Residential solar PV: a happy customer

Gail Overton Senior Editor Laser Focus World gailo@pennwell.com

There is nothing quite like opening your electric bill for the third month in a row and owing $0 (that’s a zero) dollars. This is the second winter season that our electric bill has been zero since we put in our 3.22 kilowatt solar photovoltaic (PV) system in the summer of 2010.

Now before I launch into a summary of panel output and cost (which are details often lacking in many articles that I read about residential solar energy systems), I'd like to describe a few unique issues that make our system especially cost effective. First of all, it is a ground-mount system--which made it less expensive to install compared to some rooftop systems. Secondly, we live in the desert southwest of California, with abundant sunshine and rarely a cloudy or rainy day, meaning that our solar output is maximized compared to many other locations in the world (and California gives generous rebates for residential systems). And third, we found a very efficient crew and an excellent installer in our area that helped us with rebate paperwork, interfaced with our utility company, and did the job over a 3 day period (including concrete footings and frame in a very rocky caliche soil). The name of that company by the way is "The Sun Works" (http://www.thesunworks.com/) out of Niland, CA.



Our system uses a total of 14 Sharp monocrystalline PV panels rated at 230 W each, bringing it to 3.22 kW and generating roughly 20 kWH (kilowatt hours; often written as KWH) each day. This means that we get roughly 7 hours of full generation out of our panels every day; pretty good considering they are fixed and do not track the sun (solar tracker equipment is fairly expensive).



With 20 KWH of generation per day, we output roughly 600 KWH per month, with the excess feeding into our grid-tied system. And because we typically consume about 300-600 KWH per month in the winter (depending on whether the heater is running or not), our bill is basically zero in the months between November and April. Our monthly consumption in the summer months--when it’s up to 110 degrees outside and the air conditioning is set at 80 degrees inside--is about 1200-1800 KWH, meaning that our highest bill of $230 per month is roughly cut in half. Utility rates at Imperial Irrigation District (IID) are some of the lowest in the country at $0.13/KWH, meaning a month with 600 KWH consumption runs about $80 a month.

So what was the price and what is the "payback" time for our system? The total price was $22,600. Sounds overwhelming and unaffordable for most people, but here is the bottom line: Immediately upon installation, one-third of that price is rebated against the total. The state of California pays the installer about $7500, bringing the amount we owed to $15,100. And then, another one-third of the total price becomes a full tax writeoff, taking the price down to $7600. But reality is harsh; because that tax benefit is not available until later, we financed the $15,100 through our Credit Union, which offers 6.75% fixed rate, 5-year solar loans. Essentially, we think of our solar-energy system as the equivalent of a five-year car payment. Fortunately, unlike a car that is sometimes worthless after five years (or worth just a couple thousand bucks), our solar energy system should continue cranking out the kilowatts for a 25-year lifetime, giving us 20 full years of zero dollar electric bills in the winter, and $100 maximum electric bills in the summer. Each year, we save about $1200 with the system, making it a 6.3 year breakeven point at a total price of $7600.

While making that payment now is not fun, I’ll be smiling broadly in just three more years when the loan is paid and the kilowatts continue to flow for years to come.

Watching real wavefronts in slow motion

..John Wallace ..Senior Editor ..Laser Focus World ..johnw@pennwell.com

A team at the MIT Media Lab, led by Ramash Raskar, has developed the best way yet to visualize the passage of light as it hits and passes around or through objects. They use streak cameras, femtosecond-laser pulses, and a million or more repeated measurements of a stationary scene to capture the actual laser pulse as it passes through a transparent bottle, or is intercepted by an apple or other object.

Two points I’d like to make. First, is that Senior Editor Gail Overton’s news story on this will appear in the February issue of Laser Focus World; don’t miss it, as she has talked to the researchers and describes in detail how the whole thing works.

The second point is -- this is pretty amazing. They’ve created videos of wavefronts as they propagate through an everyday scene . . . and these are no simulations; they are the real thing. The colorized gray-scale photo here shows a couple of wavefronts in passage through a bottle.


