A decade ago, entrepreneurs and investors alike believed that silicon wafer-based photovoltaics would soon be a relic. Tens of billions of venture and corporate dollars chased novel technologies that would surely replace silicon — this brittle, inefficient IC-industry material.

Back then, investors along Sand Hill Road, the VC capital of Silicon Valley, invested in the obvious thesis that covering rooftop acreage would best be done with a thin-film deposition, sputtering or plating process — rather than precisely sawing a silicon boule.

Back in the day, investor Vinod Khosla expected silicon vendors to “generally start declining rapidly by 2015 unless they reinvent silicon.” And he expected some “improbable pyro-nano-quantum-thingamajig technology” to emerge to challenge silicon and thin film.

Venture investors at Kleiner Perkins told this reporter that concentrated PV from Amonix would be cheaper than First Solar’s cadmium telluride thin-film panels.

Multi-gigawatt scale solar installations have been hyped by India and Northern Africa. Dozens of failing solar startups aimed for mass deployment of building-integrated PV. Folks in Australia hyped a solar updraft tower, capable of gigawatts of production.

None of this technology innovation happened.

What did occur was a VC-funded solar bloodbath.

Is technology disruption possible in solar power?

What’s the most significant innovation in solar technology or markets over the last year? Over the last ten years?

Thin-film PV? Other than First Solar (First Solar has shipped 25GWDC of PV modules since its founding) thin-film PV is a “rounding error” according to WoodMac Research Analyst, Xiaojing Sun. The long-incubated, thin-film debacle at Hanergy, MiaSole, Alta Devices and Global Solar would be enough to discourage most thin-film startups and financiers. A few thin-film stalwarts such as Solar Frontier and the researchers at Siva Power continue to optimize thin-film material systems.

Concentrated Solar Power? VC-funded Brightsource Energy’s “power-tower” approach to Concentrated Solar Power (with no storage) resulted in a failed IPO from a company unable to compete on price with a natural-gas plant or a photovoltaic power plant.

There are some operating CSP plants in the U.S., but there’s little growth or innovation — and as the price of solar PV-plus-storage continues to drop, CSP will become even less competitive. Several CSP plants are being developed, operated and built in China in parabolic trough and molten salt tower architectures.

Still, a silicon PV wafer and panel factory manager from 15 years ago would recognize most every step and process of today’s production (along with some incremental improvements).

Despite the hundreds of gigawatts of PV panels produced, recent innovation in solar has been limited to monofacial PERC and bifacial panels.

That’s far from the “improbable pyro-nano-quantum-thingamajig technology” we were promised.

A few venture-funded solar successes

There were pockets of innovation in solar over the last decade, but it didn’t happen at the solar module-level.

VC-funded innovation happened in power electronics with SolarEdge’s optimizers and Enphase’s microinverters, which now claim a combined 80% U.S. residential market share. VC investors and early employees actually made money at the profitable and growing SolarEdge, while Enphase survived a near-death experience to reclaim market share and a presence in residential solar.