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After running the dishwasher last night it struck he how much energy it must consume: from heating large amounts of water to the motorized pumps and spinners to the heated plate drying. Then there's also the potential water pollution by the detergents.

Got me wondering about the impact of paper plates. How much energy goes into making one dishwasher load amount of paper plates (50 plates)? What are the total pollution costs? For the sake of argument, let's say these are non-dyed, 100% natural, biodegradable (possibly recyclable) paper plates.

Which is most harmful to the Earth? The creation of 50 paper plates or machine-washing 50 ceramic plates?

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  • Good question! I'm interested to hear what people say. Something to consider is that natural detergents can be used, and the plate drying can be skipped: just open the door after the wash cycle, and let things air dry the old-fashioned way. The main considerations are then energy and water use.
    – LShaver ♦
    Commented May 30, 2017 at 15:34
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    modern dishwashers are quite efficient re water usage - mine does a full load on just under 6L. Much less than hand dishwashing. So not necessarily "large amounts of water". This is going to come down to balancing energy and water usage on one hand against pollution, landfill, land use for forestry, etc on the other. Very hard!
    – aucuparia
    Commented Jun 1, 2017 at 10:58
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    Very good question. A Netherland Institut (TNO) discussed this for cups (summary in german: br.de/radio/bayern1/inhalt/experten-tipps/umweltkommissar/…): disposable vs. washable cups. They conclude that the disposable cups are in total 20% more efficient. An Austrian-Swiss study gave a similar result. However, this was for mobile use, where the weight for transport contributed to the overall balance. At home, washable cups are probably better. Since its a close call it depends really on the details, and a conclusive answer may not be possible.
    – Rainer Glüge
    Commented Jun 2, 2017 at 9:09
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    @ChristianSchmidt your comment could be very interesting as an answer to this question about plastic cups versus ceramic mugs
    – THelper
    Commented Jun 3, 2017 at 15:12
  • Your question seems to ask to compare two things that are barely comparable: dishwasher vs paper plate. To be really accurate in our comparison, I assume we'd have to factor in the manufacturing and raw materials for the dishwasher, the ceramic plates and the detergent as well (and find an average life expectancy or number of loads for dishwashers). This might end up being quite an intricate calculation. There might be some pointers in this answer, which seems to show that polystyrene plates might be a better bet than paper plates (!).
    – stragu
    Commented Jul 12, 2017 at 2:11

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I'm not typically an answer-my-own-question kind of person, but this has been on the back of my mind for days. The challenge in answering this is that we do not have an apples-to-apples kind of comparison.

  • On the one hand we have dishwashers whose primary impact is energy they consume for electric motors / heating of water and the impact of creating the dishwasher (which will not last forever).

  • On the other had we have paper plates that use wood pulp and the energy requirements of transportation and production.

To make this an apples-to-apples comparison, we can compare based on cost. The heuristic is that when we pay for dishwashing or paper plates, we are paying for the summation of the resources that went into their production. Thus we can use cost as a proxy for environmental impact.

This website estimates that it costs $0.63 per load to run the dishwasher (cost of the dishwasher being factored in).

The cheapest paper plates I could find online are $18.86 for 600. If we assume 100% markup for retail items (i.e. the difference in cost it took the manufacturer to produce the product from the price they are charging in stores) then the cost per plate is about $.016 per plate.

Assuming that a dishwasher can wash 50 plates in a load, the equivalent for paper plates would cost $0.78.

Since $0.78 > $0.63 we can assume (under this hypothesis) that paper plates have a greater environmental cost than a load of dishes.

Note: The above estimates are based on some pretty big guesses. E.g. 100% markup for retail items. If there is %200 markup on paper plates then that reverses the conclusion. Further, as others have pointed out, even if we can accurately determine total $ cost, that does not not necessarly translate to environmental cost. Some part of production may have low $ cost, but high environmental cost.

