tag:blogger.com,1999:blog-7005412100005882053.post4887280223150439595..comments2023-03-13T01:06:40.269-07:00Comments on BountifulEnergy: EROI doesn't matterTomhttp://www.blogger.com/profile/18396160316791132955noreply@blogger.comBlogger82125tag:blogger.com,1999:blog-7005412100005882053.post-22524478884862481702021-05-14T17:16:21.059-07:002021-05-14T17:16:21.059-07:00Hi Al,
No, because that is a far outlier study. T...Hi Al,<br /><br />No, because that is a far outlier study. There are more than 40 studies on solar EROI, almost all of which report far higher values than that. The Ferroni and Hopkirk study is a far outlier which has been widely refuted (just google for it).<br /><br />An excellent meta-analysis of solar EROI is here:<br />https://ideas.repec.org/a/eee/rensus/v72y2017icp1241-1255.html<br /><br />It's a meta-analysis of 29 studies and finds an aggregate EROI of 14.4. It looks at the highest-quality studies and comes up with a reasonable, balanced figure.<br /><br />The EROI of solar PV is improving over time, so the figure of 14.4 supplants older figures. <br /><br />The reason for lower figures is often because of outdated data. The EROI of solar PV was much worse before 2008. Koppelaar points out that many new studies still rely upon outdated data. The more recent data (after 2008) indicates an EROI of 14.4. This number is not correcting for waste heat losses.<br /><br />-Tom S<br />Tomhttps://www.blogger.com/profile/18396160316791132955noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-80527352743597714482021-04-05T05:59:14.785-07:002021-04-05T05:59:14.785-07:00When you say you think solar panels have an EROI o...When you say you think solar panels have an EROI of 6, I assume you are using the primary energy equivalent EROI that is quoted by most solar panel supporters (energy input / energy output / grid efficiency), rather than basic EROI (energy input /energy output). For commercial solar panels being installed in middle latitudes the basic EROI is somewhere between 1.1 and 2.6 (Ferroni & Hopkirk 2016; Raugei et al. 2017; F&H 2017). Can you provide a reference for your numbers?Al Scotthttps://www.blogger.com/profile/06453275365041153754noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-28798374720508825502019-05-16T00:16:34.189-07:002019-05-16T00:16:34.189-07:00This comment has been removed by a blog administrator.Naveed Mughalhttps://www.blogger.com/profile/10692198202169963899noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-12890799739209624872017-04-16T20:48:08.778-07:002017-04-16T20:48:08.778-07:00Thanks David. I'll take a look.
-Tom SThanks David. I'll take a look.<br /><br />-Tom S<br />Tomhttps://www.blogger.com/profile/18396160316791132955noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-69218377646872794672017-04-13T20:08:13.407-07:002017-04-13T20:08:13.407-07:00There is a discussion here of your post that you m...There is a discussion here of your post that you might like to look at.<br />https://georgejetson.org/2017/04/13/the-eroi-energy-multiplier-hypothesis/<br /><br />" As a modern society, we choose to reinvest 20 or so percent of our production. Energy industries exist to support society, not themselves. So if we take the 20% that is surplus energy (for an EROI of 1.2:1) and multiply it by the 20% that is available for reinvestment, we get only 4% that is available to ‘grow’ the energy source."<br />David McMullenhttps://www.blogger.com/profile/08631335541115670268noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-2745399200079771152016-01-29T21:57:41.373-08:002016-01-29T21:57:41.373-08:00Thanks for the reply! I also like the idea of long...Thanks for the reply! I also like the idea of long distance HVDC lines to enable more solar connection, like being able to charge electric cars at night with solar with only about a 10% or so line loss. fireofenergyhttps://www.blogger.com/profile/02197100366012949976noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-87791320708406420442016-01-27T22:24:13.803-08:002016-01-27T22:24:13.803-08:00Dan L:
No.
