buildings conservation costeffectiveness costs dataprocessing econometricmodels economicaspects economicconditions electricpower electricpower-plants electricpowerplants electricpowerproduction electricpowersystems electricutilities energyconservation energyconsumption energypolicy estimates forecasting gasindustry georgia(republic) germany(west) governmentpolicy load mathematicalmodels mathematics norway planning powerresources rates recordingelectricmeters unitedstates