Prepaid Electricity
The "South African" model is "Old School", the STS Tokens used are a "sneakernet" communications method. If you are looking for a modern method of enabling prepaid electricity for either a project or your dorns, take a look at what are often described as "smart meters" like the echelon models. They have 2 way communications using a low freq carrier on the power lines, thet provides communications for automatic meter reading and control. Important to prepaid electricity are features like an automatic disconnect in every meter, and capabilities like "emergency credits". Utiliflex (see utiliflex.com) has software and services that integrates with these 3rd generation smart meters and enabled prepaid via the web, email, text and IVR. Electricity can even be purchased via a cash scratch card system called "juice Cards". "Juice" also provides integrated legacy support for the old token based pre-paid meters and has a couple of colleges using it for dorm electricity management. True smart meters support prepaid electricity, as well as a bunch of other features such as variable rate billing, extremely detailed usage reporting.
Possible Thesis projects include: Do pre-paid customers use electricity smarter?
and/or does variable time of use (most of the USA is flat rate) actually billing change usage patterns?
Disclaimer: I work for UtiliFlex and while our main market is utility companies, we support smaller instalations (100-1000 meters) as well. We are specifically looking for research and might be able to support a real research/thesis project based on smart metering and/or prepaid electricity.
--Mike the Geek, aka meuon from geeklabs.com and utiliflex.com