Swiss company Insolight has created the most efficient concentrating photovoltaic solar panels (CPV), a technology that uses lenses to concentrate light onto small solar panels underneath, to date.

After two years of research, its created a CPV panel that achieved 29% efficiency, verified by the Universidad Politécnica de Madrid. Today’s conventional rooftop solar panels generally see about 18% efficiency, so Insolight’s panels are able to produce about 60% more electricity with the same square footage.

Insolight claims that solar installation costs could drop 30% with their new CPV product, which has historically been stuck on the sidelines due to its high cost when compared to traditional solar panels.

How do Insolight’s solar panels work?

insolight most efficient concentrating pv solar panel

Insolight’s solar panels are actually based on the same technology that traditional photovoltaic (or PV) solar panels use: silicon. Silicon is the magic element that makes solar panels work, by converting sunlight to usable electricity.

A single conventional solar panel typically includes 60 solar ‘cells’ (which are just 6”x6” silicon wafers) for residential solar panels or 96 for larger commercial solar panels. These cells cover almost the entire solar panel and are lined up in a grid. (Look at the image at the top of this article for a good example). The solar cells are then covered with a sheet of protective glass and encased within an aluminum frame on each side.

Insolight’s concentrating PV solar panels also include a layer of glass covering the solar cells. But instead of simply protection, this glass actually includes a grid of embedded hexagonal lenses that concentrate the light (by 200x, Insolight notes).

With the sunlight so concentrated, solar cells can be smaller and the panels don’t need as many cells to produce a decent amount of electricity. Insolight’s cells are just 1mm2, compared to typical solar cells’ 156mm2. And whereas solar cells cover the entire surface of a typical solar panel, thanks to the concentrated sunlight, Insolight only needs to cover less than 0.5% of the total surface.

For max energy production, the solar panel actually moves the grid of solar cells a few millimeters each day to keep the cells aligned with the concentrated light as the sun moves through the sky each day. These hidden mechanics are contained within the solar panel itself.

Insolight isn’t the first company to develop concentrating PV solar modules. The US Department of Energy’s Sandia National Lab worked on concentrating PV throughout the 1970s, eventually co-developing a 350 kW CPV installation in Saudi Arabia in 1981. As solar panel prices began to fall in the mid-2000s, companies again began to manufacture and install CPV.

Today, CPV installations can be found in China, USA, and South Africa, as well as a dozen or so other countries. However, CPV still accounts for a tiny fraction of total solar capacity across the globe, with about 350 MW worldwide vs traditional PV solar’s 398,000 MW of installed capacity.

The biggest deterrent to CPV’s growth is its high cost when compared to traditional PV. Lenses and hidden mechanics all add cost, and this is something Insolight claims they’ve solved.

Insolight claims a 30% cost reduction over conventional PV

Just like any technology, there’s pros and cons to CPV.

While high install costs have kept the CPV industry small over the last decade, potential cost savings are the biggest draw to Insolight’s product. Insolight CEO Laurent Coulot claims: “Our technology can reduce solar electricity costs by up to 30% on rooftops in sunny countries” thanks to the higher efficiency. That would be a huge cost savings over conventional solar panels, but while the company’s module efficiency has been verified, these cost savings haven’t been substantiated by any 3rd party yet.

A 30% discount would be a major move forward for the US solar industry, especially with the federal tax credit – itself a 30% discount – beginning to fade away this year. More efficient solar panels produce more electricity, so solar developers would need less solar panels to produce the same amount of electricity, as well as less labor, and structural and electrical equipment (less wiring and mounting hardware, for example).

However, with the cost of solar panels, labor, and equipment (excluding inverter) accounting for about 43% of total costs for commercial installations, Insolight’s system would need a major breakthrough to drop total costs by 30%. With less equipment also comes less O&M costs, but that raises a potential issue with Insolight’s products on longevity and durability.

Traditional solar panels include no moving parts whatsoever. No gears, no mechanics, nothing at all. They’re simple and can withstand the endless cycle of torrential rain, burning heat, and icy cold that rooftops endure. Solar panel manufacturers typically provide product warranties between 12 and 25 years, as well as 25 year production guarantees.

Insolight’s products, however, aren’t quite as time-tested. We’ll have to wait for specifics, as the products have yet to go into commercial production and there’s no concrete data yet available on longevity and durability.

Insolight claims the solar components – the glass and solar cells – are all ‘space grade’ (ie they’re used for space travel) and able to withstand the harshest conditions. That’s great, but the greatest concern is the equipment to move the solar cells while the sun moves through the sky. Of course, the mechanics are hidden and guarded within the solar panels themselves, but even protected, gears can stick, parts can break, and water can enter – especially when left outside 24/7. Insolight has been running outdoor pilot installations for more than a year apparently without hiccups, but with solar panels expected to last 25 years or more, a year doesn’t seem long enough.

Both on costs and savings as well as durability, we’ll have to wait for more specifics.

Insolight’s unique solution to cloudy weather

Concentrated PV solar works great in sunny areas where the panels can enjoy direct sunlight. Unlike traditional solar panels though, CPV panels can’t produce electricity from ambient light, so they don’t perform well in perpetually cloudy, overcast, or rainy locations.

Most of the time, this is just lost production, but Insolight’s created an ingenious solution: Just place its concentrating system over traditional solar panels. Insolight claims that, with a few extra steps during the assembly process, manufacturers can simply overlay their 1mm2 solar cells over the larger grid of traditional solar cells, with Insolight’s special glass over the entire surface. A cool trick, and we’ll see if it’s cost-effective to have two solar panels in one.

With this efficiency testing, Insolight is moving forward to commercialization. To speed up the process, it is currently looking for manufactures to which it can license its product.

Image Source: Courtesy Insolight

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