footeab@yahoo.com + 2,187 January 11, 2020 2 hours ago, Douglas Buckland said: But common sense will tell you that when you back-up that much water (the weight of the dam itself becomes irrelevant) that there is a damn good chance (no pun intended) that subsidence will be an issue. In my opinion, the Chinese wanted an ‘engineering marvel’, which it is, but did not perform the required due diligence. This is a bit spooky as can you imagine the consequences downstream if this thing let’s go? No. Taller the dam, the higher the efficiency.  Same reason the highest efficient engines operate at the highest temperature differential. If anything should have made it taller assuming the rock beneath the dam could withstand it. 2 Quote Share this post Link to post Share on other sites
Marcin2 + 725 MK January 11, 2020 (edited) On 1/10/2020 at 9:59 PM, remake it said: That is simply a very poor assessment of how renewables scale into existing infrastructure so your Maginot has collapsed on you. It was pure calculation of the total cost of each incremental renewables capacity, it was just calculated. Lazard tables were a good help to simplify the arithmetic. The fact it is usually NOT calculated this way, and part of the costs of renewables are subisidized directly (through official EU green subsidies) or indirectly through not paying baseload plants for their role of backup to intermittent renewable sources. I am not pro or against renewables but to start meaningful discussion you need to know the facts first, wind power per MWh of generated electricity in a country like Germany is twice the cost of coal and nuclear power. Indirect financing through subdued tariffs for reserve capacity that do not adequately finance costs of keeping baseload reserve power in place is very stable, at the end of the day consumers pay for them, and it is too complex for media. Edited May 14, 2020 by Marcin2 typo Quote Share this post Link to post Share on other sites
Marcin2 + 725 MK January 11, 2020 (edited) On 1/11/2020 at 10:53 AM, footeab@yahoo.com said: No. Taller the dam, the higher the efficiency.  Same reason the highest efficient engines operate at the highest temperature differential. If anything should have made it taller assuming the rock beneath the dam could withstand it. You mean Francis turbines are more efficient ?, but the rise in efficiency is not substantial or proportional with hydraulic head it depends more on the size of installation. Large installation with comparable power capacity and say first has 20 m and second 120 m hydraulic head both would have around 93-95% efficiency of the potential power of the water transferred to the electricity, but I am not an expert, just enthusiast. You loose the height from the surface of the water to the level of intake. With 5 dams 20 m height each , you loose lets say 10 m for each dams, so effective hydraulic head of each dam is 10m times 5 it is 50 m , you loose 50% of the 100m of water potential energy. With one 100 m dam and the same intake location you loose only 10m and this is 10% of the potential energy of the water. Edited May 14, 2020 by Marcin2 typo Quote Share this post Link to post Share on other sites
Marcin2 + 725 MK January 11, 2020 (edited) Exactly, taller the dam, higher the efficiency cause you can use Francis turbines. Edited May 14, 2020 by Marcin2 typo Quote Share this post Link to post Share on other sites
Marcin2 + 725 MK January 11, 2020 6 hours ago, PE Scott said: I'll try to find the article, but I saw something in a scientific journal that suggested the mass of that damn and all the cement in that localized area has actually altered the rotation of the earth, like a wheel out of balance. In fact, it asserted that might have something to do with global warming. To be fair though, there wasn't a lot of evidence to verify some of the articles claims. Still interesting though. Our activity as far as Earth kinetic energy is concerned is not important at all. Earth rotation is slowing much more due to TIDES, the effect of Moon and Sun. But this process of slowing Earth rotation is slow, you get additional 15 minutes every 70 million years. Actually this is measured by the best clocks, so I remember a few years ago they added a fraction of the second to somehow sustain balance. Quote Share this post Link to post Share on other sites
PE Scott + 563 SC January 11, 2020 1 hour ago, Marcin2 said: Our activity as far as Earth kinetic energy is concerned is not important at all. Earth rotation is slowing much more due to TIDES, the effect of Moon and Sun. But this process of slowing Earth rotation is slow, you get additional 15 minutes every 70 million years. Actually this is measured by the best clocks, so I remember a few years ago they added a fraction of the second to somehow sustain balance. That's why I added that little disclaimer at the end about a lack of supporting evidence. I have no doubt you're right, all though tides aren't man made and the damn is. Though I guess the problem isnt as much the damn as all the massive volume of water stuck behind it.....much like a big shift of mass from something like a tide. 1 Quote Share this post Link to post Share on other sites
