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Gah, when you're speaking about tonnes just use MT (metric tons). Edit: Here's why, there a fuckload tons, long, short metric, gross (an internal volume unit), net (a dimensionless index), etc. Bar Ran Dun fucked around with this message at 06:39 on Jan 12, 2016 |
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Jan 12, 2016 06:31
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OwlFancier posted:Tonnes is metric, tons is imperial. And metric tons (MT) is what tonnes are called by people who actually engage in moving tonnes of whatever poo poo from point a to point b. Whatever poo poo, includes fossil fuels like coal. This is because whatever poo poo is transported by vessel, and MT is the unit that matters for bills of lading, hydrostatic tables, and bunch of other calculations/paperwork vessel related. People in the real world call tonnes, Metric Tons.
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Jan 13, 2016 06:28
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OwlFancier posted:And in the event I ever ask a truck driver about atmospheric science I will be sure to bear that in mind. What will be the unit of measurement for wood pellets shipped from Jacksonville to Europe to be burned in a power plant? What will the unit of measurement for a UN draft survey on a coal load in Australia bound for China? blowfish posted:the most important non-metric ton is, of course, the gross register ton to determine which u-boat captains get mentioned in the news during world wars And you're onto the reason. I use GT (gross tons) actually (they replaced GRT, gross register tons). I also use NT (net tons) and DWT (deadweight tons). All these units have international definitions. That last one DWT is the amount a vessel can load to it's summer mark in metric tons. With the exception of US flag ships on the Great Lakes (which have some wonky regionalisms, below) the unit associated with commodities moved in bulk by vessel is metric tons (MT) It's on bills of lading, draft surveys, unit prices on the markets, reports of fuel oil burned, etc. Like GT replacing GRT, MT (metric ton) was the replacement for LT (long tons) as the unit and in all sorts of loving international treaties. Now OwlFancier I know you're dumb as a post from previous conversations. But yes an atmospheric scientist should loving be familiar with the usage of the term metric tons. Because it's the unit that fossil fuels like coal, are denominated in when they are shipped. Because vessel displacements are given in Metric Tons in hydrostatic tables, and things like Load Line Certificates refer to displacements denominated in metric tons. Edit: And a bunch of people in NOAA are going to be familiar with MT. blowfish posted:A ton is a ton is a ton is 1000kg. When talking about weird and stupid non-metric tons, you specify that you are talking about And all those still get widely used. And they get conflated! On the Great Lakes when people say gross tons they mean long tons. When they say net tons they mean short tons. Lets say you want to figure out how much carbon pollution the Koch Brothers are creating with the pet coke they sell at a particular terminal. Can't do accurately if you don't know this stuff. QuarkJets posted:lol if you don't only use kg for all mass measurements MT are handier when you are dealing with heavier things. In the field it's a bit easier to do a rough conversion of MT into the force unit I use most kN. Bar Ran Dun fucked around with this message at 06:40 on Jan 14, 2016 |
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Jan 14, 2016 05:55
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fishmech posted:How could the result ever be "everything went fine" though? Having fully redundant, entirely mechanical systems that are sufficient to control everything in the system isn't possible. Many power plants can't meaningfully be run with non-digital control systems in any form other than going for a safe shutdown, which is going to gently caress the grid pretty hard. (I'm thinking particularly of nuclear) It's totally doable to run power plants without digital controls. It's more expensive and more trained operator/ engineer intensive. Pneumatic analog controls are still a thing. I've been in completely non digital control rooms. It's impossible in new power plants, but it's not impossible in a general sense.
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Jan 1, 2017 19:17
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fishmech posted:you might as well build a whole second plant to run on standby. It wouldn't have to go that far, just duplication of all the controls. There is very little a PLC can do that one cant do with analog controls. And one can even run a steam plant without controls or automation at all, but the people that can are quickly becoming a vanishingly small group.
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Jan 2, 2017 04:31
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Potato Salad posted:Is there a particular reason why nondigital control discussion is in any way expedient? It's not, but it's interesting dammit.
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Jan 2, 2017 04:38
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I didn't realize that capacity factors of renewables relative to oil and gas went through an inflection point a couple years ago. Huh.
