Guest Post by Willis Eschenbach
Inspired by an interesting guest post entitled “An energy model for the future, from the 12th century” over at Judith Curry’s excellent blog, I want to talk a bit about energy storage.
The author of the guest post is partially right. His thesis is that solving the problem of how to store city-sized amounts of electricity would make a very big difference, particularly for intermittent sources like wind and solar. And he’s right, it would. But he’s wrong not to point out how devilishly difficult that goal has been to achieve in the real world.
Storage of electricity is a very strange corner of scientific endeavors. Almost everything in a 2013 car is very different from what was in a 1913 car … except for the battery. Automobile batteries are still lead-acid, and the designs only differ slightly from those of a hundred years ago.
Figure 1. Elements of a lead-acid car battery. SOURCE
Now, we do have nicads and such, but the automobile storage battery is the bellwether for the inexpensive storage of electricity. Cars need a surprisingly large amount of energy to start, particularly if they are balky. If there were a cheaper way to store that big charge, it would be on every car on the planet. Given that huge market, and the obvious profits therein, people have been busting their heads against the problem since before Thomas Edison made his famous statement about automobile batteries.
And despite that century-long huge application of human ingenuity, in 2013 the lead-acid battery still rules. It’s an anomaly, like fusion energy, a puzzle that has proven incredibly hard to solve. Potential solutions have all fallen by the wayside, due to cost, or capacity, or energy density, or dangerous components, or long-term stability, or clogging, or rarity of materials, or a habit of exploding or melting down, or manufacturing difficulties, the number of pitfalls is legion.
So I’ll get excited when we have something other than lead-acid batteries in our cars. Because that will be evidence that we’ve taken the first step … but even that won’t be enough. The other problem is the huge amount of energy we’re talking about. Here’s some back-of-the-envelope figures.
New York City’s electricity consumption averaged over a 24/7/365 basis is on the order of 5 gigawatts (5E+09 watts) continuous. Let’s take a city a tenth of that size, there’s plenty of them on the planet, China alone has dozens and dozens of cities that big, and lets consider how much storage we’d need to provide three days of stored electrical energy for that city. The numbers look like this
5.0E+08 watts continuous times 72 hours equals 3.6E+10 watt-hours of storage times 3.6E+03 seconds/hour gives 1.3E+14 joules of storage needed
So that means we’d need to store 130 terajoules (130E+12 joules) of energy … the only problem is, very few people have an intuitive grasp of how much energy 130 terajoules is, and I’m definitely not one of them.
So let me use a different unit of energy, one that conveys more to me. That unit is “Hiroshima-sized atom bombs”. The first atomic bomb ever used in a war, the Hiroshima bomb released the unheard of, awesome energy of 60 terajoules, enough to flatten a city.
And we’re looking to store about twice that much energy …
I’m sure that you can see the problems with scalability and safety and energy density and resource availability and security for that huge amount of energy.
So while I do like the guest author’s story, and he’s right about the city-sized storage being key … it’s a wicked problem.
Finally, as usual, Judith has put up an interesting post on her interesting blog. I don’t subscribe to a lot of blogs, but hers is near the top of the list. My thanks for her contribution to the ongoing discussion.
w.
PS—Edison’t famous statement about automobile batteries? He was offered big money in those days, something like ten grand from memory, to design and build a better battery for electric automobiles than the lead-acid battery. He took the money and went back to his laboratory. Month after month, there was no news from him. So the businessmen who’d put up the money went to see him. He said he didn’t have the battery, and in fact he didn’t even have the battery design.
Naturally, they accused him of having taken their money and done nothing. No, he assured them, that wasn’t right at all.
He said there had actually been significant progress, because he now knew of more than fifty ways NOT to make a battery for an electric automobile …
Curiously, Edison ended up inventing a nickel-iron-peroxide battery, which was a commercial failure … so even he couldn’t get past lead-acid.
Similarly, we now know hundreds and hundreds of ways not to make a battery for a city. So I suppose that’s progress in Edison’s terms, but after a century the wait’s getting long. I suspect we’ll solve the puzzle eventually, perhaps with something like a vanadium flow battery or whatever, but dang … it’s a slow one.
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There is no need to store electricity as such.
