I read an interesting article in the Library Journal of February 1, 2011 about the endless supply of electricity being used in libraries these days for all types of electronics and how it is straining many library budgets. The article also talked about the problems associated with the lack of the “lowly plug” and their modern contemporary, the data port, or jack. Many library buildings were built prior to the 1980's when the only outlets needed were for a lamp or maybe a vacuum.
Our library had the same issues so our solution, on the main floor, was to add power strips along the walls. Luckily the earthquake retrofit to the Carnegie came along when it did and we were able to add a lot more outlets upstairs. Many libraries currently under construction are putting in raised floors so they can easily access power conduits under the floor. If the need arises later to add more outlets, they can just lift a square of the floor and add an outlet in that spot. Libraries want flexibility so their patrons can access electrical power in the most convenient way and so library space can be adapted to changing technology.
At some point, technology will come up with something such as longer lasting batteries or inductive-charging mats so that all those outlets will become unnecessary - somewhat like VHS tapes, 8-tracks, and CD cases.