Yesterday, we reported on Solar Junction's record-setting CPV efficiency levels and we suggested that a fundraising round was imminent. (See below for more details.)

Today, we've learned from sources extremely close to the company that the firm is in the midst of closing a $30 million D round. This is a necessary equity piece to match the potential loan guarantee the company is working on. It has been a strong week for this startup helping to enable the cost-effectiveness of CPV technology. Green Energy Reporter broke the initial news on the funding, which we confirmed with company insiders.

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Solar Junction, the compound semiconductor startup, just set an NREL-validated world-record efficiency of 43.5 percent efficiency for a commercial-ready CPV cell. 

This 43.5 percent number comes just two months after Solar Junction reported achieving an NREL-verified 41.4 percent efficiency, and three months after announcing that 40.9 percent had been achieved. The company continues to raise the bar for CPV, improving the chances for concentrating photovoltaics (CPV).

Modest gains in CPV cell efficiency can translate to significant reduction in levelized cost of energy (LCOE) -- so the increase is not trivial and bodes well for continued progress for the startup and the CPV industry as a whole. And these are not really modest gains -- actually, they border on garish. 

Additionally, the firm is on a short list of finalists chosen for post-selection due diligence within the Department of Energy’s (DOE) Loan Guarantee Program (LGP). The loan would support construction of Solar Junction’s 250-megawatt capacity manufacturing facility in San Jose, California.

Solar Junction expects to begin shipping commercial cells this year.

An investor colleague with deep experience in CPV had this to say: "I think this represents a great validation of Solar Junction's technology platform. The fact that this demonstration is on a production cell rather than small-footprint hero cells is impressive for the company at this stage and means that we can expect more interesting results in the future. Along with scale, cell efficiency is a key driver for CPV costs and can accelerate adoption in the market, as well as increasing reach to high-value, lower DNI areas."

CEO Jim Weldon made a recent appearance at an IBF/Cleanedge venture capital event in Palm Springs -- an indication that the firm is in the market for further VC funding. This was confirmed by GreenEnergy Reporter, which reported that the startup has hired an investment bank to help raise cash. Typically, DOE loan guarantees require a parallel amount of venture funding -- and these achievements don't hurt his chances.

Other developers of CPV chips include established vendors Emcore, Spectrolab, Azure Space  and newcomers like JDSU, Cyrium, Spire, Semprius, and QuantaSol. New CPV system technology has been introduced by REhnu and ZentithSolar.

Draper Fisher Jurvetson, Advanced Technology Ventures and New Enterprise Associates are investors in Solar Junction and have put more than $20 million into the firm.  The startup has also received $3 million from the DOE's solar incubator program.

2011 could be the year that concentrating photovoltaics break through.  Finally.

There is a backlog of CPV projects among system builders Amonix, SolFocus, Concentrix, Opel, and Emcore.  PPAs have been signed by utilities like Southern California Edison for tens of megawatts of CPV power.  

The Technology

The labs at Stanford University are the site of Solar Junction's technology genesis. There, VP of R&D Homan Yuen developed the one-electron-volt (1ev) bandgap platform in a lattice-matched material. Many of the record-setting efficiency cells use metamorphic or non-lattice-matched materials. 

Lattice-matched means that the boundaries of different semiconductor materials, i.e., their junctions, don't strain or shift during operation. It's an indication of the structural compatibility of two materials. Strain at the boundary of the materials can cause dark-line defects and other faults that negatively influence the performance and lifetime of these sophisticated solar cells.

The Value of Efficiency

Efficiency is always important in photovoltaics, but it's probably even more important in CPV.  According to the firm, a one percent improvement in efficiency at the cell level can result in a three percent to four percent reduction in the cost of the system -- and further improvements could improve cost in an accelerated, non-linear fashion.

Jim Weldon, the CEO of Solar Junction said that they were "delivering on the efficiency promise they made when they started the company."  He spoke of an efficiency road map that reaches up to 50 percent in lattice matched cells.

CPV Market Sizing

According to a soon-to-be-released CPV report from GTM Research, annual CPV installations will grow from 2 megawatts in 2009 to 750 megawatts in 2015.  Those numbers suggest that the market will more than double every year for the next six years, growing much faster than the PV market as a whole. If these predictions prove accurate, 750 megawatts of CPV in 2015 would account for about 2.5 percent of the total solar PV market, meaning that CPV would remain a specialized solution suited for locations with poor water resources and high DNI.

This is an aggressive forecast and will require the cooperation of developers and banks in accepting the LCOE and reliability projections of the leaders in CPV. But the recent announcements from SolFocus, Soitec and Amonix seem cause for optimism.

Progress in cell efficiency will absolutely help the CPV cause.