Roller Coaster Energy Physics: Gravity-Powered, Not Power-Consuming

Roller coasters are gravity-powered machines that consume minimal electrical energy during operation. The physics is elegant:

Energy Cycle

1. Lift hill: Electric motor + chain lift does work against gravity → stores gravitational potential energy (mgh)
2. Descent: Potential energy → kinetic energy (½mv²). Speed builds.
3. Subsequent hills: Kinetic → potential → kinetic. Each hill lower than previous (energy losses: friction, air resistance, sound, heat)
4. Brake run: Remaining kinetic energy dissipated by magnetic/eddy current/friction brakes → heat

Net Energy Balance

Input: Only the lift hill motor energy (typically 50-200 kW for 30-60 seconds)
Output: Zero electrical generation (regenerative braking rare; mostly resistive)
Cycle: Energy input = energy dissipated per train cycle

Efficiency Factors

• Chain lift efficiency: ~85-90% (motor → mechanical)
• Track losses: Wheel friction, guide wheel scrub, aerodynamic drag — 30-50% of initial potential energy lost per circuit
• Train mass utilization: Heavier trains = more momentum, better loss tolerance

Comparison

Launched coasters (LIM/LSM): High power burst (1-3 MW) for 2-4 seconds → no lift hill. Higher peak power, similar total energy.
Powered coasters: Motors on train — continuous draw. Rare.

Environmental Context

A typical major coaster cycle: ~15-30 kWh per train dispatch. At 20 dispatches/hour, 12 hrs/day = 3,600-7,200 kWh/day. Equivalent to ~300-600 US homes' daily electricity. Significant but concentrated entertainment energy.

Roller coasters don't "use power" during the ride — they spend the potential energy bought on the lift hill. The rest is gravity's free work.