Green energy, or energy that doesn't release pollution when generating electricity, comes from a variety of sources including solar, nuclear, hydro and wind. Traditional green energy is produced from renewable sources, or energy sources that are naturally replenished in a short period of time. Unfortunately, with the exception of hydro, renewable sources of energy don’t operate continuously and therefore can’t meet the ongoing energy demands of our towns, cities and metropolises. Nuclear power is a green form of energy that generates large amounts of heat continuously when atoms are split. Currently, there are 104 nuclear reactors operating in the United States providing approximately 21% of the nation’s power.