"However, any conclusions as to ...Dan L:<br /><br />No.<br /><br />"However, any conclusions as to whether the EROI of renewables surpasses that of fossil fuels would have to take into account the amount of subsidies given to each industry, which I don't see you tackling here."<br /><br />No, because the subsidies for renewable are <b>monetary incentives</b>. If some government decides to offer a $0.05/kwh subsidy for solar PV then that has no effect on its EROI.<br /><br />"It also doesn't take into account that liquid fossil fuels are used in great amounts for transport. Converting from most renewables to liquid fuels is a highly inefficient process,"<br /><br />I'm not suggesting we convert renewable electricity into synfuels. Instead, I think we should use battery-electric cars, and trains with overhead wires. It would make no sense to manufacture synfuels using electricity.<br /><br />I agree that manufacturing synfuels would greatly reduce the total EROI, mostly because small internal combustion engines are so inefficient. It would make little sense to convert a high quality source of energy such as electricity into something you would burn.<br /><br />"so the effective EROI for renewable energy used specifically for transport would be muuuuuuch lower than the EROI for fossil fuels used for transport."<br /><br />Definitely not. Small internal combustion engines have extremely low thermal efficiency (25% or lower) so most of the energy is lost as waste heat, which correspondingly reduces the EROI. The EROI of oil running your car is extremely low if you count waste heat losses (probably lower than 3). The EROI of renewable energy powering battery-electric cars is certainly far higher.<br /><br />"This also has implications for the millions of users of generators run on liquid fuel, whether it's for energy in remote areas "<br /><br />Small generators have low thermal efficiency so the EROI of the entire system (fossil fuel extraction, transportation, and the generator) would be extremely low. It's worth it for hospitals, because they can't tolerate downtime, but the EROI is very low.<br /><br />The EROI of a solar panel in a remote location would be far higher. Incidentally, the price of solar power in a remote location would be far lower (less than a quarter) than the price of generating electricity using a diesel generator.<br /><br />"It also doesn't take into account the cost of retooling infrastructure to rely on difficult-to-transport renewable energy rather than (relatively) easy-to-transport fossil fuels."<br /><br />Oh goodness, no. The electricity grid is BY FAR the most efficient means of transporting energy long distances. High voltage lines impose a loss of a few percent for every 500 km. HVDC lines are even better than that. There is no way of transporting energy which is more efficient than the electricity grid.<br /><br />"The EROI from the fuel in my car is not impacted by the distance from my home to a power plant -- only by the distance from my home to a gas station."<br /><br />The EROI from fuel in your car is impacted by <b>where the oil was pumped out of the ground</b>, and the distance to that. Not just the distance to the gas station. The oil must be transported from Saudi Arabia or North Dakota or wherever else, to a port, to a refinery, and then by truck to the gas station which is usually hundreds of miles from a refinery. Then you must drive to the gas station.<br /><br />Furthermore, tanker trucks impose enormous road wear, because damage to roads and bridges increases with the fourth power of axle weight. There is no wear upon the grid from transporting electricity. Of course the grid must be replaced gradually anyway (corrosion of electricity poles, etc) but transport of energy does not impose additional wear or the necessity of frequent infrastructure repairs.<br /><br />"It also doesn't take into account the cost of retooling infrastructure"<br /><br />Estimates of solar EROI DO take into account the cost of grid connection. The grid connection to your house was already there for other reasons.<br /><br />-Tom S<br />Tomhttps://www.blogger.com/profile/18396160316791132955noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-70088405032772975552016-01-27T21:45:29.126-08:002016-01-27T21:45:29.126-08:00Dan L:
