[omtose]

I somewhat doubt that a hollow plastic tank is significantly more expensive than a concrete block. Factor in the added cost of shipping the much heavier concrete block, and it seems like the manufacturer would also save money in the process.

[jaclaz]

The cost hasn't been cited in the "invention", but concrete is something that weights roughly 2,200 Kg per cubic meter, and has a cost (of course it depends on where it is produced) of less than 100 US$ per cubic meter, the 25 Kg counterbalance costs between 1 and 2 dollars, and is probably just barely comparable to a mass produced injected plastic tank, but I doubt that there will be any actual savings by the manufacturer.

And there is no real "visible" added cost of transport.

A 70 kg washing machine is typically 0.60x0.60x0.90=0.324 cubic meters, let's say 0.7x0.7x1,00=0.49-0.50 including packaging, it has a a very low "density" of 70/500=0.14.

On a truck with a platform of 2.40 m x 13.00 m (a normal large truck with a loading accepted of around 30,000 Kg ) you can usually put (in two levels) between 100 and 110 washers (2.40/0.7=3 13/0.7=18 2x3x18=108).

So you have this big truck, designed to carry 30,000 Kg and you load it with 8,000 Kg instead.

Do you think you will get a discount from the trucker?

And do you think that you will get a further discount if the load is 5,000 instead?

As well, do you think that you will get a discount from the delivery (and installing) guy if it weights 20 Kg less (but the guy needs to remove the top cover, fill the tank, re-assemble the cover)?

From an environmental viewpoint there are undoubtedly savings but the manufacturer (or the customer) won't be able to appreciate them in practice.

[jon-wood]

Is it that much more expensive to ship something in bulk with additional weight? I honestly don't know how distance shipping by the container works, but I always thought it was just a case of being billed based on volume.

[Retric]

In bulk you basically per 40' container which are usually kept under ~45,000lbs* and have 67.7 m3 volume. So, you are either volume or weight limited, but not really both.

Note: there are a few different container sizes, but 40' is by far the most common. Weight limits also very by location.

[joezydeco]

How much energy do you need to harvest the crude oil, transport it, and refine it into ~3kg of ABS plastic?

How much energy does it take to melt it into a slug and blow-mold it into a tank shape?