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37

I found a comparison here. My take on reading that is the following: Aluminum is the most efficient in terms of energy saved in making a new can taking only 5% that compared to working from scratch. Glass comes in second saving 20-30% of the energy in making new glass. Plastic is a distant third since you keep degenerating to a lower quality plastic ...


22

Before plastic bottles became popular, recycle meant something different than today. It used to mean 'reuse' not 'remanufacture'. I would think reuse of glass bottles would be the most sustainable. Although I'm not aware of any soda manufacturers that reuse bottles in the US, there are dairies that reuse milk bottles now that glass milk bottles are making a ...


21

It's quite a hard question to answer objectively, because you don't know how much these panels will be used. They may be left out in bright sunshine all day in which case they will likely generate more energy than was used to manufacture them over their lifespan, or they may stay locked in a cupboard on all but a couple of days a year. Their efficiency will ...


17

So the short answer is to look at 'life-cycle assessment' studies (LCA). The longer answer is to ask what you mean by 'better', and then look at a bunch of LCAs and figure out what impact categories you care about most. In either case, the goal of LCA is to collect all the different inputs and outputs for a product for all stages - not just use, but ...


13

Interestingly glass and aluminum have the same specific heat or close to it (about 0.2 J/g) but the mass of he container is much different, and aluminum has a much lower melting point (about half that F of Glass). Estimating weight of a 12 oz beer bottle at 140 grams (that's prob. low), and going by internet searches to find that empty soda cans weigh about ...


13

It's correct that the production of 1 ceramic mug requires much more material and energy than the production of 1 plastic cup, but this isn't a fair comparison. Plastic cups are generally used once or perhaps twice and then disposed of. A ceramic mug is likely to be used several hundreds of times before it breaks and is thrown away. Let's assume you use a ...


12

Both incandescent and fluorescent are quite old technologies, and have been bettered in terms of efficiency and lifecycle impact. Furthermore, compact fluorescents aren't the only type of fluorescents. So although the compact fluorescents are superior to incandescents anywhere with a high-carbon marginal electricity supply (so almost all the world, in 2013, ...


12

TLDR; cadmium telluride panels have the highest EROI of the mentioned PV panels (around 34.2) EROI estimates vary widely. This is because of differences in the method of calculation, scope of the study, installation location, assumed lifespan of a panel, etc. This also makes it relatively easy to manipulate EROI calculations. Pessimistic The most ...


10

You've pictured a disposable plastic cup. If you assume that you can use it a few times, then you might consider that you get through one a day. A ceramic cup lasts until you drop it. The cup in your photo is only for cold drinks anyway. Paper or expanded polystyrene are usually used for hot drinks. This link runs the numbers: In summary, ceramic is best. ...


9

I think this is a great example of how sustainability really is multi-faceted. LED lighting may be great from an energy consumption standpoint, and not as good with respect to finite material usage. Energy Use vs Material Supply I think it's important, however, to apply some weighting to the different factors. I don't believe we're yet at a critical ...


9

I think it really depends. For instance, for the towels, are they recycled, composted or what? Are the trees used for the paper easily regrown? For the hand dryer, is it solar powered, or does it rely on something worse for the environment? Hand dryers can be loud and produce more noise pollution than paper towels, but some are quieter. Some paper towel ...


9

Your most sustainable choice is an old straight razor, but there's a reason the replacement is called a "safety razor"... you're much less likely to kill yourself with a safety razor. But these last a long time and you can shave using a small amount of water and a soap stick. You can buy one second hand, that's how long they last. Much safer is an old style ...


7

While I have no clue which one does biodegrade better I'd like to focus on some other life-cycle aspects of liquid soap vs solid bars. But of course it's certain that liquid soaps (need to) contain substances that are simply not required for a bar of soap - such as emulsifying agents. Liquid soap contains added water and is therefore heavier. Transportation ...


7

I would be surprised if any pen would be more sustainable than a sustainably sourced pencil. In terms of sustainability, I still think that "green" pens should come after refillable pens, pencils and fountain pens. There are also refillable cartridges for standard fountain pens, which usually come with plastic cartridges. For example, this middle one looks ...


6

This will depend on where you live. It is a question of energy; First of all take into account the carbon footprint of the electric shaver relative to it's expected lifespan - this is likely to be higher than the safety razor proposed by Nui (Which I agree with by the way). Secondly - as I alluded too; it will depend on where you live, more precisely - ...


