BETZ  ·  POWER CURVE MODEL

Wind Turbine Power Calculator

An expanded rebuild of the classic rensmart.com Betz's Law calculator — which returns a single instantaneous power value from swept area, wind speed, and temperature at the theoretical Betz limit (59.3%). This version adds cut-in, rated, and cut-out wind speeds, an adjustable real-world power coefficient, and a full power curve.

Live Turbine State
— idle —
i Offshore: stronger, steadier wind but higher build/maintenance cost. Visual only — doesn't affect the calculated output.
Power Output
0 kW
% of Rated
0%
Air Density
1.225 kg/m³
Turbine & Site Inputs
Rotor
100 m
3
0.45
Tower
80 m
Power Curve Thresholds — drag the dial, or type a value
3.5
m/s · 0–8
or type:
12.0
m/s · 8–20
or type:
25.0
m/s · 18–35
or type:
Site Conditions
9 m/s
3.5
25.0
9.0 m/s at hub height (80 m)
15 °C
Power Curve — 0 to 30 m/s
Curve: P = ½·Cp·ρ·S·v³, capped at rated power Curve color = zone at that wind speed: Below cut-in Ramping up Rated Cut-out
Original single-point formula reference: rensmart.com/Information/BetzLaw — P = ½·Cp·ρ·S·v³, Cp fixed at the Betz limit of 0.593. This tool keeps that formula for the ramp-up zone, adds an editable Cp for real-world losses, and layers in cut-in / rated / cut-out behavior from standard turbine power curve documentation. "Ideal Conditions" sets Cp to the theoretical Betz limit, cold dense air, and wind speed exactly at your rated speed — the best case your current rotor geometry allows.
Wind Farm Multiplier

Scale the single turbine above into a full farm — enter a turbine count to see total capacity, farm size class, and roughly how much land or sea space that many turbines would need.

Total Rated Capacity
0 MW
Current Total Output
0 kW
Farm Size Class
Approx. Land Area
0 km²
Capacity and output simply multiply the single-turbine numbers above by turbine count. Size class follows common industry framing: small <20 MW, medium 20–150 MW, large >150 MW. Area uses a standard turbine-spacing rule of thumb — roughly 8 rotor diameters between turbines along the prevailing wind direction and 4 across it (wider offshore, where wake losses matter more) — so it scales with your rotor size, not a fixed number per MW. This is a rough footprint estimate, not a site layout; real farms follow terrain, land ownership, and turbulence modelling.
Components of a Wind Turbine
1

Blades

Capture kinetic energy from moving air and convert it to rotational torque. Most utility turbines use three, balancing aerodynamic efficiency, structural cost, and smooth torque delivery.

2

Hub

Connects the blades to the low-speed shaft. On modern turbines it also houses the pitch mechanism that angles each blade to control power and protect the turbine in high winds.

3

Nacelle

The housing atop the tower containing the gearbox, generator, and control electronics that convert rotor rotation into electricity. It can yaw to keep the rotor facing the wind.

4

Tower

Elevates the rotor into faster, steadier wind found at height. Typically tubular steel — its height is often close to the rotor diameter itself.

5

Foundation

Anchors the tower to the ground (onshore) or seabed (offshore). Floating offshore designs use a moored platform instead of a fixed foundation, enabling siting in deeper water.

Turbine Diagram
Types of Wind Turbines
Axis Orientation

Horizontal-Axis (HAWT)

Blades rotate around a horizontal axis facing into the wind, mounted on a tall tower. The dominant design at utility scale — used by both Mersey River Wind and Nova East Wind.

Axis Orientation

Vertical-Axis (VAWT)

Blades rotate around a vertical axis, so the turbine doesn't need to face the wind directly. Less common at utility scale due to lower aerodynamic efficiency; sometimes used in turbulent or urban settings.

Siting

Onshore

Land-based, fixed concrete foundations. Lower installation and maintenance cost — the approach used by Mersey River Wind's 33-turbine, 148.5 MW project near Liverpool, NS.

Siting

Offshore — Floating

Mounted on a floating platform anchored by mooring lines rather than a fixed foundation, enabling siting in deeper water with stronger, steadier wind — the approach proposed for the 300–400 MW Nova East Wind project off Goldboro, NS.

Average Wind Speed by Province
Lower average (<3.5 m/s) Moderate (3.5–5.0 m/s) Highest (>5.0 m/s) No city-level data in source
Province boundaries simplified from OpenStreetMap contributor data (via the click_that_hood open dataset, ODbL) — © OpenStreetMap contributors. Wind speed values are near-surface (standard ~10 m weather-station height) annual averages for one or more representative cities per province, from Environment Canada Climate Normals (1981–2010), via currentresults.com. These are not hub-height wind resource figures — turbine hub-height winds (measured at 50–100 m, e.g. by the Canadian Wind Energy Atlas) run considerably higher, especially at good coastal sites like Goldboro or Liverpool, NS. This map is a general reference only — production estimates in the wind case studies use site-specific resource data, not these city averages.
Canada's Renewable & Emission Goals
Economy-wide target
Net-zero by 2050
2030 interim target
40–45% below 2005
Wind's share of generation today
~8% (2025)

Canada's Clean Electricity Regulations target a non-emitting grid, phasing in through 2035–2050 as part of the legislated net-zero commitment. Wind generation hit a record 50.5 TWh in 2025 — up 10% year over year — and, combined with solar, reached its largest-ever share of total generation.

