Lesson 4: Energy Systems
Energy is the ability to do work. Engineering is fundamentally about converting energy from one form to another — and doing it efficiently. Understanding energy systems is essential for every engineering discipline.
Key Concepts
Forms of Energy
Energy exists in many forms: kinetic (motion), potential (stored due to position), thermal (heat), chemical (in fuel or batteries), electrical, and nuclear. Engineering converts between these forms. A dam converts potential energy to electrical energy.
Efficiency
No energy conversion is 100% efficient — some always becomes heat. A car engine converts about 25% of fuel energy to motion; 75% is wasted as heat. Engineers constantly work to improve efficiency. Even small improvements at scale save enormous amounts of energy.
Power and Energy
Power is the rate of energy use (measured in watts). Energy is power × time (measured in watt-hours or joules). A 100-watt bulb uses 100 watt-hours in one hour. A 1,000-megawatt power plant powers about 700,000 homes.
🆕 Energy Conversion Chain
Trace energy through a system and see how much is lost at each step.
✅ Check Your Understanding
1. What is kinetic energy?
2. What does efficiency measure?
3. If a power plant is 35% efficient, what happens to the other 65%?