the water, then the backpressure IS 5000 feet of water. Even if the pump were to just discharge 20 feet sideways, it is discharging against the full head of seawater pressing down that 5000 feet. Shallower water is possible, but then the stated benefits also go down.
I don’t accept the “ease” and reliability of running a multiple pump and generator system a mile below the sea generating that much power unmanned.
Bottom line, NO ENERGY SYSTEM IS FREE.
The inescapable Second and Third Law of Thermodynamics forces us to put in 1000 Megawatts of energy to get (less than 800 Megawatts back.) Add in the energy to build, pour, cast, and ship those spheres out 400 km (or less in some places0 anchor them to the seafloor successfully, and keep them there hooked up with that much energy flowing. Add in the power lost udnerwater thorugh current losses and heat losses. 10-14%.
the ONLY reason pumped storage works above ground is the immediate availability of CONTINUOUSLY and UNNEEDED EXCESS electricity in MASSIVE amounts at VERY, VERY cheap rates. The “cheap”power is used to pump up the storage lakes, then gravity drains those lakes downhill when the power is needed. You MUST ALWAYS put more power INTO the pumped storage unit than you get back out. At best, it moves the power cost to a different rate base.
Wind power is a known waste of resources and availability that delivers limited power only 1/6 of the time. Anchoring hundreds of those wind turbines offshore in 5000 feet water depths 250 – 300 miles at sea? To provide the source power back underwater a mile deep to an unmanned power plant 4 times the size of a big gas turbine unit? To then ship that power back to shore 250 – 300 miles away?
Even the simple “dumb” low voltage trans-Atlantic telegraph cables busted, wore out insulation, and were destroyed by undersea mud slides, tsunami’s and continental shelf movement. (Admittedly, some of these failures were in the mid-Atlantic and mid-pacific where they crossed the mid-ocean drifts, but still …. try running 48,000 volts at 1200 amperes current for years with no leaks and no faults … Then try to find that fault and bring it up the the surface to fix that pinprick of a flaw. Nasty problem.
I would suppose (and I have to suppose since there isn’t any information on how this really works) that there is a valve or flap which closes from the ocean side of the sphere, so that the water in the sphere can be pumped up to the surface and released. Then, supposedly, this flap or valve is opened at some point, allowing sea water to flow in and make contact with the turbine. The most sensible valve would be a gate valve. But, whatever is used is going to have to content with some pretty good pressure to open against, as well as being able to seal tightly so that the sea water only comes in when it is wanted. I would guess that the valve will need to be replaced every few months, along with the turbine. Sea water is rather reactive with most substances. And since the sphere is open to atmosphere part of the time, there will be plenty of oxygen embedded on surfaces, which will enhance the corrosion from the sea water.
PlainBill says:
June 2, 2014 at 8:47 pm
Well, you are sort of right.
A vented, even partially empty sphere underwater IS under pressure. Idea appears to be: You start with an empty concrete sphere, and pump the water out against the 5000 foot water head. The pump and motor are underwater at that 5000 foot depth, the replacement air is coming down the BIG vent tube that is somehow connected to a float back on the water surface. Hurricane and storm conditions topside to maintain the pipe free and clear and all of the other connections as the system and floats move are not yet known! Couple of billion for off-shore island platforms like oil rigs? The new Englanders, Virginians, North Carolina’s South Carolina’s, Florida, and New Jersey and New York and RI and CT voters have already rejected those!
So, you now have an empty sphere underwater that is resisting the compression force of the seawater at 5000 foot depth – about 2100 psig. You then flood the sphere through a pipe. The incoming flooding water drives a turbine (the original pump itself may, or may NOT work at those differential pressures and water speeds!!!!) which drives a generator which sends the AC power up to the floating vent tube to be somehow connected to a power lines running back to shore. Hopefully, you can figure out a way not to have go from 5000 feet down up to the top then back to the ocean floor -> copper is very, very expensive. On the other hand, putting a transformer under 2100 psi of salt water pressure is …. unlikely to work for long.
So, a few hours later, the sphere is now full. the power has been used up and sent elsewhere. You then but 120 – 130% of the power you just sold to send back to the pump to empty the sphere. i do want to see the pump impeller that can move water across a 2100 psig head. Both ways. Uphill. In the snow. 8<) In bare feet. Doesn't mean it is impossible.