JDN says:
June 30, 2013 at 11:54 am
Thanks, JDM. You need to investigate the concept of “energy density”. Your question is like pointing out that in a square mile at noon we get about two and a half million kilowatts of solar power … and that’s true, but it’s not dangerous because of the energy density, which is quite low.
The problems occur when you try to squeeze a NYC’s worth of energy into a small box …
w.
Tesla worked for Edison 1882 to 1885.
Tesla resigned after redesigning DC motors and generators for Edison.
1888 Tesla works for Westinghouse
1891 Westinghouse w/ Tesla wire Lauffen-Neckar (225 kW) in Germany and Ames Hydro (75kw one phase) in America.
1892: Germany sold on AC, GE board of directors overrule Edison and invest in AC.
1893: Westinghouse w/ Tesla wire Chicago World’s Fair with 3-phase (11,000 kW) and
win the Niagara Fall Power Plant contract to build ten (3,700 kW) 25 Hz. AC generators
Edison had Tesla. Edison let Tesla get away.
And J.P.Morgan made many time more money on electrical power than either of them put together.
We have fossil fuels available for thousands of years to come. That provides us with sufficient time to invent something really radical and effective. Wind mills, solar panels, batteries for mass energy storage…. forget all about it.
Stephen Rasey says:
June 30, 2013 at 12:04 pm
Thanks, Steven. This time I checked your numbers and they are 100% correct, which is what us scientists say when we mean “you agree with me” …
And that is a fascinating calculation—freezing a given mass of water requires the same amount of energy as raising that same water 34 kilometers vertically … dang, there’s a surprise for me.
The only flaw I can see in the plan is that you can’t easily turn it back into electricity. But given that the peak electrical load in many regions is for air conditioning, it certainly seems like a very feasible plan to store up “coolth” during the night and release it back into the building during the day.
w.
@Willis 1:45 pm
The only flaw I can see in the plan is that you can’t easily turn it back into electricity.
No such claim. Only it saves you from NEEDING as much electricity during the day. What has happened is that you have successfully stored the WORK. Therefore energy being generated during the peak times can be used for other demands. Think of it as better than pumped reservoir storage because of increased efficiency (thermal cooling of air) and reduced transmission capacity from pumped storaged reservoir to city.
To Scarface:
Uranium fission (or plutonium fission, for that matter) only
converts a small amount of the critical mass. For example,
the mass of uranium-235 in the Hiroshima ‘Little Boy’ bomb was
42.6 kg. You can’t make U-235 react in significantly smaller
quantities–you must have critical mass. One of the reasons
why plutonium is now used almost exclusively in fission bombs
is that you can get it to go critical by explosively compressing
it; thus you can control the size of the critical mass. But, this
involves a cataclysmic release of energy which destroys the
storage device.
The conclusion is that E=mc^2 is a powerful lever to store
energy, but releasing it is another matter.
Thinking outside the box … what about using existing water bodies in areas with sufficient drop?
In the Mpls MN area there is a large lake – Lake Minnetonka. Downtown Mpls already has hydro electric in the old grain milling area at St. Anthony Falls. It is appx 13 miles (direct freeway connects the two – would allow a comparatively clear construction corridor) and 203 feet drop.
Here are some ‘backyard mechanic’ level calculations – no idea if feasibility (ie: what problems might be incurred with the long distance etc) but if I did math right seems a fair amount of energy possibility there.
I also wonder if the connecting culvert could be also used for a regional stormwater collector system as well, which brings up another interesting option as well.
St Anthony Falls (downtown Mpls on Mississippi river) – elevation; upper pool 799 feet, lower pool 725 feet (There is existing hydro plant at this location now).
