The Coolest Solar Manufacturing Technology You’ve Never Heard Of: The Optical Cavity Furnace

by Sean Pool and Lauren Simenauer, in a Science Progress cross-post

Too often, when talking about research and innovation on clean energy technologies, policymakers, pundits, and the media tend to assume that the biggest breakthrough will come from a completely novel technology. The discovery of some new and sexy clean energy technology will suddenly change the game and make clean energy abundant and affordable overnight.

In practice that rarely happens (see “The breakthrough technology illusion“). A more likely scenario is that humble, behind-the-scenes “process innovations” will continue to increase the efficiency and drive down the costs of manufacturing the technologies we already know work.

The Department of Energy has recently completed testing on just such a humble breakthrough. The Optical Cavity Furnace is a new piece of equipment for making solar cells that is about to rock the photovoltaic industry by slashing costs and increasing efficiency. The news should not just excite tech nerds—by reducing the cost of producing solar cells by nearly three-quarters, this new technology represents another big step on the path to making clean energy the cheap kind of energy.

Here’s how it works.  By using optics to more efficiently focus visible and infrared light, the Optical Cavity Furnace can heat silicon wafers used in solar cell production much more precisely and uniformly than previous forms of solar cell manufacture. The resulting solar cells are stronger, more efficient, and have fewer impurities. The National Renewable Energy Lab, or NREL, the DOE office responsible for the research, and a corporate partner AOS Inc. are now working to bring this technology to scale. The partners plan to build an industrial-scale Optical Cavity Furnace capable of producing 1,200 highly efficient solar cells per hour. NREL has cooperative research agreements with many of the country’s biggest solar cell producers.

Even better, in addition to producing solar cells more reliably, quickly, and therefore cheaply, the Optical Cavity Furnace itself is cheaper than traditional equipment used to produce cells. As the cost of manufacturing solar cells goes down, elementary economics suggests the accessibility of solar cells will soar.  Then it’s a matter of harnessing their power in a myriad of other industries in a clean energy domino effect.


The White House has challenged the solar industry to produce clean electricity at $1 per watt. It has also set a national goal to achieve 80 percent clean energy use by 2035.  Though some tout the idea that radically new breakthroughs in energy technology are needed to achieve these goals, incremental process innovation in existing technologies is perhaps a more important part of the solution. Innovations like the Optical Cavity Furnace that make the technologies we already know about cheaper, easier to produce, and more abundant can have game-changing impacts on bringing clean energy to scale.

The concept of “grid parity”—the point at which generating electricity from alternate energy sources is equivalent in cost to generating electricity from grid power— is one key factor in enabling a massive uptake of solar. The good news is that researchers are racing toward that goal at an impressive rate.

In fact, the cost of photovoltaic, or PV, modules had already fallen 50 percent in the past two years prior to the DOE announcement.  A June 2011 projection predicted PV module prices would hit the goal of $1 per watt by 2013; now the finish line of the proverbial “race to the bottom” seems even more imminent.

For consumers weary of the daily media promises of a cure-all solution to climate change, consider this: Deflating prices of solar cell manufacturing mirror the downward price slope of other technologies we now take for granted, like cell phones and DVD players. One important driver of those price declines is the process innovation. And the government, instead of being an obstacle to competition, is uniquely poised to foster it, as evidenced by the new DOE solar furnace. In addition to the work being done at the Department of Energy’s National Renewable Energy Laboratory, dozens of other federal labs across the country under the DOE Office of Science, the National Institute of Standards and Technology, and the Manufacturing Extension Partnerships are helping push the bounds of process innovation in clean energy manufacturing.

The notion that science or innovation alone can solve our energy and climate challenges may seem over-simplistic.  Yet new technologies like the Optical Cavity Furnace are piling up, creating a stronger and stronger rationale for increased federal investment in innovation.  Through process innovation, we increase efficiency and lower costs, virtually negating the common arguments against climate-conscious energy policy. Consumers still make energy choices based on the impact those choices have on their wallets rather than based on the impact they have on the environment. With a vibrant national research ecosystem that fosters process innovation, before we know it, more and more consumers will be choosing clean energy — not because it is the socially conscious choice, but because it’s the cost-effective choice.

