Planning Engineer -- Thanks.
My question on say, New England versus Mississippi is for you to address the issue of System generation portfolio <b>flexibility</b> in integrating Renewables.
Why is having intermediate natural gas (say combined cycle) units important (regardless of any Renewable discussion)? What does load tracking ability mean, and why is this important? (again, forget any Renewable aspect)
Does a System's <b>flexibility</b> play a big part in how Planners view Renewables? Can this System flexibility address many of the concerns folks have about <b>individual</b> characteristics of Renewables?
Comment on All megawatts are not equal by Stephen Segrest
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Comment on All megawatts are not equal by Curious George
The fuel should last twice as long at a 50% power, so there should be some savings – definitely less than 50%.
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Comment on All megawatts are not equal by Peter Lang
I’m seeing a considerable lack of understanding on the part of some commenters of the fundamentals of economics and finance; in particular, the time-value of money.
I agree. That’s the fundamental problem with trying to explain these issues to people who have little understanding of finance, cost/benefit analyses, options analysis, policy analysis, but are very confident they know what they are talking about.
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Comment on All megawatts are not equal by Planning Engineer
Frank – there are more choices than you provide. I will answer none of the above. In North America we have power providers who are Municipals, Cooperstives, Federal and State entities. Not to cast aspersions on profit, but in my career the drivers to provide economic, reliable power to consumers in a publicly responsible manner has not ever been in conflict with a profit motive connected to earning a rate of return. The focus has been rates and costs to consumers. I have been part of joint projects where our partners were,
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Comment on All megawatts are not equal by Planning Engineer
Partners were getting a return on investment.
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Comment on All megawatts are not equal by Peter Lang
Thomas Stacey,
To get to the punch line, yes, wind is perhaps a fuel saver but has near zero sway to avoid constructing and maintaining dispatchable plants. Essentially wind’s value cannot exceed the value of the fuel it saves: About $40/MWh for CC Gas, $25/MWh for coal, and less than $10/MWh for nuclear.
Excellent point. In the Australian National Electricity market the capacity credit was 3% in one state and 8% in another (don’t remember which was which of Victoria and South Australia). I think the 8% has been reduced since.
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Comment on All megawatts are not equal by Peter Lang
VP,
As I’ve pointed out repeatedly, you don’t understand what your talking about on energy matters. I’ve given you all the references, but you’ve demonstrated repeatedly you’re not interested in learning, just in trolling.
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Comment on All megawatts are not equal by Peter Lang
+ 100
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Comment on Gravito-thermal discussion thread by Pekka Pirilä
I think that there has been some confusion related to different uses of the word <i>isentropic</i> and <i>isothermal</i> in this discussion.
Both words are used widely for <i>flow processes</i> in gas. In that case a parcel of gas is considered. It's assumed that the parcel is in local thermal equilibrium, but the whole system is not (otherwise we have not processes, where anything flows or changes). Isothermal processes are not of interest here. Isentropic processes are an idealization. Fully isentropic processes are not possible in real gases as some diffusion is always present when flows occur. In the idealization, where all subprocesses of the full system are isentropic, the total entropy does not change. Thus the system does not approach the equilibrium, but remains at the constant distance from the equilibrium when measured by the difference in total entropy.
In real gases we have rather a "non-conservation law of entropy" than a conservation law as the entropy of an isolated volume of gas increases always unless the system is in thermodynamic equilibrium that's reached only asymptotically.
The concept of an <i>isothermal state</i> is clear, but an <i>isentropic state</i> is not a commonly used concept. Without gravity or other similar potentials isentropic is also isothermal and thus a state of thermodynamic equilibrium. Under gravity an isentropic state is an idealization that's not fully stable and not thermodynamic equilibrium. It's stable against flow processes, but it's not stable against heat conduction, which moves it towards the thermodynamic equilibrium of an isothermal state.
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Comment on All megawatts are not equal by Peter Lang
As of course they should. And some must have the opportunity to make super profit otherwise every business that attempts to run a business must be guaranteed a fair rate of return (like in communist countries). If there is no incentive to invest and take risk, everyone may as well be an employee of the state. How is the money generated to pay their wages? :(
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Comment on All megawatts are not equal by Vaughan Pratt
I see you continue to depend on <i>ad hominem</i> arguments in lieu of anything more substantive. That's been pretty much your style with most people that you disagree with. Lots of luck with that approach.
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Comment on All megawatts are not equal by Planning Engineer
Thankfully all utility models in North America pay their employees. That’s always built into the rate first thing! Some utilities provide profits to external shareholders, Utilities without the profit motive have developed bold and brilliant projects (as have investor owned entities). And similarly investor owned utilities show great concern for impacts on their consumers (as do the rest of us).
I think it’s fortunate that we have these different models – they kind of provide a check on each other,
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Comment on All megawatts are not equal by Vaughan Pratt
Nor do I have to be very bright to see opponents are loosing their battle as more and more wind power installations are built. I sense their desperation. Experience tells me the desperate aren’t the most reliable source of information.
