Electricity is a flow of electrons caused by the outer electrons jumping from one molecule to the next in materials that have a loose molecular structure. The flow takes place when a charge (voltage) is applied across the material; for example, a copper wire.
Direct current (DC) is produced by having a constant resupply of electrons on one end that flows in the same direction constantly to return them to the source (like a battery. Alternating current (AC) reverses the direction 50-60 times per second depending on where you live. It's producing the charge to cause the current to flow that requires energy.
Solar power is created by using the sun's energy to create a chemical reaction in solar cells. Wind power uses the wind to convert the mechanical energy of the turning propellers into electricity by moving a coil of tightly wound wire through a magnetic field. Nuclear produces steam to turn a huge turbine that does essentially the same thing as wind but on a much larger scale.
DC can be changed to AC with a device called an alternator and AC can be changed to DC with a device called a rectifier. Other than the direction of flow caused by AC or DC, what's going on inside the wires downstream is the same no matter what kind of energy was used to produce it.
The thing that would do the most to clean up energy would be development of ways to efficiently store electricity. In the current system, if it is not used now, it is lost. Both solar and wind depend on the weather. At night and when it's cloudy, solar doesn't produce well and when the wind is calm the propellers don't turn. If the unused energy could be stored so that what's over-produced when the weather is favorable could be fed back into the system when it is not, that would make both solar and wind viable replacements for nuclear and systems that burn fossil fuels for energy to produce electricity.
Creating a way to efficiently store huge amounts of electricity is the ticket. Get to work! :-)
