Johannesburg - Eskom cannot guarantee that there will be no outages during the winter months as energy usage nears that of pre-recession levels experienced in 2007, The Times reported on Tuesday."We have resolved to avoid (outages), but that resolve will be tested," the power supplier's spokeswoman Hilary Joffe was quoted saying."I am not going to give you a guarantee that (load shedding) is going to happen, but I'm also not going to give you a guarantee that it's not."That's the best we can give you. It's not going to be easy," she said.Eskom on Friday announced its goal of keeping power available this winter and avoiding rotational load shedding."But the system is going to be very tight for the next two years," Joffe said.After studying weather and power usage trends, Eskom reported that 14 critical periods were expected before the end of winter.