The hearing aid industry always has been electrified (i.e., no transition of fossil fuels in that respect is needed). It is known for fast and efficient computing, and cramming as many features as possible into a tiny personal electronic device worn in or at the ear. Specifically designed internal circuits (mini-computers), Low Energy (LE) Bluetooth, and algorithms designed for speed with low computational budget have always played an important role given the limited power allowance and room for electronics available in modern hearing aids.6-8
Until 3 to 5 years ago, most hearing aids were powered by disposable Zn-Air batteries, which were not recycled and sometimes not even disposed of correctly.4 The first generation of rechargeable hearing aids used nickel-metal-hydride (NiMH) technology. It provided benefits to hearing aid users who had difficulty placing a battery in the hearing aid compartment and who now could simply put the hearing aid in a wireless charger. However, the battery capacity of NiMH batteries was limited. In recent years, NiMH batteries have been replaced by superior rechargeable Lithium-ion batteries.9
In December 2021, as an industry first, WSA/Signia published a lifecycle assessment (LCA) in which they directly compared rechargeable lithium-ion hearing aids to an identical pair of the non-rechargeable version.10 The authors showed that the relative environmental impact (use of resources, toxic substances, energy use, etc.) was 65% lower for the rechargeable hearing aids. A quote from the lifecycle assessment:
For the non-rechargeable hearing aids, on average, the battery solution (i.e., production, distribution, and disposal batteries) contributes to more than 80% of the total impacts. For rechargeable hearing aids, on average, the battery solution (i.e., production, distribution, and disposal batteries) contributes to only about 5% of the total impacts. Electricity demand for charging contributes on average 9%. Main contributors are the electronic devices, i.e., hearing aids and charger unit.†
The above lifecycle assessment implies that disposable Zn-Air batteries have a higher impact than the production of the hearing aid itself. However, a point of attention is the long-term capacity of Lithium-ion batteries. In general, the capacity reduces every year by (10-15%), so it’s important to start with a surplus of capacity. A benefit of rechargeable hearing aids not included in the lifecycle assessment is that the number of repairs is lower for rechargeable hearing aids since they are better sealed than non-rechargeable ones. The battery compartment in the traditional Zn-Air batteries is an opening for moist and dirt. If Lithium-ion batteries would be recycled in the future— which now is scarcely done— the environmental benefits may further increase.11
Updatable hearing aids, and accessory / charger compatibility for reducing environmental footprint
We might also opt for other business models in hearing aid service delivery to decrease our carbon footprint. An example is Whisper AI that provides software updates on their hearing aids.12 Could these updates lead to longer use of hardware and hence less raw materials?