(Photo: MIT Media Lab)

The bottle is perpendicular to the camera, and the pulses propagate from left to right (with no toward- or away-from-the-viewer component). I stared at this for a moment before I realized why the wavefronts look tilted -- it’s because the light from the farther-away points on the wavefront take longer to get to the camera, so these spots appear to have not progressed as far as those nearer to the camera.

This realization made me feel strangely relativistic, as if I were flying by the bottle in a spaceship at half lightspeed. (And I won’t even try to explain this.)

Is the U.S. wired Internet infrastructure weak? Revisited.

Tom Hausken Optical Networking Research Strategies Unlimited Thausken@PennWell.com

It's time to weigh in on a pet peeve of mine. The topic is the state of high-speed Internet in the U.S., in a December 4 essay in the New York Times. My peeve is that once again the U.S. wireline infrastructure is portrayed as somehow way behind, whereas a reasonable analysis presents a very different picture. For a large country, the U.S. actually has a very strong and affordable infrastructure.

The author has a point. There is a digital divide in the U.S. and in the world. It's increasingly important to treat broadband access as a necessary service for all citizens. National averages overlook that large groups of people are left out.

The problem is how the point gets twisted along the way. The way the author explains it is like fingernails on a blackboard to me. I've complained in this blog before (here and here) and I can't let this one go too.

For example, the U.S. is portrayed as 12^th in the OECD economies. That's per capita. Iceland is number 5. It has 110,000 people. You get the idea. The OECD aggregates across the whole U.S., while smaller countries will almost certainly show up in the wings of the distribution. We should compare tiny Iceland with, say, a successful regional provider in the U.S., not the entire U.S. In fact, larger countries like Germany and France are passing us up. That is important. Let's say it.

The author points out that even Portugal and Russia are upgrading to optical fiber. That's because their infrastructures were so bad in the first place. The U.S. is rewiring with fiber, but it's a big country, DSL is working pretty well, and someone has to pay for upgrading to fiber. A too-rapid deployment would recreate something on the scale of the Telecom Bubble of the late 1990s. We know how that turned out.

Broadband is also portrayed as a monopoly, yet residential users can choose from the wireline provider, cable provider, and even wireless providers. Competition is good, but we've come a long way.

The author says the providers should sell access to their networks to competitors, to reduce prices. But the problem is that everyone wants the high-end customers. There's a reason that underserved neighborhoods are underserved. There's less profit there.

Having worked in telecom policy in Washington, it is an ongoing process to improve broadband access to underserved groups. It's messy, because there is the FCC and Congress, 50 state regulators, municipal governments, and the courts. And it's "inside baseball"; pretty boring stuff if you're not a lawyer.

The author is right, we should be striving for broader broadband access.I guess it's just something about how she said it.

The top 10 laser suppliers: some tight races, but a good year for all

Tom Hausken Optical Networking Research Strategies Unlimited Thausken@PennWell.com

Now that 2011 is coming to a close we can estimate who are the leading laser suppliers for the year. Once again it looks like Trumpf and Coherent are neck and neck for Number 1, with over $800 million each. Rofin and Cymer are in a close race for 3rd and 4th places, with nearly $600 million each. IPG will roll in 5th, but this year with over $450 million in fiber laser sales. IPG's 2011 revenues would have put it at #1 as recently as 2009.

These players are familiar names. Cymer dropped out of the short list in the recession, but is back again. The order changes depending on the exposure of companies to different sectors. Trumpf and Rofin are highly exposed to heavy manufacturing, while Coherent is more diversified. Cymer is basically a one-product company.

I can't really know how the year will end up, of course. But three quarters are finished, and so far it looks like the fourth quarter is behaving as expected. Only the floods in Thailand have created surprises, but that's confined to telecom components, hard drive manufacturers, and the like.

I also can't really know what Trumpf is up to. And a lot of revenues for a company like Rofin-Sinar are really system sales, revenues that would not be counted if it were a company like Trumpf or Newport.

And then there are the telecom transceiver manufacturers. Finisar, JDS Uniphase, Oclaro, and others are all very strong in that segment, and Finisar is closing in on $800 million itself. With the companies above, and a couple others, that rounds out a list of the top 10.

It's also interesting that the Top 10 make up over 50% of all laser sales worldwide.

But I don't want to give too much away. There will be more on 2011 and 2012 at January's Laser Focus World Marketplace Seminar and our upcoming market report.

