AskPablo: Lightbulb Philanthropy

Image Courtesy of Stoughton UtilitiesAre you concerned about your contribution to the climate change crisis? Are you still unsure about carbon offset programs? Well, you are not alone. While I am a strong believer in the value and importance of offset providers such as DriveNeutral and Native Energy I also realize that there are some organizations out there, whose carbon offsets might not be as verifiable or that take too much profit for themselves. If I can’t convince you to offset your emissions with a legitimate offset provider I would certainly like to help you to neutralize your climate impact in another way.

Here is the idea: You get together with your friends and collectively replace all of your wasteful incandescent light bulbs with efficient compact fluorescent lights (CFLs), using your collective buying power to get a good deal. Then, after rejoicing about all the energy (and $$) that you have saved you figure out your remaining carbon footprint. You then buy CFLs for low-income families in your neighborhood or people that would otherwise not buy CFLs (because of their higher initial cost). Since those households would not have otherwise switched to CFLs you can take credit for the carbon emissions reduction and bam! you can consider yourself offset! And as an added bonus you will help a low-income family save money on their electricity bill!
But how many bulbs would you need to buy?

  • A 15 W CFL replaces a 60 W incandescent and its median lifespan is 10,000 hours.
  • So a savings of 45 W over 10,000 hours = 450 kWh, or 0.45 MWh.
  • In California the grid emits 0.51 metric tons per MWH (find your state in CCX Advisory 2007-01)
  • One bulb (in CA) would prevent the emission of 0.223 mT (0.45 MWh x 0.51 mT/MWh) or 223 kg (492 lbs) of CO2.

If your car emits 5 mT/year, you would need to buy 23 bulbs (5.0 / 0.223) for your neighbors to offset its emissions for the year (Calculate your annual vehicle emissions using this calculator or see my column on vehicle emissions: AskPablo: The Tailpipe Mystery.
To calculate you household carbon emissions take a look at your electric bill. Add up the kWh used in the last 12 months (if you have records that far back, otherwise multiply the last month by 12 to get a rough estimate) and divide by 450 kWh to get the number of bulbs you should buy.
There are many calculators out there that will do all the hard work for you. One that I like is the US EPA’s Personal Emissions Calculator. The following bullet points will help you calculate the number of bulbs to buy based on your result from the EPA calculator.

  • To convert pounds to metric tons multiply by 0.454 to get kg, then divide by 1000 to get metric tons of GHG emissions.
  • Next, find your state’s grid emissions factor (in CCX Advisory 2007-01) and multiply it by 0.45 MWh (the energy saved over the lifetime of one CFL). This gives you the GHG emissions prevented by one CFL, based on your state’s power generation emissions.
  • Now divide the result from the EPA calculator (in metric tons, from bullet point one) by the result from bullet point two. This should give you the number of bulbs that you need to purchase (each year) to offset your household’s GHG emissions. Always round up and remember to recalculate your emissions each year to see if you have reduced your climate impact.

I hope that you have fun with this and it helps you build a community of energy efficient climate leaders! Please submit your success stories, comments, or questions in the comments area below. Thanks for reading AskPablo!
Pablo Päster
Sustainability Engineer

8 responses

  1. Hi Pablo,
    Great idea. My worry with CFLs is their own life cycle consequences (e.g. mercury).
    2 Points:
    1) Do you take the life cycle of the CFL into account in your calculations?
    2) What about the disposal issues / other consequences of CFLs that are not being discussed. (Sure the mercury can probably be justified as less than burning coal, but you know what Bill McD says about being “less bad.”) Can we add these issues back into the equation?
    Thanks for the innovative thoughts.

  2. My friends daughter informed me that more mercury is released into the environment during the manufacture of incandescents than in the disposal of fluorescents.

  3. Pablo,
    Even though I rent, and don’t pay utilities, I have been thinking of buying cfls for the ceiling fixtures in my place. I could theoretically take them with me when I move, but now I think I will just leave them for the next renters. Thanks for the inspiration.

