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Wind turbine profit calculator

An 80 m rotor at an average 7 m/s produces over three million kWh a year; this calculator turns that energy into yearly profit at your electricity price, after operating costs. Enter four numbers and audit the result. Free in your browser.

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Worked example

If you enter

Rotor diameter: 80
Wind speed: 7
Electricity price: 0.12
Operating cost: 50,000

You get

Swept area: 5,026.5482457437
Air density: 1.225
Power coefficient: 0.4
Hours per year: 8,760

A wind turbine's yearly profit is not a mystery cell in a spreadsheet. It is the energy a rotor of a given diameter can extract from the air at a stated average wind speed, sold at a stated electricity price, minus the operating cost of keeping that machine online for a planning year. This wind turbine profit calculator takes those four numbers, applies the standard kinetic-energy flux through the swept disk, scales electrical conversion with a documented typical power coefficient of four tenths, multiplies by the eight thousand seven hundred sixty hours of a non-leap planning year, and returns yearly profit in the same currency you used for the tariff and the opex line.

What yearly wind-turbine profit is and how the cash figure is built

A wind turbine profit estimate answers a planning question, not a laboratory power-curve question. Given the rotor diameter in metres, the site average wind speed in metres per second, the electricity price in currency per kilowatt-hour, and the annual operating cost in the same currency, how much money does the machine make in a year after opex? Instantaneous electrical power follows the kinetic-energy flux through the swept disk: one half times air density times swept area times wind speed cubed times the power coefficient.

Swept area is pi times the square of the radius, which is pi times diameter squared over four. Air density is the ISA sea-level value of one point two two five kilograms per cubic metre. The power coefficient is a typical modern horizontal-axis figure of zero point four zero, which sits honestly below the Betz limit of sixteen twenty-sevenths.

Annual energy in kilowatt-hours is that power in watts times eight thousand seven hundred sixty hours, then divided by one thousand. Annual revenue multiplies energy by the electricity price. Annual profit subtracts operating cost from revenue.

Example: an eighty-metre rotor at seven metres per second, a tariff of zero point twelve per kilowatt-hour, and fifty thousand of yearly opex produces a positive annual profit you can audit from those four inputs and the documented constants. This page does not look up a manufacturer power curve, a Weibull shape factor, or a market-price time series; those are different searches.

Here the unit of value is yearly profit in currency, so a first-pass farm model, a homework check, or a quote sheet can sit next to a single auditable number instead of a snapshot in watts.

Who checks a wind project's yearly profit

Developers of farm-planning tools need a deterministic oracle that turns a rotor diameter, a mean wind speed from a mast or an atlas, a power-purchase or retail tariff, and a yearly opex line into annual profit without embedding a one-off spreadsheet in every quote. Landowners and community-energy groups comparing a small turbine against last year's bill want a number they can audit: kinetic power through the disk, eight thousand seven hundred sixty hours, revenue minus opex, not a black-box simulation.

STEM classrooms and energy-literacy sites want students to separate nameplate megawatts from yearly cash, and to see why a negative input is an error instead of a silent negative area that a buggy grader might treat as success. Automation pipelines that seed homework answers, sanity-check a customer form, or size a first-pass onshore machine call the same contract so a demo and a backend never diverge.

Keep the four inputs non-negative and finite, pin the rounded annual profit in tests, and you get reproducible yearly profit figures for quotes, classrooms, and edge workers without standing up a wind-atlas stack of your own.

What you can do with it

Onshore farm first-pass quotes

Turn rotor diameter, site mean wind speed, a PPA or retail tariff, and yearly opex into annual profit for a first-pass onshore quote.

Small turbine versus the electricity bill

Estimate how much yearly cash a backyard or farm turbine would keep after operating cost, before comparing it with last year's usage.

Classroom energy-economics oracles

Grade worksheets that convert kinetic wind power into yearly profit with a deterministic product that rejects negative and non-numeric inputs.

FAQ

How is yearly wind-turbine profit calculated?

