Scientific research by two university engineers found that your FDM printer's heated bed contributes to 60% - 70% of its total energy consumption. So if you go "off profile" and lower that temp. to 11.49°C below the glass temperature of your filament, they found, while increasing the nozzle temp. significantly above the melting temp., you could dramatically lower energy use. Couple these tips with a fast print speed and a higher layer hight, and you can drop your energy use 48% - 72%.