Lake Minnetonka – elevation; 929 feet – distance appx 13 miles – Drop = 204 feet or 62 meters
14,528 acre lake @ur momisugly 1 feet drop = 14,528 acre-feet
(1 acre foot is equal to 1233.48185532 cubic meter)
14,528 acre-feet x 1233.48 = 17,913,024 cubic meter
(1 cubic meter = 0.272 kWh – assuming 100 meter head)
17,913,024 cubic meter x 0.272 kWh = 4,872,342 kWh = 4,872 MW
10’x10’ culvert (100 sqft) = 10 cubic feet/foot
10 cubic ft = 0.28317 cubic meters per foot of culvert
Assume 13 miles of 10 sq ft culvert = 68,640 feet
x 0.28317 cubic meters per foot
= 19,437 cubic meters for 13 miles
x 0.272 kWh/cubic meter (assuming 100 meter head)
= 5,286 kW or 5.29 MW
Adjust above for 62 meter vs 100 meter drop
Chris R. says: June 30, 2013 at 2:21 pm To Scarface: “Uranium fission (or plutonium fission, for that matter) only converts a small amount of the critical mass.”
That is intrinsic to ‘bomb’ and not intrinsic to fission.
Rud Istvan says:
June 30, 2013 at 1:52 am
“Pumped hydro (or cousin variable release hydro) accounts for over 99 percent of grid storage.”
I would ;have thought that coal, natural gas and nuclear make up 95+ % of grid storage. I Can’t seem to reconcile hydro being another 99%
FYI New York City actually has an emergency pump storage facility in upstate NY.
http://en.wikipedia.org/wiki/Blenheim-Gilboa_Hydroelectric_Power_Station
The two deepest bore holes drilled (7.4 miles & 7.1 miles) ran into the common problem of 568 degrees F.
It would seem a robotic drill head with added coolant using a vacuum extraction system for the debris/cuttings could overcome that issue.
Getting another 5% in depth = “The Jackpot” for a nice 1700 degree Geo-Thermal source to drive steam driven turbines…
RE: how much of critical mass is converted to energy:
Though the chart linked below doesn’t directly answer that, it is a nifty chart I found last week while reading up on Thorium Fuel Cycle reprocessing.
Composition of Conventional Nuclear Fuel
(17×17 Westinghouse, 3% Enriched, 1100 day irrad, 33000 MWD/MTU, discharge composition
http://energyfromthorium.com/images/slide_LWRfuelComp.png
After 3 years [refueling point, I suppose]
the U-235 goes from 3% to 1.1% (U-235+U236)
the U-238 goes from 97% to 94.5%, with Plutonium going to 0.9%
with about 3.5% nuclear poisons and other fission products.
I’m not sure I fully believe it…. I read elsewhere that some of the initial load is salted with short lived poisons to account for the higher enrichment at the start of the run.
arthur4563 says:
June 30, 2013 at 5:13 am
> The idea that Edison never invented anything is about as clueless a clam as I’ve ever seen, as is the claim that Tesla was some sort of super inventor.
Thanks. I don’t have time to write much today, but Edison’s eldest daughter lived next to my grandmother – Aunt Marion as my father and I called her – gave me my first Edison books. Edison was not a scientist – but he was an incredibly prolific inventor with several inventions still going strong.
“That’s the way labs whose output includes intellectual property operate. When you sign up, you agree that things that you invent on company time belong to the company and not to you, just like in Edison’s lab. And that does NOT mean that Edison (or Hewlett and Packard) stopped inventing when they started their labs, it just means that Edison ended up with the patent rights for things invented by men in his employ, just like Hewlett and Packard.”
Willis, you are 100% right, that’s the way when one is employed by a Company.
In my former employ, with a large corporation, all professional employees had a contract that made it clear how inventions are handled.
As one who was involved with numerous patents, the procedure was that your name appears on the patent along with other inventors but the Company owned the patent and paid for all the lawyers and fees to get the patent issued. Also they get to defend it if it is challenged. My former company would provide nice monetary awards and recognition when the patent was applied for and again if the patent was issued. Currently as a consultant for a corporation I presume all relevant inventions are owned by the corporation since they pay me for my time working on the technology.
I am surprised that anyone would think otherwise.
MrX,
Since inventing commenrcial products is easy, could you invent something for us? I’d like to see how it’s done. Thanx in advance. ☺
My solar panels produce on a cloudy day in winter produce just 5% of the electricity they produce on a sunny day in summer. My latitude (from memory) is 36 degrees, and as you move toward higher latitudes, this problem can only get worse, Storing power over the annual cycle is a 2 orders of magnitude bigger problem than storing power over the 24 hours.