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    This answer is based on a large, IMO unfounded assumption: That all environmental costs can be converted to money at the same rate. If you look at industrial versus domestic energy (or water) costs in many places, you will see that this simply isn't true. The energy used in transport is also almost all fossil fuels with a little biofuel, while the dishwasher could run on anything from 100% coal to 100% solar
    – Chris H
    Commented Jun 26, 2017 at 12:37
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    Who gets along with nothing but plates? What do you cook the food in? Do you use plastic flatware? "Dishwasher vs paper plates" is an incomplete comparison. You need "Dishwasher vs paper plates and some utensils and some pots with some washing system, maybe mechanical, maybe by-hand".
    – Jean-Paul Calderone
    Commented Mar 30, 2020 at 12:28
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  1. if not recycled --> Transporting woodchuck to wood. Chucking wood using fuel, transporting wood to milling plant. Transporting extracted cellulose to paper plant. Packaging plates. Transporting plates to super market, transporting plates to your home.

  2. Electricity from renewables + bio-degradable detergent + water + some fuel to pump the water to your place

Just the amount of mass that needs to be moved in order to get those plates from the trees to your place is way higher than the amount of water used by the dishwasher.

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    You are missing the end-of-life impact (disposal) in your equation. Also to be fair you need to include impacts from manufacturing the plates.
    – THelper
    Commented Jun 3, 2017 at 15:19
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If you only focus on daily running costs, then an efficient dishwasher that consumes only a few litres of rainwater, and electricity from solar panels on your roof, will win — hands-down.

However, that dishwasher may only last 10 years, and may only complete 3,650-ish wash cycles, before failing in a manner that requires its complete replacement. So if you expand your time-frame to 10 years then it is almost certain that mass-produced, "non-dyed, 100% natural, biodegradable" paper plates will have a lower environmental impact. You don't even need to do math to know that more resources will go into a high-tech dishwasher than 3,650-ish low-impact place settings.

We use plates and utensils made of waste sugarcane pulp when camping... so there's no need to even fell any trees... or to use 'paper' at all. The pulp is a waste product that would have otherwise been burned.

If you can latch onto a local supplier of low-impact disposable place settings then I think you're onto a winner.

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Embodied vs working energy. You would have to calculate the embodied energy that went into the production of both products. At some point the dishwasher will seem like the winner here as it should last a good portion of the time and be repaired for a fraction of the embodied energy of replacing it. The opposite is true when we look at the working energy of each. The dishwasher has a relatively resource intensive operation using water, electricity and chemistry to clean the plates. Paper plates can be used and then composted.

There are a lot of variables that could change the net environmental impact of each one. That however is a rabbit hole for a more enthusiastic commenter.

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  • This answers (some aspects of) 'how to calculate', not the question 'which are worse'.
    – user2451
    Commented Aug 5, 2019 at 7:47
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My favorite home is net zero energy and I try to run it net negative for all inputs including food, trash, fuel, power, water, wastewater, and money. I have a dishwasher, but I've never used it and probably never will. As long as it remains unused, it registers zero for all inputs except trash for which it scores negative. Although it's in nearly new condition, it represents negative trash because it was salvaged from a high end remodel. My main reason for not using it at all is that it takes too much power, but if I did use it the power would be generated by the home and the waste water would go directly to the plants.

Likewise I never use paper plates for eating on. I do use them for compost and that helps me to maintain negative trash and food targets, but I never buy them or use them for eating. The main reason for this is that I am not able to calculate the impact. Even if I could work out the numbers it would be positive for water, energy and money. Paper takes a lot of water to produce, energy to transport, and money to purchase.

I realize that this answer doesn't fairly answer the question, but it explains the reasons for the strategy I've chosen and it certainly makes the calculations possible. If I absolutely had to choose between the two options you offered, I would run the dishwasher at a time when I had a lot of surplus power for the reasons stated above, but the equations would be much different for people who purchase dishwashers and haven't closed the loop for power, waste, money, water, and wastewater.

It might be interesting to note that I sometimes use banana leaves as a substitute for paper plates, and as compostable cookware that doesn't require washing at all, but I'm not sure if that pertains to the question well enough to be included here.

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