Human: I've been hearing about the new 'green' energy sources. What are they? Assistant: 
The most common green energy sources are solar, wind, and geothermal power. Solar power is generated by converting sunlight into electricity using photovoltaic cells. Wind turbines use the kinetic energy of the wind to generate electricity. Geothermal power uses heat from the earth's core to produce electricity. All three types of energy can be used in combination with each other to create a more efficient system.