Inverters’ importance in the solar market has only been emphasized by the oversupply and price pressure that has driven down the cost of components around it. Suppliers are doing their part to reduce costs as well, with incremental improvements in efficiency and component count reduction, but the holy grail for solar inverters is the implementation of wide bandgap semiconductors – specifically, silicon carbide (SiC) and gallium nitride (GaN). They offer the promise of higher efficiencies, as well as superior thermal management – critical for temperature-sensitive applications such as solar inverters. GaN and SiC offer indirect cost savings in addition to direct performance benefits – superior thermal conductivity of SiC over Si reduces the size of the heat sink in inverters. Higher switching frequencies of SiC and GaN reduce the failure probability and count of passive components, while high power density enables footprint reduction and installation cost savings. The question is, what is the opportunity for introducing diodes and transistors using these higher cost, but higher performance materials?
Microinverters offer the best absolute $/W premium for SiC or GaN diodes with Si transistors (SiC + Si, and GaN + Si, respectively) and represent the ideal niche entry for these devices in the residential segment. However, string inverters are the most attractive segment for price premiums relative to silicon with the introduction of SiC and GaN transistors in addition to diodes. Acceptable string inverter price premiums of all-GaN and all-SiC systems versus all silicon top $0.10/Wp in the residential market segment enabling price premium of greater than 20% relative to silicon-based inverters. Importantly, string inverters enable ready access to the growing commercial and residential segments, delivering both volume and price in the two segments set to dominate new solar installations in the developing world for the coming years.
Notably, SiC diodes are already hitting the market through microinverters. As GaN diodes and SiC and GaN transistors become more commercially available, they should take the same path – and will have a similarly beneficial impact, while enabling discrete device developers to penetrate the large-scale inverter market at a healthy 10% price premium. As devices fully featuring GaN and SiC hit the market, they’ll hold the biggest competitive advantage in small systems – microinverters and small string inverters, for residential and commercial solar installations – with a powerful proposition: lowering the levelized cost of energy (LCOE) and increasing margins on electricity sold through PPAs.
The race is on to position for technology-driven differentiation in these growing markets. Little surprise to see inverter mainstay Advanced Energy acquire REFUsol on this basis given the latter’s valuable SiC-based inverter IP and products. Though the payback will take some time, the $77 million Advanced Energy paid for that IP will look like a bargain down the road. Others would be wise to take note of this and ABB’s similarly SiC-related acquisition of PowerOne and act accordingly.
Source: Lux Research report “Reaching for the High Fruit: Finding Room for SiC and GaN in the Solar Inverter Market” — client registration required.
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