Solar farms: the newest crop in the desert southwest

Gail Overton Senior Editor Laser Focus World gailo@pennwell.com

In the dusty little corner of the planet--the lower Mojave desert--that I call home, it's time to start raiding the just-picked lettuce and broccoli fields for the abundant leftovers. Broccoli soup, wilted lettuce, and wedge salads will be commonplace at my house for the next few months; after all, I live just next door to Yuma, AZ, the winter lettuce capital of the world. But sprouting from the ground with concrete footers and rows of metal posts rather than green shoots are fields of silicon, steel, and glass structures that are harnessing the sunlight to power our homes rather than fill our stomachs. The latest crop in the desert southwest today is not a vegetable.

Utility scale solar photovoltaic and concentrating solar power (CSP) installations in southern California and Arizona are the latest cash crop. The small town of Gila Bend, AZ is home to three separate solar farms, most located/to be located on former agricultural fields to fast-track environmental assessments (tortoises must be moved!).



One of the largest solar fields in Gila Bend is the 280 MW Solana Solar Project, which is using CSP technology from Abengoa Solar (Sevilla, Spain). The image above, courtesy Gunther Portfolio, shows the support structures being "planted" for Abengoa's proprietary parabolic trough technology. Parabolic mirrors focus the sun on a heat transfer fluid that can reach 735 degrees Fahrenheit. The hot fluid transfers its energy to water to create steam that runs conventional steam turbines. Large "thermos-like" buildings containing the molten salt hat transfer fluid are located next to the steam boilers. At select times, instead of immediately creating steam, the heat transfer fluid will heat the molten salt. Electricity can be created immediately, or from heat energy that was created up to six hours earlier--a real benefit when the sun is not shining. The YouTube "marketing" video below gives a decent overview of the Solana Solar Project:

Another solar field in California that will also use Abengoa Solar equipment is the 280 MW Mojave Solar Project--currently underway thanks to a $1.2 billion dollar loan guarantee from the U.S. Department of Energy, which comprises the bulk of the overall $1.6 billion total investment for the San Bernardino County installation. Yes, a government loan guarantee is resulting in actual hardware and actual energy generation; it’s a shame that the Solyndra scandal is getting all the headlines.

In addition to CSP-based solar farms, photovoltaic (PV) panels from First Solar (Tempe, AZ) will comprise the 550 MW Desert Sunlight Project near Desert Center, CA (operational by Q1 2015) and the 290 MW Agua Caliente Solar Project near Dateland, CA. First Solar continues to be one of the most profitable thin-film PV manufacturers, with its cadmium telluride (CdTe) recipe competing against conventional crystalline silicon PV modules. Another alternative is solar thermal power, which will be implemented in the 392 MW Ivanpah project by BrightSource (Oakland, CA).

Sadly, solar energy still accounts for less than 1% of all the energy sources used worldwide today. But rather than dwelling on this fact, I'd rather remain optimistic that renewable energy will be the savior of our planet. Scientists are improving the optical-to-electrical energy conversion efficiency parameters daily, and solar energy is available TODAY unlike some other yet-to-be-proven energy methods such as laser fission/fusion via the National Ignition Facility. As huge swaths of arid desert land lay fallow due to lack of water and cheaper produce from Mexico and South America, why not plant a solar farm instead?

Uh oh, that fly has a wafer-scale camera

..John Wallace ..Senior Editor ..Laser Focus World ..johnw@pennwell.com

Predictions for the future of humanity range from an expansion of the human race throughout the universe to a quick self-extinction based on nuclear war or biological agents. On a just slightly less-grand scale, some prognosticators say that within a few decades we will have melded with machines, our thoughts and memories flowing throughout electronic or quantum-optical circuits. (Others would say to this, "Bah.")

But what is next, really? I'll just make one prediction: the rise of lethal nano unmanned aerial vehicles (UAVs). Here, "nano" means the size of insects. Hummingbird-sized UAVs have been around for a few years, as have those the size of dragonflies.^1,2 Real insects are also being turned into flying "cyborgs" for various purposes.^3,4 There is now even a technical journal devoted to the topic: the International Journal of Micro Air Vehicles.⁵

Larger UAVs, of course, some quite lethal, are already in operation. But the smaller ones have been described mainly as sensing devices, often for surveillance. The ideal, which I believe will be achieved within a few years, is to shrink them from the size of a dragonfly to something much smaller -- say, that of a housefly or mosquito.

