The solar windows, designed for skyscrapers, are created by applying ultra-thin layers of liquid coatings on to glass and flexible plastics. These liquid coatings produce ultra-small solar cells and form groups called ‘arrays’. 

Solar Window Technologies revealed its innovation via a webinar, with a video demonstrating the windows collecting electricity, which was then used to charge a monitor.

With standard rooftop photovoltaics on a skyscraper generating 87,000 KWh a year , the company believe that a 50-story building with solar windows can create 1.3GWh – enough energy to power 130 homes for a year.

The company says its solar windows can also harness energy from artificial light.

Solar Window Technologies’ principle scientist Dr Scott Hammond said: “Whether crystalline silicon or inorganic thin film, all conventional solar panels are inherently opaque and thus impossible to see through. In contrast organic photovoltaics from Solar Windows are so incredibly thin that it lets light through.

Easy integration

Currently solar window films are used by several big companies, including Lloyds Bank, but Solar Window Technologies expects to see rapid uptake of its product thanks to its simple installation.

The coatings would be applied inside the glass of a window unit, rather than outside, to protect the solar cells from the weather. The coatings are developed for easy integration into current glass manufacturing processes.

They also claim an ROI of under a year, compared to the 5-11 year payback on conventional solar systems.

Major achievement

The windows are being produced in collaboration with the National Renewable Energy Laboratory (NREL) as part of a research development agreement.

NREL’s senior scientist Dr Maikel van Hest said: “The development of a transparent photovoltaic is actually extremely challenging. Any typical photovoltaic device will absorb the physical light and that is converted into electrical power. However in this case we want it to be transparent so we couldn’t really use the physical light.

“Therefore we need to engineer a device in such a way that it allows for the physical light to pass through. Achieving that while also generating significant power at the same time is a major technical achievement.”

Renewable Portfolio Standards

Electricity supply companies have to comply with Renewable Portfolio Standards. In the US these standards vary from state to state with Arizona’s PRS target is 15% by 2025 and Colorado’s 30% by 2020.

With an estimated two million acres of skyscraper glass in the US, Solar Window Technologies believe that they can subsidise a £5.3bn market with solar windows.

For more information about Renewable Portfolio Standards (Renewable Obligations in the UK) click here.

Matt Mace

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