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MWt Versus MWe

11/21/2013 3:15 PM

In nuclear plants, when I saw MWt and MWe listed next to each other for the same reactor, I didn't expect such a large difference. I imagine this is because of the inefficiencies of changing from heat to steam to electricity. Can someone straighten my head out if I'm wrong? Thanks.

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#1

Re: MWt versus MWe

11/21/2013 3:33 PM

No you are correct, it's about 3 to 1 needed.....

http://answers.yahoo.com/question/index?qid=20130813103610AAJ5uAl

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#2
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Re: MWt versus MWe

11/21/2013 4:36 PM

Also explains why people who quote the great efficiency of electric cars vs ICE (as in this recent thread http://cr4.globalspec.com/thread/87246/In-Search-Of-The-Perfect-Vehicle) need to be reminded of 'where's the electricity coming from?'

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#3
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Re: MWt versus MWe

11/21/2013 5:04 PM

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#4

Re: MWt versus MWe

11/21/2013 5:47 PM

The price of electricity does reflect all those inefficiencies. Sometimes it's more enlightening to think of an EV as putting its exhaust pipe in the utilities' stack.

But there are economies of scale that work in favor of large power plants. My son's Chevy Volt gets 4-5 miles per kWh, at 18 cents/kWh that's about 4 cents per mile, there are very few ICE's that can come anywhere near that cost per mile for their fuel unless they're getting around 75 mpg or gasoline costs $1.00 per gallon and you have a 25mpg car.

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#7
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Re: MWt versus MWe

11/23/2013 10:12 PM

I have just come back from Malaysian Borneo ( Sabah ) where the fuel is indeed around $1/gal and the vehicles do get better than 25mpg. So why is fuel more expensive in our countries? Here in Oz the Gov't adds about a dollar per litre to make it too expensive to waste. ( Why o why can't I turn off this bold text!!!!!!! ) Of course it is just a revenue raising ploy. As such it is clear to me that if electric cars were more common electricity would taxed at a higher rate to raise the revenue that is now lost. A precedent has been set here with solar panels. An incentive was given by the gov't to its' people to help them buy solar panels and then sell the power generated back to the grid. The initial rate was 48c/Kwh, as more people took up the option the rate dropped to 16c/Kwh and now the purchase incentive is totally removed and the c/Kwh will soon be removed as well. The reason? Too many people opted for the scheme and the power generaters couldn't sell enough to remain viable. wtf?

Back to the topic. Do you know the actual cost of an electric vehicles' fuel vs an ice vehicles' fuel? It is a very hard question to answer. Fuel in an arab state is less costly than in Texas for example. Electricity in Tasmania where there are hydro electric schemes is cheaper than electricity where I live, and so on.

If electricity were to be generated by renewable means AND the gov't didn't, or couldn't, tax us for it I would opt for electric cars in a heartbeat.

Jim

P.S. I got rid of bold text in the preview > edit page

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#8
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Re: MWt versus MWe

11/23/2013 11:20 PM

Sometimes when "they" give the mpg of a car, I suspect that they conveniently forget the cost that the electricity adds to their electric bill. Therefore, some measure such as $/mi would make more sense; trouble is it varies so much across the country.

So the bold text doesn't continue, I try to wait a few words after the bold, then go back to bold it, then continue where I left off.

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#9
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Re: MWt versus MWe

11/25/2013 3:37 AM

Thanks for the tip but that wasn't the problem ( that is the way I did the bold, anyways ). What happened is that every word I wrote after the bold was also in bold and couldn't be returned to standard. Until, that is , I went to submit and the preview page. I then selected edit text and then i could remove the rest of the bold text so the page ended up as you saw it. I didn't edit out my annotation as I hoped someone would say they had the same problem. It all seems work well enough now. Oh noo it doesn't. This time the underline stayed on. Last time I had also selected both bold and underline as well. Is that a clue?

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#5

Re: MWt versus MWe

11/22/2013 8:01 AM

Dear Mr.Lehman57,

It is the THERMO DYNAMIC EFFICIENCY of the TURBINE plays vital role, which depends upon the Steam Temperature and NOT the Pressure. In the Nuclear Power Plant SUPER-HEATING of STEAM isNOT DONE as IT IS NOT POSSIBLE. Hence Low Efficiency.

The Theoritical Thermo Dynamic Efficiency maximum possible - for Sub-Critical Pressure is just 39% and actual will be around 32 to 33%.

DHAYANANDHAN.S

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#6

Re: MWt Versus MWe

11/22/2013 12:11 PM

http://www.engineeringtoolbox.com/carnot-efficiency-d_1047.html#.Uo-PKPnnY5s

The base efficiency of any heat engine is defined by the Carnot Efficiency and it all goes down hill from there ?

http://www.engineeringtoolbox.com/power-plant-efficiency-d_960.html#.Uo-PpPnnY5s

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