— Sean Pool is the editor of Science Progress; Lauren Simenauer is an intern with Science Progress. You can find the original post and more great content on science and technology at the Science Progress website.

14 Responses to The Coolest Solar Manufacturing Technology You’ve Never Heard Of: The Optical Cavity Furnace

  1. sydb says:

    Nice to see more good news. As solar advances, let’s hope it can eventually blow off the Koch-bought congress.

  2. Mike Roddy says:

    Thanks, Sean, this could be really important.

    Will the process be patented and licensed, or can anyone build per the NREL design? Who is corporate partner AOS?

    I’ve been around solar long enough to remember BP moving into the market in the late 70’s (I worked for Alten Solar of Mountain View at the time, a high tech panel startup). BP kind of screwed around with fancy PV troughs for a while, pretty much sticking to demo projects, and then abandoned it.

    Taxpayers funded this research. All results and implementation need to be in the public domain. Can you verify that this will happen?
    You can either answer here or via private email.

  3. dick smith says:

    If you want to see just how true this is, read today’s NYT.

  4. Ormond Otvos says:

    It won’t do any good to make the panels cheaper if the savings just increase the profit of the installers. There also needs to be big pressure to allow them on roofs without $5k in permits, fees, inspections, etc for what is becoming an appliance.

    Engineering studies to verify a roof is strong enough to hold panels that weigh far less than the people walking around on the roof? Really?

  5. Mike Roddy says:

    You’re right, Ormond. Panel costs for a home installation are only roughly 30-45% in California.

    Roofs are normally designed to take at least 15 lbs/sq.ft live load. Even if the house has concrete tile, that should leave plenty of capacity for the panels. Solar companies should do their homework for plan checkers, who may be operating out of ignorance.

  6. Bill G says:

    What about Thorium powered reactors? Cheaper, more plentiful fuel, less problems with radioactive waste by far, a tested technology. Small thorium reactors perfect for third world locations. (no terrorism threat).

    Do you know who Alvin Weinberg is? A brilliant man who ran Oak Ridge for years. He developed a thorium reactor that worked well.

    This genius spelled out global warming and its consequences long before anyone else. He feared it and said it could end life on earth. Read Weinberg and be amazed.

  7. lizardo says:

    Thanks Sean/Lauren/Joe for this. Amazing. And cheering.

    As for comment #4: Did you even read this post? Do you even know what thorium is and the energy balance involved in this always-in-the-future “breakthrough technology” ??

  8. Mulga Mumblebrain says:

    Bill, if we do renewables correctly, thorium reactors won’t be necessary.

  9. Great news here. Thanks for sharing it. Solar should be required on new build in anyplace sunny enough for it to make sense! Which means just about all the populated parts of my state, California…

  10. Jeff says:

    Two things to keep in mind, although this technology seems awesome:

    1. Most of the cost of PV is associated with installation, not manufacturing.

    2. PV module price decreases are a result of cost pressure from China & Taiwan, not necessarily from new tech innovations or any significant industry advancements. Not saying that new tech doesn’t help, but the current trend can’t be attributed to it and it probably won’t be sustained.

    Just my two cents.

  11. Jay Alt says:

    Thanks Sean and Lauren. The article should make clearer that this is a screening step to weed out potentially defective cells much earlier in manufacturing.

    The partners plan to build an industrial-scale Optical Cavity Furnace capable of producing 1,200 highly efficient solar cells per hour.

    The furnace does not produce the cells itself, as the sentence above suggests.

  12. Eric Ingram says:

    I thought First Solar already had their manufacturing costs down to 75 cents per watt. So whats this about not hitting the $1 mark until 2013 or is the $1 goal the price to consumers?

  13. Sean Pool says:

    Thanks Jay for pointing that out. You’re right we didn’t do a great job of explaining exactly what roll the OCF plays in the manufacturing process.

  14. john searles says:

    great news – looking forward to going solar!