Point Load Power releases latest version of flat rooftop solar tracker

Point Load Power announced the launch of its flagship technology, PV Booster Gen 2, a rooftop tracking system designed to maximize solar production from monofacial and bifacial solar panels, producing up to 70% more energy per panel compared to fixed-tilt rooftop mounting solutions.

This advancement in solar performance means that building owners, occupants and project integrators investing in rooftop solar can install 50% less solar panels than required with fixed-tilt and still achieve the same annual savings, increasing return on investment (ROI) by 40% or more.

PV Booster has been engineered to solve the challenges of weight and wind that have prevented solar tracker deployments on rooftops, until now. This dynamic rooftop tracking solution meets the requirements of UL 3703 and the wind loading requirements of ASCE 7-16, and has been tested and certified by CSA U.S., a Nationally Recognized Test Lab allowing PV Booster to deploy on most flat rooftops across the United States.

Solar project integrators looking for a competitive advantage in the C&I solar market have already ordered thousands of PV Booster units. Option One Solar in California’s Apple Valley has completed its first project using the PV Booster.

“We vetted the PV Booster offering thoroughly, even went so far as to install a showcase system on the roof of our headquarters to validate the performance gains,” said Scott Thomas, president of Option One. “Almost immediately we saw that the performance is so significant that this will rapidly accelerate our growth plans in the C&I space.”

Option One Solar is fully trained to resell, install and service PV Booster in addition to receiving other partner benefits including sales support, supply allocations and volume pricing.

PV Booster Gen 2 trackers are now being delivered to customers through Point Load’s U.S.-based supply chain. This highly-anticipated solution has received accolades year-over-year from industry peers since its invention, garnering Solar Power World’s Top Products of 2017 and 2019 as well as its Editor’s Top Product Picks 2018 and winning the Cleanie’s 2019 Platinum Award for Product of the Year and Startup of the Year at the Solar Power International annual conference in 2019.

Six-junction solar cell sets two world records for efficiency

Scientists at the National Renewable Energy Laboratory (NREL) have fabricated a solar cell with an efficiency of nearly 50%.

The six-junction solar cell now holds the world record for the highest solar conversion efficiency at 47.1%, which was measured under concentrated illumination. A variation of the same cell also set the efficiency record under one-sun illumination at 39.2%.

“This device really demonstrates the extraordinary potential of multijunction solar cells,” said John Geisz, a principal scientist in the High-Efficiency Crystalline Photovoltaics Group at NREL and lead author of a new paper on the record-setting cell.

The paper, “Six-junction III-V solar cells with 47.1% conversion efficiency under 143 suns concentration,” appears in the journal Nature Energy. Geisz’s co-authors are NREL scientists Ryan France, Kevin Schulte, Myles Steiner, Andrew Norman, Harvey Guthrey, Matthew Young, Tao Song, and Thomas Moriarty.

To construct the device, NREL researchers relied on III-V materials — so called because of their position on the periodic table — that have a wide range of light absorption properties. Each of the cell’s six junctions (the photoactive layers) is specially designed to capture light from a specific part of the solar spectrum. The device contains about 140 total layers of various III-V materials to support the performance of these junctions, and yet is three times narrower than a human hair. Due to their highly efficient nature and the cost associated with making them, III-V solar cells are most often used to power satellites, which prize III-V’s unmatched performance.

On Earth, however, the six-junction solar cell is well-suited for use in concentrator photovoltaics, said Ryan France, co-author and a scientist in the III-V Multijunctions Group at NREL.

“One way to reduce cost is to reduce the required area,” he said, “and you can do that by using a mirror to capture the light and focus the light down to a point. Then you can get away with a hundredth or even a thousandth of the material, compared to a flat-plate silicon cell. You use a lot less semiconductor material by concentrating the light. An additional advantage is that the efficiency goes up as you concentrate the light.”

France described the potential for the solar cell to exceed 50% efficiency as “actually very achievable” but that 100% efficiency cannot be reached due to the fundamental limits imposed by thermodynamics.

Geisz said that currently the main research hurdle to topping 50% efficiency is to reduce the resistive barriers inside the cell that impede the flow of current. Meanwhile, he notes that NREL is also heavily engaged in reducing the cost of III-V solar cells, enabling new markets for these highly efficient devices.

