Solar Power Windows Ready For Production – PlanetSave

Solar Power Windows Ready For Production

Solar power windows nearing production


This story was first published at Green Building Elements. Reprinted with permission.

Imagine if every building in the world had solar power windows that could generate a small amount of electricity from the sun. The technology exists. It has been tested and it is ready for production. In Manhattan alone, there are 47,000 buildings with over 10,700,000 windows, according to a 2013 estimate from The New York Times.

Transparency Versus Efficiency

The first challenge for researchers is to make the solar power windows transparent. “No one wants to sit behind colored glass,” Richard Lunt, an assistant professor of chemical engineering and materials science at Michigan State University. “It makes for a very colorful environment, like working in a disco.”

Lunt and his team have developed a new type of transparent luminescent solar concentrator (TLSC) that creates solar energy when it is placed over a window. MSU’s technology can not only be used on windows for building but also on cell phones and any other device that has a clear, uncolored surface. “We take an approach where we actually make the luminescent active layer itself transparent,” Lunt says.

The problem for MSU at the moment is that its technology is only 1% efficient. A typical solar panel is 15% efficient or more, which means 15% of all the sunlight that strikes the glass is converted into electricity.

“When you’re looking at transparent or clear photovoltaics, it’s not necessarily a function of power conversion efficiency as it is about using the vast amount of space available for that tech,” says Solar Window CEO John Conklin. “We’re making use of the space that right now is not available for solar energy production. Passive windows are turned into active energy generating windows.” In other words, transparent solar PV is about not wasting perfectly good real estate in order to supplement a building’s power requirements.

Perovskite Is A Game Changer

In 2013, Oxford University researchers did a study on how neutral colored, semi-transparent solar cells made of perovskite could be used in building and car windows to generate electricity. Perovskite is an oxide used in ceramic superconductors. The Oxford researchers said their transparent solar cells can be made up to 20% efficient using a simple cell architecture.

The university’s work is being commercialized by a spin-off company, Oxford Photovoltaics, which is planning to produce colored and semi-transparent glass that works as a solar cell. Its glass could be integrated into windows and into the facades of buildings.

Two Companies Ready For Production

Solar power windows nearing productionTwo companies say they are ready to bring solar power windows to the marketplace, according to Computer World. They say the windows will cost about 40% more than ordinary windows, but claim the extra cost will be recaptured in a year through lower utility bills.

One is Solaria, a company that currently manufactures rooftop solar panels. It uses existing photovoltaic (PV) cells and slices them into 2.5mm strips. It then sandwiches those thin PV strips between glass layers in a window. “The way the human eye works, you don’t even notice them,” says Solaria CEO Suvi Sharma.

As the PV strips absorb light striking a building’s window, they also reduce solar heat gain, which lowers air conditioning costs.  Solaria is targeting its technology for windows that will be installed in newly constructed buildings. It says its windows are about 8% efficient.

A second company is Solar Window Technologies. Its approach uses a different form of transparent photovoltaic cell technology that is suitable for new construction, replacement windows and retrofits to existing windows. Its organic photovoltaics can vary in color and transparency, depending on the needs of the customer.

CEO John Conklin says because his product is based on a photovoltaic film, it can be used on existing windows or incorporated into manufactured products relatively easily. The company has not released data on the efficiency of its technology.

Delivering The Electricity

Once solar power windows generate electricity from the sun, who is that energy connected to the building? Each company uses a different approach. Solaria, embeds its wiring in the window frame. From there, it is connected to a dedicated electrical line that conducts it to a central power inverter. The inverter then converts the direct current from the solar window to alternating current that is fed into the the electric panel for the building.

The Solar Window technology offers more flexibility. It can power a micro DC-to-AC power inverter to provide electricity for a single room. It can also be connected to a distributed microgrid inverter to power a single floor of a building. Finally, it can be fed to a central inverter that supplies elecrticity to an  entire building.

New Clean Power Opportunity

Many buidings are not good candidates for rooftop solar power systems. Skyscrapers and large urban apartment buildings cannot participate in the clean power revolution that rooftop solar is bringing to many homeowners. Solar powered windows could change that dynamic by providing the benefits of electricity from clean solar power to all buildings.

Solaria estimates that a skyscraper with south facing windows could generate up to a third of its annual electrical needs from solar power windows. Apply that to buildings around the world and you have the potential for a significant new source of clean, renewable energy that will pay for itself in a matter of months rather than a period of years.

Photo Credits: Solaria; Solar Window Technologies

About the Author

writes about the interface between technology and sustainability from his home in Rhode Island. You can follow him on Google + and on Twitter.
  • John

    Wow very nice

  • Robert Christ G

    whatever happened to our solar firkin roadways?

    • SkillyDog

      Solar frickin roadways were responsible for a billion roadkill incidents last year.

      • yehuda braun

        We NEED solar-powered cats to chase the roadkill away or eat it off the side of the road!

        • Arfer

          No, for that you need solar powered buzzards

  • Ian Renert jail breaking exper

    Very innovative and useful device to save electricity

    • rob

      The cost of implementation is ridiculous. To overhaul the system and be able to properly store and transport the electricity would make the cost of the panels themselves seem tiny. It’s not an economically viable solution.

      • Wildlebendes

        We have had to change the infrastructure of our cities and towns before. Gas lighting to electricity. Trains and rail cars to automobiles. Cellphone towers have popped up all over the place over the last few decades. How much do you think all those changes cost? We managed to pay for all that.

        • rob

          I was actually referring to solar roadways posted by the guy below me. Apparently I misclicked. Solar windows are pretty reasonable. That being said, even the transition from trains to automobiles was due to autos being more efficient and effective for daily use due to the size of our country. The problem with solar roadways is that this is more significant a change, and while the potential for power generation is there, it would also require updates of our power infrastructure (which is also a good 30 years behind schedule) before we could even think about integrating a country/state/county/city wide replacement of roads with solar panels.

          • Wildlebendes

            To be fair, even the solar roadways people stressed on the older version of their FAQ website that their goals are long term. They don’t plan on repaving every road in the US with solar roadways over night. They plan on more limited releases and years of testing and product improvements before they are ready for full scale roads.

            “it would also require updates of our power infrastructure (which is also a good 30 years behind schedule) before we could even think about integrating a country/state/county/city wide replacement of roads with solar panels.”

            I agree here, but it should be stressed that even the solar roadways people realize this. Recall how many years it took from the first mobile phone concept to where we are now. Their goal is not to change the world overnight, their goal is to anticipate future changes in the price and availability of traditional road paving materials, and make their products suitable alternatives. It could take a while, of course.

            I realize that the potential for failure is their and there are plenty of reasons to be skeptical, but that risk is always there when it comes to innovation. Nothing ventured nothing gained.

          • rob

            I’m just sick of the people and their constant complaining.

  • Kurtis Engle

    This is a very good thing. As of now, as many as a billion birds die annually in the United States from striking glass. They should be able to see this new photo-glass.

    Oh. And, I suppose, there is also the electricity.

    • MD

      A billion birds annually? In the US alone? This is a joke, right?

    • Joey G

      More are killed by cats. So clearly, we need solar powered cats.

      • Astralfury

        Given how much mine loves to sleep in the sun, I’m not convinced we don’t already have those.

        • john


    • yehuda braun

      Ok…ummm… you don’t quite get it.

      That, and light-to-power conversion factor, is the whole point.

      • Kurtis Engle

        I get it. “Look just like regular windows” to humans. Birds and insects see a little differently.