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Apr 25, 2017 04:56
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BattleMoose posted:Would you care to clarify? The ratio of actual output to potential output. Enough renewables have been built out that adding more improves the capacity factor of renewables in the system while making worse the capacity factor of fossil fuels plants. That's a strong reinforcing loop for renewables going foward.
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Jun 23, 2017 16:42
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Smiling Demon posted:This is not how capacity factor works. It is roughly actual output to potential output, though technically it is the slightly more arbitrary nameplate capacity which allows generators to go beyond 100% capacity. Since this is a ratio, adding more of the same type of generator will not increase the capacity factor! For the whole power system buddy, not individual plants. The more renewables you have the more you can use those renewables and the less the generating capacity of the existing conventional plants gets used. You thinking about parts, think about the whole drat thing.
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Jun 23, 2017 20:54
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http://www.bloomberg.com/news/articles/2015-10-06/solar-wind-reach-a-big-renewables-turning-point-bnef Link where I took that from. Won't do you much good though, unless you can use a Bloomburg terminal. I posted that first comment in april and the article I was basing it on has since been archieved.
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Jun 23, 2017 21:02
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Smiling Demon posted:edit: have more renewables does not let you use existing renewables more frequently No it does that. Found something that was based on the bloomburg article and quotes it (edit, nearly not everything on a second reading) entirely. https://www.google.com/url?sa=t&sou...NtZu1xo030Q1gjQ Here's the tldr https://imgur.com/3l5ujuC Edit: the important part As Bloomberg explains: "It’s a self-reinforcing cycle. As more renewables are installed, coal and natural gas plants are used less. As coal and gas are used less, the cost of using them to generate electricity goes up. As the cost of coal and gas power rises, more renewables will be installed." The table above shows how the capacity factors of coal and natural gas are starting to be affected, while wind and solar are starting to do better because bigger and taller wind turbines catch more wind and more solar is being installed in the U.S. Southwest where sunny days are more frequent. It's kind of like a flywheel, and the more solar panels we install, the more wind turbines are built, the faster it spins. At some point, doesn't make any sense to run fossil fuels on sunny or windy days, and overall capacity factors go down enough that prices are simply not competitive with storage, and rather than build new natural gas plants, utilities will simply buy more renewables combined with storage. Bar Ran Dun fucked around with this message at 21:11 on Jun 23, 2017 |
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Jun 23, 2017 21:07
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Smiling Demon posted:Then again, I'm a filthy nuclear power supporter. I am too. Even have a nuke minor.
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Jun 23, 2017 21:39
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Bloomberg says that's what's going on. Ignore if they are correct or not for a moment. Think about the repercussions of that it is Bloomburg saying it.
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Jun 23, 2017 21:56
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hobbesmaster posted:Full life cycle costs don’t mean much for existing plants. It's eye popping that it's lower than just maintenance and fuel for existing though. Are there any other limiting factors? When steam was transitioning to slow speed diesel on ships the limiting factor for steam was not initially fuel costs. It was reduction gears. Direct drive diesel bypassed a bottle neck in reduction gears. Unless there is a similar bottle neck for renewables that cross over makes them a slam dunk for anything new.
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Nov 24, 2017 21:08
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Trabisnikof posted:There are a lot more details on the LCOE at the Lazard website Holy poo poo wind is cheaper than Cogas! Fishmech and Orvin, I think you both make good points.
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Nov 25, 2017 06:33
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GreyjoyBastard posted:
You should look at SNAME. It's been long time for me but they had a whole bunch of good papers on that. All for Marine propulsion, but that's roughly equivalent to shoreside power generation. That's basically what I did my undergrad capstone on. We had to design the plant ( and sub systems ) for an LNG carrier and calculate the life cycle costs for the different options.
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Nov 26, 2017 06:41
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I've gotten higher meter readings off coal than enriched Uranium.
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Mar 29, 2018 18:40
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Potato Salad posted:Theoretically, wouldn't that trend change in a hurry with the sudden and magical availability of bigass clean 10GW plants? Depends on what the system in the future looks like. Lines are expensive.
