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Solar Startups Stepping Forward

Posted February 08, 2012 9:30 AM by cheme_wordsmithy

The prospect of solar grid parity is becoming more of a reality every day. In 2010, the LCOE (levelized cost of electricity) for PV solar was $.150/kwh, fairly close to other sources - nuclear is $.10, coal is $.08, and natural gas is $.064.

Particularly responsible for this movement is the significant drop in the cost of manufacturing solar panels. Currently, commercial plants can produce electricity at $3.00 to $3.50 per watt, with solar panels attributing only a third of that cost.

<--Image Credit: ArrayPower

But the drive continues for solar companies to bring prices down and efficiencies up. In the past month, three startups have taken some steps towards further advancement of this technology.

From Sawing to Peeling

Conventional silicon solar manufacturing can produce three solar-cell wafers from a millimeter of silicon. It requires sawing blocks of crystalline silicon into wafers around 180 micrometers thick. This cutting technique produces silicon sawdust equivalent to a 100-150 micrometer layer. The sawdust is discarded as waste in most cases.

Astrowatt is a startup company looking to reduce the amount of wasted silicon, which is still the most expensive item for solar-panel manufacturing. Its new process saws wafers nearly a millimeter thick, and then modifies the top of each wafer to act as a back of a solar cell with a later of metal deposited on it. The wafer is then heated, causing stress and cracking from expansion. From this, the engineer can peel off a 25-micrometer silicon-metal film. The end result is multiple thin films and a thicker one which can be recycled back into the process.

The metal backed film (shown right - Credit: Astrowatt) is said to be more durable than past attempts to make thin wafers using other methods. However, the films tend to curl up slightly, which could present difficulty in handling during production. This could be detrimental to the feasibility of this process, since current machinery is built for stiff/flat cells.

A Simpler Inverter

Current large-scale solar plants use either a single "central" inverter or a number of "string" inverters to convert from DC (from solar panels) to AC (grid-ready power). Both approaches suffer lower efficiencies because the connection limits the output of the system to the level of its lowest-producing panel.

ArrayPower is a startup company seeking to maximize power through the use of a new inverter mounted to each panel. Microinverters, which are similar in function, maximize the output of each cell, increasing system output from 3 to 10 percent. They are typically more expensive, however, and yield single-phase current which is only suitable for residential use.

The new "sequenced" inverters are of a more simple design and utilize the system to carry out the filtering and smoothing. The creation of three-phase current rather than single-phase allows the inverter's to store smaller amounts of electricity for shorter durations. This means cheaper and longer lasting inductors can be used in place of capacitors for energy storage. Experts say that the technology, though promising, needs longer field trials to test the long-term durability of the devices.

Smaller Is Better

While most solar cells are made from silicon, a better absorbent used in smaller cells is gallium arsenide. But the costs of this material - along with required optics, cooling systems, and tracking systems - make concentrated solar modules much more expensive.

Semprius, a startup attempting to lower these costs, boasts that its miniscule solar cells are much better at dissipating heat, making them much cheaper. Third-party tests have also certified the concentrated solar panels at 33.9 percent efficiency, making them the most efficient commercially designed solar panels to date. Conventional silicon panels convert less than 15 percent of light into electricity.

Shown left is an array of solar modules on a two-axis solar tracker, built by Semprius for testing. (Image Credit: Semprius)

The production process forms tens of thousands of tiny solar cells on a single wafer of gallium arsenide. Then chemical etching and a robotic system transfer each layer to an inexpensive substrate. The same wafer is used many times, reducing costs and making the concentrated module more attractive.

However, other important factors regarding the technology were not mentioned, including the expected lifetime, the transportability, and the fragility of the new design.

Looking Forward

The solar industry, which is going on 20+ years of experience with silicon cells, proves that it takes a substantial amount of time for new technologies to develop to a competitive level. The energy industry cannot expect one breakthrough technology to solve all the problems of tomorrow's "energy crisis". It's the little steps made over time that will make the difference.

