When evaluating fossil fuels shouldn't we also consider the direct heating effect of using the fuel?

[honest.abe]

So for example when a car is operating there is tremendous waste heat being generated along with CO2. This heat is given off into the air around the car and adds to the overall heat level of area. Its really noticeable when you park your car in your garage and shut the garage door. It's get incredibly hot. So considering there are over a billion cars on this planet, this effect would seem to be significant.

Then of course all the other uses of fossil fuels.. heating homes, generating electricity, powering all sorts of engines and equipment, etc. This all adds to the direct heating of the environment.

Is this level of heating insignificant in comparison to the effect of CO2?? I don't know for sure but I would think it would have a significant additive effect, a bit like operating a wood stove in a greenhouse.

We can also think of this like injecting heat into the environment that was captured from the sun eons ago. This energy has been stored in fossil fuels and we are now releasing it. It's like we are increasing the current sun's output.

I don't know what specifically can be done but seems its something that needs to be seriously considered.

[Think. Again.]

1. That's a good point...

...we should start considering ALL of the peripheral effects of any of our energy uses, like that disregarded waste heat, and of all our energy generation too.

Since we're just beginning the transition from fossil fuels to...everything else, now seems like the time to re-frame the way we think about all of this stuff.

[markie]

2. another reason to

love my induction stove... no extra heat!

[calimary]

3. Yes. Good idea!

Chip away at it.

Keep chipping away at it!

[elleng]

4. SHOULD be PART of the evaluation.

[Bernardo de La Paz]

20. Should not be. It's miniscule, lost in the noise. 8320 global warming vs 44.4 heat

I'll grant you it's easier to hand-wave than to calculate.

Fuel type MJ/litre MJ/kg
87 Octane Gasoline 32.0 44.4[4]

Carbon dioxide (CO2) 417 ppm (up 50% from 280) 1130 TW increase

The atmosphere has a mass of about 5.15×10^18 kg. That's 5,150 followed by 15 zeroes.

CO2 is 0.042% of atmosphere, and that is up 50% from about 0.028%. About half of CO2 is ultimately absorbed or converted, so there needs to be a factor of 2. We multiply the difference in percent by 2.

417-280 = 137. Multiply by 2 = 274 parts per million injected into the atmosphere.

So 5.15 x 10^18 x 274 / 1,000,000 = 1.41 * 10^15 kg of CO2 caused 1130 TWatt increase in warming.

1130 * 10^12 W / 1.41 * 10^15 kg = 8 W per kg C02.

1 kg of gasoline produces 3.30 kg of CO2. That is 26.4 Watts of global warming from the emissions.

Watts measure power. Power exerted over a period of time is energy. 1 watt for one hour = 0.0036 Mega Joules of energy of heat retained by the CO2.

26.4 W for one hour = 26.4 watt-hours = 0.0950 MJoules.

The CO2 sits in the air, warming it hour by hour (averaged over night and day) at 0.0950 MJ per hour. Run this for 10 years:

0.0950 x 24 hrs x 365 days x 10 years = 8320 MJ of global warming per kg of gasoline. Compare that to 44.4 MJ of heat per kg of gasoline. Miniscule by comparison.

[mahatmakanejeeves]

5. Urban Heat Implications from Parking, Roads, and Cars: a Case Study of Metro Phoenix

Urban Heat Implications from Parking, Roads, and Cars: a Case Study of Metro Phoenix

Christopher G. Hoehne , Mikhail V. Chester , David J. Sailor & David A. King

To cite this article: Christopher G. Hoehne , Mikhail V. Chester , David J. Sailor & David A. King
(2020): Urban Heat Implications from Parking, Roads, and Cars: a Case Study of Metro Phoenix,
Sustainable and Resilient Infrastructure, DOI: 10.1080/23789689.2020.1773013

To link to this article: https://doi.org/10.1080/23789689.2020.1773013

[Bernardo de La Paz]

7. Parking lots do not combust fossil fuels. They do collect energy, so they should all be white. . nt

[Think. Again.]

23. Better yet...

...cover parking lots with solar, creates a cooler, shaded environment below and doesn't waste excellent sun exposure space.

[Bernardo de La Paz]

24. Yes. You made me think again. . . nt

[honest.abe]

13. Some interesting information in the introduction.

Reddy et al., 2015), the influence of urban vehicle travel on the urban energy balance has been less rigorously studied compared to other heat sources. This is due in part due to poor quality transportation sector heat emissions (Smith et al., 2009). Hart and Sailor (2009) found up to 2°C warmer air masses above urban roads during the weekday compared to the weekend in Portland, Oregon, indicating that increased weekday vehicle travel may be the primary cause. Sailor and Lu (2004) found that heating from vehicles dominated the summer anthropogenic heating in six US cities, accounting for 47% to 62% of the total.

