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[Discuss] Eclipses Re: Great talks last night, however...
- Subject: [Discuss] Eclipses Re: Great talks last night, however...
- From: grg-webvisible+blu at ai.mit.edu (grg)
- Date: Mon, 24 Jul 2017 00:10:43 -0400
- In-reply-to: <8cb2284f-5a37-3798-c859-164e4afa7a98@gmail.com>
- References: <20170721205754.4BE3F143BB3@localhost> <366e0a2a-3192-e9b0-13ec-1f27fb321434@gmail.com> <20170722051439.GA20578@marjoram.csail.mit.edu> <9355baea-e212-e00e-2cf5-1073e51dd254@gmail.com> <20170723040038.GA24279@marjoram.csail.mit.edu> <14796dd4-4a0d-bdf6-0fd6-ca839ab3f709@gmail.com> <20170723162906.GA5184@marjoram.csail.mit.edu> <5d6022a7-48e9-39e5-d3fa-ad6fe9825016@gmail.com> <20170723194217.GB5184@marjoram.csail.mit.edu> <8cb2284f-5a37-3798-c859-164e4afa7a98@gmail.com>
On Sun, Jul 23, 2017 at 04:59:08PM -0400, Richard Pieri wrote: > On 7/23/2017 3:42 PM, grg wrote: > > In the paper they show that a conventional li-ion battery holds 90% of the > > original charge after 3000 cycles (~9 years of daily cycling); and after > > BS. > > http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries Hmm... did you look at the peer-reviewed journal article published in "Advanced Energy Materials" in 2014 which is the one making the claim you're calling BS (on the basis of "batteryuniversity.com")? Here are those links again for your perusing convenience: http://onlinelibrary.wiley.com/doi/10.1002/aenm.201401408/abstract;jsessionid=CBDD74C72BBF0C1C53B7FBB1AC2DB1B5.f04t03 https://www.osti.gov/pages/biblio/1185480-solid-electrolyte-key-high-voltage-lithium-batteries As for the "batteryuniversity.com" page which appears to have been written in 2010, can you point at which part of it you think contradicts the peer-reviewed article? For one, I fear that "batteryuniversity.com" page isn't reporting on the same battery technology; e.g. they say "Figure 1 illustrates the capacity drop of 11 Li-polymer batteries" but the numbers I quoted from the journal article aren't measuring Li-po batteries at all, they're measuring li-ion batteries with a liquid electrolyte (not polymer). Indeed, the whole point of that journal article is that the choice of electrolyte is critical for battery longevity. Second, the "batteryuniversity.com" article is showing numbers for 1-hour charge and discharge cycles, while the journal article is showing numbers for 10-hour charge and discharge cycles, much more relevant for solar power storage. Cycles as short as 1 hour significantly reduce the lifetime of these batteries; even that batteryuniversity.com page warns not to go any faster than 1 hour. My takeaway here is that when engineering solar power storage I'd pick the 2014 liquid electrolyte batteries the journal paper used as a baseline instead of the 2010 Li-polymer batteries that batteryuniversity.com reported on, and use ~12 hour charge and discharge cycles. > > Nor do those characteristics describe millions of homes and buildings. How > > many buildings do you think are destroyed in Kansas by tornados each year? > > Hundreds, for a survival rate of 99.99%. So no, it's not because cows are > > running away from approaching tornados or because they're sharing Farmer > > John's storm cellar, it's actually because 99.99% of the spots in Kansas > > don't have a tornado land on them. > > The size of a home or even a large barn in rural Kansas is a tiny > faction of the size of a 150km^2 (say) power station. Rural homes in > Kansas are spread out dozens to hundreds of kilometers apart. So when a > tornado touches down the chances of hitting a given home is small and > the chances of it hitting several is practically nil. > > Unless it hits Topeka. > > That 150km^2 power station? That's the size of Topeka which got > clobbered by a sequence of tornadoes in 1966. Yes, that was an awful awful natural disaster in the middle of the last century - claimed to be the 7th most damaging tornado event in all of recorded history. Of the 50,000 homes in Topeka at the time, almost 850 of them were destroyed and 3,000 were damaged in some way. So ~2% of homes in Topeka were destroyed, and ~6% had some damage. Of the 900,000 homes in Kansas at the time, that's ~0.1% destroyed, so only 99.9% survival rate of homes in Kansas for that year instead of the long-term average of 99.99%. Terrible for those who fell into that small percentage (and even worse for the 17 people killed, giving a human survival rate of only 99.99% in Topeka and 99.999% in Kansas); but with this outcome for one of the worst tornado disasters of all time, I still feel the cows and corn and solar panels have the odds in their favor. > > I guess you'll be surprised to learn that the ground is actually an > > effective heat sink; see the ground loops in heat pumps, which provide air > > conditioning by sinking the