For example
But a mosquito does more than sense its surroundings; it also can deliver an itch-causing toxin to a human or animal. Perhaps all a nano UAV would need is a needle and some toxin to take out a target. Or a fly-sized surveillance nano UAV could work in concert with a larger, more lethal nano UAV. All this would hinge upon getting enough power to the UAV (such as in Ref. 4), and creating optical sensors small and light enough to be carried along. Wafer-scale cameras fit the bill nicely.


Through-silicon-via technology enables
low-cost CMOS cameras smaller than a
match head. (Image: Awaiba GmbH)

I'm just making a guess (meaning I have no insider info!). Is my prediction an obvious one ("Anyone coulda guessed that")? A lunatic one (“Here’s a tinfoil hat for you, young fella”)? I don’t know, but I’d love to hear from Laser Focus World readers about their own ideas for what strange photonics-enabled devices might be appearing in our future.

REFERENCES:

1. http://www.militaryaerospace.com/index/display/article-display/298457/articles/military-aerospace-electronics/volume-18/issue-7/electro-optics-supplement/features/engineered-by-nature-uav-designs-modeled-after-biological-sources.html

2. http://www.delfly.nl/?site=diii&menu=home&lang=en

3. http://www.ns.umich.edu/new/releases/20087-insect-cyborgs-may-become-first-responders-search-and-monitor-hazardous-environs

4. http://www.pratt.duke.edu/node/3181

5. http://www.multi-science.co.uk/ijmav.htm

Lasers can make brown eyes blue--but should they?

Gail Overton Senior Editor Laser Focus World gailo@pennwell.com

The daily news posting at http://www.laserfocusworld.com/ entitled "Laser turns brown eyes blue" generated much discussion on LinkedIn. The comments weren't centered around how 'cool' or 'neat' the concept was, but instead focused on the technology details and the philosophical aspects of the procedure. After all, the LinkedIn audience to whom we share our Laser Focus World postings is not your average non-technical crowd; these are photonics industry professionals who are clearly concerned about how something works and what impact it has on society as a whole.



Turning brown eyes to blue may seem magical to a non-laser audience, but it is merely an extension of laser aesthetics--a topic profiled in our Photonics Applied feature series for November called "Looking good with lasers." Laser hair removal works on the principle of targeting melanin in the hair shaft and through laser heat, destroying the melanin and the hair follicle. Laser aesthetics also includes wrinkle removal, liposuction, and tattoo and lesion removal--different wavelengths of light attack different colored pigments in the tattoo or lesion, and it really works!



But even though lasers can turn brown eyes blue by targeting melanin, should they? One LinkedIn respondent said that they wished scientific research could be channeled into curing unsolved medical problems that we suffer rather than in trying to alter one's appearance for cosmetic reasons. I wholeheartedly agree; however, my sentiments will not change the fact that as long as people have "disposable incomes", money will be spent on luxuries. I was amazed to learn while researching the laser aesthetics article that teeth whitening is a $5.5 billion dollar global market, while the entire laser market is around $7 billion. Maybe we're all in the wrong business!

Still other LinkedIn comments focused on the technology. "Mankind has always sought to change his/her appearance--hair color, skin, and eyes," said Gennady Medvedkin. "Tomorrow we may witness artificial eyes made from silicon."

Medvedkin says that image sensors are really artificial eyes with great spatial resolution and color-sensing capabilities that can even exceed the capabilities of human vision. Thin silicon plates the size of the pupil could be implanted within the human body, completely replacing the eye, and recent computer algorithms allow extensions of the dynamic range in sensors up to 140 dB that are comparable to the human eye. Medvedkin says that the eye must adapt to very low light intensities for minutes and sometimes hours, whereas CMOS image sensors operate in the millisecond to second time range at low voltage with great success.

Personally, I'll keep my green eyes green and will be glad when this story fades from my memory; I'm getting tired of humming the "Don't it make my brown eyes blue" song from Crystal Gayle!