More specific details on the programme are available in a news release issued by the Mossel Bay Municipality on Feb 27, 2012 (nearly one full year ago). In a nutshell, as per the news release, "a small control unit (relay) is installed next to or inside the electrical distribution board in the home of the customer. This device then switches off the power supply to the geyser between 18:00 and 20:00 on weekdays."
The relay is installed free of charge. If this sounds like something you might be interested in, contact the Residental Load Management project office at 083 228 0268.