But the pump vanes that work one direction CANNOT be equally efficient the other way at high pressures AND high flows. So I think they will need to end up with a turbine + pump + motor + generator combination. Slowing pumping out at high delta pressure and lower flow, fast turbine flowing in at high dp and greater control. But then you need many hours of pumping out to get only a few hours of flowing back in.
if yo ever loose control or power, the whole thing floods and you hope you have NOT flooded the pump+ motor+turbine+generator+controller+transformer room below. Or you have a flooded and very expensive basement of burned copper and melted bearings.
From the thread I linked to earlier, another comment from A. Scott:
No Roger, you left out the most important part – MIT tells us the spheres are $12 million each – and they tell us it would take 1,000 of them to provide the equivalent of 2 hours of energy from a typical conventional power plant. That comes out to $12 BILLION dollars in initial capital costs to provide the equivalent of 2 hours of power from a typical SINGLE conventional power plant.
Now to be fair, the MIT paper doesn’t say “two” hours, it says a “few” hours. But that hardly changes the point. When the capital cost of the system can provide power for only a “few” hours, while the same money buys a conventional plant that can operate continuously for years, it should be patently obvious that the capex expenditure for the storage capacity is simply uneconomical.
Of course, capex is only part of the equation. One has operating expenditures to consider also. The conventional plant needs a constant supply of fuel, plus maintenance to operate. For a wind farm coupled with this type of storage, the fuel is in theory free (provided that the wind does indeed blow). But what of maintenance?
As the MIT article says, the spheres have to be sunk in water ranging from 1200 to 2500 feet. The logistics of pouring them, transporting them, sinking them, and then hooking up all the plumbing to allow water to be pumped out and air to fill the void are daunting to say the least. Putting the pumps and generators and valves at depth would be a maintenance nightmare, every single adjustment and failed part requiring deep see divers and/or remote controlled robots to perform maintenance or repair tasks. It would be far more cost effective to simply run the plumbing to a floating platform where all the pumps and turbines and valves could be easily accessed.
Of course that doesn’t solve the problem of cracked or broken spheres or cracked or broken plumbing at depth. But it still wouldn’t be inexpensive by any stretch of the imagination. First of all, the floating platform will move up and down with everything from tides to storm surges, so your plumbing had best take that into account. Of course any plumbing with that kind of flexibility in it will be prone to cracking and breaking from constant mechanical stress. Then there is the cost of just getting to all the platforms (1000 of them!) at all. Since they need to be in 1200+ feet of water, they won’t be close to shore. Plus you are trying to maintain, even if several spheres are ganged together to serve a single platform, hundreds of pumps, turbines, and valves.
But worse than all of that is the distributed nature of the system. A conventional plant is basically central power generation that can be transmitted cost effectively to a distributed load, but the distribution network itself represents considerable cost and line losses . Wind mills represent a far less efficient means of generation. They are, essentially, a distributed generation system trying to serve distributed load. This means that there is considerably more network to build up front to gather the energy for distribution, and considerably more line losses as a consequence. Add a storage facility to the picture that is also distributed, and you’ve doubled the cost and line losses of the up front structure.
For me, the argument is over on the strength of the capex alone. It just makes no sense to build something that can provide power for a “few” hours when the same money builds a plant that can produce the same for years. But while the idea itself is pretty interesting, it fails also I believe on opex. The maintenance would be horrendous, and the efficiency losses associated with pumping water out (nothing is 100% efficient) plus lines losses and maintenance of the front end generation network itself, combine to far outweigh the price of fuel in a conventional plant.
From Roger Sowell on June 2, 2014 at 5:32 pm:
>The MIT spheres will do exactly the same function: draw power from the grid at night to pump water out of the spheres.
The proposal was storage of potential energy (not power) from the floating wind turbine farms, on site, not energy off the grid. The surging variable wind-derived energy might not be desirable during the day to maintain grid stability, especially when combining with photo-voltaic sources that are varying on a partly cloudy day. So it might be smoothed out by storage now and tapping later.
