How much CO2 is in a gallon of gasoline?

[XemaSab]

How about running a conventional light bulb for an hour?

Keeping a flourescent bulb on all day?

Heating an average room from 50 to 70 degrees with a natural gas wall heater?

Heating up a 50 gallon tank of water with natural gas?

ps I have taken o chem.

[freethought]

1. Someone may correct me on this but I believe that

one gallon of gasoline used in an internal combustion engine translates to 15-17 pounds of CO2 released into the air. Sorry, I can't site an information source but that is the figure I keep hearing.

You may think that a gallon of gasoline does not weigh even near 17 lbs. But remember, as you run the engine you taking in large amounts of air so you can combine it with the fuel to burn it in the engine. The air, of course, is being fed through a carburetor or through fuel injection. That fuel and air mix adds up as you drive along.

[TreasonousBastard]

5. Eight atoms of carbon and 10 of hydrogen...

in a gasoline molecule. (Ignore all the other stuff in there)

If combustion was perfect, you would end up with 5 oxygen atoms hooking up with the hydrogens to make water, and 16 oxygens hooking up with the carbons to make CO2-- an extra 21 atoms, or three times as much stuff as you started with. Combustion is mever perfect, but this gives the idea.

As far as weight goes, there's that atomic weight stuff-- hydrogens are 1, oxygens are 8, and carbons are 14. So, you started with a total atomic weight of 122 and added 168 of oxygen, and the total weight of the water and CO2 is more than double what you started with.

If I remember right, gasoline weighs a little over 6 pounds per gallon, and with the CO2 being a lot heavier than water, up to 17 pounds sounds about right. (But that one I'm not doing in my head.)

There is, of course, other stuff coming out of the tailpipe, and incomplete combustion means some carbon monoxide and unburned gas-- most of which is supposed to be taken care of by the emissions systems.

[eppur_se_muova]

8. Linky: How can 6 pounds of gasoline create 19 pounds of Carbon dioxide?

http://www.fueleconomy.gov/feg/co2.shtml

[nebenaube]

2. too much considering

I have to heat this house...

[freethought]

3. Don't get too bent out of shape about home heating

the biggest contributors of GHG to the atmosphere are the activities of transportation and energy production. A single coal-fired plant could belt out in one day many multiples of what a series of homes would use in burning fuel oil or natural gas.

That is not to say one shouldn't be conscious of it just that lets do something about the big contributors first. Turning the thermostat down a few degrees and wearing a sweater helps.

[XemaSab]

4. Hey, I had the gas guy here earlier in the week

and I asked him to turn the heater OFF. Like, OFF off.

Right now I am wearing a sweater and questioning my decision. :D

[kestrel91316]

10. Get a little electric space heater to get you through the rough times.

Heat only the room you are in; keep the doors to spare rooms closed. Wear long johns and make sure your socks are wool blend or pure wool (angora is particularly warm).

I have done all this. It works. And makes me feel particularly virtuous in my sacrifices.

[XemaSab]

11. It's Santa Barbara

There were two nights about a month ago when I put a pot of water on the stove for a bit of heat. Otherwise I just get in bed and pull the covers up. :D

[kestrel91316]

17. I know exactly what you went through. I'm down in the San Fernando Valley.

That was a hellacious cold snap!!!!

It's perfect for a space heater - really. No need to be shivering. Another SoCal trick in cold weather is to start a bunch of baking, and make a pot of soup or two. All that stove activity will keep a place nice and comfy.

I LOVE to sleep in a cold room, with warm jammies and socks and blankets piled up high, breathing that cold air!

[TreasonousBastard]

6. There are "carbon calculators" on the web, but...

they are necessarily vague. A lot depends on the source of your electricity-- hydro, nuclear, coal, gas... And none can really tell if you are really using energy efficiently.

The trick is to be as efficient yourself as you can afford to be. Electrical appliances should have a high EER rating, use "on demand" water heaters instead of tanks, insulate the house, turn off the lights and TV, ride a bicycle when possible...

[XemaSab]

12. I always feel like the carbon calculators

don't estimate my usage properly. I am probably more frugal at home but less frugal when I am out and about. :P

[GreenZoneLT]

7. I think we're worrying about the wrong end of the equation

Deforestation for subdivisions (in America and Europe) or lumber (in the tropical Third World) is a much bigger problem than burning fossil fuels. If we grew more trees, they could soak up all that atmospheric carbon.

And along with eliminating the carbon-storing mechanisms, deforestation leads to erosion, disruption of rainfall, and destruction of fish habitat. I just read Jared Diamond's book "Collapse," and every example of a historic civilization that outgrew its food supply and suddenly vanished started out with deforestation, from Easter Island to the Mayas to the Greenland Norse.

On the plus side for the planet, when we do reach the limits of what it can handle, the human population will crash like a jet liner that ran out of fuel, because our population is dependent on technology, and technology levels are dependent on the number of intercommunicating people. Global warming may be a moot point in two centuries, because there may be few hundred million humans by that point.