"But if the cost of energy from renew...Dan L:<br /><br />"But if the cost of energy from renewables is actually so much lower than the cost of fossil fuels, then we would not expect such a heavily subsidized industry to gain so little market share over the course of several decades."<br /><br />Wrong, because the price of renewables has been dropping. Renewables were much more expensive decades ago, but are cheaper now. That explains why they didn't obtain market share over prior decades, but are quickly gaining market share now.<br /><br />-Tom S<br />Tomhttps://www.blogger.com/profile/18396160316791132955noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-78745018116035112392016-01-27T21:42:46.363-08:002016-01-27T21:42:46.363-08:00Dan L:
"But you implicitly argue that price ...Dan L:<br /><br />"But you implicitly argue that price is not even correlated with EROI"<br /><br />I do not implicitly argue that. Read the material again.<br /><br />"It's certainly possible that price and EROI are completely uncorrelated"<br /><br />That's not what I'm claiming.<br /><br />Incidentally, if EROI and price were highly correlated, then that would imply that renewable sources of energy have comparable EROI to gas or coal right now, and much higher EROI than oil. Renewables are CHEAPER at present than fossil fuel sources of electricity. They have intermittency problems etc, but their cost is low.<br /><br />"More capital is required to supply the same amount of energy at an EROI of 10 than would be required by an EROI of 20 (not twice as much, necessarily, but certainly more). ..everything else being equal..."<br /><br />If everything else were equal, then the source of energy with an EROI of 10 would require only 5% more capital than the source with an EROI of 20. Since everything else is <b>not</b> equal, that 5% difference would be overshadowed by other factors.<br /><br />"And this rather simple logical error on your part suggests to me that the overall tone of this blog"<br /><br />There is no logical error on this blog which you've pointed out; there is only your own misunderstanding.<br /><br />"is unjustified by your acumen in research and argumentation"<br /><br />In my opinion, your own acumen in argumentation is seriously impaired. Your argument basically consists of misunderstanding what you're reading.<br /><br />-Tom S<br /><br />Tomhttps://www.blogger.com/profile/18396160316791132955noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-47343526043716980982016-01-27T19:47:48.319-08:002016-01-27T19:47:48.319-08:00Hi fireofenergy,
That's okay, I was able to u...Hi fireofenergy,<br /><br />That's okay, I was able to understand your post just fine.<br /><br />I think the ERoEI of solar PV would still be high enough that it would make little difference. The storage would only reduce the aggregate ERoEI of solar PV+storage by a modest amount.<br /><br />Let's assume that solar PV has an ERoEI of 6, which I think is a reasonable estimate. Also assume that storage has a round-trip efficiency of 90% and an ESOI of 10. Also assume that the sun shines for 5 full-sun hours per day, that electrical demand is twice normal during mid-day, and that storage is relied upon the rest of the time (in other words, 2/3rds of electricity demand comes from storage).<br /><br />With those assumptions, it appears to me that the adjusted ERoEI of solar PV plus storage (including storage losses) would be 5.24. This is calculated as follows: (1/3 * 6) + (2/3 * (6*0.9*0.9)).<br /><br />This does not assume any over-building of storage or solar panels, so there would still be some days when gas backup was required. If we overbuilt storage and solar panels then the ERoEI would be lower.<br /><br />However, the ERoEI of 5.24 is still fine. It implies that 19% of the output of the solar panels would be needed to construct the replacement solar panels. Since solar panels are rapidly becoming cheaper (in money) than other sources of generating electricity, we could build slightly more solar panels to obtain the same net energy as fossil fuels for the same cost. This includes storage.<br /><br />In my opinion, the ERoEI of solar (and the ESOI of storage) is good enough that it doesn't matter. The bigger problems with solar+batteries are: 1) monetary cost; 2) potential limitations on lithium and cobalt availability to make the batteries; and 3) seasonal storage. During the winter, solar insolation is much lower and we can't store 2 months of electricity using batteries.<br /><br />-Tom S<br />Tomhttps://www.blogger.com/profile/18396160316791132955noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-18118257067416383412016-01-26T17:17:25.496-08:002016-01-26T17:17:25.496-08:00My (phone) bad.
