Wind Energy Non Conventional Energy Sources

Shree Swami Atmanand Saraswati Shree Swami Atmanand Saraswati Institute of TechnologyInstitute of Technology

Introduction• Wind power is good renewable, clean and free

source of energy for power production.

• Reduce dependence on fossil fuels including

imported oils.

• Reduce emission of greenhouse gas and other

pollutant.

• One major concern is the noise – can be improved.

• Intermittency and variability of the wind.

Theoretical limit of rotorefficiency is 59%.

Most modern wind turbinesare in the 35 – 45% range.

All wind power cannot be captured by rotor or air would be completely still behind rotor and not allow more wind to pass through.

A wind turbine converts a fraction of the wind energy into mechanical energy.

A part is transferred to the rotor of the wind turbine. The efficiency is the ratio of actual power developed by wind

turbine rotor to the available wind power.

Wind Turbine Power and Efficiency

– Effect of swept area, A

– Effect of wind speed, V

– Effect of air density,

R

Swept Area: A = πR2 Area of the circle swept by the rotor (m2).

Power in the Wind = ½ρAV3

RotorSolidity is the ratio of total rotor plan

form area to total swept areaLow solidity (0.10) = high speed, low torque

High solidity (>0.80) = low speed, high torqueA

R

a

Airfoil Shape

Just like the wings of an airplane, wind turbine blades use the airfoil shape to create lift and maximize efficiency.

Types of Wind Turbine

Horizontal axis - Primarily of the axial flow types - requires control mechanism to take account of variation in wind direction

e.g Savonius wind turbine

Vertical axis - Can handle winds from all directions

e.g Darrieus wind turbine

Number of Blades - Two

• Need teetering hub and or shock absorbers because of gyroscopic imbalances.

• Capture 5% less energy than three blade designs.

Number of Blades - Three

• Balance of gyroscopic forces.

• Slower rotation– increases gearbox &

transmission costs

– More aesthetic, less noise, fewer bird strikes.

• Mostly used in india three bladed wind mill.

Blade Composition Metal

• Steel– Heavy & expensive

• Aluminum– Lighter-weight and

easy to work with– Expensive– Subject to metal

fatigue

Blade Fiberglass

• Lightweight, strong, inexpensive, good fatigue characteristics.

• Variety of manufacturing processes

• Most modern large turbines use fiberglass.

Manufacturing of Blade

Pitch Control Mechanisms

Wind is free, wind farms need no fuel.

Produces no waste or greenhouse gases.

A good method of supplying energy to remote areas.

Although wind turbines can be very tall, they only take up a small plot of land.

Wind farms are appealing to the landscape.

Remote areas that have no other energy source available can use wind turbines to produce their own supply.

Advantages of Wind Energy

The amount of wind available always varies. There will be times when they produce no electricity at all.

Wind turbines can be noisy. It can be equivalent to the noise of a car traveling at 70 mph.

Because wind turbines have to be anchored to the ground this could possibly impact soil structure.

They do not produce enough electricity to power large amounts of homes.

Disadvantages of Wind Energy