Alternative Energy: C. Crutchfield
From GeoClasses
Contents |
Solar Electricity
How does it work?
Solar electric technology converts sunlight directly into electricity. It works anytime the sun is shining, but more electricity will be produced when the light is more intense (a sunny day) and is striking the panels directly (when the sun is perpendicular to the solar panels). (spinning globe video)
Solar electric panels do not use heat to make electricity. Instead, solar electric panels produce electricity directly from electrons freed by the interaction of sunlight with semiconductor materials in the solar panels.
How much solar electricity do I need?
Solar electric panels typically generate about 10 watts per square foot and the panels are mounted on your rooftop.
The maximum amount of solar electricity that can be efficiently generated usually is determined by the amount of southerly roof exposure available that remains completely unshaded most of the day. Solar electric systems produce power intermittently because it only works when the sun is shining. (Ohio clouds video)
This is not a problem for solar electric systems connected to a utility grid, because additional electricity you need is automatically delivered to you by your utility.
Is solar electricity less expensive than utility supplied power?
Solar electricity is usually more expensive than conventional utility-supplied electricity. Improved manufacturing has reduced the cost to less than 5% of what it cost in the 1970's, but the cost is about 25 cents per kilowatt-hour. Solar rebates and incentives can help make solar electricity more affordable and practical. Unlike electricity purchased month by month from a utility, solar electric power comes with a high initial investment. Buying a solar electric system is like paying years of electric bills up front. By financing your solar electric system, you can spread the cost over many years, and rebates and incentives will certainly lighten your load.
Buying a solar electric system:
People decide to buy solar electric systems for a variety of reasons. Some want to preserve the earth's fossil-fuel resources and reduce air pollution. Others would rather spend their money on an energy-producing improvement to their property than to send money to a utility. Some people like the security of reducing the amount of electricity they buy from their utility, because it makes them less vulnerable to future rate increases in the price of electricity. Finally, some people just don't like paying utility bills and appreciate the independence that a solar electric system provides.
Your home is a good place for a solar system:
Is your roof free from shading by trees, nearby buildings, or other obstructions? Solar panels should face as close to south as possible and have a clear "view" of the sun for most or all of the day. Shading will substantially reduce the amount of electricity produced.
Wind Power
History
Babylonians and the Chinese were using wind power water for irrigation crops 4,000 years ago and sail boats were around long before that.
 Chinese junk |
 windpump, pumping water from the ground |
Used in the Middle Ages in Europe to grind corn. This is were we get the term “wind mill”.
How it works:
Sun heats our atmosphere unevenly, so some patches become warmer that others. These warm paths of air rise the air blows in to replace them and we feel a wind blowing. (convection video)
We can use the energy in the wind by building a tall tower, with a large propeller on the top.
The wind blows the propeller round, which turns a generator to produce electricity.
Building many towers close together makes a wind farm and produces more electricity. wind turbines in the mountains |
The best place for wind farms are in coastal areas, at the tops of rounded hills, open plains and gaps in mountains; places that have strong reliable wind.
Methane Hydrates:
Methane Hydrates may contain a major energy resource.
It maybe a significant hazard because they alter sea floor sediment stability, influencing collapse and landslides.
The hydrate reservoir may have a strong influence on the environment and climate because methane is a significant greenhouse gas.
When you combine water and swamp gas under low temperatures and high pressures, you get a frozen latticelike substance called methane hydrate.
Huge amounts of which underlie our oceans and polar permafrost. This crystalline combination of a natural gas and water (known technically as a clathrate) looks remarkably like ice but burns if it meets a lit match.
 map of distribution of gas hydrates |
No one has yet figured out how to pull out the gas inexpensively, and no one knows how much is actually recoverable.
Because methane is also a greenhouse gas, release of even a small percentage of total deposits could have a serious effect on Earth's atmosphere.
For example, ocean-based oil-drilling operations sometimes encounter methane hydrate deposits. As a drill spins through the hydrate, the process can cause it to dissociate. The freed gas may explode, causing the drilling crew to lose control of the well. Another concern is that unstable hydrate layers could give way beneath oil platforms or, on a larger scale, even cause tsunamis.
