Wind Turbine Payback in Sussex County, DE
Wind turbine payback in Sussex County
No. The turbine wears out before it pays for itself.
At 30 m, the height a home turbine tower usually reaches, the wind in Sussex County, DE averages 5.87 m/s (13.1 mph). A 10 kW turbine there would make about 18,742 kWh a year, worth $3,370 at DE's 17.98¢/kWh. Against an installed cost of about $100,000, that is a payback of 30 years, and the turbine is built to last about 20.
What to do in Sussex County
A home turbine is not worth buying for savings in Sussex County unless your spot is far windier than the county average, 7.1 m/s at the hub against 5.87 m/s here. Per kW, solar panels would make about 1,226 kWh a year here against the turbine's 1,874, so get a solar quote first.
What would have to change
- Power would have to cost 27¢/kWh, 1.5 times what DE pays now.
- Or the average wind at the hub would have to be 7.1 m/s instead of 5.87. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of DE
Sussex County is the 1,026th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. It is the windiest county in DE.
Month by month in Sussex County
March is the strongest month here, at 6.70 m/s and about 2,115 kWh. August is the weakest, 4.51 m/s and 797 kWh, so the best month makes 2.7 times the worst. November to March brings in 52% of the year's output in Sussex County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.68 m/s | 2,098 kWh | $377 |
| February | 6.72 m/s | 1,920 kWh | $345 |
| March | 6.70 m/s | 2,115 kWh | $380 |
| April | 6.61 m/s | 1,988 kWh | $357 |
| May | 5.63 m/s | 1,443 kWh | $259 |
| June | 5.12 m/s | 1,097 kWh | $197 |
| July | 4.63 m/s | 861 kWh | $155 |
| August | 4.51 m/s | 797 kWh | $143 |
| September | 5.20 m/s | 1,142 kWh | $205 |
| October | 5.95 m/s | 1,643 kWh | $295 |
| November | 6.30 m/s | 1,805 kWh | $325 |
| December | 6.46 m/s | 1,960 kWh | $352 |
What a taller tower would buy
Measured at 10 m the wind in Sussex County averages 4.52 m/s; at 50 m it is 6.63 m/s. That gives a shear exponent of 0.238, typical of ordinary open country. Going from 20 m to 50 m takes output from 14,827 to 24,362 kWh a year, 64% more, before counting the extra cost of the taller tower. Why tower height decides it explains the shear behind these numbers.
| Hub height | Average wind | Output | Payback |
|---|---|---|---|
| 20 m | 5.33 m/s | 14,827 kWh | 38 years |
| 30 m | 5.87 m/s | 18,750 kWh | 30 years |
| 40 m | 6.29 m/s | 21,833 kWh | 26 years |
| 50 m | 6.63 m/s | 24,362 kWh | 23 years |
Counties around Sussex County
2 of the 6 closest counties are windier at turbine height; the windiest, Worcester County, averages 7.01 m/s.
- Wicomico County, MD: 5.87 m/s, 18,742 kWh, payback 25 years (26 mi)
- Caroline County, MD: 5.7 m/s, 17,492 kWh, payback 27 years (30 mi)
- Kent County, DE: 5.7 m/s, 17,492 kWh, payback 32 years (31 mi)
- Worcester County, MD: 7.01 m/s, 27,114 kWh, payback 17 years (31 mi)
- Cape May County, NJ: 6.6 m/s, 24,142 kWh, payback 17 years (39 mi)
- Dorchester County, MD: 5.21 m/s, 13,976 kWh, payback 34 years (42 mi)
Sun versus wind in Sussex County
Sussex County gets 4.2 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,226 kWh a year; one kW of the turbine above makes 1,874. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.5 times. Panel output assumes an 80% system performance ratio. Wind or solar runs the same comparison for every county.
How this is worked out
Wind is NASA's Power climate record, the 2001-2025 average at 10 m and 50 m for the county's centre, carried to 30 m with this county's own measured wind shear and spread into hours with a Rayleigh distribution. The turbine is a generic 10 kW, 7 m rotor machine with 10% losses. Cost is $10,000 per kW installed with no tax credit, because the federal one ended in 2025. One county-centre number cannot see your hilltop or your tree line, so treat it as the starting point for a site survey, not a substitute. The full method and its weak spots are in how the numbers are made.