Aluminium Cans - Liquid Energy
A person said to me a while ago
their father referred to aluminium as liquid energy. Their father I believe
worked in a smelter and had a feeling for how much energy is required to melt
aluminium.
More recently I've been recycling aluminium cans by collecting
them. You don't get much from the recycling company for a box of squashed cans,
but at least it feels like I'm making a difference.
The generally stated
figure is that for each aluminium can recycled 95% of the energy used to create
a can from bauxite is saved. That made me wonder how much energy does it take
to make an aluminium can from bauxite. Those figures aren't generally stated.
Saving 95% of some unknown amount to me isn't really providing the full picture
so I decided to investigate.
The best figure I could find was that the
energy saving for each recycled can is equivalent to running a 100W light for
3.5 hours which is 350Wh or 0.35kWh. Since this is a saving of 95% the energy to
make one can from recycled material is 1/19th of this or 0.018kWh and the energy
used to make a new can from bauxite is this 20 times this or 0.368kWh (368Wh).
The reason I'm using the figures in kWh (kilowatt hours) is this is the
figure typically used in our electricity bills.
I thought about this for
a while and then thought for each can that is disposed of as waste a new can has
to be made. If you see a can on the street, that can is most likely going to end
up as waste in landfill so if you pick up a can someone else has thoughtlessly
disposed of then the entire energy saving is achieved. I often wonder if the
food courts where the rubbish isn't separated simply ends up as landfill or not.
I personally would prefer not to take the chance and bring my containers home
for recycling where possible.
OK. To put this in perspective.
The
average electricity usage I'd estimate is around 20kWh per day for a household.
Our usage is now running at around 7kWh (our last bill was 6.85kWh per day).
I read the average office worker consumes the contents of 2.5 aluminium cans
per day. If those cans are recycled it would save 0.875kWh or around 4.3% of the
electricity used for an average home, or in our case around 12.5% of our
electricity usage. For us a single can discarded is equivalent to 5% of our
daily electricity usage for our household.
Given we are a family of four,
just by recycling our containers we go a long way to offsetting our electricity
usage. We've reduced our electricity usage by over 50% by simple changes of
habit in our household, but now we can see how our recycling further helps to
see how we can reduce our energy usage impact by offsetting our behaviour.
This actually brings up two strategies for people to think about.
By
not using containers, as in drinking fresh water from the tap, you save the
energy required to make a container in the first place. The second is if you see
a container that someone has discarded and pick it up for recycling, you save
the container from ending up as landfill and you'll have offset some of your
energy usage by taking action.
The words, reduce, reuse, recycle start to
make sense once you can relate it to our real world activities.
Kelvin Eldridge
www.JustLocal.com.au
References:
www.visyclosedloop.com/index.php?id=10
www.envirobank.com.au/about-envirobank/recycling-facts.html