>Instead, they are vented by a pipe to the atmosphere. The sphere acts exactly like the lower reservoir. It is at atmospheric pressure at all times.
Thus will be needed extra-strong piping all the way down to 400 meters, or perhaps 1500 meters, thus many joints that cannot be permitted the slightest leakage lest the incoming high pressure water spray promptly erodes all material around the breach causing the sphere to flood. And over those lengths, you would not have absolute rigidity, but a pipe that would sway with the ocean currents, flexing joints.
>During the day, when peak power is required, seawater is allowed to flow by natural pressure from the ocean through the turbine/pump into the sphere, turning the generator and producing power to the grid. Water flowing in forces air out of the sphere through the vent line into the atmosphere.
Flow by gravity, from the surface. Which requires filtered water inlets to avoid sucking in debris, seaweed, and all the fish, aquatic mammals, and sea snakes that will have the Sierra Leone Club camping out at the UN and every environmental impact public input meeting the backers will ever have.
Let alone the incalculable amounts of sludge that will accumulate, from precipitating sediments, and during the growth and from the death of the myriad organisms of the rich organic soup called seawater.
>As to the servicing and maintenance issues someone asked above, this is trivial.
No comment needed.
>Likely, an elevator will convey workers and materials to the submerged sphere, much like in a mine shaft on land. There is no need to contemplate high-pressure underwater activities.
Tell OSHA you will not be providing reinforced emergency shelters in case of a pressure breach throughout the shaft length (as it could need servicing), that the elevator cab itself will not be one, and you’re not even drawing up a plan to ensure the workers can reach shelter before they are inundated and crushed during a catastrophic containment failure. You’ll likely end up with everyone encased in a personal armored submarine “suit” once they leave the surface.
>Purists will say, at this point, yes but what about screens to keep fish and other marine life out of the turbines? Those screens or similar devices may require periodic cleaning, but that can be done remotely with ROVs. (remote operated vehicles, think unmanned submarines).
If all such cleanings can be so easily done, why do they still dry dock ships for barnacle scraping? The inlets would be near the surface, so why use expensive ROV’s? The inlets would not be in use during maintenance, send over a guy in a wet suit.
>Spheres have a nice property for that, as materials required go up with the square of the radius, but volume increases with the cube of the radius.
Sphere volume is (4/3)*pi*r^3, r = radius. The concrete (with embedded reinforcements) has fixed pressure per area requirements, so a fixed wall thickness is a suitable approximation, thickness = T. Concrete used is outside volume minus inside volume.
So concrete used is
(4/3)*pi*r^3 – (4/3)*pi*(r-T)^3
= (4/3)*pi*[r^3 – (r-T)^3]
= (4/3)*pi*[r^3 – (r^2 – 2rT + T^2)(r – T)]
= (4/3)*pi*[r^3 – (r^3 – r^2T – 2r^2T + 2rT^2 + rT^2 – T^3)]
= (4/3)*pi*[r^3 – (r^3 – 3r^2T + 3rT^2 – T^3)]
= (4/3)*pi*(3r^2T – 3rT^2 + T^3)
Material required, at least the concrete for a uniform sphere of uniform wall thickness, does not go up by the square of the radius.
But to address a basic problem, it would be reasonable to project a material failure rate per unit of surface area. Larger spheres would thus have larger failure rates. Spheres can be automatically isolated from the system in case of failure. So why use harder-to-deploy giant spheres instead of nesting smaller ones?
>It was overlooked, apparently, by the naysayers that MIT stated the cost per sphere will decrease as more are deployed. This is the economy of mass production. Henry Ford recognized this with automobiles; it still applies today.
This is not cranking out 10,000 assemblages of 2000+ discrete parts every day of the year. This is the assembling of inside molds, wrapping around them multiple layers of reinforcements like stainless steel mesh and fabricating welded bent rebar frames in place, assembling the outside molds, then mixing up and pouring as many batches of concrete as each requires, being careful to avoid air bubbles. Then comes drying time. And as they are pressure vessels, testing, possible repair and retesting, and certification.
That’s not an assembly line. That’s simultaneously making multiple identical one-offs. All you’re really saving is some set-up time, and perhaps some bulk quantity material discounts.