[NNadir]

9. I did the calculation for lightbulbs here in Nov-05.

More important is the greenhouse gas emissions. Let us suppose that I didn't have the benefit of our New Jersey nuclear stations, and I lived in an area where power was produced by coal. Over three years the incandescent would consume 526 kilowatt-hours of electricity or 1.89 billion joules. The fluorescent would consume 123 kilowatt-hours or 442 million joules. If we (generously) assume that a coal station can operate at 40% efficiency, the incandescent bulb would require that 442 kg of coal be burned injecting about 1.6 tons of CO2 into the atmosphere, whereas the the fluorescent would require the burning of 189 kg of coal and the injection of 0.7 tons of CO2 into the atmosphere. The savings is thus about a ton of CO2 per bulb over the lifetime of the fluorescent.

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x34359

[XemaSab]

13. Excellent!

:bounce:

ps I just went and paid homage to the desal plant. It's a boondoggle, but it's OUR boondoggle dammit. :D

[NNadir]

14. What desal plant?

Are you speaking of the plants at Morro Bay and Diablo Canyon, or is another planned?

[XemaSab]

15. The desalination plant for water

:D

[NNadir]

16. Which one?

Are there new plants being built?

[XemaSab]

18. It's a boondoggle, but it's OUR boondoggle...

http://www.santabarbaraca.gov/Government/Departments/PW/DesalSum.htm

[NNadir]

21. If the plant did run, it would have required significant energy.

One day Santa Barbara is going to be short on water. It's inevitable.

I fondly recall "if it's yellow, let it mellow" conservation campaigns from my days in LA and SD. As I recall, Santa Barbara and the entire mid coast depends wholly on local rain run-off.

I am suprised that it has never gone completely dry in any California city. Of course California agricultural areas have gone dry, most famously the Owens valley.

The water problem is not easy to address, not in the West, not anywhere.

[XemaSab]

22. At the same time the plant was built

SB got hooked up to State water. But we still use a LOT of local run off. :P

[NNadir]

25. I left California just about that time.

It would seem to me that State water is hardly unlimited.

What about the central coast, Santa Cruz, Morro Bay, San Luis, etc?

It is not immediately clear to me that desalination is energetically less intense than recovery of water from sewage, but I don't actually know that.

[muriel_volestrangler]

19. Question: what energy density for coal did you use?

It looks to be something like 11 MJ/kg - which looks very low - for black coal, anyway - about half, if not a third, of a typical figure.

For the incandescent bulb:

Calculation: 442kg at 40% efficiency is the same as the pure energy of 442 * 0.4 = 177 kg

For the incandescent bulb:1890 MJ / 177 kg = 11 MJ/kg .

On edit, for the fluorescent:

189 * 0.4 = 76 kg

442 / 76 = 6 MJ / kg

Huh?

[NNadir]

20. Without having the calculation in front of me, I generally ballpark coal

at 25MJ/kg.

Sometimes when I am feeling generous toward advocates of the use of dangerous fossil fuels, I use 30MJ/kg.

I should have explicitly stated what value I was using in the post, but for some reason I didn't.

Note that 40% efficiency means that more coal is required to give a specific amount of usable electricity, not less.

Look at the calculation this way. Suppose coal has 30MJ/kg. Then 442 kg contains 13 billion joules of primary energy. If we generally assume 40% efficiency - and few coal plants ever achieve such efficiency - then we have 40% of that energy = or 5.3 billion joules recoverable as electricity.

If we divide this amount by the 31.6 million seconds in a year, we see that this is about 170 watts electric. Note that I am not accounting for the inevitable losses in transmission of the energy and the need to actually produce an amount of energy over and beyond the actual demand (spinning reserve.) My original calculation referred to the 3 year lifetime of the flourescent bulb.

[muriel_volestrangler]

23. Let's redo the calculation with 25 MJ/kg

incandescent: 1890 MJ electricity = 1890 / 0.4 = 4725 MJ heat from the coal

4725 MJ / 25 MJ/kg = 189 kg coal

fluorescent: 442 MJ = 442 / 0.4 = 1105 MJ coal

1105 MJ / 25 MJ/kg = 44.2 kg coal

189 kg coal = 189 * 44/12 = 693 kg CO2 (presuming the coal is pure carbon)

44.2 kg coal = 44.2 * 44/12 = 162 kg CO2

Saving: 531 kg CO2

(We know that since the power required by the fluorescent bulb is just under a quarter of the incandescent one, the amount of CO2 should also be just under a quarter - as it is in this case, but not in your original calculation).

Note that 170 watts of electric power, over a year, would be more or less 60 watts over 3 years - but your example was for a 'real world' bulb - ie not one you kept on 24 hours a day. You said 8 hours a day in your original thread (in which the other calculations look OK).

[NNadir]

24. Thanks. In any case the carbon impact of a single light bulb is enormous

in the case where one chooses to use dangerous fossil fuel plants to power them.

The amount of dangerous fossil fuel waste that must be dumped is unacceptable in my view.

It would be unacceptable if it were 50 kg per light bulb.