According to Eriksson, windmills operate in the southern portion of the island and there is also a need to reinforce the existing grid. “AC transmission would have difficulties in these circumstances” he notes “and, in any case, a 130 kV AC line would simply not be considered in this environmentally-sensitive area.” Eriksson also points out that wind power results in a variable power output with disturbances resulting in flicker. “To stabilize that flicker” he says “reactive power must be controlled at the point of connection to the network by using static var compensation.”
“There is an incubation time in this business of anywhere from two to seven years depending on where customers are in their planning process.”
“If you compare the cost of the HVDC Light alternative in this case with a 70 kV AC line” states Eriksson, “perhaps the AC line would be the more cost-effective. However, in that event there would still be a further need to re-inforce the island’s network. But, compared to building a 130 kV line, HVDC Light becomes competitive from the cost point of view.” The HVDC Light installation in Gotland, is scheduled to be delivered by the first half of 1999 and will control the reactive
power in both converter stations independently.
Looking at the worldwide situation today for DC systems in general, Eriksson remarks that during the 1970s many people in the power industry said that if this technology proved cost effective then about half would seriously consider installing it. “But,” he observes, “many of these same people are still saying that it is a new technology.” In this respect he is quite realistic about how fast the HVDC Light concept will be understood and accepted. Says Eriksson “there is an incubation time in this business of anywhere from two to seven years depending on where customers are in their planning process. New technology such as this often takes a long time before it is widely accepted. Therefore, it is still too early to project total world demand.”
