Global Emissions, Swept Away by Wind Power

In 2023, the world’s cumulative installed wind power capacity passed the 1 TW (1,000 GW) landmark for the first time. It was a record year, with 113 GW of new wind power capacity connected to power grids, the majority in China (76 GW). There are now ten countries which generate more than 20% of their electricity from wind power.

The demand for wind energy continues to grow rapidly, from 8% of global electricity generation in 2023 to a predicted 14% in 2030, according to the IEA. While there are economic, regulatory and supply chain challenges to overcome, investment in wind is strong around the world, and ambitious targets are looking achievable.

The key to efficient power conversion

Power conversion is required in a wind turbine, since it typically generates variable frequency alternating current (AC) electricity, which is first rectified to direct current (DC), and then subsequently converted to high voltage AC at a frequency and voltage compatible with the grid.  

It’s a booming sector – according to Yole Intelligence, the market for power converters for wind power will grow at a compound annual growth rate (CAGR) of 10.4% from 2022 to 2028.

To maximise their output of useful energy, wind power systems need this power conversion to be as efficient as possible. To achieve this, there is an increasing shift to use wide bandgap (WBG) power semiconductors to handle switching in the turbine’s inverter, rather than the traditional silicon IGBTs.

While silicon has been the material of choice for switching in inverters for decades, its limits are now being reached – and Wide Bandgap devices are taking up the mantle of the drive towards ever-higher efficiency.

SiC vs IGBT in wind power

The two most commonly-used WBG semiconductor materials are silicon carbide (SiC) and gallium nitride (GaN). They both provide fast switching and excellent efficiency, but SiC is often a better choice for wind power.

Why is SiC preferred? It provides the capability to operate at high voltages and high temperatures, making it an excellent fit for use in wind turbines. This is particularly true in large, utility-scale installations where voltages are typically above 1000 V.

SiC-based devices reduce switching losses in the inverter, compared to silicon IGBTs. SiC also provides lower turn-on, turn-off, and conduction losses than silicon. The losses experienced, and their relative size, do depend on the load on the power converter, which in turn depends on the wind’s speed. By varying the switching frequency as a function of wind speed, efficiency at low loads can be maximised.