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Powerful PVs Approach 50 Percent Efficiency

Start-up Solar Junction thinks it has the right recipe in a triple-cell scheme

3 min read
Powerful PVs Approach 50 Percent Efficiency
Photo: Solar Junction

Silicon Valley start-up Solar Junction has raised the bar for solar efficiency to 44 percent, and even higher values are in the cards: The company has a road map for reaching 50 percent efficiency and beyond.


To break the efficiency record, Solar Junction built a cell with three regions, known as junctions, that are stacked on top of one another; each absorbs a different spectral region of the sun’s rays. The result is a device that delivers far more energy than conventional cells do. Ordinary photovoltaics have just a single junction. Each junction in the triple-junction cell operates at a different output voltage, and they are connected in series, so the total power produced gets a boost. 


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This photograph shows a car with the words “We Drive Solar” on the door, connected to a charging station. A windmill can be seen in the background.

The Dutch city of Utrecht is embracing vehicle-to-grid technology, an example of which is shown here—an EV connected to a bidirectional charger. The historic Rijn en Zon windmill provides a fitting background for this scene.

We Drive Solar

Hundreds of charging stations for electric vehicles dot Utrecht’s urban landscape in the Netherlands like little electric mushrooms. Unlike those you may have grown accustomed to seeing, many of these stations don’t just charge electric cars—they can also send power from vehicle batteries to the local utility grid for use by homes and businesses.

Debates over the feasibility and value of such vehicle-to-grid technology go back decades. Those arguments are not yet settled. But big automakers like Volkswagen, Nissan, and Hyundai have moved to produce the kinds of cars that can use such bidirectional chargers—alongside similar vehicle-to-home technology, whereby your car can power your house, say, during a blackout, as promoted by Ford with its new F-150 Lightning. Given the rapid uptake of electric vehicles, many people are thinking hard about how to make the best use of all that rolling battery power.

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