Big Breakthroughs In Solar Technology

Did you know that solar is the fastest-growing energy technology in the world? From approximately 20 gigawatts (GW) of installed solar production ten years ago, the end of 2019 saw installed solar power output leap to about 600GW.

A decade ago, the average commercial solar panel could convert 12 percent of the sunlight striking it into electricity. Today, that figure is up to 17-19 percent and relentless researchers are seeking innovative ways to
increase solar production efficiency even more.

Based on average use, a single American home needs about 40 square meters of solar panels to generate enough power for 24 hours.

China and Taiwan dominate 70 percent of global solar cell manufacturing. The wafer-thin slices of silicon crystals used to make solar cells have been computed to have a maximum efficiency of around 30 percent.

But combining six different materials to make a multi-junction solar cell boosts efficiency up to 47 percent under concentrated light conditions.

Simply adding an extra layer to a solar cell’s backing that reflects unabsorbed light back through the cell a second time increases energy efficiency by 1-2 percent.

Another small change in a manufacturer’s production lines is adding an outside layer to a solar cell that reduces losses from silicon touching the metal contacts. The small tweak raises efficiency by a modest 0.5-1% in efficiency, but every little bit counts in making solar power cost-effective for commercial markets.

Using lenses to focus the sunlight hitting a solar cell is another technique to exceed silicon’s maximum efficiency rating. This pricey solution is beyond the means of most homeowners but useful on satellites.

A normal solar cell converts sunlight into energy and transfers it to a storage device. The heat energy created as a by-product dissipates and is wasted. In 2016, a team at the Massachusetts Institute of Technology (MIT)
successfully recycled lost solar panel energy by building a working solar thermophotovoltaic device (STPV). 

The revolutionary system added a new layer to the structure of a solar cell to absorb thermal energy and convert it to light, which is then reflected off to another solar cell. The reflected light delivered to the second cell is the perfect wavelength for peak efficiency.

The MIT developers said STPV could potentially double solar cell efficiency and studies on this cutting-edge technology continue in India and other parts of the globe intent on making solar energy affordable for everyone.

A mineral called perovskite (named after 19th-century Russian mineralogist Count Lev Alekseevich von Perovski) has superior solar absorption properties due to its crystalline structure. Thin films (about 300 nanometers,
much thinner than a human hair) made from fluid solutions can be produced at low cost. The coating is easy to apply to buildings, vehicles, and fabric.

Perovskite films offer other advantages. They perform better than silicon with lower light levels, on cloudy days, or indoors. They can also be printed using an inkjet printer. How nifty is that? 

As of May 2020, only about 10 startup companies on the planet are developing perovskite technology. In the UK, Oxford PV, a university spin-off, reported that its commercial perovskite-based solar cell reached 28% efficiency in late 2018. The venture will have an annual 250-megawatt production line operational in the
second half of 2020.

Oxford PV and another outfit, Swift Solar, manufacture tandem solar cells: silicon panels with a thin layer of perovskite film.

Swiss startup Insolight is pursuing a different approach to increasing solar conversion efficiency by embedding a grid of hexagonal lenses in the glass that protects the panel, concentrating sunlight 200 times.

The system follows the sun’s movement, shifting the cell array horizontally by a few millimeters as the day progresses. The miniaturized sun-tracking mechanism is integrated within the module.

The solar energy institute at the Polytechnical University in Madrid, Spain, (Universidad Politécnica de Madrid) gauged the efficiency of Insolight’s current model at 29 percent and is working on a module projected to reach 32 percent efficiency.

In February 2020, Australian researchers at the University of Queensland set a world record for converting solar energy to electricity when their innovative increased solar efficiency by almost 25 percent over the prior
world record. The energy engineers used nanoparticles called “quantum dots” that pass electrons between each other to produce an electrical current when exposed to sunlight in a solar cell.

Quantum dots are flexible and printable. This technology lends itself to making transparent skins to power vehicles (including airplanes), buildings, and even wearable tech.

Based on the wide variety of engineering approaches being applied to create eco-friendly energy solutions, the forecast for global solar power is clear and sunny with a distinct change of extraordinary innovation ahead.

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