4.3 Power from the sun and earth

Solar cells are flat solid cells that convert solar energy directly into electricity.

Solar heating panels use the Sun's energy to heat water directly.

• Advantage: Renewable, free reliable in hot countries(sunshine), non-pollutant
• Disadvantage: Solar cells only produce small amount of electricity, only reliable in sunny countries.

Geothermal energy comes from the energy released by radioactive substances deep inside the Earth.

Water pumped into hot rocks underground produces steam to drive turbines that generate electricity.

• Advantage: Renewable, free, mom-pollutant
• Disadvantage: Only economically viable in a view places around the world, Drilling deep into the ground is hard and expensive.