1,478 calories required!
15 calories:    To make ice go from -15ºC to 0ºC

80 calories:    To make ice at 0ºC change to liquid water at 0ºC
                     (Latent heat of fusion)

100 calories:  To make liquid water go from 0ºC to 100ºC

539 calories:  To make liquid water at 100ºC change to steam at 100ºC
                     (Latent heat of vaporization)

5 calories:      To make steam go from 100ºC to 105ºC

          Multiply the sum of those calories by 2
      because we are figuring for 2 grams of water!