Wind Turbine Payback in Kent County, DE
Wind turbine payback in Kent 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 Kent County, DE averages 5.7 m/s (12.8 mph). A 10 kW turbine there would make about 17,492 kWh a year, worth $3,145 at DE's 17.98¢/kWh. Against an installed cost of about $100,000, that is a payback of 32 years, and the turbine is built to last about 20.
What to do in Kent County
A home turbine is not worth buying for savings in Kent County unless your spot is far windier than the county average, 7.1 m/s at the hub against 5.7 m/s here. Per kW, solar panels would make about 1,188 kWh a year here against the turbine's 1,749, so get a solar quote first.
What would have to change
- Power would have to cost 29¢/kWh, 1.6 times what DE pays now.
- Or the average wind at the hub would have to be 7.1 m/s instead of 5.7. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of DE
Kent County is the 1,132nd windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in DE is Sussex County at 5.87 m/s, payback 30 years.
Month by month in Kent County
March is the strongest month here, at 6.56 m/s and about 2,027 kWh. August is the weakest, 4.35 m/s and 718 kWh, so the best month makes 2.8 times the worst. November to March brings in 54% of the year's output in Kent County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.54 m/s | 2,016 kWh | $362 |
| February | 6.62 m/s | 1,865 kWh | $335 |
| March | 6.56 m/s | 2,027 kWh | $364 |
| April | 6.41 m/s | 1,870 kWh | $336 |
| May | 5.41 m/s | 1,307 kWh | $235 |
| June | 4.92 m/s | 988 kWh | $178 |
| July | 4.45 m/s | 766 kWh | $138 |
| August | 4.35 m/s | 718 kWh | $129 |
| September | 4.99 m/s | 1,022 kWh | $184 |
| October | 5.83 m/s | 1,565 kWh | $281 |
| November | 6.16 m/s | 1,719 kWh | $309 |
| December | 6.32 m/s | 1,877 kWh | $337 |
What a taller tower would buy
Measured at 10 m the wind in Kent County averages 4.39 m/s; at 50 m it is 6.44 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 13,755 to 22,964 kWh a year, 67% 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 | 5.18 m/s | 13,755 kWh | 40 years |
| 30 m | 5.7 m/s | 17,512 kWh | 32 years |
| 40 m | 6.11 m/s | 20,497 kWh | 27 years |
| 50 m | 6.44 m/s | 22,964 kWh | 24 years |
Counties around Kent County
2 of the 6 closest counties are windier at turbine height; the windiest, Sussex County, averages 5.87 m/s.
- Caroline County, MD: 5.7 m/s, 17,492 kWh, payback 27 years (24 mi)
- Cumberland County, NJ: 5.8 m/s, 18,226 kWh, payback 23 years (26 mi)
- Sussex County, DE: 5.87 m/s, 18,742 kWh, payback 30 years (31 mi)
- Queen Anne's County, MD: 5.49 m/s, 15,965 kWh, payback 29 years (31 mi)
- Salem County, NJ: 5.23 m/s, 14,116 kWh, payback 29 years (34 mi)
- New Castle County, DE: 5.23 m/s, 14,116 kWh, payback 39 years (34 mi)
Sun versus wind in Kent County
Kent County gets 4.07 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,188 kWh a year; one kW of the turbine above makes 1,749. 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.