Offsets for flying

Traveling for the holidays and want to offset an airplane trip? I was asked about this recently: first, how much, and second with what organization. Unfortunately, it seems to me that many of the offset organizations I looked at have been under attack for not assuring additionality (my offset funds buys greenhouse gas reductions in addition to what would have happened without my help), etc, etc.

Atmosfair calculates your greenhouse gas emissions for flying. They supplement time at high altitudes to account for the greater effects of water vapor, etc at that altitude, and supplement short trips to account for the relatively high percentage of time spent in takeoff or landing.

I tried two examples, both from my area, multiplying kg by 2.2 to get pounds:

SF – London with a layover in NYC 5,780 kg = 12,700 pounds carbon dioxide equivalent
SF – LA 380 kg = 840 pounds CO2e

SF to NYC to London is 12,000 miles round trip, so this trip comes in at just over a pound CO2e/mile. SF to LAX is 675 miles RT, or about 1 1/4 pound CO2e/mile.

What can I do to offset this?
One possibility is replacing incandescent bulbs with compact fluorescent. Soon, we all will, but in the meantime, you can donate bulbs to the local food bank, the one getting bags of food every few months to locals for whom the food dollar doesn’t always make it to the end of the month.

Other possibilities?

So how many bulbs do I need to give away?
Go to EPA to find out how much greenhouse gas 1 kWh produces in your area. Just enter your zip code, and verify your utility. The first chart gives the mix of energy sources in your area, the second one the number of pounds of carbon dioxide equivalent for each 1,000 kWh you use. (1 MWh = 1,000 kWh)

Let’s assume that all of the offset will come from 75W equivalent bulbs. These last longer than incandescents, and will more than pay for themselves during their lifetime in cheaper energy use, as they use about 1/4 as much electricity. You’re going to give away bulbs to people who haven’t yet bought them.

Assume the 75W equivalent bulb last 8,000 hours, yes, the package says more, my local hardware store says 8,000 hours. Over that time, the bulb will reduce emissions by
3/4 * 0.075 kW * 8,000 hr = 450 kWh

Now multiply the number of kWh by the local GHG/kWh, for example, if you live in California, a 75W equivalent compact fluorescent displaces
450 kWh * 879 pounds CO2e/1,000 kWh = 400 pounds CO2e

If you live in the Twin Cities, a 75W equivalent compact fluorescent displaces
450 kWh * 1,814 pounds CO2e/1,000 kWh = 820 pounds CO2e

Now divide GHG emissions from flying by GHG emissions/bulb to get the appropriate number of bulbs to give away:
12,700 pounds CO2e/(400 pounds CO2e/bulb) = 30 bulbs in CA
12,700 pounds CO2e/(820 pounds CO2e/bulb) = 16 bulbs in MN

Yes, it’s cheaper for people in MN to offset flying, but it’s cheaper for people in CA to offset their electricity use. More on this is January.

7 Responses to “Offsets for flying”

  1. If you fly in an airplane it leaves a condensation trail. This white cloud reflects sunlight away from the Earth, causing the Earth to cool. This reflection mitigates the heating caused by carbon dioxide released during the flight. It might make flying a positive factor when it comes to reducing global heating. Who knows? People should be a bit more evidence driven when they plan out how they are going to control the climate.

  2. Karen Street says:

    Randal, there's that, but do check out the IPCC Special Report, Aviation and the Global Atmosphere, to see the net effect. It would suprise me if aviation is considered a net benefit in addressing climate change any time in the near future, but there was that Woody Allen movie about how they discovered 200 years in the future that hamburgers and fries are the most healthful food, so who knows...

    Currently the net effect of adding water to the atmosphere is that it increases the Earth's temperature more than it deflects sunlight.

  3. D. Jaber says:

    Although the reason those in MN find it cheaper to offset flying is that the MN utili(ies) have been less aggressive in investing in renewables and efficiency (admittedly much of CA is invested in nuclear and less so in large hydro,but even controlling for that it would still be somewhat cheaper). Let’s hope that all areas of the country will eventually find it harder and harder to cheaply offset with electricity efficiency — because their utilities are getting closer to carbon negativity (beyond neutrality!)

  4. Joffan says:

    The thing that will bring this nice simple scheme to an end in a few years is when the normal lightbulb is CF. Then you can’t really claim any credit; so enjoy it while it lasts.

    You’ll have to enlighten us, D.Jaber, on how investing in efficiency makes any difference to this calculation across states.

  5. Karen Street says:

    Joffan, It is much cheaper to reduce GHG emissions today because there is so much low-hanging fruit. CFL save money over the lifetime of the bulb. Once we elect a government that mandates the freebies, we will find offsets more expensive.

    David, perhaps the major investment that MN will make is in technology to capture and sequester carbon emissions from all those coal plants. We can expect electricity prices to rise there.

    How can a utility get beyond carbon neutrality? I know of only one method: combining low GHG forms of electricity (nuclear, wind, and solar) with biomass with carbon capture and storage. Without CCS, whatever carbon dioxide from the atmosphere is stored in the plants, that same amount is released when the plants are burned to make electricity. However, with CCS, the atmospheric carbon stored in the plant is stored in oil wells or coal mine seams. Is that what you had in mind?

  6. Mark says:

    The EPA’s Power Profiler web site also lists the N2O pounds/MWh. Given that N2O is 300 times more potent at trapping heat than CO2, the calculation really needs to add N2O as well: (300 * 0.8 lbs/MWh N2O) + 879 lbs CO2/MWh = 1119 lbs/MWh or 1.119 lbs/kWh CO2e .

  7. Karen Street says:

    Mark, Much thanks for calling my attention the ignored gases. NOx is a combination of gases, only some of which is N2O), the one with the really high global warming potential.