———-
As many people have pointed out in the comments, political/social issues are the main obstacle to building stored hydro facilities. The way around this is to build integrated stored hydro and water distribution systems. This brings powerful lobbies onboard like farmers.
These systems could be used to produce low head hydro in the real time pricing scenario crosspatch describes.
And what about looking at using storm water outflow in areas with significant rain events? The city of Mpls alone has 550 miles of stormwater pipe, 17 miles of stormwater tunnels, 16 ponds and 384 outfalls (where the system discharges to surface waters). Additionally MNDOT has a huge system that collects massive amounts of water from the highways.
Why not, as the systems are rebuilt, do what we did with sanitary sewer many years ago, and create a collector system that aggregates and directs that water to one of several processing points – where it can be used to generate power before being discharged into the rivers etc. Now all sewage is directed to a single huge plant along the river. Most of the surrounding suburbs do the same – directing raw sewage to a single plant in the south metro located on the MN River.
Seems we could do same with stormwater – instead of treatment plants could be generating plants.
Maybe combine with type pumped storage system that used area water bodies during normal times that could capture stormwater and use it when it rained.
The Mpls “chain of lakes” comprise over 1,000 acres, are (or could easily be) interconnected, are appx 130 feet above the elevation of the St Anthony Falls hydro plant in downtown Mpls, and are appx 4 miles away. At 1,100 acres surface area, a 1 foot drop if we assume 100 meter head height would equal about 369 MW if I did math right – this would have to be adjusted to the actual 128 foot (39 meter) head that exists – appx 40% of the 100 meters.
This link has interesting discussion on “National Battery”
http://physics.ucsd.edu/do-the-math/2011/08/nation-sized-battery/
Excerpts:
Running a 2 TW electrified country for 7 days requires 336 billion kWh of storage.
A 12 V battery rated at 200 A-h (amp-hours) of charge capacity stores 2400 W-h (watt-hours: just multiply voltage and charge capacity), or 2.4 kWh. Large lead-acid batteries occupy a volume of 0.013 cubic meters (13 liters) per kWh of storage, weigh 25 kg/kWh (55 lb/kWh), and contain about 15 kg of lead per kWh of storage.
Putting the pieces together, our national battery occupies a volume of 4.4 billion cubic meters, equivalent to a cube 1.6 km (one mile) on a side. This battery would demand 5 trillion kg (5 billion tons) of lead.
A USGS report from 2011 reports 80 million tons (Mt) of lead in known reserves worldwide, with 7 Mt in the U.S. A note in the report indicates … the estimated (undiscovered) lead resources of the world at 1.5 billion tons.
At today’s price for lead, $2.50/kg, the national battery would cost $13 trillion in lead alone, and perhaps double this to fashion the raw materials into a battery (today’s deep cycle batteries retail for four times the cost of the lead within them). The … $25 trillion price tag is more than the annual U.S. GDP. Recall that lead-acid is currently the cheapest battery technology.
Even if we sacrificed 5% of our GDP to build this battery (would be viewed as a huge sacrifice; nearly a trillion bucks a year), the project would take decades to complete.
But even then, we aren’t done: batteries are good for only so many cycles (roughly 1000, depending on depth of discharge), so the national battery would require a rotating service schedule to recycle each part once every 5 years or so. This servicing would be a massive, expensive, and never-ending undertaking.
RE: how much of critical mass is converted to energy in fission in a nuclear reactor.
Wikipedia: “When a uranium nucleus fissions into two daughter nuclei fragments, about 0.1 percent of the mass of the uranium nucleus[6] appears as the fission energy of ~200 MeV. ”
This only applies to the fissioning nucleus.
From the LWRFuelComp image above, Maybe only 4 % of the mass fissions.
That would make only 0.0004 of the core’s fissionable mass get converted to energy.
Let’s work backwards.