[Bernardo de La Paz]

6. No need. The level of heating is insignificant compared to CO2, because CO2 operates for decades

Heat from fuel is a one-time event.

[honest.abe]

9. Yeah but direct heat doesn't go away either.

It may dissipate over time but once the heat energy is released its basically there forever in our environment in one form or another.

[Bernardo de La Paz]

21. Sure. But you are comparing a one-time energy release to decades of heating by trapping solar

See my calculations in post #20.

[Blues Heron]

8. Insignificant compared with the suns heat

[honest.abe]

10. Yes, that's the question I was asking.

But I would like to see some numbers. Is it possible to do a calculation of the the sun's energy hitting the Earth compared to the heat released by all the fossil fuels being used?

[Blues Heron]

11. think how hot your garage got from that engine vs how hot the sahara desert gets

[honest.abe]

12. I was looking for a more quantitative answer.

[Blues Heron]

14. OK - world energy demand is about 624 exajoules/year, the sun gives us 3,850,000 exajoules/year

[honest.abe]

15. Would you mind providing a link to support your numbers?

TIA.

[Blues Heron]

16. no prob

https://en.wikipedia.org/wiki/Solar_energy


https://www.iea.org/reports/world-energy-outlook-2022

[honest.abe]

17. Thank you.

However, I guess the actual comparison I am looking for would be the effect of warming directly caused by CO2 versus warming by direct heating. I suspect no numbers exist for such a comparison.

[Blues Heron]

18. directly caused by our added CO2 above pre industrial levels? or total CO2

[Bernardo de La Paz]

22. Numbers do exist. See my post #20. . . . nt

[Blues Heron]

25. there are numbers for that - the total energy demand per year vs the radiative forcing of CO2

Last edited Fri Jul 7, 2023, 08:47 PM - Edit history (1)

the share of increased radiative forcing from CO2 since preindustrial times is 1.82 W/square meter

times the surface area of earth, times hours per year

Versus

our total energy demand per year of 624 exajoules



https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf

[honest.abe]

26. Thanks. I will take a look later.

[Blues Heron]

27. radiative forcing of 1.8 W/M due to our added CO2 is like space heaters 72 feet apart

radiative forcing of 1.8 W/M due to our added CO2 is like 900 watt space heaters 72 feet apart in all directions over the entire surface of the planet running continuously.

[honest.abe]

29. That's intense!

Thanks

[muriel_volestrangler]

19. World energy consumption in 2021 was 167,781 terawatt-hours

https://ourworldindata.org/energy-production-consumption

or 167781*3600 terajoules, or 6*10^20 joules.

The radiative forcing from greenhouse gases is about 3.2 watts per square metre: https://www.epa.gov/climate-indicators/climate-change-indicators-climate-forcing

or, for the globe (area: 4 * pi * radius squared) 3.2 * 4 * pi * 6,371,000 * 6,371,000 = 1.63 * 10^15 watts

or, for a year, 3600 * 24 *365 * 1.63 & 10^15 watts = 5 * 10^22 joules

So the warming from greenhouse gases is about 85 times the warming from energy usage.

This energy heats the atmosphere; when that temperature goes up, it will emit a little more into space. If we were to stop the extra greenhouse effect, and the direct heat from burning fuel, it would dissipate the heat, and the temperature would come back down.

Think of it as a bed; burning the fuel is like a hot water bottle - it will raise the internal temperature a bit, but this eventually dissipates if it's not replaced. Greenhouse gases act like a blanket - they raise the temperature under them (in a bed, because humans emit heat; on the planet, because sunlight heats the surface). We're adding blankets, and that's the main reason we're getting hotter here. Go back to the former state, and the temperature will too, eventually (but it'll take centuries for the greenhouse gases to leave the atmosphere, even if we stop emitting today).

[NNadir]

28. You know what?

This is not an issue, as others have pointed out, but I applaud you asking the question.

When I was young and nowhere near as well educated as I am now, I asked myself the very same question (long before the days of the internet.)

The general topic of heat flows is thermodynamics, a science essential if we are to save the world, which we may not do.

A sub-discipline of thermodynamics is heat transfer, one of the most important topics in energy and environmental engineering.

We can capture some of the waste heat for use, and a great deal has been written about this, under the general rubric of "efficiency," but in engineering terms, "process intensification."

Process intensification using high temperature systems is a key to saving the world.

Thank you for asking this question. It elevates my faith in the world that you have done so.