Sunny Side Up Christine Bordonaro Chapter 31

Summary Christine Bordonaro, materials engineer explains: How the energy in sunlight – solar energy – can be used to generate electricity; The pros of using photovoltaic (PV) cells to provide electrical power; The cons of using photovoltaic (PV) cells to provide electrical power; Discusses why more people use them in other countries; and What her company, Evergreen Solar, is doing to make solar panels cheaper and more efficient.

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Centralized electrical generation systems In the systems, large volumes of fossil fuels are mined, stored, and transported to power stations to generate and distribute electricity through an extensive network of wires. Much of the energy in the fuels is lost on the way to end users.

Decentralized electrical generation systems Solar electrical generation is a decentralized electrical generation system because: It does not need storing, transporting, and burning fossil fuels. It does not require connection to a grid. In such system, very little energy is lost before it gets to end users, and there is much less pollution.

Some other key points Radiation is the energy transported by light – any kind of light, not just sunlight. Sunlight provides energy to make charge flow in photovoltaic panels. While photovoltaics offer many advantages, they are quite expensive and not very efficient.

Question 1 Question Why is it beneficial to use renewable energy sources? Answer The supply of fossil fuels is limited. Fossil fuels will become more expensive, and be used up eventually. Renewable sources of energy like the sun will not be used up. Solar energy also has less impact on environment.

Question 2 Question Why does Christine say that solar technologies represent decentralized power generation? What are the advantages? Answer Solar technologies do not need to be connected to the grid. They can be set up anywhere. No need to extract, transport, and store fuels.

Question 3 Question How do homes powered by PV panels get power at night? Answer Homes get power at night from the grid or with a battery that stores excess electricity the solar cells produced during the day.

Question 4 Question Christine says that solar panels are only about 15% efficient. What are the inputs and outputs of the solar panel system that Christine is using to determine efficiency? Answer The input is solar energy from sunlight; the output is the energy in electricity.

Question 5 Question What are some differences between how solar panels generate electricity and how a generator in a coal-fired power plant generates electricity? Answer In a coal-fired power plant, coal is burned to heat water and turn a turbine, which spins an electrical generator. A solar panel is made up of solar cells. Each cell produces an electric current when exposed to sunlight – no moving parts are needed. Another difference is cost. Energy from solar cells costs a lot more because of the high production and installation cots of solar panels.