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Old 11-21-2010, 12:31 AM   #29
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Originally Posted by Nuvite-F View Post
For what it's worth, Wikipedia would beg to differ with you,

Fossil fuel power station - Wikipedia, the free encyclopedia

That is, 33% for straight Rankine-cycle plants and 50% for combined cycle plants using a gas turbine front end (Brayton cycle) followed by a heat recovery boiler and steam turbine. Plants meeting the former description are far more numerous than the latter.


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I'll try to find non-wikipedia source, but here's wikipedia disagreeing with wikipedia

Rankine cycle - Wikipedia, the free encyclopedia

Quote:
The efficiency of a Rankine cycle is usually limited by the working fluid. Without the pressure reaching super critical levels for the working fluid, the temperature range the cycle can operate over is quite small: turbine entry temperatures are typically 565C (the creep limit of stainless steel) and condenser temperatures are around 30C. This gives a theoretical Carnot efficiency of about 63% compared with an actual efficiency of 42% for a modern coal-fired power station. This low turbine entry temperature (compared with a gas turbine) is why the Rankine cycle is often used as a bottoming cycle in combined-cycle gas turbine power stations.
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Old 11-21-2010, 12:42 AM   #30
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Quote:
Originally Posted by Nuvite-F View Post
For what it's worth, Wikipedia would beg to differ with you,

Fossil fuel power station - Wikipedia, the free encyclopedia

That is, 33% for straight Rankine-cycle plants and 50% for combined cycle plants using a gas turbine front end (Brayton cycle) followed by a heat recovery boiler and steam turbine. Plants meeting the former description are far more numerous than the latter.

You do have a good point about auto engines operating at reduced efficiency on account of varying power requirements, and regenerative braking is certainly a big plus in urban driving conditions with lots of starts and stops. (If I remember correctly Mercedes Benz was building a hybrid diesel-electric city bus back in the 70s because it made sense, not because of government subsidies.)
.
The best modern combined cycle plants are getting close to 60% efficiency; the straight steam plants are approaching 50% but are limited by temperatures....

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Hybrid and electric vehicles make sense for some drivers, but my guess is, not most of us.
.
My guess is that hybrids make excellent sense for drivers in urban/suburban areas; certainly the number I see driving around and their resale value indicates people like them.

- Bart
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Old 11-21-2010, 12:45 AM   #31
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It's the plastics in the battery materials and chemicals that worries me.

I do think that Mazda is really on to something here!

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Sure. That's why you see old Airstreams in the landfill, right?
No? You mean that all that metal is worth something?
Perhaps the hundreds of pounds of metal in the batteries will be
worth recycling as well...

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Old 11-21-2010, 05:50 AM   #32
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Are electric cars a scam(or sham)?
Are electric cars a scam(or sham)?

No, not a sham, just a powertrain road trip to meet government fuel standards. Despite the perceived benefits of electric, hybrid technology, sales of these vehicles still represent only a tiny fraction of the U.S. marketplace. Americans purchased about 250,000 hybrid vehicles in 2006, accounting for just 1.5 percent of the 17,000,000 cars and trucks sold here last year. Gasoline powertrains will be around for decades, powertrian future will be hydrogen, but that is very far off.

http://www.greencar.com/articles/5-f...rogen-cars.php


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Old 11-21-2010, 07:42 AM   #33
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Most alteranitive fueled vehicles have their place, where the fuel and particular transportation need makes sense. This is very different answer for regionally. as well.
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Old 11-21-2010, 07:58 AM   #34
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While I do agree with the need to find renewable energy sources, and better ways to manage items we no longer need or find useful, I find the idea human activity can change the climate on a global scale to be hard to swallow. True science offers no real proof either. There are gaping holes in all the available theories. Even respected researchers have been caught leaving out data that is against the idea.

No better way to take more of our freedoms and MONEY than to create a problem the population wants to solve, and get passionate about, and make us believe is our fault.

The cap and trade idea will take the rest of any "disposable" income we have left.

Look at every dollar you spend. I would estimate the average person here pays in the neighborhood of 80% in taxes and government fees. Sales taxes, property taxes, income taxes, Universal Service Fees on phones and internet access. Fees to own a dog, have a garage sale. And now fees on the energy that we have already paid fees on. Figure it out.

End of rant, thanks for listening!
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Old 11-21-2010, 08:01 AM   #35
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Where are all the spent batteries gonna land eventually? A nice eco landfill?
scrap lead prises are on the rise andd i've notice that the battery core charges keep going up.
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Old 11-21-2010, 08:20 AM   #36
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. . . hybrids make excellent sense for drivers in urban/suburban areas; certainly the number I see driving around and their resale value indicates people like them.
Yes, but hybrids are highly prized by Bay Area drivers on account of their exceptional smug emissions.
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Old 11-21-2010, 08:48 AM   #37
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yeah. the same government that mandated corn liquor for gas.
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Old 11-21-2010, 09:11 AM   #38
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Do your lights go out when the wind stops blowing?
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The grid is big. It's always blowing somewhere.