Marcin2 + 725 MK January 11, 2020 (edited) On 1/11/2020 at 4:25 PM, PE Scott said: That's why I added that little disclaimer at the end about a lack of supporting evidence. I have no doubt you're right, all though tides aren't man made and the damn is. Though I guess the problem isnt as much the damn as all the massive volume of water stuck behind it.....much like a big shift of mass from something like a tide. Yes, "at all" is also a bit of a stretch. The effect is the great mass of water is moved 100 meters further from Earth's axis of rotation, it is like when we spin when ice skating, you take the hands closer to your body you spin faster you bring them more far apart you spin slower All the elevators on Earth also have this effect. Edited May 14, 2020 by Marcin2 typo Quote Share this post Link to post Share on other sites
remake it + 288 January 11, 2020 7 hours ago, Marcin2 said: The fact it is usually NOT calculated this way, and part of the costs of renewables are subisidized directly (through official EU green subsidies) or indirectly through not paying baseload plants for their role of backup to intermittent renewable sources. I am not pro or against renewables but to start meaningful discussion you need to know the facts first, wind power per MWh of generated electricity in a country like Germany is twice the cost of coal and nuclear power. Germany is democracy so phasing out nuclear and having more expensive electricity from renewables was a people's choice, conscious or not. Knowleadgeable people, like those for example, that finance new wind power sources, are all aware of the cost structure presented, it is part of report you need to bring to loan committee to get money in the first place. Indirect financing through subdued tariffs for reserve capacity that do not adequately finance costs of keeping baseload reserve power in place is very stable, at the end of the day consumers pay for them, and it is too complex for media. Lazard's tables show both subsidized and unsubsidized for new installations and the math is such that with the right circumstances wind and solar beat their fossil fuel counterparts and nuclear. The error in your thinking relates to compartmentalizing baseload when it in fact is legacy component which in Europe can continue via gas for at least 30 more years by which time battery technology CAGR will have reduced prices enough to take over. Quote Share this post Link to post Share on other sites
Marcin2 + 725 MK January 11, 2020 43 minutes ago, remake it said:  The error in your thinking relates to compartmentalizing baseload when it in fact is legacy component which in Europe can continue via gas for at least 30 more years  46 minutes ago, remake it said: Lazard's tables show both subsidized and unsubsidized for new installations and the math is such that with the right circumstances wind and solar beat their fossil fuel counterparts and nuclear. 1. Baseload is legacy component ?, was before renewables so we need to treat it as for free ? Nobody treats baseload this way, they do pay for the baseload capacity, only not the right price. 2. For the 3 time you pretent to not understand my comments and also add this generic sentences I do not know why. This sentence that starts with "Lazard's tables" has no meaning, as "with the right circumstances" could be anything. Quote Share this post Link to post Share on other sites
remake it + 288 January 11, 2020 10 minutes ago, Marcin2 said: 1. Baseload is legacy component ?, was before renewables so we need to treat it as for free ? Nobody treats baseload this way, they do pay for the baseload capacity, only not the right price. Strange thinking as the commercial imperative is to build the most cost effective product and this is now in renewables which on a continuing basis will displace legacy baseload power which has already been costed within the system. Quote Share this post Link to post Share on other sites
Marcin2 + 725 MK January 11, 2020 (edited) This is an interesting idea. Edited May 14, 2020 by Marcin2 typo Quote Share this post Link to post Share on other sites
remake it + 288 January 11, 2020 Just now, Marcin2 said: Intermittent renewables will displace baseload power ? it does not have sense. OK I leave this thread for a while, to continue discussing China and Iran. Yes, because you did not work out that as battery technology keeps getting incrementally cheaper the curtailed energy of renewables can fill batteries for "free" over and above any demand driven requirement for that energy: remember the grid is not being built from scratch but instead is being regularly reshaped. Quote Share this post Link to post Share on other sites