In order, they're is supposed ...My (phone) bad.<br />In order, they're is supposed to be there, fire is supposed to be "due",<br />Out is supposed to be it, and "is" is supposed to be "us". <br />I think it's possible but that it may be close. If we had to rely on lead acid, it would be impossible because they only get an ESOI of about 2, and that the extra capacity build up of solar already would lower it's EROEI. Thus, it would all be wasted on the old battery and in the battery inefficiency (33% lost).<br />Thankfully, we have better batteries and pumped hydro! <br />The reason i say "the extra capacity buildup" is bad is because of the following thought pattern: Say there is a gigawatt each of space based solar, and ground based, and that they both had the same eroei. Since the ground based solar had to have up to 4x the build up, it'll eat up that much extra energy plus all the extra energy to make and recycle batteries. Whereas, the space based would be (at least for sake of argument here) a constant base load source. <br />So the point is that it has to be a fact that eroei alone is not accurate until capacity factor and storage is factored in. <br />Again, i still believe it's possible (because both solar and batteries are improving all the time). In fact, i believe that we should build a global grid using fossil fuels to further the carrying capacity, so to speak, of the extra solar capacity that will have to be built here on earth. That'll reduce storage requirements, too. <br />I tried to figure an equation which accounts for these variables but i think it could be wrong. ..<br />http://whatsthebackupplan.com<br />Under the oil and excess co2 widgets. fireofenergyhttps://www.blogger.com/profile/02197100366012949976noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-6854706801004369092016-01-26T12:16:00.411-08:002016-01-26T12:16:00.411-08:00Like your post. I kinda have a question. Because m...Like your post. I kinda have a question. Because most don't want nuclear, that fusion is a ways off and that renewables require storage or global powerlines, that: will they're be enough of an EROEI for all of civilization after storage and additional capacity is accounted for.<br />Say solar gets 7 but has a capacity factor of 25% (and that out will be the primary source fire to fossil fuels causing too much excess co2. Also assume that batteries will get an ESOI or energy stored on investment of less than 10. Also, that their charge/discharge efficiency is 90%. Also assume that there will not be global power lines giving is solar power at night because of political resistance. <br />Will there still be enough Overall EROEI to power everything without resorting to fossil fuels and nuclear fission? <br />Thanksfireofenergyhttps://www.blogger.com/profile/02197100366012949976noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-51170127114216090402015-07-24T10:06:01.644-07:002015-07-24T10:06:01.644-07:00"More capital is required to supply the same ..."More capital is required to supply the same amount of energy at an EROI of 10 than would be required by an EROI of 20 (not twice as much, necessarily, but certainly more)."<br /><br />Assuming the same source, of course. But if the cost of energy from renewables is actually so much lower than the cost of fossil fuels, then we would not expect such a heavily subsidized industry to gain so little market share over the course of several decades.<br /><br />More importantly, when we build a solar plant, the price of that plant (and therefore the resulting energy) is driven in part by the price of energy used to construct the plant (in addition to the cost of actually producing energy with that plant). Thus, the current market price of energy (based largely on the costs of producing and refining fossil fuels) feeds back into the price of energy from renewables.Dan L.https://www.blogger.com/profile/07663505945922022288noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-40904944107084789552015-07-24T10:00:09.426-07:002015-07-24T10:00:09.426-07:00"So, an apparent ERoEI of 4 (without counting..."So, an apparent ERoEI of 4 (without counting everything) is sufficient to maintain the civilization we have. If an apparent ERoEI of 4 is sufficient to maintain society than the actual ERoEI must be higher than 1."<br /><br />First of all, you can't assume that because <i>liquid fossil fuels</i> have an apparent EROI of 4 and an effective EROI >1 that <i>any</i> energy source with an apparent EROI of 4 will have an effective EROI >1. As a I pointed out above, electricity supplied by renewables cannot simply be substituted for fossil fuels -- they are simply too different in terms of distribution and utility.<br /><br />Second of all, you're neglecting change over time. You concede that EROI for fossil fuels has dropped (significantly) over the course of the 20th century, but the argument above (implicitly) relies upon a steady-state model. One can plausibly argue that the higher EROI in the early 20th century provided an energy surplus (relative to the current situation) that was used to build much of the infrastructure that it still in use. Therefore, while you can argue that we are obviously capable of maintaining the civilization we have in the short term, but you cannot get from there to either arguing that an apparent EROI of 4 is enough to maintain the economic and technological growth of the 20th century or that an apparent EROI of 4 is enough to retool our infrastructure in the ways that would be needed to accommodate renewables rather than liquid fossil fuels.<br /><br />You also neglect that possibility that an apparent EROI of 4 is only enough to stave off total disaster, but that it doesn't produce enough of an energy surplus to maintain existing infrastructure. That is, we may be engaged currently in a slow decline that is masked by potentially fictitious "economic growth", or that any actual economic growth that is occurring is inertial in nature, similar to the fact that even when birthrates decline, population continues to grow for several decades. I don't really expect you to come to grips with such possibilities since your purpose is clearly not to understand the world but to push a particular point of view.Dan L.https://www.blogger.com/profile/07663505945922022288noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-56236089283513804722015-07-24T09:42:22.152-07:002015-07-24T09:42:22.152-07:00It's very plausible that the EROI of renewable...It's very plausible that the EROI of renewables has increased as research into renewable technologies has progressed. However, any conclusions as to whether the EROI of renewables surpasses that of fossil fuels would have to take into account the amount of subsidies given to each industry, which I don't see you tackling here. The string "subsid" doesn't even appear in the OP.<br /><br />It also doesn't take into account that liquid fossil fuels are used in great amounts for transport. Converting from most renewables to liquid fuels is a highly inefficient process, so the effective EROI for renewable energy used specifically for transport would be <i>muuuuuuch</i> lower than the EROI for fossil fuels used for transport. This also has implications for the millions of users of generators run on liquid fuel, whether it's for energy in remote areas or backup generators for hospitals.<br /><br />It also doesn't take into account the cost of retooling infrastructure to rely on difficult-to-transport renewable energy rather than (relatively) easy-to-transport fossil fuels. And it doesn't take into account the fact that overall energy efficiency would <i>decrease</i> if the relative amount of energy supplied via the grid increased versus energy supplied on-the-spot because transmission inefficiencies now need to be taken into account. The EROI from the fuel in my car is not impacted by the distance from my home to a power plant -- only by the distance from my home to a gas station. For the electric equivalent, the overall EROI of the energy used to charge the battery would indeed be affected by my distance from the power plant.Dan L.https://www.blogger.com/profile/07663505945922022288noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-42322221125137303952015-07-24T09:30:21.899-07:002015-07-24T09:30:21.899-07:00Do you realize how unconvincing this argument is?