On our 8,000 mile trip this fall I was amazed at how many wind farms and turbine parts being trucked we saw.
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Old 11-21-2010, 10:14 AM   #39
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Yes, but hybrids are highly prized by Bay Area drivers on account of their exceptional smug emissions.
.
that was an absolutely hysterical episode of SP, I will say.
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Old 11-21-2010, 10:28 AM   #40
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Originally Posted by jdalrymple View Post
Look at every dollar you spend. I would estimate the average person here pays in the neighborhood of 80% in taxes and government fees. Sales taxes, property taxes, income taxes, Universal Service Fees on phones and internet access. Fees to own a dog, have a garage sale. And now fees on the energy that we have already paid fees on.
They has been a huge shift in income from the middle class to the upper class. From a recent NY Times article:

Quote:
The share of total income going to the top 1 percent of earners, which stood at 8.9 percent in 1976, rose to 23.5 percent by 2007, but during the same period, the average inflation-adjusted hourly wage declined by more than 7 percent.
Remember this when they ask for lower tax rates for those making over 250K year.

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Old 11-21-2010, 10:29 AM   #41
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What is fuel?

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Originally Posted by toastie View Post
Are electric cars a scam(or sham)?

No, not a sham, just a powertrain road trip to meet government fuel standards. Despite the perceived benefits of electric, hybrid technology, sales of these vehicles still represent only a tiny fraction of the U.S. marketplace. Americans purchased about 250,000 hybrid vehicles in 2006, accounting for just 1.5 percent of the 17,000,000 cars and trucks sold here last year. Gasoline powertrains will be around for decades, powertrian future will be hydrogen, but that is very far off.

5 Facts About Hydrogen Cars | GreenCar.com


toastie
Toastie,
Thanks for the link.

The one thing that stuck with me was this quote.
"Hydrogen in itself is not fuel, but rather an energy carrier. Thus, energy must be expended to produce hydrogen."

It fits right with the point I was trying to make when I started the thread.

That point being: Before one becomes "smug", think about what your vehicle is really being powered by. Electricity is not a fuel. It is simply a method to transport energy (fuel?) from its point of origin to its point of use. In my mind there is no such thing as an electric car. It is a coal car, a solar car, a natural gas car, a wind car, a water pressure car, a nuclear car, or in all likelyhood a combination of all of the above and probably some more that didn't come to mind.

I also often wonder what effect our energy production has on our climate. I know it is all a matter of magnitude.

First of all, I have a degree in meteorology, some I'm not pulling all of this out of my hat, just most of it.

If we put up wind turbines, we slow the speed of the wind passing through that turbine. Since wind (moving air) is one of the ways energy is distributed around the planet, there is obviously an effect on the micro climate down wind from the turbine. The question is - how many turbines do we have to place in a giving location, to have a measurable effect.

The same thing is true of large arrays of solar panels, The radiation that is being converted to electricity was originally falling on the earths surface and warming it thus storing thermal energy at that location. Among other things this heat was causing air currents to form that were affecting the micro climate in that area.

This can be carried on to just about any form of what is referred to as "renewable energy".

What I am curious about is, has anyone attempted to analyze the combined effect of all of our renewable energy plans when they are carried to the extreme necessary to end the use of fossil fuels.

I am not attempting to start an argument. I don't think enough research has been done to have anything to argue about. Its just something to think about.

Regards,

Ken
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Old 11-21-2010, 11:05 AM   #42
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If we put up wind turbines, we slow the speed of the wind passing through that turbine. Since wind (moving air) is one of the ways energy is distributed around the planet, there is obviously an effect on the micro climate down wind from the turbine. The question is - how many turbines do we have to place in a giving location, to have a measurable effect. .
As you know, wind is the indirect result of solar energy driving the climate. Winds dissipate; normally the resulting energy goes into slightly heating the air itself. Wind turbines capture this energy (typical a small fraction, since turbines capture less than the theoretical max of 59%, and only cover a small fraction of the available area ) and move it elsewhere as electricity... and when it's used, is typically converted to heat - exactly where it would have ended up in the first place.

Long term, if we wish to maintain an industrial economy and a livable climate, we will have to switch to a more sustainable source of energy. That source is directly or indirectly (wind, hydro, biofuels) going to be solar; nuclear power will likely play a small role as well. What you're seeing now is those looking to plan ahead coming into conflict with those who wish things to remain the same.

Remember what happened with the ozone attacking chemicals - years of disinformation campaigns by Dupont and Dow Chemical attempting to discredit the research. We now realize the planet ducked a bullet - if we had not taken action, skin cancer rates would have been much higher.

The Skeptics vs. the Ozone Hole : Weather Underground

We are watching exactly the same behavior now w/ climate change....

- Bart
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