Marcin2 + 725 MK January 11, 2020 (edited) BAttery technology is still too expensive. Edited May 14, 2020 by Marcin2 typo Quote Share this post Link to post Share on other sites
footeab@yahoo.com + 2,187 January 11, 2020 9 hours ago, Marcin2 said: You mean Francis turbines are more efficient ?, No. Francis turbines are not the most efficient and NOTHING comes even close to 90+% efficient. Pelton comes the closest to perfection(impulse~80+%) and requires the most head pressure. The more the merrier. You could put a francis turbine after a Pelton to get the highest efficiency and it could probably hit 90+% if the head pressure was REALLY high. As in 1000m high Quote Share this post Link to post Share on other sites
remake it + 288 January 11, 2020 7 minutes ago, Marcin2 said: Yes, sure. I have heard about this revolutionary technology lately. Curtailed energy diverted into hydrogen production is not a battery although here is what renewable cost curves look like as scale affects production Quote Share this post Link to post Share on other sites
NickW + 2,714 NW January 12, 2020 16 hours ago, PE Scott said: I'll try to find the article, but I saw something in a scientific journal that suggested the mass of that damn and all the cement in that localized area has actually altered the rotation of the earth, like a wheel out of balance. In fact, it asserted that might have something to do with global warming. To be fair though, there wasn't a lot of evidence to verify some of the articles claims. Still interesting though. Possible it could impact local gravity although I doubt it. The capacity is 39km3 39bn tonnes and there are many reservoirs around the world that are bigger. The 3 Gorges is the 27th biggest on the planet. https://en.wikipedia.org/wiki/List_of_reservoirs_by_volume  There is a local gravitational issue with the Ice caps and if they melt why sea level rises will be higher in the tropics than in the high latitudes as the ice caps create a local gravitational effect drawing water towards them. Quote Share this post Link to post Share on other sites
NickW + 2,714 NW January 21, 2020 On 1/8/2020 at 2:14 AM, footeab@yahoo.com said: Solar in winter = zero. Not some, it equals ZERO. Solar panels do not even turn on for 3 solid months other than maybe one or two days a month at VERY low capacity factor of maybe 20% for at most 4 hours due to that nasty sun residing down south... Why Germany by capacity factor of its solar panels is good for 85% of its entire power needs but by yearly needs obtains ONLY 5%..... Wind in winter = lots usually unless you have a high pressure which means you get.... zero. Not some. Zero. Fine, you want to quibble? Maybe 10% if you have a short low front move through. So, most of the year, yup, wind is great. But summer it dies off in many regions as well. Be thankful Europe resides in the 40's lattitudes and greater. Still, assuming you tried to go 100% wind/solar you need 100% backup for a week and far more likely 2 weeks as it happens usually twice or so a winter when there is zero solar and zero wind or near zero wind. Lets put this in perspective shall we? Eastern USA Grid is approximately equal to the Euro Grid. To power either of these grids via pumped hydro storage(disregard the inefficiencies assume it already in place), you would have to dump the entire great lake of Erie to sea level every day and a half. So, in one week, you need the equivalent pumped hydro storage of 5 Lake Erie's, 200m head, and 500km^3. Reality states you need at least twice this much. So, 10 lakes with 200m head by 500km^3...  Or one lake with 200m head by 5000km^3 or 1 lake with 1000m head with 1000 square km area by 1000m depth. Or another way of saying You would have to dam up the Baltic sea by 75m and use that as your "pumped" hydro storage. Good luck on that one... Or..... Dam up Every valley in the Alps(Austria/Switzerland so sorry, but your countries have to disappear under water) to around 3000m level with lower dams below(1000m). 🤣🤣🤣 Oh, do not forget the perfect electrical grid sharing plan... Good Luck filling those dams with water that isn't all salt water. As I type we have a very high pressure system over the entire UK. Very little apparent wind At 20.00 21.01.20 - 2GW of metered output which is about 5% of total demand including 1GW of export to Ireland. Unmetered is probably another 0.3- 0.5GW which is from single turbines / smaller turbines linked into the local grids.  Quote Share this post Link to post Share on other sites