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County · United States Nebraska

Johnson County, Nebraska

2.75GWh
every year, from one 325-watt panel on each of 6,181 buildings.

What that is equal to

🏠 262
homes powered for a year
at the US average of 10,500 kWh per household
🌍 1,019 t
CO₂ avoided annually
displacing grid power at 0.371 kg CO₂e/kWh (EPA eGRID)
🚗 222
cars taken off the road
an average passenger vehicle emits 4.6 t CO₂e a year
⚡ 7.85 million
electric vehicle miles
at roughly 0.35 kWh per mile

The pay-off

It pays for itself here. A panel on this roof delivers electricity at 8.6¢ a kWh against a local price of 13.6¢ — 37% cheaper than local power. The install is repaid after 15.4 years, inside the panel's 25-year life.
8.6¢ vs 13.6¢
cost per kWh: this panel vs the grid
levelised over 25 years including 0.5%/yr degradation
$5.56 million
to fit every building here
6,181 panels at $900 installed each
15.4 years
to break even
saving $373 thousand a year area-wide at today's price

Assumes $900 to install one 325 W panel — hardware, mounting, microinverter, electrical work, labour and permitting — repaid only by the electricity it avoids buying. No subsidies, tax credits, net-metering premium, financing cost or future price rises are counted, and the figure is undiscounted. Electricity price is the NE residential average (EIA, May 2026). A single panel is unusually expensive per watt because it carries a whole array's fixed costs, which is why these numbers look worse than rooftop solar generally does.

How this is calculated

Buildings with roofs6,181
×  Panel rating325 W
×  Annual yield per panel here444.4 kWh
Annual generation2,746,956 kWh
Assumptions and limitations
  • Yield is specific to this location: 444.4 kWh per panel per year, from NASA POWER climatology transposed onto a tilted roof plane. The same panel makes roughly 596 kWh in Phoenix and 265 kWh in Anchorage.
  • Assumes a south-facing roof at a typical residential pitch, with a ~22% total system loss for soiling, shading, wiring, inverter, and heat.
  • Counts every above-ground structure with a footprint of at least 20 m², so garages and outbuildings are excluded but barns and sheds of real size are not. Building data is machine-derived and imperfect.
  • No account is taken of roof orientation, obstructions, structural condition, or whether the owner wants a panel.

Places like Johnson County

Valley County · 2.87 GWhPolk County · 2.71 GWhChase County · 2.93 GWhSherman County · 2.67 GWhThurston County · 2.52 GWhStanton County · 2.62 GWh