Assume a 1GW reactor running about 3 years, with 33% efficiency conversion from core thermal to electricity. Based upon E = mc^2
Electrical energy from Fuel Load: 1 GW * 3 yrs = 1100 GW-Days (rounded)
1 GW-day = 86 TeraJoules
1 TeraJoule = 1.00E+12 Joules
Electrical energy from Fuel Load: 1 GW * 3 yrs = 9.50E+16 Joules
assume 33% efficiency thermal to electricity. = 2.88E+17 Joules (core thermal)
Thermal E = mc2 = 2.88E+17 kg-m^2/sec^2
speed of light = c = 3.00E+08 m/sec
c^2 = 8.99E+16 m^2/sec^2
mass converted to Energy in 3 year run = E/c^2 = 3.20 kg
If core uses = 24000.00 kg uranium
Fraction of core converted to energy in 3 year run: = 0.000134
Stephen Rasey says:
June 30, 2013 at 2:04 pm
@Willis 1:45 pm
The only flaw I can see in the plan is that you can’t easily turn it back into electricity.
No such claim. Only it saves you from NEEDING as much electricity during the day. What has happened is that you have successfully stored the WORK. Therefore energy being generated during the peak times can be used for other demands. Think of it as better than pumped reservoir storage because of increased efficiency (thermal cooling of air) and reduced transmission capacity from pumped storaged reservoir to city.
Stephan … to me that’s brilliant out of the box thinking – its finding a solution to the problem rather than to a component of the problem. And why couldn’t that tech be adapted to the “home” level – and used to operate both AC but also possibly refrigeration as well.
Dealing JUST with the AC peak electric demand with widespread use of these systems could make a significant difference in our peak energy needs. Creating a home and small business sized module would allow a true large area distributed energy storage system. I wild guess would be that the savings in electrical generation capacity could potentially pay for a large part of this system.
And if I recall there are ways to use cold to generate heat – heat exchangers and ideas like this:
http://www.gizmag.com/cold-water-heater/26941/
Any idea of the physical size that might be required for a home?
@A. Scott 3:44 pm “National Battery”
I remember reading that about a year ago, but I lost the reference. I’m glad you found it and thanks for posting it. It is a good one, especially the part about the comparison between lead requirements (5 gigatons), current US reserves (7 megatons) and estimated world resources (1.5 gigatons (extractable at much higher prices)
“Philip Peake says:
June 30, 2013 at 9:33 am
I looked at my bill for Feb. My house is all electric………”
Philip,
Taking your figures of 100KWH per day to run your house on electricity in the winter = 100*1000*60*60= 3.6*10^8 Joules per day
I found a modest car battery (063 Lucas Car Battery Length 210 mm Width 175 mm
Height 175 mm) on EBay for 40 GBP say 60 USD which holds a full charge of 41 AH at 12 volts which I make 12*41*60*60 = 1.771*10^6 Joules. You suggest 50% efficiency and we are looking for 3 days of power so the number of batteries needed is 3*(3.6*(10^8))/(0.5*(1.771*(10^6)))= 1,220 at 60USD each but I’m sure there would be a deal for bulk purchase so= just over 73K USD at worse.
Now where would one keep 1,220 car batteries, that’s 7.8 Cubic Meters of batteries (call it 2Mx2Mx2M) costing 73K USD. Small is beautiful. But they are guaranteed for 2 years so I’d expect a recurring replacement cost of 36K USD per year. Then there is the cost of recharging them when the wind is blowing etc la-la-la.
And just outta curiosity but what about home generation? What is the cost/benefit of running a small generator powered by natural gas during peak times? Many/most homes in the urbanized areas of the US have natural gas to the home. Rural areas often have propane. Decent backup generators are avail for $3000 – $10,000, which would go down further with more widespread use.
Most can generate far more than the needs of the home, or could be scaled up in capacity to do so – any reason they couldn’t sell power back to the grid.
Again – a different form of peak demand generation – wide area distributed network. In effected a form of stored energy, albeit one that requires natural gas to operate. Most also will run on gasoline I think – which provides emergency power in case a natural disaster disrupts the grid and or natural gas distribution.
Three days supply is more than excessive.
1) In an emergency we usually lose electricity for part of a city.
2) A wiser solution would be to design grid distribution for rationing out power for essential requirements in an emergency – a few light bulbs, operating essential equipment and appliances – maybe 10% of the usual supply to the areas that are down.
3) Have back-up power – large and small for generating emergency power (we generally do have).
4) Work like heck to restore the power. It would be cheaper to employ 2 or 3 times as many electrical workers than to have some massive storage replacement.
5) Even one tenth of your storage would make for a serious target.