mead cohen berger shevtsova garfinkle michta grygiel blankenhorn
Sun Stroke of Genius
Are Wet Roads the Key to Solar Power's Future?

Scientists at MIT have figured out a way to harness the sun’s energy much more efficiently than the photovoltaic panels that you may be more familiar with. The researchers have focused on using the sun’s heat to boil water, and to use the resulting steam to drive turbines. This approach, called solar thermal, isn’t a new one, but the group at MIT may have found a way to make it much more efficient. As the Economist reports, the team drew inspiration for their new method from wet roads:

[A] group of researchers at the Massachusetts Institute of Technology (MIT) has come up with an…approach that borrows from the wet road. Steam is generated at the surface of water, but the mass of liquid below acts as a heat-sink that conspires against steam generation. This is why sunshine can readily turn a thin layer of water on a road into steam but cannot do the same for a lake.

The MIT researchers sought to address this in a laboratory set-up that consists of a double-layered black disc floating on the surface of water in an insulated beaker…This simple disc turns out to be a very efficient steam generator. For one thing, it produces steam when sunlight is magnified by a factor of just ten. This requires little more than cheap lenses and it increases the efficiency of using solar energy to make steam to 85%. With some refinement of the graphite layer, thinks Dr Chen, the technique could be made to work with sunlight that is concentrated as little as three times.

This is an excellent example of the kinds of research governments and green groups interested in sustainably powering the future ought to be funding. Instead, countries like Germany have thrown massive amounts of money behind current-generation photovoltaic panels, a solar technology that is incapable of competing with fossil fuels on its own merit. Not only is this kind of short-sighted subsidization a drain on government coffers, it carries with it a hefty opportunity cost. Who knows where we’d be if policymakers had taken all of the money with which they’ve been propping up today’s solar technologies and invested it in the research and development of cost-effective and more efficient methods of capturing the sun’s energy.

More of this, please.

Features Icon
show comments
  • Fat_Man

    The sun still sets every day. The sun is still lower in the sky during the winter. You still need lots of land area to gather sun light. Forget it. There is not, nor will there ever be, an economically viable solar energy system as long as we can still find fossil fuels or we can use nuclear energy.

  • Rick Johnson

    There is another technique that can be used to generate steam. It’s called combustion. Apparently, if you ‘combusts’ certain fossil fuels, they produce enough heat to generate enough steam to produce enough energy to power whole cities and major industries. It’s cheap and proven technology, with most of the necessary infrastructure is already in place. But the best bit is that you can still make electricity when the sun isn’t shinning. How cool is that. Electricity being generated at night. Who would have thought that would ever happen! 🙂

    • Ernst Bloefeld

      Rick Johnson, this sounds like an outlandish idea. Has it ever been tried or is it strictly theoretical?

      I’m sticking with wood, nothing ever got harmed by using wood.

      • Rick Johnson


        I believe it has been tried and the results have been promising.

        I also recall hearing of a report that in some parts of the world it has been successfully operating on a fairly large scale, possibily even the main source of electricity in some parts.

        I understand your attachment to wood, I may be wrong, but I believe that one day, fossil fuels could become the main source of energy for humanity. Sounds far fetched, I know, but it is possible.

        • Ernst Bloefeld

          Rick Johnson, wow, we are living in the future. Are you speaking of coal, I guess you must be, because I don’t think there are any reliable sources of things like petroleum oil or gas are there? How would we get them and how would we move them? Its all very fascinating.

    • Dan

      Hmm. Your ideas are intriguing to me and I wish to subscribe to your newsletter.

  • Duperray

    Walter, are you familiar with Thermodynamics?
    This beautiful MIT invention is nothing else than a scam from “scientists” looking for mediatic promotion. Even with a 3-times concentration factor, yielded steam temperature would even not reach 50% when they extract 85% of received solar heat.
    What can we do with such low temp steam (almost equal to that one exiting from the lowest pressure steam turbine) ? Nothing. It’s even not worth for home heating purposes, let’s alone gathering cost, high volume (about 20 cubic meters for one single kilowatt-hour…).
    When Universities also fall into such mediatic behaviour, I consider that their scientific worth dwindles down to nothing.
    FYI, existing higher concentration systems can yield acceptable higher temperatures for energy conversion and storage…

    • Ernst Bloefeld

      Duperray, that damn Second LAW of Thermodynamics. It makes a lot of this stuff a bitch to make work.

  • imapopulistnow

    Absurd. Totally absurd. After reading this article, I want my 5 minutes back.

© The American Interest LLC 2005-2016 About Us Masthead Submissions Advertise Customer Service