In Switzerland, the electricity is provided by the municipalities. This results in a large variety of electricity meters present in the buildings. Ideally, the electricity meters would have a visibly pulsing LED that indicates the energy consumption. That was the case for a few buildings. Sometimes the LED was infrared. However, in some cases, the electricity meters were old analog meters, which could not be interfaced easily. In anticipation of the problem, I called a few electricity suppliers about that issue. Some providers offered to replace the old meters on demand and for free since they would replace the electricity meters anyways eventually. Other providers would refuse to cooperate.
Electricity meters caused an additional issue. The detection of the LED flash worked in the lab but did not work in the buildings. It turned out that the LED flashes of the electricity meters in the buildings were significantly shorter than the LED flashes of the electricity meter in the lab. The sensor module for pulse detection (electric pulses or light pulses) used a debouncing IC (MAX6816). The LED flashes from the electricity meters in the lab were long enough to be detected after the debouncing. The LED flashes from the electricity meters in the buildings were shorter and were ignored by the debouncing IC. The issue was solved by removing the debouncing IC for detection of light pulses. In hindsight, this is an obvious and straightforward issue.
The municipalities also provide gas. However, in the region, where the case study took place, all meters were analog, and there were no plans to replace them anytime soon. However, in other places digital gas meters with a pulsing LED as an indicator can be found (e.g., Zurich).