Elgin in €400m Irish solar farm investment plan

Elgin Energy, a solar energy developer, has said that it plans to spend up to €400m developing solar farms in Ireland over the next five years.

The company, which has been in Ireland since 2015, has a pipeline of about 500 megawatts (MW) of projects that it hopes to deliver into the energy system by the mid-2020s.

The 500MW of solar projects will provide enough clean electricity to power more than 140,000 homes, 220,000 electric vehicles annually and offset 275,000 tonnes of carbon per year.

Ronan Kilduff, managing director of Elgin Energy in Ireland, said that it was important Ireland developed a mix of renewable power projects and did not just focus on wind.

“We can’t just keep delivering wind,” he said. “In this new decarbonised energy environment, it has to be a portfolio approach, which is wind, solar and storage.

“That portfolio approach will deliver the new energy economy. We are focused on solar and don’t work with any other technology.

“In terms of continuing investment in Ireland, we are continuing to develop projects. We are continuing to take the view that delivers projects for the 2030 targets.”

Kilduff said he does not expect any of the projects to be grid-connected until 2022.

In June of this year, the first auction of the Renewable Electricity Support Scheme is scheduled to take place.

The scheme invites renewable electricity projects to bid for capacity and receive a guaranteed price for electricity they generate.

Solar will be afforded a 10pc carve-out in the first auction. Kilduff said Elgin Energy had several projects that were eligible for this scheme.

Elgin is aiming to participate in the upcoming round with about 80MW worth of projects, representing an investment of up to €60m.

Kilduff added that the money the company uses to develop solar farms in Ireland would be coming from investors such as utility companies or pension funds. He said he was talking to these investors on a “monthly basis” for all the projects across Ireland, the UK and Australia – including with Danish utility Orsted and senior investment funds like Blackrock.

Last month, Elgin closed its fourth fundraising round for £4.7m (€5.5m) in partnership with Cantor Fitzgerald Ireland.

The funding was obtained from Irish investors and will provide capital to complete the development of 250MW of solar projects in the UK.

The fundraising round was the second successful raise completed in partnership with Cantor Fitzgerald Ireland.

The first round with Cantor Fitzgerald was closed in June 2019 and raised £4.3m (€5m).

Kilduff is planning another funding round for UK projects. It is planning to raise another €5m through Cantor Fitzgerald’s Ireland channels before the summer.

“Ireland is the only market we are participating in an auction,” he said. “That’s huge. The market is maturing; we need to move beyond subsidy.

“We were in this subsidy-driven piece, but we now are competing head-on with fossil fuels.”

Elgin Energy has delivered operational solar farms across the UK with an output of more than 230MW. This portfolio includes Scotland’s largest operational solar farm and Bann Road in Northern Ireland, which has a capacity of 46MW.

As of 2020, Elgin Energy has successfully obtained planning permission for 650MW across 55 projects.

A further two gigawatts worth of projects are at late stages of development across the UK, Ireland and Australia.

A breakthrough approaches for solar power

The Met Office says it has probably been the sunniest April on record and the solar power industry reported its highest ever production of electricity (9.68GW) in the UK at 12:30 on Monday 20 April.

With 16 solar panels on his roof Brian McCallion, from Northern Ireland, has been one of those benefitting from the good weather.

“We have had them for about five years, and we save about £1,000 per year,” says Mr McCallion, who lives in Strabane, just by the border.

“If they were more efficient we could save more,” he says, “and maybe invest in batteries to store it.”

That efficiency might be coming. There is a worldwide race, from San Francisco to Shenzhen, to make a more efficient solar cell.

Today’s average commercial solar panel converts 17-19% of the light energy hitting it to electricity. This is up from 12% just 10 years ago. But what if we could boost this to 30%?

More efficient solar cells mean we could get much more than today’s 2.4% of global electricity supply from the sun.

Solar is already the world’s fastest growing energy technology. Ten years ago, there were only 20 gigawatts of installed solar capacity globally – one gigawatt being roughly the output of a single large power station

By the end of last year, the world’s installed solar power had jumped to about 600 gigawatts.

Even with the disruption caused by Covid-19, we will probably add 105 gigawatts of solar capacity worldwide this year, forecasts London-based research company, IHS Markit.