>This wraps up the MIT sphere grid-scale storage technology. It works. It has zero energy cost.
So the making of raw materials, manufacturing, transport, installation, etc, used no energy? There are zero operational energy losses?
Or are you offsetting those costs with FREE wind energy, of which the offsetting amount would not be available for sale thus is a loss of revenue?
>Yet another cost reduction will occur as spheres are installed along trunk power lines laid on the ocean floor. It will not be necessary to build the electrical infrastructure again for each sphere.
and previously
>Proper design will have the entire turbine/pump and generator/motor equipment in the atmospheric pressure zone above the sphere. Simply put, that building will also be vented to the atmosphere.
Way too much complexity. If you pumped air instead, that equipment is on the surface, minimizing maintenance costs. You can use surface electrical cables, strung between buoys. And no intake water filtering, no great maintenance inside the shaft or sphere.
Of course just using a weight gives you those benefits and more.
The more I look at this, it seems MIT built a carbon-fiber frame and body, added low-profile low-mass wheels supported on liquid nitrogen cooled superconducting magnetic bearings mounted on polished chromed shafts cushioned by Kevlar composite leaf springs, included drive-by-wire electronic steering, and utilized a high performance bucket seat with integral heating and cooling, with GPS and a “Beats by Dr. Dre” satellite radio system thrown in, for a soap box derby.
Kadaka (quoting Sowell)
>Yet another cost reduction will occur as spheres are installed along trunk power lines laid on the ocean floor. It will not be necessary to build the electrical infrastructure again for each sphere.
The challenges with maintaining 1,000 connections into the trunk power lines on the ocean floor would be staggering. They are sealed and laid in a continuous fashion for a reason. Just installing the connections on the ocean floor would be cost prohibitive, not to mention that the failure of a single connection would allow water intrusion and the whole trunk line would fail. Plus, in order to take advantage of this supposed cost saving, you’d have to build the spheres in a long line following the trunk power line instead of in a given area. It is highly unlikely that the trunk power line would even follow a path through water that is the appropriate depth for the spheres.
No matter how you slice it, this would be an outrageously expensive thing to build, and outrageously expensive to operate, all for just a few hours of capacity.
I have experience with large scale application of seawater as a cooling agent. The system we designed and built pumps approx. 28000 liters per second (of seawater (once-through) through massive heat exchangers and condenser to cool a 1000MW power station. The debris load in seawater is huge. In order for our system to work reliable we apply multiple filter steps in which we filter the seawater to prevent ingress of fish, jellyfish, mussels, seaweed, plastic, wood, etc. etc. First we have a floating debris barrier with underwater openings, next a coarse filter consisting of vertical bars with 2 inches gree space between them. This screen is continuously raked clean by redundant automatic raking systems. Next are travelling band screens which filters to 1/4″ inch, continuously rotated and sprayed clean by high pressure water. It also ewuipped with a special (very expensive) fish return system, allowing fish to escape. Then comes another self-cleaning (backwash) filter system to get the last debris out.
Additionally we dose a small amount of hypochlorite is the water to prevent bio-fouling inside the very large seawater system. If we do not do this within one season the pressure drop due to growing musselbanks is so large we have to shut down.
If any one of these systems fail, the power plant has to shut down.
Good luck with the long term operation of the seawater filled concrete domes…
Friends:
We are at 99 comments in this thread which has been so successfully trolled by Roger Sowell that more than half the posts have been about his nonsense instead of the thread’s subject.
Perhaps when Sowell makes a post to any future threads pertaining to ‘renewables’ then someone could note his record of trolling such threads and his ‘contribution’ be left at that?
Richard
The “power spheres” are no different in function than water reservoirs on land. Except that they are significantly more complex to build and maintain as compared to the amount of energy they can store. Concrete does not like to flow in spheres, it like to lie flat during forming, making curved surfaces difficult at best. There are also issues with the pumping efficiency of air (compressible) as compared to water.
All and all, the power sphere are very much in line with the EPA’s politically correct message that you can raise the cost of energy production and somehow this structural inefficiency will benefit the economy. Russia (the former Soviet Union) was big on just such projects. Perhaps the United States will also get a new name when it too goes bankrupt.