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Re: Natural Gas Vehicles

Unread postby misterno » Tue 17 Jan 2012, 23:00:13

Let me get this straight

So due to many transitions than NG/LNG has to go thru, an EV is essentially using less energy than a NG powered vehicle?

Is this correct? Or an assumption?
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Re: Natural Gas Vehicles

Unread postby TheAntiDoomer » Wed 18 Jan 2012, 08:57:35

This is as good a place as any to mention natural gas is now 2.55. Also I have filed a missing persons report for arthur berman, I am very concerned about his whereabouts!
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Re: Natural Gas Vehicles

Unread postby JRP3 » Wed 18 Jan 2012, 22:04:32

$this->bbcode_second_pass_quote('misterno', 'L')et me get this straight

So due to many transitions than NG/LNG has to go thru, an EV is essentially using less energy than a NG powered vehicle?

Is this correct? Or an assumption?

You are correct. EV with NG sourced power from a Combined cycle NG plant at 60% efficiency, 7% transmission loss, 10% charging loss, 10% driving loss, = 45%
CNG ICE = 20% at the vehicle, not counting compression losses to get it into the vehicle tank.
I don't know the total numbers for LNG but "L"ing NG probably takes substantial energy, and you're still burning it in an ICE.
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Re: Natural Gas Vehicles

Unread postby ralfy » Wed 18 Jan 2012, 22:58:33

Safety problems for smaller vehicles, probably better for larger ones like buses. Likely, to, as public transport will be very important in the long run.
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Re: Natural Gas Vehicles

Unread postby Plantagenet » Wed 29 Feb 2012, 21:45:39

T Boone Pickens pays a buck a gallon to run his Honda CNG car.

buck a gallon? Sounds good

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Re: Natural Gas Vehicles

Unread postby JRP3 » Thu 01 Mar 2012, 00:39:24

Still a waste of a limited fossil fuel resource, less efficient than an EV, with a higher cost per "gallon". The electricity he wastes compressing the gas to fill his tank before he moves an inch would drive my EV 50 miles. NG might make some sense for larger trucks or buses for longer distances where batteries aren't quite good enough yet but not for passenger vehicles.
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Re: Natural Gas Vehicles

Unread postby Plantagenet » Thu 01 Mar 2012, 01:51:05

$this->bbcode_second_pass_quote('JRP3', 'S')till a waste of a limited fossil fuel resource...


Where do you think EVs get their electricity from? :lol:

Currently, Currently around 71% of all US electricity comes from fossil fuel. -- About 49% of electricity is generated from coal, 21% from natural gas, and 1% from petroleum. Adding those together, you get about 71%.
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Re: Natural Gas Vehicles

Unread postby JRP3 » Thu 01 Mar 2012, 10:45:51

Are you intentionally being dense? I clearly explained that using NG fossil fuel in a generating plant to charge EV's is more efficient than burning it in an ICE. I provided numbers as to why that is true. So yes I know where electricity comes from, and if you are going to use NG for personal transportation you get more miles per BTU if you use it in a large combined cycle generating plant to charge EV's than you do if you burn it in an inefficient ICE. It's really a simple concept, and other fuel sources are irrelevant to the discussion, which is about using NG as a transportation fuel.
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Re: Natural Gas Vehicles

Unread postby Plantagenet » Thu 01 Mar 2012, 13:23:38

Hi JRP

Please try to control yourself. Take a deep breath or count to three or something before you post.

The mods here want to reduce personal attacks and have the discussions focussed more on the topics.

$this->bbcode_second_pass_quote('JRP3', 'I') clearly explained that using NG fossil fuel in a generating plant to charge EV's is more efficient than burning it in an ICE.


Your explanation doesn't match the actual facts, because much more electricity for EVs is generated by COAL-fired plants, not NG plants.

AND even where NG is used, it still isn't more efficient. I've previously explained why burning NG directly in an engine (one step) is more efficient then burning NG in a massive central power plant (1), transmitting electricity through a grid (2), storing it in a battery (3), and then taking electricity from the battery to power the engine (4), where some of the energy is inevitably lost at each of the four steps. You have to subtract energy loss at each of the four steps required to power an EV when you consider total efficiency of EVs vs. CNG cars
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Re: Natural Gas Vehicles

Unread postby Plantagenet » Thu 01 Mar 2012, 14:20:14

$this->bbcode_second_pass_quote('pstarr', '')$this->bbcode_second_pass_quote('Plantagenet', 'I')'ve previously explained why burning NG directly in an engine (one step) is more efficient then burning NG in a massive central power plant

no you haven't. I reviewed this thread and I found no such data. Just conjecture.