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Mar 29, 2018 19:15
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Here's another way to put it, when they decide to build anything they are estimating the lifespan of whatever it is and future of the system. It's a bigass loan to build any of this power stuff, and the capital heavy nature of it makes fast changes undesirable to utilities.
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Mar 29, 2018 19:18
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I would think anything built new would be CoGas these days. Vanilla steam cycles have the whole 2/3 of the heat goes out the condenser as waste problem.
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May 20, 2018 20:02
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About coal: Several things contribute to the likelyhood of pile and hold fire. The first is ambient temperature. This is especially the cargo ship hold fires. Coal loaded in places like Indonesia at high ambient temperatures has a much higher rate of evolution of methane and self ignition. Next is moisture content. At some moisture contents coal has a very high heat of wetting. Basically it's best to avoid the moisture content levels where that is the case. Either keep it drier or wetter. This must be balanced with wetting for dust abatement. Size and type, some types of coal a just more prone to gas evolution and self heating. Generally the shittier the coal the more prone it is. Blends can have problems particularly if different grades are mixed. The different sizes of the pieces mixed together can cause water to migrate out of one part of the blend and into another causing the heat of wetting problem mentioned earlier. When there are hold fires what they do is discharge the burning coal to the pier with clam shell grabs. Often they do just let it burn out there. Bar Ran Dun fucked around with this message at 16:47 on May 25, 2018 |
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May 24, 2018 04:17
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Actual output / maximum output.
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May 25, 2018 23:38
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Hey that's a neat trick there. And they've already made a demonstration plant of the cycle.
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Jun 2, 2018 01:49
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Don't forget that stuff matters on the EV side too. If the EV is getting the electricity from a coal fired traditional plant with a steam cycle, it could also be a poo poo show.
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Jun 11, 2018 18:54
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Megillah Gorilla posted:
That was one of the investment banks. The Kochs run mostly petrochemical businesses. Oil, gas, pet coke, coal, plastics, manufacturing, I think they own some rail lines too.
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Oct 28, 2018 04:40
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There all over up here in Seattle too, and way more than I saw the last time I was in California.
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Oct 29, 2018 19:19
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VideoGameVet posted:I have a friend who worked on the construction of the San Onofre Nuclear Generators. Most power generation has issues like this during construction. Building ships is the same way it's always a cluster gently caress because of the scale and number of people involved.
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Dec 13, 2018 19:13
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Killer-of-Lawyers posted:You can make jet fuel the same way you make gasoline with water and air. The navy is wxpermenting with doing it on carriers with the excess thermal energy from the reactor. They've wanted something like that for a while. A long time ago as an undergrad we modeled a system that had a hydrogen generator that used the waste heat from a PWR cycle in one of my nuclear engineering classes.
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Dec 30, 2018 03:57
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The Dipshit posted:Odd request perhaps, but would you have a good recommendation on textbooks for reactor design and economics? Especially if it has PHWR or the CANDU types. It's on my "to get" list for my engineering textbook library hobby. We used ISBN 978-1-4613-5866-4 Nuclear Reactor Engineering, Glasstone and Sesonske
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Dec 30, 2018 17:56
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Harik posted:Big-ship engines are one of them, when well maintained they last forever because the cost of replacing them is scrapping the entire multi-hundred million dollar freighter. The hulls tend to corrode first, at least in salt water. In freshwater which is basically only the lakes they last forever and there is the occasional plant replacement or conversion to ITB. Oldest one I've done surveys on was 1923 build. I have co-worker who has surveyed 1896 builds. Ocean going most vessels you are looking at like 20-25 years for lifespan. Some push 30-35 maybe 40 if well maintained. The saltwater even with a good impressed current system just eats up hulls eventually.
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May 11, 2019 17:41
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Galvanic corrosion is a hell of a thing. They try to seperate the different metals (usually steel and aluminum ) with various types of barriers but sometimes they gently caress it up cause ships are hard to build.
