Wind EnergyEmma O’Reilly

Sam Pennington

About Wind Energy

Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth.

Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetative cover.

This wind flow, or motion energy, when "harvested" by modern wind turbines, can be used to generate electricity.

Wind Turbines

Wind Turbines use blades to collect the wind’s kinetic energy. › The wind flows over the blades creating lift (like

the effect on airplane wings) which causes them to turn.

› The blades are connected to a drive shaft that turns an electric generator to produce electricity.

A turbine is the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity.

Types of Wind Turbines Horizontal-axis :

› like the traditional farm windmills used for pumping water

Vertical-axis :› eggbeater-style

Darrieus model, named after its French inventor.

Most large modern wind turbines are horizontal-axis turbines.

Who?

Wind resources are characterized by wind-power density classes› Class 1 (the lowest) to class 7 (the highest).

Class 3 is the average class with good wind resources because they have an average annual wind speed of at least 13 miles per hour

These locations in the United States include: › Alaska › mid north western states such as Colorado,

Wyoming, and Indiana, the Dakotas and Montana

Cost The technology requires a higher initial

investment than fossil-fueled generators. Roughly 80% of the cost is the machinery, with

the balance being site preparation and installation.

However, wind costs compared to fossil fuels are much more competitive with other generating technologies because there is no fuel to purchase and minimal operating expenses.

Costs $0.04 per kWh The initial cost of wind turbine is split into 3

categories› 500 for 400 W› 6,000 dollars for 4kWh› 50,000 dollars for 20 kWh

Cost

Cost of tower› The higher tower the better because of wind consistency and

less turbulence› 30-50 ft tower = 5,000-8,000 dollars› 80-120 ft= 12,000-30,000

Cost of instillation (foundation/electrical): › equipment could cost between $3,000-7,000› Instillation cost also depends on terrain and heat

Maintenance costs:› 1-3% of initial cost of wind turbine each year on

maintenance. Ex: $200-600 for a 20,000 $ turbine

Making a turbine can be a lower cost› EX; 200 $ for 800 W.

Cons- Environmental There is some concern over the

noise produced by the rotor blades,

Visual impacts Birds and bats having been

killed by flying into the rotors. Most of these problems have

been resolved or greatly reduced through technological development.

Can be damaged by heavy winds or storms

Cons

Wind does not flow when energy is needed so this power can be inconsistent and intermittent.

Wind cannot be stored › although wind-generated electricity can be

stored, if batteries are used Not all winds can be harnessed to meet

the timing of electricity demands.

Pros Wind energy is a free, renewable

resource› Power cuts and power failures are almost

non existent. Wind energy is also a source of clean,

non-polluting, electricity. › Unlike conventional power plants, wind

plants emit no air pollutants or greenhouse gases.

According to the U.S. Department of Energy, in 1990:› California's wind power plants offset the

emission of more than 2.5 billion pounds of carbon dioxide,

› 15 million pounds of other pollutants that would have otherwise been produced.

› It would take a forest of 90 million to 175 million trees to provide the same air quality.

Pros In 2008, wind machines in the United States generated a total of 52 billion kilowatthours, about 1.3% of total U.S. electricity generation.

Cheapest forms of energy available therefore can be used by mostly everyone

Many utilities around the country offer green pricing options that allow customers the choice to pay more for electricity that comes from renewable sources to support new technologies

Pros Generation from wind in the

United States nearly doubled between 2006 and 2008.

New technologies have decreased

the cost of producing electricity from wind, and growth in wind power has been encouraged by tax breaks for renewable energy and green pricing programs.

Surplus

Batteries in wind turbines store and harvest wind energy.

http://windeis.anl.gov/guide/basics/index.cfm

http://www.eia.doe.gov/kids/energy.cfm?page=wind_home-basics

http://www.buzzle.com/articles/wind-energy-pros-and-cons.html