...Do you realize how unconvincing this argument is?<br /><br />You argue that EROI is not identical to price. That is correct. But you <i>implicitly</i> argue that price is not even <i>correlated</i> with EROI -- that they're completely independent variables:<br /><br />"No, because EROI is not price. An energy source could have a high EROI but still be expensive. Similarly, an EROI could have a low EROI but be cheap."<br /><br />It's certainly <i>possible</i> that price and EROI are completely uncorrelated, but it seems extremely <i>implausible</i> for that to be the case. The price of energy is determined, as all prices are, by supply and demand. EROI seems at least intuitively like it would have a big effect on the supply side of the equation. More capital is required to supply the same amount of energy at an EROI of 10 than would be required by an EROI of 20 (not twice as much, necessarily, but certainly <i>more</i>). Thus, we would expect that the cost of energy at a lower EROI, everything else being equal, would be higher.<br /><br />You need to make a better argument that EROI and price are truly statistically independent to make this stick.<br /><br />And this rather simple logical error on your part suggests to me that the overall tone of this blog -- quite an arrogant one -- is unjustified by your acumen in research and argumentation.<br /><br />That's assuming it's an honest error and not an intentional misdirection.Dan L.https://www.blogger.com/profile/07663505945922022288noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-48169826913546953622015-06-28T12:57:34.542-07:002015-06-28T12:57:34.542-07:00Hi Angus,
If that's true, then renewables alr...Hi Angus,<br /><br />If that's true, then renewables already have an EROI which is much better than oil, because renewables cost less than oil. It also implies that the EROI of renewables has been improving greatly and continues to improve, because their cost has been dropping. It also implies that the EROI of renewables is only modestly worse than fossil fuels, because they cost only modestly more.<br /><br />-Tom S<br />Tomhttps://www.blogger.com/profile/18396160316791132955noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-65371692149316109222015-06-26T02:58:33.067-07:002015-06-26T02:58:33.067-07:00Hi Tom,
That might be true in theory, but my feel...Hi Tom,<br /><br />That might be true in theory, but my feeling is that (for the energy sources we actually have available) EROI is inversely related to the cost of net energy. The transition to renewables can be described as a transition to power with a higher cost of net energy, surely?<br /><br />Cheers, AngusAngus Wallacehttps://www.blogger.com/profile/01518875828382696708noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-9885002796513347862015-05-01T20:54:32.172-07:002015-05-01T20:54:32.172-07:00Hi Tom,
I think the second part of your argument...Hi Tom, <br /><br />I think the second part of your argument and mine are not contradictory, but stem more from a different vision of what constitutes GDP and the associated asset base. Consider the two following situations :<br />Situation A : The self replicating solar power plants are operated and built by the same company ACME Global Inc. The EROI of the technology is 1.1 across 20 years lifetime. Little labor, no scarce material. Seen from outside, ACME Global is a source of cheap net energy with Infinite EROI and the value of its assets is the actualisation of the income derived from the sale of net energy. In such case, 100% of GDP comes from the consumption of that net energy. All fine and good. That is your vision. This is for instance what happens when EDF uses one its plants to enrich its nuclear fuel.<br />Situation B : The building and the operating of the power plants are done by two different companies, ACME E&C and ACME Power.<br />ACME Power sells 90% of its power to ACME E&C and 10% to the Public, ACME E&C uses that power to replace the power plants that reached the end of their lives and sells them to ACME Power with a 5% profit margin. From the point of view of accounting, GDP is multiplied by 10, power plant construction is 90% of GDP, and, as the average life of power plant in ACME Power is 10 years, ACME Power shows a balance sheet with an asset base equal to 10*90% of GDP = 900% of GDP. This is my vision.