You essentially either need a power drop to each section of shelving, or you have to replace batteries on every sign through your store every X months or years.
You can see the labels available from Pricer, one of the big players in the space: http://www.pricer.com/en/Solutions/
France retailer Carrefour uses ESLs in all their stores, for every SKU. They use ESL's from Pricer who says Carrefour uses 12 million labels, deployed in 2004, and they are updated via in ceiling infrared transmitters. [1]
ESL's are also common in Germany. And in the USA some Whole Foods use them.
This random blog claims "The ESL market is estimated to grow from 186.5 million dollars to 399.6 million dollars by 2020" [2]
Ses-imagotag showcases some interesting applications of their tags including manufacturing [3] and office use.
Finally a list of companies in the space [4]
[0] https://en.wikipedia.org/wiki/Electronic_shelf_label
[1] http://www.pricer.com/en/PressRoom/Case-Studies/Electronic-S...
[2] http://www.retailintelligencelab.com/blog/2016/11/24/the-ris...
[3] http://www.ses-imagotag.com/en/benefits/
[4] https://iot-daily.com/2015/03/19/best-electronic-shelf-label...
Since the tags are networked with infrared, they can flash on command. For example when store employees are trying to find a particular product for stocking, or retrieving it for a delivery order (example safeway.com delivery).
[1] http://www.lebensmittelzeitung.net/storechecks/Neues-Real-Ko... (e.g. pics 9, 20-24).