Power Density by Source

A nuclear plant produces about 1,000 watts per square meter of land it occupies. A solar farm produces about 5-10 watts per square meter. A wind farm produces about 1-2 watts per square meter. These three-order-of-magnitude differences explain why a nuclear plant fits on a few hundred acres while a solar farm covering the same output needs tens of thousands.

Power density measures energy output per unit of land area, in watts per square meter (W/m²), using average power (nameplate times capacity factor). It captures the fundamental land-use tradeoff between energy sources:

Source	Approximate power density (W/m²)
Nuclear	500-1,000
Natural gas plant	200-500
Coal plant (with mine)	100-300
Solar farm	5-10
Wind farm	1-2
Biomass	0.5-1

These numbers use average power (not nameplate) and include the full land footprint. Wind farms allow dual use (farming between turbines), which complicates direct comparison, but the physical spacing requirements remain.

Worked Example

A region needs 10 GW of average power. Compare land requirements for nuclear versus solar.

• Nuclear at 750 W/m². Area = 10 x 10^9 / 750 = 13.3 x 10^6 m² = 13.3 km² (about 5 square miles).
• Solar at 7.5 W/m². Area = 10 x 10^9 / 7.5 = 1.33 x 10^9 m² = 1,333 km² (about 515 square miles).

How does the solar land requirement compare to a familiar reference?

1,333 km² is roughly the size of Los Angeles. The nuclear option is about the size of a large university campus. The same energy, 100x difference in land. This is why power density drives siting and permitting conflicts for large-scale renewable installations.

Power density determines whether an energy source creates land-use conflicts at scale, making it a first-order policy variable for any buildout plan.

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