We don’t have to rip our mountains apart to power our toasters.  A terawatt is equal to one trillion watts, and the sun hits earth with 20 TW.  Our biggest power plants produce puny gigawatts of power a small fraction of  the terawatts that the sun is bathing the earth with — easily enough to satisfy all of our energy needs, if only we knew how to harness it.

Of course, the solar energy level varies from place to place according to geography and weather.  Here in Wisconsin we get about half the solar energy that is bathing Arizona, but it is still plenty of energy for all our needs.

So why isn’t everything humming along on solar power right now?  People still think it costs too much.

Michael S. Arnold, assistant professor of materials science and engineering, and director of the Advanced Materials for Energy and Electronics Group at the University of Wisconsin-Madison, who spoke at this week’s Wednesday Nite at the Lab symposium about how researchers are working to bring that cost down so that the percentage of solar power we are using is not where it currently is.  RIDICULOUSLY MINISCULE.  Check out this DOE chart.

Sun light is converted into electricity in a solar cell using semiconductors made of silicon – the second most common element in the earth’s crust, but converting the raw material into pure sheets of silicon is a complex and costly process.  You can check it out on this You tube.  The interesting part about manufacturing pure crystalline silicon is about 2 minutes into this 9 minute video and lasts for about 2 minutes.  It forms the same kind of crystal as carbon-based diamonds, but with more space between the Si-Si bonds.  I had never seen an actual purified silicone crystal before till I saw this video.  It is about a foot in diameter and 8 feet long.

Once created, that very hard crystal has to be sliced it into very thin slices and polished and polished and polished to create a surface I can barely imagine.  It’s not cheap, and it has taken decades to develop the technology to this point. Most of the effort has been focused on silicon wafers for the computer chip industry where high value-added costs are fairly easily tolerated for a tiny little micro-processor.  But solar panels need to be big and cheap. That’s a huge challenge.

...This is part of Earthship, an experimental, sustainable development in Brighton England. It's just a demo. No one lives here. Why is that? (photo credit Dominic's pics Flickr)

Dr. Arnold is at the cutting edge of research to make solar panels more affordable.  Teams are trying to find both cheaper ways to make silicon as well as exploring other materials that might work as well and be easier to handle.   He noted that since 1975, the cost of solar energy has dropped ten fold, and he expects we will see even more impressive advances in the coming decades.

The way to get from here to there is to push for more solar energy in every way we can.  Be solar pioneers. Let our legislators know that we want them to be visionary here.  Maybe more important — with our dollars.  The more people who are demanding and producing solar power, the faster the industry will mature.

..This is the idea! Solar panels across campus at Arizona State University. This is already paying off. 7% reduction in energy bill and 7% reduction in carbon footprint. (photo credit Kevindooley's photostream, Flickr)

My power company, MG&E offers Green Power Tomorrow. Your power company probably offers something similar.

For about $7.50 per month, you can buy enough green power for your home to offset 100 percent of your electricity-generated carbon dioxide emissions.  Businesses pay more.

You can make a point to support businesses who are buying green power.  MGE lists those businesses who are, and yours may too.

Better yet, put on solar panel.  We are working with Andrew Bangert at H&H Electric one of our area’s solar power leaders.

Yes, it will cost you, but think of it this way.  Lot’s of stuff we choose to do is not economically justified.  We do things for the intrinsic satisfaction.  We own pets.  We buy  boats.  We vacation.  We eat out and take in a movie.  Why not add green power surcharge to that category?

...Way to go Wayne! The Solar Expansion Project at Wayne National Forest is funded by the American Recovery and Reinvestment Act (ARRA) of 2009. In March, the Forest was given $400,000 to add 250 additional solar panels to a facility that already had 50 previously installed.

13 replies

    • Good question. thanks for asking, Paul.
      Our house design is a passive solar plan that does not have a south-facing roof, HOWEVER, we built our barn roof specifically for solar panels. check out my post https://digginginthedriftless.wordpress.com/2009/11/17/greens-in-the-greenhouse-almost-there/ to see a good photo of that roof. It was designed asymetrically so that most of the roof is facing south and has the average best alignment for solar panels.
      We are also considering a second, free-standing solar array that would not be grid tied, and would be used for certain house circuits and possibly to charge an electric car. Our one-car garage is not attached to the house, and we are planning to put hot water solar on that surface.
      As we learn more, the plans may evolve, but that’s our best guess so far of what we will build in 2012 when the house is scheduled to go up.

      • I watched the video of the making of silicon crystals. Impressive model of hyper technology.. the thought occured to me. How much energy is embedded in the manufacture of a solar panel.
        In the life of the panel will the energy costs be recouped? In other words is the EROEI positive? I suspect it’s negative and that it’s not a fruitful direction for out civilization to be heading in…

      • Yes, tracking down all the energy expended to save energy is complex, and the results can be depressing.
        Ultimately we just have to learn to live with less. A lot less, and it’s a lesson we can learn voluntarily or when all other options have been exhausted.
        I personally prefer designing for passive solar use. Did you see Doug’s guest post on the solar and lunar energy?

      • The energy payback time of photovoltaic solar cells is not something in which I am an expert. However, my understanding is that even Si solar cells, which are energy intensive to produce, are energy positive.

        The drive to make lower cost solar cells fortunately coincides with lower-temperature, much-less-energy-intensive semiconducting processing techniques. Thus, moving forward the energy payback time should only get better.

        This study from PROGRESS IN PHOTOVOLTAICS: RESEARCH AND APPLICATIONS suggests that the energy pay back time for CdTe thin film solar modules is only 1 year whereas they are designed to operate for 20+ years.

        Click to access Photovoltaic_Energy_Payback_Times.pdf

        Denise, I linked to your blog entry from the outreach section of my webpage. Best, Michael Arnold

      • This is great information, Michael! I wrote the recent cover story for Isthmus on the local implications of global warming. I’m particularly grateful to you for your info on the energy cost differentiating this from the dollar cost. In the long run, I believe this will be a hugely important consideration.
        Thanks for the reference documenting this information.
        I haven’t written on this topic in a publication to date, but if I do, would you be interested in being interviewed on the present and future viability of solar electric?
        Thanks again. This is information that needs to be available to people deciding whether and when they will invest in solar energy, both business and residential.

      • Hi Denise,
        Yes, I’d be happy to be interviewed. Just give me a call or send me an email anytime.

  1. Above, Michael referenced a paper from Dr Fthenakis of the Center for Life Cycle Analysis. The CLCA, and Dr Fthenakis in particular, are the world’s leading experts in studying the total impact of energy systems. Dr Fthenakis has actually put out another paper recently on this subject, reflecting improvements in manufacturing technology that have gotten the energy payback time to 8 months for CdTe modules.

    Another important point to make for CdTe is that it has been demonstrated the CdTe solar modules result in less cadmium released into the environment than coal, natural gas, or any other solar technology.

    Being less wasteful with energy will of course be a requirement, but the old idea of solar being ‘too expensive’ doesn’t match with the state of the technology anymore, particularly with CdTe.

    This is a very nice website you’ve got, by the way!

    • Thanks for reminding me about this topic. I want to do some follow up research on this very important topic!

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