New ‘Rock Candy’ Process To Manufacture Silicon Could Make Solar Power Even Cheaper

By Tina Casey Via Clean Technica

Researchers at the University of Michigan have come up with a low-cost way to manufacture high-grade silicon, based on a concept familiar to anyone who has tried to make rock candy at home. If the breakthrough can be translated into a commercially viable process, it would make ultra-cheap solar tech like V3Solar’s Spin Cell (which we were just raving about the other day) even cheaper.

Ironically, funding for the research project came from the American Chemical Society Petroleum Research Fund, but maybe they know something we don’t.

Cooking Up a Batch of Low-Cost Silicon

Silicon is the key component of conventional solar cells. It comes from silicon dioxide, aka sand, which is one of the cheapest and most abundant materials on Earth, but converting sand into high grade silicon is a high cost, energy intensive process with a pretty significant carbon footprint.

As described by U of Mich writer Kate McAlpine, the new process works at just 180 degrees Fahrenheit, which is a far cry from the 2,000 degrees needed for conventional silicon manufacturing.

The method basically consists of covering a liquid gallium electrode (gallium is a soft whitish metal that has a melting point around room temperature) with a layer of a solution based on silicon tetrachloride (a colorless, flammable liquid).

As in conventional silicon processing, electrons from the metal convert the silicon tetrachloride into raw silicon. The new twist is that by using soft metal with a low melting point, the research team was able to get the raw silicon to form crystals without exposing the solution to additional heat.

A Ways to Go for Low Cost Silicon

The team has observed films of silicon crystals forming on the liquid gallium electrodes, but so far the individual crystals are only about 1/2000th (yes that’s 1/2000th) of a millimeter in diameter.

There is still a long way to go before the process jumps from the lab into commercial viability, and the next steps include experimenting with other metal alloys that have low melting points.

Meanwhile, other routes to low-cost silicon based solar power are at or near commercial development, and they could go even lower if the U Mich research pans out.

One approach, illustrated by the aforementioned V3Solar Spin Cell (which by the way began life as Solarphasec), is to squeeze more power out of conventional solar cells by reconfiguring the solar module.

The Spin Cell reboots the typical flat solar panel into a 3-D cone. Along similar lines, MIT researchers have come up with a solar “tower of power” that takes advantage of 3-D angles.

The 3-D concept can also be internalized, as demonstrated by a company called (what else) Solar3D.

On a completely different note, the Obama Administration is also focusing on lowering the “soft costs” of solar power, which typically account for half the cost of a completed solar installation.

The Petroleum Research Fund

Well, here’s hoping. In any case, the really interesting part of the story is the involvement of the Petroleum Research Fund, which states at the top of its home page that its mission is to support “fundamental research directly related to petroleum or fossil fuels.”

In its vision statement following that declaration, the Fund waxes a little more expansive, describing itself as dedicated to “significantly increasing the world’s energy options,” though directly after the following note appears: “Proposals will no longer be considered in solar power, which includes photovoltaics and solar cells.”

Apparently the U Mich project got in under the wire, but it shouldn’t be surprising that a grant-making organization with roots in the petroleum industry was at least once open to solar power research.

Solar power has long been used as an economical way to provide energy to remote oil fields, where grid connections would be difficult if not impossible.

Given the energy intensity of harvesting unconventional oil, most notably from Canada’s tar sands, low-cost power in any form would be a welcome development for the petroleum industry.

Tina Casey, reprinted from Clean Technica with permission

15 Responses to New ‘Rock Candy’ Process To Manufacture Silicon Could Make Solar Power Even Cheaper

  1. rollin says:

    Now we need a way to get past the energy intensive reduction step.

  2. Paul Klinkman says:

    It’s nice that people are doing basic research, several years away from a product.

    When they get to product development, where we want them to get, they’ll discover that most of the cost of a photovoltaic system is the labor of putting it on the roof, of taking it off the roof to fix the roof, of replacing the PV panels. There’s the cost of getting the electrician to check their work so that the system doesn’t give off fatal shocks or blow a fuse. Then there’s the cost of successful weather encapsulation of silicon for 20 years or more. So, we’re grateful if the total cost of a PV system drops 10%.

    We need training/safety for affordable roof laborers and electricians. We need every other piece of the system to get rated. This is the 90% of the cost that can be driven down more quickly.

    Finally, we need power storage for nighttime electricity. You’ve heard of turning on the electric light at night. We want nearly 100% replacement of fossil fuels with solar. 30% isn’t good enough now.

  3. I am certain that the Koch brothers are thrilled.

  4. Tim says:

    ACS-PRF grants have long been disconnected from “petroleum research”, since you asked. They are intended mostly for basic research – so my suspicion is that this might just be the U of Michigan’s PR department trumpeting results that are very far from ready for deployment.

  5. Artful Dodger says:

    Deposit the pure silicon on the inside of a fiber optic tube. Use light-collecting mirrors to funnel adequate photons into the fiber optics. Run the fiber optic cable to a battery or other load device. Original idea Copyright (C) claimed by me, 2013.

