Overview

We have burned dead dinosaurs (fossil fuels) for 200 years. It made us rich, but it’s cooking the planet. Renewable Energy is the transition to infinite fuel sources: the sun, the wind, and the heat of the earth. It is the biggest engineering challenge of the 21st century.

Core Idea

The core idea is Sustainability. Using energy that doesn’t run out and doesn’t destroy the biosphere.

Formal Definition

Energy collected from renewable resources that are naturally replenished on a human timescale. Types: Solar, Wind, Hydro, Geothermal, Biomass.

Intuition

  • The Bank Account: Fossil fuels are like spending your savings (Capital). Once it’s gone, it’s gone. Renewables are like living off the interest (Income). The sun comes up every day.

Examples

  • Solar PV: Turning photons directly into electrons. The price has dropped 90% in 10 years. It is now the cheapest electricity in history.
  • Offshore Wind: Giant turbines in the ocean where the wind is stronger and steadier.
  • Hydroelectric: The Hoover Dam. The original renewable. (But it hurts fish).

Common Misconceptions

  • It’s unreliable: “The sun doesn’t always shine.” True. That’s why we need Storage (Batteries) and a Smart Grid to move energy from where it’s windy to where it’s calm.
  • It’s expensive: It was expensive. Now it’s cheaper than coal.
  • Intermittency: The main problem. Matching supply with demand when you can’t control the generator.
  • Decarbonization: The goal. Reaching Net Zero emissions.

Applications

  • Electric Vehicles (EVs): They are only “green” if the grid charging them is green.

Criticism / Limitations

  • Land Use: Solar farms take up a lot of space.
  • Materials: We need massive amounts of Lithium, Cobalt, and Copper to build this new infrastructure.

Further Reading

  • MacKay, David. Sustainable Energy — Without the Hot Air.