<br />From outside, it is the same thing, the public still gets the same amount of dividend from ACME E&C and ACME Power than from ACME Global in Situation A, and consumes the same amount of net energy, but my vision ads new information in that it shows how the economy is operationally leveraged. Just a 10% adjustment on the useful life of the solar panels and the economy tanks ! That should get everyone worried. Replace "useful life of the solar panel" with "depletion rate of the fracked wells" and you get something much closer to present reality....<br />At some point, society could decide that it is better to go for the energy source with "real" infinite ERoEI even if it is more expensive on a net basis, because there is less operational leverage risk.<br />Amazingly , this is actually a central argument in favour of Nuclear Power. I say amazingly because Nuclear Power is deemed as risky because of accidents and waste, but most people underestimate the risk reduction coming from the ability to store many years of full (so no geopolitical supply risk as for oil) and the vast capacity for improvement of EROI with breeding technology.Anonymoushttps://www.blogger.com/profile/11157490892243319936noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-58176902492659215272015-05-01T15:59:02.225-07:002015-05-01T15:59:02.225-07:00Hi Charles,
Thanks for your insightful remarks.
...Hi Charles,<br /><br />Thanks for your insightful remarks.<br /><br />"The bottom line (and the word is appropriate here) is that one has to have an "engineer margin" over the threshold of 1 to to be sure that one is indeed above 1"<br /><br />I see your point. Something with a reported ERoEI of 3 may have an actual ERoEI of 1 when everything is considered, which means civilization is in trouble.<br /><br />I was referring to the actual ERoEI in my article, including all energy investments.<br /><br />The thing is, the ERoEI of oil is certainly very low. The reported ERoEI of 15 or so is the "mine mouth" (or well mouth) figure which does not include refining, nor does it include waste heat losses from the engine of your car. Counting those obvious losses puts the ERoEI of oil at around 4 or so, which is much lower than any renewable source of energy.<br /><br />Oil has an ERoEI of 4 or so _before_ we start counting policemen, judges, the army, management of oil companies, and so on.<br /><br />So, an apparent ERoEI of 4 (without counting everything) is sufficient to maintain the civilization we have. If an apparent ERoEI of 4 is sufficient to maintain society than the actual ERoEI must be higher than 1.<br /><br />"At an EROI of 1.1, 91% of the economy is the energy sector, which leaves only 9 % of the economy for essentials"<br /><br />I think that's a mistake. With an ERoEI of 1.1, 91% of all _energy_ is devoted to the energy sector, not 91% of the economy.<br /><br />If the source of energy were extremely cheap (meaning it takes very little labor, capital, or scarce materials) then the total energy INPUTS for society could be much higher than they are now. If we were generating 10x as much gross energy as now, then devoting 91% of that gross energy to obtaining energy would yield almost as much net energy as we have now.<br /><br />As an example, having 2GW worth of solar cells (2GW average continuous output, not nameplate capacity) with an ERoEI of only 2, would yield the same net energy as 1GW of some other energy source with infinite ERoEI. In that case, half of the energy of the society is devoted to obtaining energy, but the gross energy produced is twice, leading to the same net output. It would be better to pursue the energy source with an ERoEI of 2 (rather than the source with an ERoEI of infinity) if the capital and labor cost of the infinite ERoEI source were more than twice as much. That's why it's the cost of net energy which matters, not ERoEI.<br /><br />-Tom S<br />Tomhttps://www.blogger.com/profile/18396160316791132955noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-3841562742014152592015-05-01T07:20:41.483-07:002015-05-01T07:20:41.483-07:00The second remark is about what an economy with lo...The second remark is about what an economy with low EROI looks like.<br />If one equates energy production with working, an economy with low EROI is essentially an economy where most of the work is devoted to producing energy. At an EROI of 1.1, 91% of the economy is the energy sector, which leaves only 9 % of the economy for essentials (food, shelter and clothing) and fun (movies, spring break parties, etc...). That would not be a fun economy, it would be a subsistance one, like in the middle ages. As an economist, you should not be satisfied by it.