  6. Dennis Tomlinson says:

    Questions and comments (submitted in hope of attaining co-inventer status on your patent submission): Do you mean silicon dioxide (glass) instead of “silicon”. I once worked with (not for) a company whose specialty was remote detonation of explosives via huge pulse of light conductec down a fiber optic cable. I believe the light source was a He-Ne laser very tightly coupled at the launch end of the cable. Light collection and launch via mirrors is going to be quite a challenge, as typical fiber diameters are measured in microns. Another issue is that lossless (perfectly pure) fiber optic cable is not yet possible. Additionally, the reflective cladding that coats the core must be 100% reflective to prevent leakage – also not yet feasable. The heating effects of cable losses would be problematic. The explosives company got away with it because their light pulse was short and intermittently applied. At the receiving end, I’d suggest diffusers illuminating PV panels directly. But again, losses and the resultant heating will be issues to be dealt with. Rolling up my sleeves; resumé available upon request.

  7. Dave Bradley says:

    Eeks! Don’t they ever use fact checking anymore at Clean Technia?

    Silicon Tetrachloride (SiCl4) can even be handled in a pure oxygen atmosphere. SiCl4 is made by burning elemental silicon in a chlorine atmosphere. It is not flammable, unless you have a fluorine based atmosphe, and then it will burn to make SiF4 and Cl2. And that is unlikely to be a frequent event. SiCl4 is, however, hydrolytically unstable and reacts energetically to form HCl and silica (SiO2) on contact with water, including any moisture in the air.

    Even if you had slaves and free electricity/raw materials to make the solar cells, PV power is still going to be really expensive. The bulk of PV costs in the US are with the installation, and that is running about $4/kw of capacity. The PV panels are going to cost around $1/kw of capacity to make, assuming those making the units want to actually not lose money and at least want to make a modest profit. Last year, essentially no manufacturer made any money anywhere in the world, but especially in the US and Europe. And how people expect to have a multi-billion or multi-tens of billions of dollars in annual sales but yet make no profit is a mystery to many……

    So what if PV sourced electricity is never cheap (and try using regular priced electricity to make them and not ultra-subsidized coal, hydro or nuke based electricity – see what that does to production costs)? Maybe you can learn to live with that, and with unsubsidized PV electricity, too. Most of Europe does, especially Germany. What is it with so-called environmentalists that they insist on being energy welfare queens, just like the coal and nukes users? Will they ever grow up?

    Far more important than the technology to manufacture these systems is a sane renewable energy pricing system that actually creates a demand for viably priced renewable electricity. Why is that so hard to get?

  8. Jay Alt says:

    They are rather late to the party. It does sound like a PR piece to tout research. Cheaper technologies already exist to support the global solar build-out. e.g.

    Value Chain Activity: Producing Polysilicon
    Analysis of market, competitors, prices and processes, ~2011)

    Producing Poly-Silicon from Silane in a Fluidized Bed Reactor
    (Ydstie & Du @Carnegie-Mellon 2011 Review)

  9. Oro Lee says:

    “Ironically, funding for the research project came from the American Chemical Society Petroleum Research Fund, but maybe they know something we don’t.”

    Who would own the patents? Would they license them?

  10. Omega Centauri says:

    Well you can find panels for as low as $.65/watt. I am in partial agreement, I don’t think roof mounted small scale PV will ever be cheap, although the German’s are approaching $2/watt total system cost. Utility scale ground mount installations may come in at half that. I think the greatest amount of PV that we will build will be utility scale ground mount plants. But they should soon be affordable. Large size amortizes the soft costs (paper work, inspections, etc.), and is rapidly becoming economically competitive.

  11. Omega Centauri says:

    If you take a techno-economic perspective, affordable solar could be good for oil in the long run. The oil age will end when the cost of oil (including the energy cost to get ever more marginal deposits out of the ground), exceeds its benefits. With cheap solar, we could relegate oil to specialty, and backup purposes, which could command a premium price that we would never be willing to pay if oil were still a primary energy source. I don’t think these guys need fear solar.

  12. Dave Bradley says:

    Oil is a liquid fuel – it is transportation energy, and a highly dense form of stored energy. PV is electrical energy, and on an unsubsidized basis, quite expensive, compared to other forms of non-pollution sourced electricity, or other transportation fuels. Very little electricty presently is used for heat, and even less for transportation for some time, though that presumably will gradually change. You are likely to see electricty used to power trains, subways, trolleys, some city buses, and some urban car diving. But because of the high cost of PV electricity, it won’t be used to make Hydrogen which can be used to make fuels by reduction of biomass, CO2 or N2. PV is just too expensive for that in the US, and wind is much cheaper as an electricty source on a real (as opposed to subidized) basis. Things like H2 production consume massive quantities of electricity, and the cost of that electricity determines the cost of the H2, which then determines the cost of the fuels made from that H2. At best, it’s about 21.2 kw-hr per lb of H2 made, and probably 22 kw-hr/lb of H2. And that’s where real costs and real prices of electicity become important, or at least noticeable…

  13. We’ve been living off grid with pv as our power source since 1984…we do not ‘do without’.

    We’ve more than recouped the costs of our system many times over…and have yet to need to ‘decommission’ any panels, even the ones which had been previously decommissioned from the Carrizo Solar plant in California we got from Steve Baer nearly three decades ago.

    Battery technology is what I’m interested in having real progress in…we are excited about the prospects of the flow batteries.

  14. Dr.A.Jagadeesh says:

    Rapid developments in increasing the efficiency of solar cells. This is exciting.
    Dr.A.Jagadeesh Nellore(AP),India

  15. Photon says:

    Regarding the V3Solar… please do not “rave” about it. That company has been kicking around for years, making bizarre promises using suspect figures.

    It’s “chief inventor” has zero prior experience in PV or anything related to it.

    The entire rotating solar cone concept is overly complex, poorly thought out, and utterly pointless.

    I’m disappointed Cleantechnica even did a piece on them.