2025 generation share from Statistics Canada. 2022–2050 projection (Canada Reference case) from the U.S. EIA International Energy Outlook 2023. The 2060 point is an illustrative extrapolation of that trend, not an official government or EIA projection — actual growth depends on policy, grid buildout, and technology costs.
Operating Wind Farms — One Per Province

Not exhaustive — Canada has 300+ operating wind farms. These are each province's largest as a representative sample.

Alberta

Buffalo Plains Wind Farm466 MW

Canada's largest single-phase wind farm, 83 turbines west of Lomond built by Copenhagen Infrastructure Partners, delivering first power to the Alberta grid in 2024.

buffaloplainswindfarm.com →

Quebec

Seigneurie de Beaupré Wind Farms363.5 MW

A multi-phase complex on the Séminaire de Québec's Côte-de-Beaupré lands, co-owned by Boralex and Énergir — one of the largest wind sites in Canada.

seigneuriedebeaupre.com →

Ontario

Henvey Inlet Wind300 MW

Canada's largest First Nation wind partnership, jointly owned by Pattern Energy and Nigig Power Corporation (Henvey Inlet First Nation) on Georgian Bay.

patternenergy.com →

Saskatchewan

Golden South Wind Energy Project200 MW

Saskatchewan's largest wind farm, 50 turbines near Assiniboia developed by Potentia Renewables, powering roughly 100,000 homes.

potentiarenewables.com →

British Columbia

Meikle Wind179 MW

BC's largest wind facility, on Treaty 8 territory near Tumbler Ridge and Chetwynd, operated by Pattern Energy since 2017.

patternenergy.com →

Manitoba

St. Joseph Wind Farm138 MW

A community-initiated project in the Rural Municipality of Montcalm, operating since 2011 and owned by Pattern Energy.

patternenergy.com →

New Brunswick

Kent Hills Wind Farm167 MW

New Brunswick's first wind farm, built in three phases near Prosser Brook by TransAlta with power sold to NB Power.

nbpower.com →

Prince Edward Island

West Cape Wind Farm99 MW

PEI's largest wind farm, 55 turbines near O'Leary built by Engie (formerly GDF Suez), with most output exported via New Brunswick.

bullfrogpower.com →

Nova Scotia

South Canoe Wind Energy Project102 MW

Nova Scotia's largest wind farm, 34 turbines in Lunenburg County co-owned by Oxford Frozen Foods, Minas Basin Pulp and Power, and Nova Scotia Power.

southcanoewind.com →

Newfoundland & Labrador

Fermeuse Wind Project27 MW

One of two operating wind farms on the Avalon Peninsula, 9 turbines near Fermeuse owned and operated by Elemental Energy.

elementalenergy.ca →
Upcoming & Under Construction
Mersey River Wind148.5 MW

Under construction near Milton, NS — 33 turbines developed by Roswall Development. Its retail arm, Renewall Energy, plans to sell power directly to customers, bypassing Nova Scotia Power. First turbines targeted for late 2026.

merseywind.ca →
Nova East Wind300–400 MW

A proposed floating offshore wind project off Goldboro, NS — roughly 20–25 turbines at ~15 MW each, targeting commissioning around 2030. Not yet under construction.

novaeastwind.ca →
Des Neiges Wind Farms1,200 MW (target)

Now under construction in Quebec's Côte-de-Beaupré / Charlevoix region — a Boralex, Énergir, and Hydro-Québec joint project billed as Canada's largest wind energy development to date.

boralex.com →
Status and capacity figures change as projects move through permitting and construction — verify current details on each project's own site before citing them elsewhere.
Formulas Used
1

Power in the wind (Betz's Law)

P = 0.5 × Cp × ρ × A × v³ — power output scales with air density (ρ), swept area (A), and the cube of wind speed (v). Cp is the power coefficient; the Betz limit caps Cp at 16/27 ≈ 0.593 — no turbine can extract more than 59.3% of the wind's kinetic energy, since some airflow must pass through to avoid stalling the rotor.

2

Swept area

A = π × (D/2)² — the disc traced by the rotating blades, from rotor diameter D.

3

Air density (ideal gas law)

ρ = P / (R × T) — P is atmospheric pressure (101,325 Pa, sea level), R is the specific gas constant for dry air (287.05 J/kg·K), T is absolute temperature (K). Colder air is denser and carries more energy at the same wind speed.

4

Wind shear power law

V_hub = V_ref × (H_hub / H_ref)^α — extrapolates wind speed from a 10 m reference height up to hub height. α (the shear exponent) depends on terrain roughness: lower over smooth surfaces like open water, higher over rough terrain like forest or urban areas that create more ground friction and turbulence.

5

Power curve zones

Below cut-in: no output. Between cut-in and rated: output follows the cubic power equation. Above rated: blade pitch holds output flat at rated power. Above cut-out: turbine shuts down for safety.

Assumptions & Limitations
Simplification

Constant Cp

Cp is held fixed across all wind speeds. Real turbines have a Cp curve that varies with tip-speed ratio and blade pitch, peaking near rated speed and falling off elsewhere.

Simplification

Standard atmospheric pressure

Air density assumes constant sea-level pressure. Elevation and humidity both shift real air density, which this model doesn't account for.

Simplification

Fixed shear exponent

The power-law α is a single static value per terrain class. Real shear varies with atmospheric stability, time of day, and season — this is a directional estimate, not a site-specific wind resource assessment.

Simplification

Offshore toggle

Switching onshore/offshore resets α to a typical default and swaps the visual ground/water, but doesn't independently verify site conditions — always adjustable via the terrain dropdown.