What is Worse, Energy-wise?
I've long wondered about the "real" energy cost of materials. For instance, a couple of years ago, my father bought a solar panel to power his RV while camping. According to the literature that came with the panel, it would have to be active for 4 straight years, given average daily sunlight, to recoup the cost of it's own production. Meaning, to replace the energy used to create the panel itself, it would take 4 years of constant use. This could be called "embodied energy" -- energy is emodied in the product because it was created using a certain amount of energy.
This panel has had nowhere near that use, and not only because it was obsolete about the time Dad bought it, but also because he was using it only for extended camping trips. Home panels surely get more use than that and are not replaced that fast. My mother & step-father have had panels on their roof for about 4 or 5 years now, so they've recouped production energy-costs, though they are taking a loss on the actual energy costs (they knew this; they bought to support renewables... truth is their home is highly efficient, despite being built 25 years ago.)
What about paper towels vs clothe?
What about paper cups vs a reuseable?
I'm not saying I necessarily believe we should all be using paper cups & plates. What I'm wondering is: do we know for a fact that it is not as environmentally friendly to use a disposable replacement? I don't think we do, but as a society bent on a green future -- one I've supported for years, by-the-way -- we should have more information.
Like:
- How many paper Starbucks cups does it take to replace a porcelain or reuseable metal and plastic mug?
- How many paper plates replaces that more sustantial china you bought for special occasions?
- How long before replacing your house with a more efficient modern home does the cost of all that new energy pay off?
I know there are units of measure for energy. It's probably a calorie or a footcandle. I'm not even going to google it because I don't want this to be about my imperfect understanding of units-of-measure. For illustration, I'm going to create my own: the footcalorie.
Say it takes 1000 footcalories to create your average reuseable coffee mug. One of those with a lid on top so you don't spill it in the car or on your desk. Say over the 18 month life (come on, you don't really use it for 10 years like you think you do) of that mug, how much water does it take to clean? How much energy did it cost to get that water to your house? How much did it cost to heat the water you washed it with? It's tap water, having gone through a treatment plant. How much did it cost to treat the water at the plant? How about the energy to get the mug to the store? Are the raw-materials recyclable or renewable?
I'm going to just throw out some numbers, which are to illustrate my point. I don't doubt these are way off (we're using the footcalorie, a mythical unit of measurement, remember).
- Energy used to create the product (embodied energy): 1000 footcalories
- This product's share of the energy used in packaging, shipping: 15 footcalories (a container of them might be 15,000 total footcalories but we're taking just one mugs share)
This product's share of the energy used to transport, sanitize and heat water used for repeated uses for 18 months: 500 footcalories (see above)
So, best guess in this fictional argument: 1515 footcalories for the life of the product.
Now, what about it's counterpart, the paper cup? Say we used an average of 1.5 paper cups per day, instead of the coffee mug. Some days you use two, some days just one. So, you are going to use about 825 in an 18-month window. If it takes 10 footcalories to create, package and ship, on average, each individual cup, then you are wasting energy (though perhaps not landfill space) by using a travel mug. Given that drinkable water might be our most precious resource in the future, saving water just for drinking (and, um, showering...) might make that an even better figure. Swinging the other way, maybe our landfills would fill up much faster, making it an ugly option, even if more efficient.
I am not arguing that it takes 1 footcalorie to create a paper cup. It might be 5 or 10 or 100. Maybe each paper cup costs about as much as each reusable mug. ** I don't know.** That's my point. We should probably find out. We spend a lot of time assuming things in our world. The scientific method is a great process to test out ideas, and re-test them, to check on old assumptions as we learn more, to update our ideas and thought processes.
Our world is shades of a rainbow of colors, but I feel like we're looking at this stuff in black and white.
Update: what about replacing your car or house? We might bulldoze a house in order to put up something more efficient, but just the act of building a new home, and destroying the old home and all the embodied energy could mean that it takes decades to recoup. The old house has the embodied energy already. It only goes away when you destroy it.
Is it really better to run a cash-for-clunkers program partially built on getting more efficient cars on the road (I know it was also a way to "save Detroit" but Uncle Sam also required you trade up to a more fuel-efficient vehicle)? What if your old Ford Escort took 1,000,000 footcalories to build but had been in use for 10 years. It already contains embodied energy and will get little more (maybe the embodied energy in the new tires or a rebuilt engine). A new vehicle might take only 900,000 footcalories to build, and might be more efficient to operate, but that is still 900,000 more footcalories than before. You just tossed 1,000,000 footcalories of energy, too.
So, get your new home if you want one. Trade up for a new car for safety, style or just because. But if you are doing it for energy savings, I think you're barking up the wrong tree.
Update 2:
Several links; I finally looked up some terms. I'm not re-editing my post, though. I'd like to have it stand as-is. A lot of the issues I brought up are in these links and explained differently and probably better.