No doubt some of these startups may fail with oversupply and reduced manufacturing costs, but ultimately my hope is that solar power technology will continue to grow on its own and make a noticeable impact in both the residential and commercial sectors.

Sources:

Concentrated Solar Startup Sets a New Efficiency Record

Technology Review - Device Could Drive Down Solar's Cost

Technology Review - Startup Makes Peel-Off Solar Cells

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#1

Re: Solar Startups Stepping Forward

02/08/2012 10:24 AM

At $.15 per kWh that is much closer to twice the price than fairly close to equal.

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#2
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Re: Solar Startups Stepping Forward

02/08/2012 11:45 AM

Very true. In addition I understand that the LCOE is quite variable depending on what assumptions are made and where the numbers are taken from, so a true cost comparison is hard to make. These numbers were from the California Energy Commission, taken from this site.

Safe to say however that from an affordability standpoint, solar is much closer than it used to be, which is encouraging.

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Re: Solar Startups Stepping Forward

02/09/2012 9:48 AM

This is all good news. I'd like to see more work being done on the small residential units..............small, efficient, affordable. It would be nice to be able to cut the cord in my lifetime.

What is .15 per kWh based on? The cost of the unit? Is it based on the projected lifetime of the unit?

The solar industry, which is going on 20+ years of experience with silicon cells, proves that it takes a substantial amount of time for new technologies to develop to a competitive level. The energy industry cannot expect one breakthrough technology to solve all the problems of tomorrow's "energy crisis". It's the little steps made over time that will make the difference.

No doubt some of these startups may fail with oversupply and reduced manufacturing costs, but ultimately my hope is that solar power technology will continue to grow on its own and make a noticeable impact in both the residential and commercial sectors.

Thanks for that. I think solar is incrementaly going to get better and better over time................through the free market, and driven by profit potential. New technology cannot be forced or mandated.

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Re: Solar Startups Stepping Forward

02/09/2012 10:07 AM

[Edit]

Before someone yells at me. I definitely think that the government should be involved.

Limited grants given to promote research and developement of promising technology.....................on a small scale. No launching private companies!

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#6
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Re: Solar Startups Stepping Forward

02/09/2012 1:25 PM

To answer your question, kramarat, the basic math behind the .15 kWh LCOE is (Life cycle cost) / (Lifetime energy production) for the utility/unit in question. In this case, the study is for utilities, not residential solar use. The costs include capital, operation, labor, depreciation, and residual (no subsidies which would skew comparisons). If you want the full summary look under the Utility Cost of Electricity section of this page.

For the details of the LCOE comparison, the page points to this this article, published in 2010. I found it particularly interesting that the author estimates prices for solar will drop dramatically once loans for new facilities are fully paid off (see page 3 and 4). He assumes a 6% loan rate for startup utilities of all types, even though solar generally comes out ahead since there is less risk involved and less dependency on outside factors (fuel prices).

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Re: Solar Startups Stepping Forward

02/09/2012 2:00 PM

Thanks. I feel confident that that number will come down substantially with time. There's so much incredible stuff being worked on that it's impossible to keep up with it all.

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Re: Solar Startups Stepping Forward

02/09/2012 11:46 AM

There are excellent web sites that give you information regarding your local solar insolation. The proponents of PV always like to give you the performance data from the Mojave desert with dual axis tracking controllers in the summertime. Not exactly Joe Schmoe's roof top in Minnesota in January. As with EPA mileage, your results may vary.

http://eosweb.larc.nasa.gov/cgi-bin/sse/sse.cgi?+s02#s01

http://www.anotherurl.com/therm/sol_calc.htm

http://www.nrel.gov/gis/solar.html

Keep in mind that these kilowatt values represent the total broad spectrum energy NOT what a 5-8% efficient PV panel will produce.

I guess my point here is that any wise person will do their due diligence and research the true performance of any system, renewable or otherwise for their particular location and application and make the choice that suits them best. For some people it is a question of economics, for others it may to be assauge their perceived guilt or to make a socio-political statement.

