1. Lesson 18.3 Solar and Wind Energy
In one day, the Earth receives enough energy from the sun to meet human energy needs for 25 years—if it could all be harnessed. 1

2. Solar Energy
Nearly ALL renewable energy comes directly or indirectly from the sun.
Solar energy helps power the wind and the water cycle.

3. Harnessing Solar Energy for Heat
Passive solar heating: Designing a building to efficiently capture, store, and distribute the sun’s energy; can be used to heat homes and businesses
Active solar heating: Uses technology, such as solar panels, to capture, store, and distribute the sun’s energy
Did You Know? Greenhouses, thick window drapes, and south-facing windows are all passive solar energy “devices.” 3

4. Harnessing Solar Energy to Make Electricity
Photovoltaic cells (solar panels): Convert solar energy directly into electricity
Concentrating solar power: Uses mirrors to focus the sun’s rays on a vessel containing fluid; creates steam to push turbines and generate electricity.
Solar Panel 4

6. Benefits and Costs of Solar Power
Inexhaustible
Clean—no air or water pollution produced during operation
Low maintenance devices
New jobs to make solar devices
Costs:
Some pollution during manufacture
Many regions aren’t sunny enough.
Devices are expensive. 6

7. The Power of the Wind Fastest growing source of energy in the world.
The sun warms the Earth’s surface unevenly, which causes air masses to flow throughout the atmosphere.
Wind energy is converted into electric energy by using machinery called “turbines”

8. Using Wind to Make Electricity
Wind turbines (windmills) convert wind’s kinetic energy to electrical energy.
Wind turbines can be placed on land or offshore.
Turbines can be solitary or built in groups called wind farms.
Did You Know? Average wind speeds are 20% faster offshore than on land. 8

10. Benefits and Costs of Wind Power
No pollution or greenhouse gases produced during operation
Under good wind conditions, produces far more energy than it uses
Relatively cheap to operate 10

11. Costs: High startup costs Winds can be unpredictable
Fastest winds are often not near population centers.
Communities complain about the looks and noise of wind farms.
Can be harmful to birds and bats