You can use various kitchen electric appliances to boil the same cup of water, but electricity consumption for everyone of them will be different. The rough estimate of energy efficiency for a microwave is 50%, for stovetop - 70%, for electric teakettle - 80%, and for induction stove - 85%.
Energy efficiency of boiling water with natural gas stove is around 70%, what rivals electric stove - extra efficiency gains you get from burning natural gas directly are offset by the inefficiency of the flame, which wastes energy around. However human behaviour is the most important factor in terms of saving energy in kitchen. Unfortunately, we often boil more water than we need, sometime we leave the stove or microwave running after the water has already reached a boil. Taking into account that, for example, every American drinks in average two cups of tea or coffee per day, and that about 0.05 kWh of energy is needed to boil two cups of water, the potential for energy saving in kitchen is quite significant... Read more at http://innovationtrail.org/