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#8

Re: Solar Startups Stepping Forward

02/09/2012 5:51 PM

I still don't understand why we aren't using the sun to heat water and put this technology to use. This has been on these pages a couple of times, I've asked the question and never got an answer. No solar cells necessary, and a relatively small amount of natural gas, etc. for night time power generation.

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Re: Solar Startups Stepping Forward

02/09/2012 7:37 PM

Oops...........forgot to post the link.

http://www.yourownpower.com/Power/

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Re: Solar Startups Stepping Forward

02/10/2012 8:47 AM

Nothing but crickets.

My thinking here is that solar could easily heat water to well over 100° F, by just using exposed black piping, rather than using mirrors to convert water to steam, or silicon wafers...............................my well water from 200 ft down is very cold all year long. Probably cold enough for the heat exchange.

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#12
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Re: Solar Startups Stepping Forward

02/12/2012 5:46 PM

Solar hot water is just not as glitzy as PV. There's also not nearly the profit in it as there is in solar. It makes a lot of sense, though. It's a whole lot easier to use your 1000 watts/m2 to directly heat water rather than lose most of it converting to electricity first.

I have a friend who has a geothermal loop in his back yard. He put it in over 20 years ago before vertical wells were in vogue, so his is a horizontal system. In the coldest days of January & February, his resistive heat will kick in. The loop is too cold. I tried to convince him to set up a collector to warm up the ground during the sunny days. No dice though.

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Re: Solar Startups Stepping Forward

02/12/2012 6:59 PM

Glad somebody's paying attention.

The Alaska project is looking at 7 cents per kWh. Granted, the water is already hot from the ground, but it only has to be over 100° F for the system to work. Seems like the profit would be in the sale of the electricity.

I'd like to have a small one of those systems in my yard. I can easily use solar to get water hotter than 100 degrees, for at least 8 months of the year, and at 200 ft deep, my well water stays cold enough to complete the heat exchange.

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#14
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Re: Solar Startups Stepping Forward

02/14/2012 9:29 PM

Actually, you are going to see a lot more about solar thermal in the years ahead. The next wave, which is already coming, will be PV/Thermal. PV/Thermal combines PV with thermal for a system to produce electricity and hot water or hot air. New systems are coming to market now and will have combined efficiencies of around 50%. This will make PV/Thermal costs lower than most other forms of energy. The payback will be much faster than PV alone at only marginally higher cost per panel.

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Re: Solar Startups Stepping Forward

02/15/2012 6:08 AM

Cool. I can't imagine that they would be too much more expensive. The water in my garden hose gets hot enough scald if it's laying in the sun in summer.

Do you know of any links I could look at?

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Re: Solar Startups Stepping Forward

02/15/2012 1:57 PM

PV/T systems are a bit more expensive than PV because they use piping, water storge, etc. However, they are much more efficient at 40-50% than PV only at 12-15% efficiency. The payback is therefore much faster. Most new PV/T systems are coming out of Euorpe but there is also one in Turkey. My company will be producing one in the USA.

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#11

Re: Solar Startups Stepping Forward

02/10/2012 11:57 AM

In Pohnpei State - Federated States of Micronesia the folks are paying $.54/ KWH for electrical power.

If someone knew how to harness the Sun, Wind, and Tidal Channel flows, connect it to the existing grid, and had the investment capital to do it; they could probably sell it at $.35 / KWH.

Is there room to wiggle there?

It's getting to be that way in a lot of places in Oceania where the power comes from diesel generators.

http://www.micsem.org/forum/comments.php?DiscussionID=9702&page=1#Item_0

The revenue would be a little more than 3 million a year / per megawatt of average power. The existing utilities would probably handle all of the admin and billing for you.

The Federated States of Micronesia. I was in Yap State a few years ago. Great diving and snorkeling. Huge potential for Tidal Channel Power and adequate topography for Pumped Storage.

Could be some real opportunity for someone who knows this stuff.

Gav

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