By Cecile Mantovani and Caroline Pailliez PARIS (Reuters) – Ski resort managers in the French Alps are scrambling to find ways to conserve energy as part of a national effort to reduce consumption, with about half the resorts also bracing for power bills to be three to six times higher than in prior years. In Chamonix, close to Switzerland, if there is no crowd, the lift will go 10% slower. And if the resort gets an alert that power supplies cannot meet demand, Chamonix will slow the lifts by 30%. A number of ski resorts including Chamonix and Val Thorens have also pledged to limit artificial …