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May 13, 2019 05:25
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Phanatic posted:It’s a well-understood problem and the standard way to prevent it is with cathodoc protection, where you bond in a chunk of metal with a higher electrochemical potential that will act as the anode in a battery and preferentially corrode. This has been well-understood and easily-incorporated for well over 100 years. Commercial practice is generally impressed current systems. Generally one sees those on ships rather than sacrificial anodes. Sacrificial anodes when they pop up are often inside of ballast holds or even (rarely) ballast tanks. Basically only smaller boats will have zincs on the hull. GD hosed up big. Edit also my personal opinion is that aluminum house on steel hull is dumb dumb dumb. Bar Ran Dun fucked around with this message at 16:37 on May 13, 2019 |
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May 13, 2019 16:34
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Phanatic posted:Why? Yeah i just mean the mixing of the two in general. And galvanic corrosion is the biggest why. They have to goto great lengths to isolate the steel and aluminum to prevent it. Just mixing the two is bad news and potentially turns the ship into a battery. I'm not sure the maneuvering performance the navy shoots for is nessisary, given the nature of new threats to ships. Aluminum construction also contributes to the decline in institutional knowledge in the navy. Also aluminum melts/burns/weakens to cyclical stress differently than steel does.
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May 13, 2019 20:58
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gaj70 posted:Personally, I'd guess a bunch of mid-construction change and feature requests (iirc, this is where defense contractors actually make their money; the original bid is always a bit low). Some of the big shipyards have taken the navy to court over that. They brought in McKinsey and modeled what the change orders at the last second from the navy actually did to the work flow and costs. It rather dramatically increases both.
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May 14, 2019 02:57
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There were some good models of what under staffing for a big project does to a work force too. That's also as bad as one would expect.
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May 14, 2019 03:24
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Platystemon posted:It all goes back to specific strength, and in that there is little difference between steel and aluminum. What do moderate cyclical stresses do to steel vs aluminum? The answer, that's not a little diffence.
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May 14, 2019 21:15
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Platystemon posted:Yeah there are exceptions for things that cycle frequently and do so over long periods of time, but I’m sceptical they apply to the typical bicycle. My brain is still thinking ships, and that's exactly the case with rolling motions.
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May 14, 2019 22:40
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Pander posted:And capacity factor for wind is low, so if you eliminate baseload you DO have to factor in storage and/or generation oversizing. A reminder that we've reached the cross over point for renewables on capacity factor. As we build more renewables the capacity factor going forward increases for renewables and decreases for conventional power generation. That was a couple years ago now.
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Aug 25, 2019 17:19
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silence_kit posted:What? Why is this true? Here are my post on it from earlier: http://www.bloomberg.com/news/articles/2015-10-06/solar-wind-reach-a-big-renewables-turning-point-bnef Link where I took that from. Won't do you much good though, unless you can use a Bloomburg terminal. I posted that first comment in april and the article I was basing it on has since been archieved. Smiling Demon posted:edit: have more renewables does not let you use existing renewables more frequently No it does that. Found something that was based on the bloomburg article and quotes it (edit, nearly not everything on a second reading) entirely. https://www.google.com/url?sa=t&sou...NtZu1xo030Q1gjQ Here's the tldr https://imgur.com/3l5ujuC Edit: the important part As Bloomberg explains: "It’s a self-reinforcing cycle. As more renewables are installed, coal and natural gas plants are used less. As coal and gas are used less, the cost of using them to generate electricity goes up. As the cost of coal and gas power rises, more renewables will be installed." The table above shows how the capacity factors of coal and natural gas are starting to be affected, while wind and solar are starting to do better because bigger and taller wind turbines catch more wind and more solar is being installed in the U.S. Southwest where sunny days are more frequent. It's kind of like a flywheel, and the more solar panels we install, the more wind turbines are built, the faster it spins. At some point, doesn't make any sense to run fossil fuels on sunny or windy days, and overall capacity factors go down enough that prices are simply not competitive with storage, and rather than build new natural gas plants, utilities will simply buy more renewables combined with storage.
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Aug 25, 2019 21:49
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There is not any completely replacing fossil fuels on ships at the present time. The class societies hold that opinion, too.
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Aug 26, 2019 01:36
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