Renewable energy is a ploy which government officials use to get elected, and which has no further useful practice, due to the fact of the immense cost and low effectiveness of the materials used.
Hydrogen Cars: They seem to be oh-so-perfect at using Renewable Energy until you realize that hydrogen is not readilly mined out of the ground, like fossil fuels. Instead, it must be manufactured using other methods, such as burning coal, or using solar panels (which generate a feeble amount of electricity at a high cost). Furthermore, the energy which is produced by the hydrogen is less than what was originally put into it, making it wasteful. The only thing it might accomplish is to keep the burning of materials in some other location. The fuel cells are a waste because they only provide about 0.8 volts per cell, meaning you would need a lot of space to store them. Hydrogen is also extremely explosive, and isn't practical unless you use a heavy storage tank to store it in.