Solar installers and project developers are avidly exploring emerging power electronics technologies, such as microinverters and power optimization through maximum power-point tracking (MPPT). Although these new technologies genuinely increase power harvest in certain solar applications, their low efficiencies and high up-front costs in others have been obscured by hype, according to a new report from Lux Research.
The report, titled, “Shorting Out the Myths of Solar Power Electronics: What Fits and What Fails,” surveys the expanding landscape of power electronics options available to solar installers and project developers, and helps them determine which technologies provide the best performance and lowest cost in residential, commercial, and utility markets.
“Firms offering microinverter or MPPT technology are making expansive claims that their technologies offer benefits across the board,” said Matthew Feinstein of Lux Research, the lead author of the report. “Although the potential benefits of these new technologies are real, their value often depends on the specific size and application of the solar installation in which they’re used.”
In preparing its analysis, Lux Research calculated how various inverters and power optimizer configurations would impact its proprietary levelized cost of electricity (LCOE) model, which offers an apples-to-apples comparison between solar generation costs and those of other power plant types. It then applied its updated model across all three key classes of inverters and power optimizer configurations in each market segment (residential, commercial, and utility) to sort out where they work and where they aren’t worth the extra cost. Among its key findings:
- Smaller solar systems favor increased distribution architecture. Models of performance factor–a measure of the usable power delivered to the grid–indicated that smaller solar applications dramatically favor more distributed-power electronics architectures–giving microinverters an edge. That trend reverses, however, toward the utility-scale side of the spectrum where the sum of losses creates a more favorable market for centralized inversion.
- Cost-of-electricity analysis shows a market awaits every power architecture. LCOE is a metric used to indicate the cost-per-kilowatt-hour of generating power from a given solar system, accounting for the net present value of the up-front cost of the system, installation, and continuous maintenance. Looking at the LCOE for each power electronics option across applications, microinverters appear to be best suited for the residential market segment, string inverters to the commercial segment, and central inverters to the utility segment.
- Installers and project developers emphasize reliability and lifetime. All other factors being equal, installers and product developers considered reliability as the single most important factor in new and old inverter technologies. Inverter efficiency and system performance, however, were close behind. Looking towards the future, cost and ease of maintenance–which aren’t mutually exclusive–are prominent areas for improvement.
Some of the leading microinverter companies closely watched by SB.com for green investing include: Enphase Energy, SolarBridge Technologies, and SolarEdge Technologies.
(correction: While SolarEdge’s module-level MPPT technology makes it a competitor in this market niche, it is not a microinverter company. Installations using SolarEdge technology covert power from DC to AC with a single inverter, after module-level optimization.)
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