  4. Brilliant idea! (no pun intended)
    If a CFL is about $4-5, you can offset 1 year of car emissions for a little over $100. Not a bad little charity scheme. I’m excited about this and will put my money where my mouth is. Just remember, the 23 bulbs purchased will only offset one year. So until next year’s big idea, I’ll get to work on this CFL scheme. Thanks!

  5. Hi Pablo,
    You are doing fantastic work on this site. I am sorry, but I have to disagree with you on this one though.
    The litmus test for carbon offsets projects is that they are “additional”, e.g. that they would not have happened anyway without the additional money from the offset.
    It may sound strange, but the worst carbon offset projects are therefore the ones that make the most sense economically to do. If a project is profitable it is difficult to claim that people wouldn’t figure out that they could make money by doing it some time in the near future.
    Your example claims the emissions rights for the next 10,000 hours of the CFL light bulb. You are essentially saying that in any time over the next several years that family would not figure out that they can save money by buying cfls.
    You have to be careful with your assumptions here. Saving energy is particularly important for poor families. I was recently in West Africa, and have spent a lot of time in Latin America and you see cfls everywhere. That is because poor people can’t afford not to buy them.
    It is also quite difficult to predict the future. Perhaps when you wrote this cfls were quite expensive, but I just bought 10 cfls for $10, as part of a GE promotion. Also, there is legislation to mandate that no more incandescents be sold. If you are claiming emissions reductions into the future your assumptions may be turned upside down. This is similar to the idea that if you plant a tree you can’t guarantee that it will not be burned, or that someone will burn a tree somewhere else (leakage), or that the tree itself will eventually die (which it will) and all the CO2 will go back into the atmosphere.
    By definition then, legitimate carbon offset projects are marginal, i.e. they are not financially viable without the additional money. This has to do with messy things like discount rates and perceived risk. Because there are so many opportunities to make money by saving carbon (and energy) most carbon offset projects will tend to run into this trap until the market matures and all low hanging fruit is used up and there is increased demand for higher quality offsets.
    Good carbon offset projects, in my opinion, also have additional co-benefits, such as poverty reduction. This is what makes your idea most compelling. But beware. Symbolic meaning is important. If you approach a poor family with a bundle of light bulbs they may be initially grateful but they may also question your motives. If you explain it is partly a way to purge yourself of your climate debt they may be quite offended if your logic is based on the assumption that this family would not figure out that they can save money by purchasing cfls themselves.
    My favorite offset projects are by The Gold Standard One example is a methane capture project in India that was working but failed. The carbon offsets money helped the project get back online and make the venture profitable. Someone will no doubt find problems with these projects as well.
    Thank you for opening a dialogue on this important topic. Only through open discussion can we move the voluntary carbon market forward.
    BTW, if you are interested in calculating your household’s climate footprint from food, goods and services, as well as lifecycle emission on transportation and energy, try this site: Full disclosure…I developed this one so I am personally biased.

  6. Chris,
    I always appreciate a well thought-out comment like yours, and I fully agree with you. I very much understand the issue of additionality. In writing this column I was working under the assumption that there will be no significant subsidies for CFLs, no gov’t regulations banning incandescent bulbs, and no real societal shift. This is, of course not realistic since Australia has banned bulbs already, and California is discussing it too. What else can an individual do to personally and directly offset his/her emissions (after exhausting all feasible emissions reduction opportunities)? I would love to hear some ideas.
    Thanks for writing, and thanks for reading AskPablo!

  7. Hi Pablo
    I live in Melbourne, Australia and this is the first that I have heard of incandescent bulbs being banned. It was vaguely considered some months OK, but, nothing happened.
    As for CFL’s, the bases still get very hot (one I checked was too hot to hold) and I have had them last from ~2 weeks to a maximum of perhaps 12 months!!
    I have not quite given up on them, but, they had better behave better in future.
    I am also not convinced of them really being “greener”. Do you know of a study which compares different bulbs “dust to dust” so to speak?

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