Swept area A = π·D²/4. Annual energy in kWh is P·8760/1000.

Why is the power coefficient fixed at 0.40?

Zero point four is a typical modern horizontal-axis figure and sits below the Betz limit of 16/27. This first-pass estimator does not take a manufacturer curve; it documents the constant so every caller can audit the cash figure.

What happens if I enter a negative value or zero?

Negative diameters, wind speeds, prices or costs are refused. Zero is accepted, so still air or a zero price is a valid thought experiment; the profit then often turns negative while operating costs remain.

Which currency does the profit come out in?

The same one you used for the electricity price and the operating cost. Any currency works, as long as both inputs are in it; the calculator never converts between currencies.

Does it use a manufacturer power curve or a wind distribution?

No. It uses the energy flowing through the rotor disk with a fixed air density of 1.225 kg/m³ and a power coefficient of 0.40, and keeps your wind speed constant for 8760 hours. Power curves and market prices are not included.

Related tools

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/eco/wind-turbine-profit

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/eco/wind-turbine-profit \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"rotor_diameter":80,"wind_speed":7,"electricity_price":0.12,"operating_cost":50000}'

const res = await fetch("https://api.kit.forhosting.com/eco/wind-turbine-profit", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "rotor_diameter": 80,
    "wind_speed": 7,
    "electricity_price": 0.12,
    "operating_cost": 50000
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/eco/wind-turbine-profit",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "rotor_diameter": 80,
    "wind_speed": 7,
    "electricity_price": 0.12,
    "operating_cost": 50000
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/eco/wind-turbine-profit", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"rotor_diameter":80,"wind_speed":7,"electricity_price":0.12,"operating_cost":50000}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"rotor_diameter":80,"wind_speed":7,"electricity_price":0.12,"operating_cost":50000}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/eco/wind-turbine-profit", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "rotor_diameter": 80,
  "wind_speed": 7,
  "electricity_price": 0.12,
  "operating_cost": 50000
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "eco.wind_turbine_profit",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Technical notes

Negative diameters, wind speeds, prices, or costs are rejected as invalid_input, as is any value that is not a finite number, so a missing cell or a sign error never invents a farm.

Input contract, response fields, and error behaviour

Any input that is negative is rejected with a message that the field must not be negative, because a negative diameter, wind speed, tariff, or opex is not a physical or accounting quantity this estimator will invent. Zero is accepted: still air, a free tariff, or a zero opex line is a valid thought experiment that yields a finite profit, often negative when opex remains. Failed validation is not billed. Send a JSON body with four required finite non-negative numbers. rotor_diameter is the rotor diameter in metres (aliases: diameter, d, rotor_d, rotor). wind_speed is the site average wind speed in metres per second (aliases: speed, v, average_wind_speed, wind, ws). electricity_price is the selling price of electricity in currency per kilowatt-hour (aliases: price, tariff, kwh_price, rate). operating_cost is the annual operating cost in the same currency (aliases: operating_costs, opex, costs, annual_opex, opex_year). Values may arrive as JSON numbers or numeric strings. Missing fields, empty strings, objects, and non-finite values fail with invalid_input naming the field. On success the body echoes the four rounded inputs, returns swept_area, the documented air_density and power_coefficient and hours_per_year, power_watts and power_kw, annual_energy_kwh, annual_revenue, and the primary annual_profit, plus a formula string restating the closed form. Pricing is a flat $0.002 per successful request with unit item. This endpoint does not convert currencies, does not apply a second capacity factor on top of the kinetic estimate, and does not consult a weather file.

Technical questions

What units should I send?

rotor_diameter in metres, wind_speed in metres per second, electricity_price in currency per kilowatt-hour, and operating_cost in the same currency per year. The result annual_profit is in that currency per year.

What happens if an input is negative or not a number?

The task fails with invalid_input naming the field. A negative diameter, wind speed, tariff, or opex is not a physical or accounting quantity, so the estimator refuses to invent a farm and the call is not billed.

What does the wind turbine profit calculator cost?

The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.

Read the full KIT documentation →

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