Power utility Eskom on Wednesday called on consumers to switch off geysers, pool pumps and all non-e.
None of the 68 goals scored at the Confederations Cup needed the technology, which was being used for the first time at an international tournament.
But Webb told reporters in Rio de Janeiro on Monday that the "reassurance the system gives us is a big benefit" and referees had full confidence in the technology provided by German company GoalControl.
"We have no concerns about the reliability of the systems," he said.
Ruling whether a ball had crossed the goal line or not "has not been really taken out of our hands but the fact that it has given us some more certainty is a great positive", Webb said. GoalControl seemed likely to get the backing of the world governing body Fifa to use its system at the World Cup.
"It worked well, so if something is working well, why would you change it?" Fifa secretary-general Jerome Valcke asked.
Webb, who was in charge of the 2010 World Cup final between Spain and the Netherlands, is one of 52 referees pre-selected for the 2014 World Cup. The English referee described his second Confederations Cup after 2009 in South Africa as "a positive experience" and praised the high sportsmanship and open play experienced in Brazil, where the home team took the trophy on Sunday by beating Spain 3-0.
"The players need to take credit for the way they have approached these games," he said.