Above – an example of a 5% efficient transparent solar cell
* the calculation of power provided is not 80% but 25%
* the transparent solar cells are still just laboratory demonstrations
* the cells do not have commercial grade stability or years of usability. Currently they degrade quickly
* getting to commercial deployment of any product is still some years away
* the transparent solar needs to get to a competitive price
* they need to scale up production and make factories
Verifying the window claim seems to come up with 25% of US electricity from all windows being transparent solar
There is an estimated 5 billion to 7 billion square meters of glass surface in the United States. There are 100 million houses and apartments in the USA. They have about 10-100 square meters of windows for each residence.
The US receives sunlight that at 100% efficiency would produce about 4.5 kwh per square meter per day. 10% efficiency would be 0.45 kwh per square meter per day. This would be 164 kwh per year. For 6 billion square meters that would be 985 TWh per year.
Materials with switchable absorption properties have been widely used for smart window applications to reduce energy consumption and enhance occupant comfort in buildings. In this work, we combine the benefits of smart windows with energy conversion by producing a photovoltaic device with a switchable absorber layer that dynamically responds to sunlight. Upon illumination, photothermal heating switches the absorber layer—composed of a metal halide perovskite-methylamine complex—from a transparent state (68% visible transmittance) to an absorbing, photovoltaic colored state (less than 3% visible transmittance) due to dissociation of methylamine. After cooling, the methylamine complex is re-formed, returning the absorber layer to the transparent state in which the device acts as a window to visible light. The thermodynamics of switching and performance of the device are described. This work validates a photovoltaic window technology that circumvents the fundamental tradeoff between efficient solar conversion and high visible light transmittance that limits conventional semitransparent PV window designs.