<br />The way to escape this predicament is to actually to NOT equate energy production with working. I.e. energy production is mostly associated with automated process that require little human input. The power plants essentially become self-replicating robots who devote most, but not all, of their production to create a clone of themselves. The energy sector would then be a boring part of the economy, with huge assets and low return on these assets. People would work to produce and consume the stuff they are interested in (the 9% above), and, provided that the energy sector is a common good, you are right, life would go on as usual, albeit with a huge gross production of energy, which can be a problem in its own right (but that is for another comment).<br />I really thank you that the reading of your blog made me realise the tight relationship between automation and EROI.Anonymoushttps://www.blogger.com/profile/11157490892243319936noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-15863000160887188082015-05-01T06:52:06.899-07:002015-05-01T06:52:06.899-07:00I have two and a half remarks about your argument ...I have two and a half remarks about your argument :<br />First, when some people put the threshold for viability of modern civilisation at 7, it doesn't necessarily mean that they don't agree with your argument. As you pointed out in a later post about the computation of EROI for renewables, the EROI goes as low as your analysis deepens. Must the police and the justice apparatus costs be allocated to energy (after all, without police, people would steal energy with impunity)? And what about the army (especially when it is dimensioned to conduct expedition in oil rich desert countries) ? And the cost of teachers who teach the workers of the energy industry ? and the farmers who grow the food to feed the energy industry ? Etc... etc...<br />The bottom line (and the word is appropriate here) is that one has to have an "engineer margin" over the threshold of 1 to to be sure that one is indeed above 1, because the consequence of being below 1 are really frightening (it means essentially eating the seed corn, and as an economist, you know where it ends...). Establishing such margin is more an art than a science. Maybe the people who say that 7 is critical are too conservative, but again, maybe not...Anonymoushttps://www.blogger.com/profile/11157490892243319936noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-45884740632226760942015-05-01T06:38:25.859-07:002015-05-01T06:38:25.859-07:00I discover this site today, as I was doing some go...I discover this site today, as I was doing some googling on Solar EROI. I took pleasure reading your posts, which shows that you have done some homework. However, I think that you are underestimating some human and physics limitation, so I don't entirely share your optimism. I'll try to make my points in the posts I feel are most appropriate. See you in this space !Anonymoushttps://www.blogger.com/profile/11157490892243319936noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-27004803336578110132014-08-06T12:54:01.717-07:002014-08-06T12:54:01.717-07:00ALI B:
"Cant help but say, that if you spend...ALI B:<br /><br />"Cant help but say, that if you spend time building 10 powerplants with an eroei of 5 instead of building one with an eroei of 50 you are now using more energy, work force and raw materials for a lesser return on investment,"<br /><br />No, because eroei is not the same thing as work force or raw materials. It's possible to have an energy source with a very high eroei but which is still much more expensive in terms of work force or raw materials.<br /><br />That's why it's the cost of net energy which matters, not eroei.<br /><br />-Tom S<br />Tomhttps://www.blogger.com/profile/18396160316791132955noreply@blogger.comtag:blogger.com,1999:blog-7005412100005882053.post-14188693067697052212014-08-06T12:51:38.644-07:002014-08-06T12:51:38.644-07:00Paulo:
"1) The price of energy will increase...Paulo:<br /><br />"1) The price of energy will increase significantly over the years, as the average EROI go down. This will have an inflationary effect on increasing prices of all products."<br /><br />No, because EROI is not price. An energy source could have a high EROI but still be expensive. Similarly, an EROI could have a low EROI but be cheap.<br /><br />Price depends on a lot of things, like the amount of skilled labor available, the amount of capital required, whether it can be mass-manufactured (like solar panels) or must be one-off power plants (like nuclear), research and development costs, and so on.<br /><br />That's why it's the cost of net energy which matters.<br /><br />-Tom S<br />Tomhttps://www.blogger.com/profile/18396160316791132955noreply@blogger.com