September 22nd, 2015 by William Steel
Danish wind giant Vestas have introduced a new turbine engineered for high performance at low wind speeds — the V136-3.45 MW.
According to Vestas, the technologies engineered into its new turbine enable it to increase annual energy production by more than 10% compared to its predecessor, the V126-3.3 MW. More important yet is that these improvements will hold for operations even in low-wind environments.
Efficient operation at low-wind sites is a major catalyst for development in today’s wind industry because it opens up new frontiers for installing wind power. But there are challenges. A key obstacle is that at low wind speeds there isn’t sufficient torque on turbine blades to make them rotate and generate electrical power, leaving the turbine uneconomical.
In acknowledging this problem — and the market opportunities that low-wind sites represent — wind turbine manufacturers like Vestas have engineered solutions which enable what wind is available to be harnessed. The minimal wind speed at which turbines can begin operating is referred to as “cut-in speed” — for most machines it’s around 4m/s. Vestas’ new turbine has a cut-in speed of just 3m/s.
Breaking Down the Technical Features
The V136-3.45 MW features Vestas’ largest onshore rotor diameter of 136 meters, and a swept area of 14,527 metres-squared. Swept area is the area of the plane through which blades travels as they rotate, and it’s a critical value in determining the power that a wind turbine produces.
Vestas note that “advanced aerofoil blade design” is a key feature of the new model. This is a reference to the aerodynamic profile of the blades; a subject of major research in an effort to produce blades which respond as efficiently as possible to winds.
“Aerofoil” simply refers to a curved surface designed to produce a preferred ratio of lift to drag — where lift is one of the principal forces that make wind turbines work. Blade aerofoils are highly variable across the wind industry, and there’s not one ideal design. Rather, different designs are deemed more suitable to particular wind environments, or favoured due to their implications for the rest of the turbine architecture.
The aerofoil of each of the V136-3.45 MW’s three 66.7 metre blades, in particular the blade tip profile, are key to its ability to harness slower winds.
Vestas have also made note of the claim that the turbine operates with significantly reduced noise compared to its other models — an important factor for consideration in the context of onshore wind projects.
Alongside these technological advances, there’s good reason to anticipate the new turbine will be successful. Much of its architecture, including its nacelle and hub design, is based off of Vestas’ 3 MW platform — the company’s proven and versatileportfolio of varied 3 MW turbines. With collective installations around the world on both land and at sea totalling close to 7 GW, it’s Vestas’ most popular platform with a strong track record of success.
The first V136-3.45 MW turbine will be installed sometime in 2016 at the Østerild National Test Center for large turbines in north western Denmark. Thereafter, Vestas expect to be ready for production in the second half of 2017.