California —Solar advocates usually fall into one of two categories: Either you believe that today’s conventional thin films and crystalline PV technologies will enable mass penetration of solar, or you believe that some fundamental technological breakthrough is needed.
Favorable changes in the economics of the current generation of PV technologies is making the first scenario most likely. But that isn’t stopping companies and research teams from experimenting with semiconducting polymers, inks and other materials in the hopes of changing the solar paradigm.
Experimenting in the lab is the easy part. Bringing third and fourth-generation solar technologies to commercial scale and proving them in the marketplace is much more difficult. We held a roundtable at last month’s Solar Power International conference (which you can watch below) on creating a pathway to market for exotic technologies. Here are three key needs for the industry, as outlined by the panel:
Establish Testing Standards
The reliability and testing standards in conventional PV are well-established; not so for organic and dye-sensitized cells. The lack of continuity in testing has allowed labs to publish inconsistent data about the performance of devices. The same is true of companies doing internal testing.
Damoder Reddy, CEO of Solexant, a company producing nano-crystal semiconducting inks, said that the accuracy of reported efficiencies “is all over the place.”
That’s not a good thing for investors who need to be confident in the claims made by companies.
In 2007, a well-respected NREL researcher publicly criticized another researcher at Wake Forest University for using poor testing methods that inflated the efficiency of an organic solar cell by 50%. The disagreement highlighted how differently labs were using equipment and interpreting data.
(Editor’s Note: We originally reported that the solar cell tested by Wake Forest was from Konarka. In fact, Konarka says it has never had any relationship with the lab).
In order to avoid this type of conflict and ensure consistent results, there’s been a greater push to establish a set of standards for equipment and measuring techniques in the organic PV space. Until that happens, investors should examine efficiency and lifetime claims with a very critical eye.
“We need to…compare apples to apples and maintain industry credibility,” said Vishal Shrotriya, director of the Lifetime Project for Solarmer Energy, a company developing plastic solar cells for building-integrated applications and portable electronic devices.
Test Early, Test Often
Getting these nascent solar technologies ready for market is about far more than finding the initial efficiency of the cell; it’s about testing the device as a function of an entire system. You can’t get those results in a lab, said Jennifer Granata, team leader of the PV testing and reliability team at Sandia National Laboratories.
“You need to know how to test, how to test outdoors quickly, and test to failure,” Granata said.
Sandia examines every kind of technology, from crystalline-silicon PV to dye-sensitized thin films. By taking a systems-level approach to testing, researchers at Sandia create models to determine energy production in varying locations, how a system will perform with different components and how long the system will last. Granata calls the performance of third and fourth-generation solar technologies “very mixed.”
While peak and stabilized efficiencies are important, she said, “it’s all about kilowatt-hours. If you can’t get electrons out for a long time, it doesn’t matter how big your manufacturing plant is.”
For example, the leading organic-PV company, Konarka, recently built a 1-GW manufacturing facility for its plastic solar cells. But the market hasn’t demanded anywhere close to a GW of demand. That’s because low lifetimes (a couple years) and low efficiencies (3-5 percent) limit the applications of plastic solar cells mostly to charging consumer electronics and other portable devices. Until organic PV companies can greatly improve those two factors by doing aggressive testing in the field, the market for such technologies will be very niche.
But that might not always be a bad thing.
Find a Niche
Rapid degradation and low efficiencies make most exotic materials uncompetitive with conventional technologies that have proven lifetimes of 25-30 years. Unless, of course, you’re not looking to beat those technologies.
Plastic solar cells and solar inks aren’t going to match up head-to-head with crystalline PV. So rather than try to enter that market, Solarmer’s Vishal Shrotriya said that companies need to exploit the niche they’re suited for. It’s okay that organic PV stays in the realm of consumer electronics and recreational applications if that’s where it works best, he said.
Shrotriya also pointed to the building-integrated market where transparent plastic solar cells could be installed on windows. Assuming an organic PV module lasts 5-10 years (where many researchers think the technology will be in the next 5 years), that could potentially match well with the replacement of windows.
“It’s about finding the right business model for your product. You don’t have to be as efficient or stable to enter the market,” Shrotriya said.
So even if this new generation of solar technologies can’t reach the scale of cadmium-telluride thin film or crystalline-PV in a short time horizon, there are still opportunities for companies to bring them to market.
To hear the full discussion on commercializing next-generation solar, watch the video below or listen to the podcast, linked above.