Answer to Question 1
Monocrystalline silicon panels, advantage: most prevalent bulk silicon material. Disadvantage: must be cut from a larger silicon cylindrical ingots.
Bifacial monocrystalline panels, advantages : converts light into electrical power from both sides of the panel. Disadvantages requires special mounting and reflectors to get the light to both sides of the panel.
Polycrystalline silicon panels, advantages less expensive to manufacture than monocrystalline panels. Disadvantages less efficient than monocrystalline panels.
String ribbon panels, advantages lower production cost to less waste. Disadvantages lower efficiencies than the polycrystalline silicon.
Amorphous silicon thin film panels, advantage of thin film panels is low manufacturing cost and versatility. This advantages lowest efficiency of any other current photovoltaic technology.
Cadmium telluride panels advantages: very efficient light absorbing material for the thin-film cells and large-scale cells. Disadvantages cadmium is toxic with about the same amount of cadmium as a NiCad battery.
Answer to Question 2
The parabolic trough generating system consists of large solar reflectors with piping running through the middle of them. The fluid flows through the piping that continually picks up heat energy from the solar energy. A heat exchanger allows the fluid to heat water in a second loop until it reaches steam which is used to move a typical electrical generating turbine. At night or when the fluid flowing through the piping becomes too cool to produce steam, and alternative energy such as natural gas issues to heat the water to steam.