SiC, GaN lead market for solar inverters

According to the latest report from Lux Research, wide bandgap semiconductors, particularly silicon carbide (SiC) and gallium nitride (GaN), will lead the charge as the market for solar inverter discrete devices. The reason behind this is the strong downstream demand for solar modules that is forecast to grow to $1.4 billion in 2020, indicating a solid seven per cent CAGR growth, slightly lower than the nine per cent for all renewables and grid-based power electronics.

As devices featuring GaN and SiC hit the market, they'll offer the biggest competitive advantage in small systems—microinverters and small string inverters, for residential and commercial solar installations—with a powerful proposition: lowering levelized cost of electricity (LCOE), and increasing margins on electricity sold through leases and power purchase agreements. They also will deliver improved performance and reliability.

"The performance benefits from both are such that inverter suppliers could charge a premium price and still achieve a significantly lower LCOE," said Pallavi Madakasira, Lux Research analyst.

To understand the performance benefits of switching to GaN and SiC, Lux Research analysts modelled the three major types of inverters—microinverters, string inverters and central inverters—with Si, SiC and GaN components.

Lux Research said the power electronics with discrete devices made from GaN and SiC, rather than incumbent silicon, can increase efficiencies for solar micro- and string inverters to over 98 per cent. The diodes increase harvested energy by more than 1.5 per cent while the transistors can increase it by more than four per cent. GaN-on-silicon offers the lowest cost solution while GaN-on-SiC and SiC-on-SiC offer far superior efficiency.

Also, microinverters will command highest premiums. SiC and GaN have the greatest price premium power (>$0.10/Wp) in microinverters, without increasing LCOE. Though a niche solution, the microinverter segment is also an attractive segment for SiC and GaN to see early adoption and ramp up volumes.

GaN and SiC also result in indirect cost savings in the form of a reduced failure rate of passive components, footprint reduction and savings in installation cost. Also, their superior thermal conductivity reduces the size of the heat sink in inverters.

Likewise, after an industry shakeout, companies such as SMA and Power-One that took an early lead in SiC technology are well-positioned with negligible debt. Consequently, start-ups that include Enecsys and mPowerSolar are under pressure to either implement SiC or GaN and absorb the extra cost, or lose their foothold in the market.