In the second half of 2020, we published an addition to the 2018 LCA document to include the assessment of our new product, KeepCup Thermal (the first LCA has been read over 9000 times on ResearchGate - a significant reach for a scientific document of this type). They’re technical, scientific reports that many people won’t engage with in depth, so we aim to summarise findings to make them accessible. In doing so we use breakeven points as a useful indicator of impact.
Making the information easy for a large audience to digest is always a balancing act; the result of oversimplification is greenwash. With that in mind, we revisited the report and have added the product lifespan to the carbon impact statement.
We make LCA research publicly available and open for anyone to scrutinise, as well as taking onboard opportunities for improvement.
So, let's provide comparison over a number of metrics:
The embodied energy in our stainless steel KeepCup Thermal is 24-26 times that of a single use cup.
Embodied energy is the hidden energy used to extract, transport, manufacture and assemble a product. Embodied energy is fixed, it's all the energy used before the product is used.
The embodied energy of KeepCup Thermal is 23600kj, an average polyethylene coated paperboard cup 880kj and PLA coated paperboard cup 948kj.
When we analyse one year of coffee drinking (5 coffees a week over 50 weeks – 250 uses), after eight uses, KeepCup Thermal has a lower impact than disposable cups after 8 uses and, compared to the compostable cups assessed in the study, KeepCup Thermal has lower emissions after just four uses.
This is based on KeepCup Thermal lifespan – it means you’re using your Thermal for one coffee five days a week for eight years - 2000 times. The breakeven point is based on analysing use, not cup versus cup, so the embodied carbon of one year of use is amortised.
Over this span of time, every use equals about 8.7 grams of CO2e (about 90% of this is tied to washing it after each use).
This is more than 4 times lower than a single-use disposable cup.
But it's about use
It is not meaningful to just compare a Thermal KeepCup against a single-use disposable cup – we need to look at the full life cycle and use, not just the materials.
When conducting an LCA, it is important to express an objective functional unit to make sure we compare like with like.
For the KeepCup LCA, the functional unit that allowed us to compare different cups, was defined as one year of use.
Therefore, the Thermal KeepCup starts with 1/8th of the embodied carbon of the cup, that is 219 g CO2eq.
For each wash you add 7.8 gCO2eq.
After 8 uses you have accrued 295 gCO2eq using the Thermal KeepCup, which is about the same as 8 paper cups with lid (8 x 37 gCO2eq = 300 gCO2eq).
After the eight uses, you have paid off that year’s carbon debt invested in the product, and yes you’ll add carbon emissions from washing every time (7.8 gCO2e) but it’s far less than using a new single-use cup every time (37gCO2e per cup).