What can be accomplished by accusing the desperate of being desperate? It is about as useful as accusing the poor of being poor, or a murderer of being a murderer.
If you want to accomplish something fruitful of that sort, tell a sympathizer that they’re sympathetic, or a charity donor that they’re generous.
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Comment on All megawatts are not equal by Peter Lang
PA,
I second the comment you Are very knowledgeable. I really appreciate your contributions.
You said:
So producing power at 50% costs twice as much per kilowatt as power produced at 100%.
I agree that it makes no sense to use the current nuclear designs for intermediate load following. There are cheaper ways to do it.
However, I think your quote is not a strong reason why not. Gas turbines averaging 10% capacity factor are also very high cost per MWh. The Australian Government AETA report, Table 5.2.6, summarises the projected LCOE figures. Central estimate for nuclear is $98/MWh and OCGT at 10% capacity factor and no carbon price is $211/MWh. So nuclear at double the LCOE is cheaper than OCGT at 10% CF. (Australia’s gas prices are higher than US and heading up, they’re projected to double or triple in the next few years.)
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Comment on All megawatts are not equal by jim
Reblogged this on <a href="http://pdxtransport2.wordpress.com/2014/12/13/all-megawatts-are-not-equal/" rel="nofollow">pdx transport</a>.
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Comment on All megawatts are not equal by vukcevic
From an EDF france email:
Origine 2013 de l’électricité vendue par EDF : 79,3 % nucléaire, 14,4 % renouvelables (dont 9,3 % hydraulique), 3,3 % charbon, 1,7 % gaz, 1,0 % fioul, 0,3 % autres. Indicateurs d’impact environnemental sur http://www.edf.fr
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Comment on All megawatts are not equal by Peter Lang
Thanks,
France’s electricity has been generated by around 80% nuclear for over 30 years. It’s electricity is near the cheapest in EU. It exports large amounts of electricity to it’s neighbours which demonstrates it meets requirements, is fit for purpose, and does what customers want – i.e provide reliable electricity. Furthermore, it’s emissions from electricity are 15% of Germany’s and Denmark’s (the RE advocates pin-up example of RE penetration).
It’s difficult to understand why the CAGW alarmists aren’t pushing for it. Just to be clear, I am pushing for the least cost system that meets requirements over the long term. I am not ;pushing for nuclear if it doesn’t meet this requirement. For me, if the CAGW alarmists couldn’t care less and block one of the best solutions, I couldn’t care less either. I’ll advocate for least cost energy that is likely to best meet requirements.
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Comment on Gravito-thermal discussion thread by Pierre-Normand
To be clear, in this thread I’ve always used “isothermal profile” to refer to a property of the combined vertical temperature and pressure profiles such that the (slow) vertical displacement of any air parcels would be a reversible *process* that conserves potential temperature as it adjusts to the pressure of the surrounding. So, the therm isentropic really characterizes a process. I agree it is better simply to call this profile the adiabatic lapse rate.
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Comment on Gravito-thermal discussion thread by Pierre-Normand
Vaughan Pratt,
I was specifying equilibrium conditions. As Pekka notes, loss of particles prevents equilibrium from being reached. It’s analogous to evaporation. It cools the TOA. So, what I am saying applies either to a tall gas column enclosed in a box, or a conditions where as many particles come down from infinity as do reach escape velocity.
The latter isn’t a fantastic idealization either since it is a common property of star cluster formations in young galaxies, or gravitational collapse of gas clouds from initial inhomogeneities in an initially uniform thermal bath of radiation and particles. In both cases, in spite of the initial gravitational ‘heating’ from contraction, the star cluster tends towards an ‘isothermal’ Maxwell distribution of speeds since the loss of stars from the cluster is compensated by the random capture of new stars in the young ‘isothermal’ galaxy. The same is true for the gas cloud after its temperature allows it to balance the gravitational force and it isn’t contracting anymore. The Virial theorem thereafter still applies to the evolving collection of star (or molecules) since the escaping stars have the same speed distribution as the newly captured stars that replace them. It’s akin to enclosing the star cluster into a large spherical container such that the fastest stars, including those that have escape velocity, bounce back with the same speed and kinetic energy.
Regarding your second objection, I think it is misguided. The two cancelling effects in the case where g is uniform with height are (1) the slowdown of the particles that are climbing the gravitational potential, and (2) the drop off from the molecular populations at any level of the molecules that have the least amount or total mechanical energy (PE+KE). As Coombes and Laue have showed, those two effects cancel out. If the gravitational acceleration decreases with height, then there is less of a slowdown of the rising molecules and also less of a drop off rate. So, the two effects both are smaller and they still cancel out exactly, as Toth demonstrates in the link that I provided (towards the end of the webpage).
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Comment on Gravito-thermal discussion thread by Pekka Pirilä
P-N,
Do you really mean “isothermal profile” in your latest comment to me. I think, you must have had “isentropic profile” in mind.
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