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How Sustainable Is Stored Sunlight?

99 点作者 stonlyb大约 10 年前

12 条评论

Hermel大约 10 年前
Great to see someone actually doing some calculations instead of just presenting a cosy vision. For example, they argue that - contrary to what Elon Musk implies with his illustrations - the solar cells on the roof of the gigafactory will only be able to generate a small fraction of the energy required to run it.<p>&gt; The average solar insolation in Arizona is 1,964 kWh&#x2F;m2&#x2F;yr (in Phoenix). If we assume a solar PV efficiency of 15%, one m2 of solar panels would generate at most 295 kWh per year. Consequently, almost 68 square kilometers of solar panels (6,800 ha) would be required to power the factory -- a calculation that also relies on the assumption that solar energy is equally distributed throughout the days and the seasons (or stored in batteries), and that there&#x27;s no open space between the panels. Remarkably, Tesla shows an illustration of the factory with solar panels on the roof. Knowing that the factory will occupy a surface of 1 ha, while 6,800 ha of solar panels is required to run it on renewable energy, Tesla&#x27;s claim is an obvious example of greenwashing -- and everyone seems to buy it.
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ars大约 10 年前
Money quote: Using the worst assumption in each case, solar cells with storage emit 631 gCO2e&#x2F;kWh vs 337 gCO2&#x2F;kWh for normal hydrocarbon fuel in spain.<p>Important takeaway: A solar cell embodies a huge amount of energy, yet can be shipped. Make solar cells in places with lots of clean energy and ship them elsewhere.
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dpierce9大约 10 年前
The conclusion of this article is that a life cycle analysis of solar with storage is better than the marginal contribution of greenhouse gases from operating a traditional plant but not by a lot. Has anyone seen a life cycle analysis of decommissioning a coal or nuclear plant or managing tailing ponds? I commend the effort to make apples to apples comparisons but that would need to be added in to make this genuinely apples to apples.
lotsofmangos大约 10 年前
<i>&quot;the manufacture of 1 kWh of lithium-ion battery storage requires 400 kWh of energy, the factory would require 20,000 GWh of electricity per year to manufacture all these batteries.&quot;</i><p>The 20,000 GWh figure is clearly bollocks, one factory a hectare in size is not going to be using the same amount of electrical power as the whole of Nigeria.<p>edit - also, one thing I do not understand with their argument, is if Tesla&#x27;s illustration is really supposed to show that the factory can run entirely on rooftop solar, why would it feature around 100 large wind turbines dotted all across the hillside?
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Jedd大约 10 年前
They lost me at their second sentence:<p><pre><code> &gt; In order to fill these gaps [ night, cloud ] , a storage solution &gt; or a backup infrastructure of fossil fuel power plants is required &gt; -- a factor that is often ignored when scientists investigate the &gt; sustainability of PV systems. </code></pre> If you&#x27;re approaching the problem with solar power with the assumption you need storage or fossil fuel, you&#x27;re basically arguing with yourself.<p>Note they did say &#x27;solar power&#x27;, not &#x27;solar cells &#x2F; PVC &#x2F; etc&#x27;. Solar thermal plants ride through periods of cloud, and well into the night, reasonably well. But the big problem is that assumption that you must either store solar, or you burn coal &#x2F; oil ... followed by a complaint that scientists ignore important factors.
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throwaway90446大约 10 年前
I&#x27;m <i>still</i> trying to figure out why everyone, including Deutsche Bank, seems to think the Tesla Battery is such a great deal at $3500 for 7kwh.<p>I can buy 18 35Ah 12v AGM batteries, plus 0 AGW conductors, for about $1350. That&#x27;s 7.5kwh for $1350.<p>What <i>exactly</i> defines the &quot;good deal&quot; argument I keep seeing?
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ChikkaChiChi大约 10 年前
I keep imagining a world where Solar is our primary source of electricity and I keep seeing that world lose its mind when a volcanic ejection leaves us powerless.<p>I get that it should be part of a much larger plan, but Solar in its current iteration doesn&#x27;t seem like that safe of a bet.
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nnain大约 10 年前