6

Unless you're into printing color photos, the laser printer is the way to go. The retail prices of toner cartridges may seem a bit steep, but there are ways to refill them. The toner lasts a long long time (a few thousand printed pages if you know what you're doing) and does not dry up, ever. Laser printers are efficient, very fast, and hardly ever break ...


6

It is hard to say because there is such a wide variation in ink formulations. Also, no company is going to tell you what is in their ink, as they will consider that a trade secret. That being said, the only consumable part of a mechanical pencil is made entirely of graphite which is 100% Carbon and Clay. Go with the pencil! Here is a "How it is made" video ...


5

Let's break down some of the elements of whole-life costing, to glean some clues about when old might be better, and when new might be better. Manufacturing costs If the manufacturing impact of a new device is a high proportion of total lifecycle impact, and if there is a chance that the impact of the latest model will lessen within the extended lifetime ...


5

One if the issues with LCA is that it's very data intensive, and that generic products/processes can be subject to a lot of uncertainty. These factors merit a need for time investment to generate the data, standardize it, and develop tools for using it. That's why the products are expensive, often have high learning curves, and why people take multiple ...


5

Executive summary It's too early to tell what the resale value is, as contemporary turbine designs are not as old as the lifetime of a wind-turbine, so we have very little experience of the economic value that results from decommissioning 1.5MW turbines; however, a rough first-order calculation puts the scrap value of the metals, based on Feb 2016 UK prices,...


5

Life cycle assessment (LCA) is about assessing the environmental impacts of a product, process or service over it's full life cycle, so from production, usage and disposal. This assessment includes the impact of all subcomponents/subprocesses down to the (extraction of) the natural resources. There isn't really a single 'best use' for a LCA. LCAs are ...


4

Software The most basic, free tool to create an LCA would simply be a spreadsheet like OpenOffice Calc. However, dedicated LCA software does make things easier for you, but most software is not free. The few good and free LCA software packages I know are: OpenLCA: open-source software, supports databases in EcoSpold or ILCD format, also has free and paid ...


4

Please consider using an economic input-output model. Alternative (other-than-process-based) methods of calculating net product impact can provide quick, cost effective, and yet comprehensive life-cycle assessments. A free economic input-output LCA is available via the Green Design Institute at Carnegie Mellon. Some background: LCA can currently be ...


4

The issue with answering this question is that there are inherent assumptions in how one creates a boundary for answering. For example, Voreno's answer suggests comparing two similar products in terms of the eco-footprint of their lifecycle. This is sound, but assumes that use of any product is warranted, and that levels of use and maintenance are fixed. ...


4

Measuring impact I've yet to see a meaningful metric that relates directly to materials, other than the EROEI (Energy Returned On Energy Invested); and there's discussion about whether or not EROEI is at all a useful measure: its probably not that useful, since once it's over 1.0, it's completely subsumed into the economics. The same would be true of a more ...


4

I was able to find several different news articles discussing this topic: "Paper towels least green way of drying hands, study finds" - The Guardian "Electric Hand Dryers vs. Paper Towels" - Slate "The Use and Abuse of Paper Towels" - The New York Times The most thorough treatment I found comes from an MIT study*, referenced by The Guardian: "Life Cycle ...


4

Update. In my original answer I inadvertently divided at one point when I should have multiplied -- I found the mistake thanks to comments from Frank and THelper. So here's a new tl;dr: By mile 4,000 at the latest, total emissions from a hybrid Prius beat emissions from a standard Corolla. Hybrid electric vehicle (HEV) specific components The HEV ...


4

Diversify In a paper unearthed recently by our friend LShaver question, a key point is that the worst identified menace today is Biodiversity loss, beyond Nitrogen cycle disruption, and way beyond Climate change... So my answer will encourage you to diversify!, locally. For example, think about the extremes: if there is only milk - too many cows, ...


3

Liquid soap can and should be diluted. As with toothpaste, manufacturers profit from consumers inadvertently using too much – often far too much. Dish soap in particular is usually sold explicitly as "concentrated", but the sustainability gain from less bulk is lost unless consumers take great care to use tiny quantities. Dilution is much easier. Packaging ...


3

I have often wondered the same thing. This video by ASAPScience finally answers the question in a satisfying way. Hygiene: If you do it right, both options are the same in terms of hygiene - but paper towels are faster. Environment: Dryers win - the energy used is less than what it takes to produce an equivalent amount of paper towel, and of course no ...


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