removed heat into the ground. Here's a source > > for you: https://energy.gov/energysaver/geothermal-heat-pumps > > The ground can hold a lot of heat energy but it doesn't conduct it much. > That's why a GHP spreads its ground loop system out across a large area. > You're not getting that from burying big battery packs unless you also > install the same kind of extensive ground loop system which costs to > install and maintain. Look at it this way: if you put a battery in the ground underneath a solar panel, the warming of the ground from that battery is going to be strictly less than the warming of the ground from the sunlight hitting it directly before the solar panel was installed. With an 85% charge/discharge efficiency, the ground is being warmed only 15% as much as under direct sunlight. Since there wasn't runaway heat buildup under sunlight, only 15% of that amount of heating is also not going to exceed the earth's ability to sink the heat away. Taking a step back, you don't really think that keeping a battery in its operating temperature range is going to be an insurmountable technical obstacle, do you? > Can ground-based work? Maybe. I don't think so. But even if it can be > done? It's still just a stop-gap being marketed as a solution by a man > who has a vested interest in selling batteries. I get that you don't want it to work and especially don't want Elon Musk to make any money off it, but are there any remaining technical problems which cause you to say you don't think this is technically feasible? To recap, in this thread we've established many technical reasons it can succeed: * 0.15% of land in the continental US (10,000 km^2) is all that's needed to provide all the electricity consumed in the US * you'd need an additional 0.02% of land if you put all the panels on the NY/VT Canadian border * but the Nevada and southern California deserts might be a better choice * battery storage only adds 15% to solar power generation needs * batteries last for many thousands of 12-hour charge and drain cycles * temperatures underground are moderate and stable; batteries housed there put much less heat into heat the ground than the sunlight would * electric vehicle batteries work pretty well even above ground in cold snow and in hot deserts * the Great Plains are large, flat, and exist in the North * as an annual average, 99.99% of things (corn, cows, houses, etc.) in Kansas aren't destroyed by tornados; and in the worst tornado disasters in history that goes down to only 99.9%. (this was part of a technical discussion on solar power feasibility? seriously?) * solar panel installations scale up and down pretty nicely; the total of 10,000 km^2 can be in one or across millions of sites, and either will still provide all the electricity consumed in the US. Given these facts I don't see it as a stop-gap at all; rather, I see it as the complete solution to our power generation needs for the coming centuries. Thousands of times more power than we're consuming is falling from the sky; it has been for eons and will be so for eons to come. Right now it's just heating up sand and dirt, but we today have the technology to convert just a 60 mile square patch of that into enough electricity to power the entire US, or a 150 mile square patch to power the entire world's electricity. Photovoltaics are solid-state, no moving parts, and convert light energy directly to electricity without putting stone-age steps like boiling water in the middle of it. This is a technical slam-dunk. --grg
- Follow-Ups:
- [Discuss] Eclipses Re: Great talks last night, however...
- From: bogstad at pobox.com (Bill Bogstad)
- [Discuss] Eclipses Re: Great talks last night, however...
- References:
- [Discuss] Eclipses Re: Great talks last night, however...
- From: rlk at alum.mit.edu (Robert Krawitz)
- [Discuss] Eclipses Re: Great talks last night, however...
- From: richard.pieri at gmail.com (Richard Pieri)
- [Discuss] Eclipses Re: Great talks last night, however...
- From: richard.pieri at gmail.com (Richard Pieri)
- [Discuss] Eclipses Re: Great talks last night, however...
- From: grg-webvisible+blu at ai.mit.edu (grg-webvisible+blu at ai.mit.edu)
- [Discuss] Eclipses Re: Great talks last night, however...
- From: richard.pieri at gmail.com (Richard Pieri)
- [Discuss] Eclipses Re: Great talks last night, however...
- From: grg-webvisible+blu at ai.mit.edu (grg)
- [Discuss] Eclipses Re: Great talks last night, however...
- From: richard.pieri at gmail.com (Richard Pieri)
- [Discuss] Eclipses Re: Great talks last night, however...
- From: grg-webvisible+blu at ai.mit.edu (grg)
- [Discuss] Eclipses Re: Great talks last night, however...
- From: richard.pieri at gmail.com (Richard Pieri)
- [Discuss] Eclipses Re: Great talks last night, however...
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