This new push towards off-grid, battery-powered solar power just doesn&#x27;t sound right. Batteries might have improved, but they are high maintenance and polluting. Moreover this requires the addition of a lot of new electrical circuitry at the point of installation - a waste of space, time and money.<p>It&#x27;s the responsibility of the world&#x27;s governments to work out ways to keep the grid-connected solar solutions working. Maybe change the &#x27;Net metering&#x27; rules to buy the solar power from customers at a lower price, and let the supply-demand work itself out.<p>It&#x27;ll be very stupid if we let go a well-functioning grid based solar power solution just because some power distribution companies don&#x27;t find it profitable.
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kstenerud大约 10 年前
It&#x27;s a bit silly to argue over where materials are made when considering sustainability, as that requires an assumption that the &quot;dirty&quot; productive capacity would otherwise not be used for anything else.
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spenrose大约 10 年前
He&#x27;s completely ignoring the effects on the grid, which will be huge. Batteries are also a complement to wind, for example. Here&#x27;s one piece discussing that dynamic; there are many others at e.g. Greentechmedia.com.<p><a href="http:&#x2F;&#x2F;rameznaam.com&#x2F;2015&#x2F;04&#x2F;14&#x2F;energy-storage-about-to-get-big-and-cheap&#x2F;" rel="nofollow">http:&#x2F;&#x2F;rameznaam.com&#x2F;2015&#x2F;04&#x2F;14&#x2F;energy-storage-about-to-get-...</a>
ansible大约 10 年前
The article mentions getting 7000 charge&#x2F;discharge cycles from lithium ion batteries. That doesn&#x27;t sound right to me. Most consumer electronics are lucky to get 300 or so at 100% discharge.
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csirac2大约 10 年前
I had to abandon my reading before I reached the end, I was too angry at the disgustingly sloppy referencing. In particular his second paragraph put me in a bad mood straight away:<p>&gt; In order to fill these gaps, a storage solution or a backup infrastructure of fossil fuel power plants is required -- a factor that is often ignored when scientists investigate the sustainability of PV systems.<p>Um. Pardon? Either he&#x27;s having an argument with himself, or he&#x27;s reading some pretty lame journals. Or is he just confused? Let&#x27;s see:<p>&gt; Obviously, this strategy requires a backup of fossil fuel or nuclear power plants that step in when the supply of solar energy is low or nonexistent. To make a fair comparison with conventional grid electricity, including electricity generated by biomass, this &quot;hidden&quot; part of the solar PV system should also be taken into account. However, every single life cycle analyse of a solar PV ignores it. [3, 2].<p>Yeah, okay. That&#x27;s a perfectly debatable paragraph. So let&#x27;s see the science behind the claim: [2] has nothing to do with anything! It <i>addresses</i> energy storage, but is not <i>about</i> energy storage; and it does NOT claim to be a literature review, nor does it claim to reference &quot;every single life cycle analysis&quot;. Am I missing something? Is this citation of &quot;[3, 2]&quot; supposed to represent the entire sum of human scientific knowledge on this matter? Am I an idiot? Surely I&#x27;m the idiot, I didn&#x27;t waste my time reading this article - that point must be shooting straight over my head!<p>Okay, let&#x27;s read the paper. It&#x27;s on energy payback&#x2F;cannibalism - a logical presentation from what I skimmed - but is absolutely focused on the energy life cycle analysis of a <i>whole technology</i> experiencing <i>rapid growth</i> - Eg. nuclear back in the day - whereby the energy invested to rapidly establish new technologies may be greater than or at least massively offset any efficiencies (or indeed, &quot;zero emissions&quot;) they may have over existing (think &quot;sunk cost&quot;) incumbent energy production.<p>Which has nothing to do with central thrust of this article which seems to be that we should point and laugh at all those idiot scientists who forgot that the sun disappears each night!<p>But this writing forgets one thing - who is saying that PV (or wind for that matter) can replace established baseload power generators in a 1:1 swap?<p>Nobody sane, that&#x27;s for sure. So I&#x27;ll give you a hint: it&#x27;s electricity buyers. They don&#x27;t give a damn that they&#x27;re destroying the planet by using PV solar, the fundamental fact is that in countries like Australia, even though you seemingly can&#x27;t swing a cat without tripping over high-grade thermal coal ideal for cheap power, we pay among the highest electricity rates in the world. It&#x27;s that kind of corrupted and&#x2F;or government-regulated inefficiency that is the only thing to blame for the fact that PV solar can compete at all, even when subsidies are withdrawn.<p>I can&#x27;t keep reading.