Yes I have previously posted on how energy is lost at each of the multiple steps requiring to charge to power an EV. I had a prior discussion with JRP about this in either the VOLT thread or the EV thread. I summarized the concept again in my post above. Please re-read my post above, or check those threads if you don't understand the various energy losses and inefficiencies in the EV fuel cycle.

A related topic is the total CO2 emissions from EV cars. While EV boosters often claim their cars have zero CO2 emissions, in actuality when you add up the CO2 emissions from the fossil fuels used to power generating plants, and the concomitant energy losses due to energy transmission and storage, EVs often have HIGHER CO2 emissions than ICE cars.

TRy using this program called GOOGLE and search it out yourself. The facts may surprise you.

Pardon me---I'd like to continue this discussion but I've got to dash to meet some folks at the ski area just now. Cheers!
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Re: Natural Gas Vehicles

Unread postby Plantagenet » Thu 01 Mar 2012, 17:28:52

$this->bbcode_second_pass_quote('JRP3', 'e')fficiency...CNG ICE = 20% at the vehicle


There's a big big big problem with your math---the 20% number you are using is bogus. CNG has a much higher octane than conventional gas, so the efficiency is higher than a conventional ICE.

Natural gas, which is 90 percent methane, has a much higher octane rating than gasoline, allowing for higher compression ratios and therefore greater efficiency in the engines that use it.

The actual efficiency of a CNG car is actually about 45%- 55%, i.e. a factor of almost 3 times higher than the 20% number you assumed.

This high efficiency and high octane is one of the reasons CNG cars have such low emissions and low cost to operate.

pdf of US DOE report CNG engine efficiency at 45-55%
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Re: Natural Gas Vehicles

Unread postby JRP3 » Fri 02 Mar 2012, 19:36:46

Unfortunately the real world numbers for an actual CNG vehicle don't match up with your numbers:

$this->bbcode_second_pass_quote('', 'R')ange on a full 3600 psi fill is variable, depending on driving conditions and driving technique. While Honda claims an estimated 225–250 miles from a full CNG tank charge,[10] independent tests have found a lower ranges, at 180–200 miles[21] and "just over 200 miles" (about 300km).[22]The EPA rates the 2009 Honda Civic GX at 24 equivalent MPG city and 36 equivalent MPG highway.[23] Independent tests with mixed driving usage found rates of "nearly 32"[24] and 26.8[22] equivalent MPG.


http://en.wikipedia.org/wiki/Honda_Civic_GX
That doesn't even factor in the energy lost in compression to fill the tank, over 12kWh's of electricity, which would take an EV 50 miles. You keep talking about the "steps" required for an EV without using any actual numbers, which I provided, and you leave out the "steps" involved in a CNG vehicle, which include piping it through thousands of miles of pipelines to individual homes and commercial CNG stations, and include using grid electricity to compress the gas at high pressure. The 3 inefficient steps of a CNG are worse than the 4 more efficient steps in using NG to charge an EV.
And again, the topic us best use of NG for transport, the use of other fuels, coal, nuclear, wind, hydro, solar for EV's, and gasoline and diesel for ICE's, is completely irrelevant to the argument. The discussion is what is the best way to use NG, a limited resource, for personal transportation. The answer is in an EV.
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Re: Natural Gas Vehicles

Unread postby Plantagenet » Fri 02 Mar 2012, 21:32:20

$this->bbcode_second_pass_quote('JRP3', 'Y')ou keep talking about the "steps" required for an EV .... and you leave out the "steps" involved in a CNG vehicle, which include piping it through thousands of miles of pipelines to individual homes and commercial CNG stations


Thats because no natural gas is lost in sending it through pipes. Zero. Nada. No gas is lost.

In contrast, when a power plant sends electricity to your home so you can plug in your EV, about 6-7% of the power is inevitably lost just due to resistance in the transmissions lines.

When a comparison is made of the relative energy efficiency of CNG and EV cars, the EV cars have lost 6-7% in the power lines, and then there is the huge energy losses at the coal-fired or NG fueled central power plant that is feeding electricity into the lines, where 30-50% of the energy is lost right at the start!!! The EV is 40-50+% in the hole relative to the CNG before you even turn the key!!!!!!

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Electrical systems waste about 50% of the energy going into the system before an EV car is even turned on !!!!!
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Re: Natural Gas Vehicles

Unread postby Plantagenet » Sat 03 Mar 2012, 03:47:04

$this->bbcode_second_pass_quote('JRP3', ' ')Honda claims an estimated 225–250 miles from a full CNG tank charge,[10] independent tests have found a lower ranges, at 180–200 miles[21] and "just over 200 miles" (about 300km).


Compare that with an EV----the GM VOLT claimed 40 miles on a charge, but independent tests show it only goes 25-30 miles.

