Solar PV Scale

In 1976, solar PV modules cost about $97 per watt. In 2024, modules cost about $0.26 per watt. That 99.7% cost decline, driven by manufacturing scale and learning curves, transformed solar from a space technology into the cheapest source of new electricity in most of the world.

Solar PV deploys at three scales, each serving different markets. Residential (5-20 kW rooftop systems): highest cost per watt ($2.50-$4.00 installed) because of customer acquisition, permitting, and labor-intensive installation. Commercial (100 kW to 5 MW on warehouses or carports): moderate cost ($1.50-$2.50/W). Utility-scale (50-500+ MW ground-mounted farms): lowest cost ($0.70-$1.20/W installed) because bulk purchasing and optimized installation drive economies of scale. Capacity factors range from 15-20% in northern latitudes to 25-30% in the sun belt.

Calculate LCOE for utility-scale. A 200 MW farm in Arizona at $1.00/W installed costs $200 million. Capacity factor 28%. Annual output: 200,000 kW x 8,760 hours x 0.28 = 490,560 MWh. Over 30 years: ~14.7 million MWh.

Simplified LCOE. $200 million / 14.7 million MWh = roughly $14/MWh (before financing and maintenance).

Why is residential solar 3-4 times more expensive per watt installed than utility-scale, despite using similar panels?

Soft costs dominate residential. The panel itself is under 30% of a residential system's total cost. Permitting, labor, inverters, customer acquisition, and financing make up the rest. Utility-scale systems spread these costs across millions of watts.

Solar's challenge is no longer cost. It is integration: managing intermittency, building storage, and expanding transmission to match where the sun shines with where people live.

---