The Intersolar Exhibition in Europe is in full swing this week, and that means it's prime time for new solar products. This year's exhibition featured 2,200 exhibitors from around the world, more than 75,000 visitors, and 200 speakers. We don't have room to cover everything, but here are a few highlights from the industry this week.

  • SunPower (Nasdaq: SPWRA) announced the first commercially available solar panel with 20% efficiency. The E20 series panels are 96-cell panels using SunPower's 22.4% efficient Maxeon cells. The panels will be available in Europe and Australia this year and extended to North America and Asia in 2012.
  • Power-One (Nasdaq: PWER) unveiled four new inverters for the renewable-energy market. They include the Aurora Micro-0.3, the company's first microinverter.
  • Suniva introduced Optimus modules, which deliver efficiency of 16%. That threshold falls behind SunPower but leads most Chinese manufacturers and are "Buy America" compliant.
  • Last but not least, away from Intersolar, First Solar (Nasdaq: FSLR) met a major milestone, passing 4 GW of thin-film modules manufactured.

Suntech Power (NYSE: STP), Trina Solar (NYSE: TSL), and JA Solar (Nasdaq: JASO) also announced new products, which I covered earlier this week. Overall efficiency was the theme of the week, with many companies announcing new, more effective products.

In the past, falling silicon prices led to much of the cost-per-watt improvement in solar panels, but with the low-hanging fruit having already been picked, cutting costs now comes down to who can be the best innovator. SunPower is out ahead of the pack on efficiency, but Chinese manufacturers are slowly starting to improve on their products and catch up, as we've seen this week.

In the coming year, we're likely to see companies turning their attention from expanding capacity to squeezing more MW per dollar out of each line. The announcements this week were one small step in that direction.

Fool contributor Travis Hoium owns shares of First Solar and SunPower. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings , or follow his CAPS picks at TMFFlushDraw.

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