HHhhhmmmmm......200 miles per fill up in a CNG car versus 25 miles per charge in a VOLT? Let me do the math for you---The CNG car goes 8 times farther then the EV---

Wow! No wonder CNG cars are far far far outselling EVs around the world---they can actually go far enough to be practical and useful. Hahahahahahahahahahahahah! :)
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Re: Natural Gas Vehicles

Unread postby SolarDave » Sat 03 Mar 2012, 04:06:14

$this->bbcode_second_pass_quote('Plantagenet', '')$this->bbcode_second_pass_quote('JRP3', 'e')fficiency...CNG ICE = 20% at the vehicle


There's a big big big problem with your math---the 20% number you are using is bogus. CNG has a much higher octane than conventional gas, so the efficiency is higher than a conventional ICE.

Natural gas, which is 90 percent methane, has a much higher octane rating than gasoline, allowing for higher compression ratios and therefore greater efficiency in the engines that use it.

The actual efficiency of a CNG car is actually about 45%- 55%, i.e. a factor of almost 3 times higher than the 20% number you assumed.

This high efficiency and high octane is one of the reasons CNG cars have such low emissions and low cost to operate.

pdf of US DOE report CNG engine efficiency at 45-55%


You are reporting the goals from that report and not the results, and you are reporting on a HIGHLY modified diesel engine at over 50% load - which is not comparable to the ICE in a typical single-passenger gasoline car. In other words, your own argument shows how hard you have to work to fall far short of the numbers you posted above.

From the report:

 Program A Engine Efficiency Goals
% Full Load Engine Efficiency (%, LHV)
10-20% 26-30% <- missed
40-60% 34-38% <- claimed
80-100% 38-42% <- claimed

So there's a big big big problem with your math---the 45%- 55% number you are using is bogus. ESPECIALLY bogus when mis-applied to typical ICE auto use.

Read the report.
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Re: Natural Gas Vehicles

Unread postby JRP3 » Sat 03 Mar 2012, 12:34:21

$this->bbcode_second_pass_quote('Plantagenet', '
')
Thats because no natural gas is lost in sending it through pipes. Zero. Nada. No gas is lost.
So the gas is pushed through pipelines by magic, with no energy loss? Nope.$this->bbcode_second_pass_quote('', '
')In contrast, when a power plant sends electricity to your home so you can plug in your EV, about 6-7% of the power is inevitably lost just due to resistance in the transmissions lines.
Amazing, an actual factually correct statement. Nice work.
$this->bbcode_second_pass_quote('', '
')When a comparison is made of the relative energy efficiency of CNG and EV cars, the EV cars have lost 6-7% in the power lines, and then there is the huge energy losses at the coal-fired or NG fueled central power plant that is feeding electricity into the lines, where 30-50% of the energy is lost right at the start!!! The EV is 40-50+% in the hole relative to the CNG before you even turn the key!!!!!!

Electrical systems waste about 50% of the energy going into the system before an EV car is even turned on !!!!!

And then you fall apart again. Try really really hard to pay attention, we aren't talking about any other fuel besides NG, we are discussing how to best use NG, not coal, not diesel, not fairy dust. That means we are talking about combined cycle NG plants at 60% efficiency, heck we can even use 50% efficiency. In any case let's go with your number of 50% of the energy going into the system lost before the EV is turned on. A CNG ICE losses about 75-80% as soon as you turn on the key, and it's already lost some of that energy due to piping losses and compression losses to get it into the vehicle. You are so concerned with the upstream EV losses you close your eyes to both the upstream and in use losses of the CNG ICE. You also use fantasy numbers for CNG ICE efficiency. Other than all that, good work as usual.
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Re: Natural Gas Vehicles

Unread postby Plantagenet » Sat 03 Mar 2012, 12:49:10

$this->bbcode_second_pass_quote('SolarDave', 'y')ou are reporting on a HIGHLY modified diesel engine at over 50% load - which is not comparable to the ICE in a typical single-passenger gasoline car.
So there's a big big big problem ---the 45%- 55% number you are using is ... mis-applied to typical ICE auto use.


Hi Solar:

Amazingly, you completely missed the point of the data, the DOE paper I linked to, and the topic of this whole thread. None of this has anything to do with the efficiency of a "typical single-passenger gasoline car" you are talking about.

This topic is about natural gas cars. The reason that the DOE report I linked to contains effciency numbers higher than those for typical gasoline cars in modified engines is because CNG cars are more efficient than typical ICE gasoline cars after the engine is modified to optimize the use of natural gas. The octane content of NG is much higher than the octane of gasoline making the whole engine much more efficient.

If you don't know about CNG vehicles, I suggest you check it out---AGAIN, if you want to talk about "typical gasoline cars" you are in the wrong thread---this is a discussion vehicles fueled by NATURAL GAS.

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