Comments on: Reusable vs. Disposable Cups: Saving Money and Energy

By: David Schatsky

David Schatsky — Thu, 29 Jul 2010 10:29:17 +0000

Hi Jefferson,

Thanks for your comment. Labor is not a big factor in overall cost. I estimated that 1000 cups could be loaded into a dishwasher and unloaded in about a half hour. At the minimum of wage of $7.25 per hour, that adds a cost of $.004 per washed cup, about one tenth the cost of a reusable cub (which carry their own labor costs of receiving, unpacking and storing).

The analysis is centered on power usage. Square footage for equipment and storage and utilities for the space (not operating the equipment) are probably about neutral. Reusable cups will require dishwasher space and cup space but disposable cups will require significant space for an inventory of cups.

- David

By: Jefferson Seaver

Jefferson Seaver — Thu, 29 Jul 2010 04:45:33 +0000

What about these other costs associated with washing dishes?

- Labor: a huge factor in overall cost

- Real estate: additional square footage needed for equipment and storage, and utilities for this extra space

By: greg hunt

greg hunt — Fri, 02 Apr 2010 18:05:46 +0000

isn’t Hocking’s analysis flawed in that it doesn’t include disposal energy? How can you have a life-cycle analysis without, well, the whole life cycle?

By: David Schatsky

David Schatsky — Mon, 09 Nov 2009 21:45:01 +0000

Hi Joseph–thanks for providing those links to your papers.

By: Joseph Aamidor

Joseph Aamidor — Mon, 09 Nov 2009 18:49:31 +0000

It’s absolutely true that the multitude of environmental factors complicates this decision. It’s good that life-cycle and embedded environmental impacts are becoming better understood. My firm recently published a piece on embedded environmental impact and the movement from building new infrastructure to retrofitting existing assets:

“Embedded Environmental Impact: The Roman Coliseum vs. the New Yankee Stadium”
http://civicus.com/uploads/425/Embedded_Environmental_Impact-The_Roman_Coliseum_vs_the_New_Yankee_Stadium.pdf

In addition, we published a piece on green standards, and the fact that they are in their infancy.

“Needed: Standards to Set Goals, Measure Progress and Enable Collaboration”
http://civicus.com/uploads/301/2009-7_MRN25-eqsp-Needed-Standards_to_Set_Goals,_Measure_Progress_and_Enable_Collaboration.pdf

By: LT

LT — Mon, 28 Sep 2009 00:49:55 +0000

This was a helpful update to the Hocking paper. I wonder, though, how many times you can realistically wash those plastic cups in a commercial dishwasher before they start looking dingy.

By: Pranava Levine

Pranava Levine — Mon, 07 Sep 2009 05:44:06 +0000

Soap is only needed when there is oily substances to be cleaned. Most drink do not contain oily substances so hot water alone wash it perfectly well.

PS: Every one should have his/her own cup. You using the same cup all day long and rinse it lightly if you drink something different. You may do that at home or at work.

Awarness should take over convenience!

By: David Schatsky

David Schatsky — Tue, 21 Jul 2009 02:04:22 +0000

Hi Pinny,

This analysis is aimed at commercial settings with large volumes of cups where automatic dishwashers almost always make sense. The model considers the cost of electricity, water, and gas, and does indeed reflect the costs of heating the water. Soap is not included because it’s cost is relatively small and doesn’t affect the overall conclusions in a significant way. (But I could easily add it to the model.)

I believe all significant factors are considered here.

Thanks for your question.

By: Pinny Cohen

Pinny Cohen — Tue, 21 Jul 2009 01:28:46 +0000

I assume most people will be washing their cups by hand…have you calculated the cost of the water, soap, etc. (bearing in mind that the water needed to be heated).

I think there are quite a few factors that come into play here…