What sets solar energy apart from other renewables, to me, is not just how real it is (compared with, say, clean coal or cellulosic methanol) but how much rapid improvement is possible within the space.
Some of those improvements require real breakthroughs – new ways of building cells, new materials for using different wavelengths and heat. That work is ongoing, and when such a breakthrough emerges into commercial production it’s a day to celebrate.
People have long debated whether such concentrated photovoltaic (CPV) systems are really more efficient than standard photovoltaics (PV). Critics worry about the lenses, whether efficiency can be maintained over the long haul
The latest CPV system from Solar Junction shows some of what’s possible. By using old-fashioned optics to concentrate sunlight on a multi-junction solar cell they claim to have a breakthrough in efficiency. The National Renewable Energy Lab took a unit off its production line and measured efficiency of 41.4%.
The multi-junction cells use a different manufacturing process than conventional PV. As the name implies multiple layers of material are deposited on the substrate, in this case gallium arsenide. Connect them serially and you can make 20 passes of material, the company says.
These cells would go onto IMAX-sized panels like those made by Amonix, which include mirrors and lenses to concentrate the light, sit on a large pedestal, and can be the heart of the kind of multi-megawatt systems utilities are looking for.
The combination of better cells and efficient system manufacturing has analysts calling this the big year for CPV. But more important, a breakthrough like this, which starts out in a market like CPV, can with mass production move directly into the standard PV market, increasing efficiency for home systems years down the road.
Breakthroughs like this don’t just sit in isolation. They pile up on one another, along with those in lower-cost manufacturing, distribution, packaging and distribution, Total energy delivered by solar includes this year’s installations as well as those of previous years, rising at ever-increasing rates, pushing further into urban and suburban as well as rural markets, forcing utilities to add intelligence and create smart grids.
A truly virtuous circle.