Most solar cells are made from wafer-thin slices of silicon crystals, 70% of which are made in China and Taiwan.

But wafer-based crystalline silicon is bumping pretty close to its theoretical maximum efficiency.

The Shockley-Queisser limit marks the maximum efficiency for a solar cell made from just one material, and for silicon this is about 30%.

However, combining six different materials into what is called a multi-junction cell can push efficiency as high as 47%, under concentrated light.

Another way to break through this limit, is to use lenses to focus the sunlight falling on the solar cell.

But this is an expensive way to produce electricity, and is mainly useful on satellites.

“Not anything you would see on anybody’s roof in the next decade,” laughs Dr Nancy Haegel, director of materials science at the National Renewable Energy Laboratory in Boulder, Colorado.

The fastest improving solar technology is called perovskites – named after Count Lev Alekseevich von Perovski, a 19th Century Russian mineralogist.

These have a particular crystal structure that is good for solar absorption. Thin films, around 300 nanometres (much thinner than a human hair) can be made inexpensively from solutions – allowing them to be easily applied as a coating to buildings, cars or even clothing.

Perovskites also work better than silicon at lower lighting intensities, on cloudy days or for indoors.

You can print them using an inkjet printer, says Dr Konrad Wojciechowski, scientific director at Saule Technologies, based in Wroclaw and Warsaw. “Paint on a substrate, and you have a photovoltaic device,” he says.

With such a cheap, flexible, and efficient material, you could apply it to street furniture to power free smartphone charging, public wifi, and air quality sensors, he explains.

He’s been working with the Swedish construction firm Skanska to apply perovskite layers in building panels.

According to Max Hoerantner, co-founder of Swift Solar, a San Francisco start-up, there are only about 10 start-up firms in the world working on perovskite technology.

Oxford PV, a university spin-off, says it reached 28% efficiency with a commercial perovskite-based solar cell in late 2018, and will have an annual 250-megawatt production line running this year.

Both Oxford PV and Swift Solar make tandem solar cells – these are silicon panels which also have a thin perovskite film layer.

Since they’re made from two materials, they get to break through the Shockley-Queisser limit.

The silicon absorbs the red band of the visible light spectrum, and the perovskite the blue bit, giving the tandem bigger efficiency than either material alone.

One challenge is when “you work with a material that’s only been around since 2012, it’s very hard to show it will last for 25 years,” says Dr Hoerantner.

Insolight, a Swiss startup, has taken a different tack – embedding a grid of hexagonal lenses in a solar panel’s protective glass, thus concentrating light 200 times.

To follow the sun’s motion, the cell array shifts horizontally by a few millimetres throughout the day. It is a bid to make concentrated solar cheap.

“The architecture of these conventional concentrated photovoltaics is very costly. What we’ve done is miniaturise the sun tracking mechanism and integrate it within the module,” says Insolight’s chief business officer David Schuppisser.

“We’ve done it in a cheaper way [that] you can deploy anywhere you can deploy a conventional solar panel,” he says.

The Universidad Politécnica de Madrid’s solar energy institute measured Insolight’s current model as having an efficiency of 29%. It is now working on a module that is hoped to reach 32% efficiency.

Current silicon technology is not quite dead, though, and there are approaches to make tiny, quick wins in efficiency. One is to add an extra layer to a cell’s back to reflect unabsorbed light back through it a second time. This improves efficiency by 1-2%.

Another is to add an outside layer, which lessens losses that occur where silicon touches the metal contacts. It’s only a “small tweak”, says Xiaojing Sun, a solar analyst Wood Mackenzie research – adding 0.5-1% in efficiency – but she says these changes mean manufacturers only need to make small alterations to their production lines.

From such small gains – to the use of concentrated solar and perovskites – solar tech is in a race to raise efficiency and push down costs.

“Spanning this magical number 30%, this is where the solar cell industry could really make a very big difference,” says Swift Solar’s Max Hoerantner.

Six-junction solar cell sets two world records for efficiency

Scientists at the National Renewable Energy Laboratory (NREL) have fabricated a solar cell with an efficiency of nearly 50%.

The six-junction solar cell now holds the world record for the highest solar conversion efficiency at 47.1%, which was measured under concentrated illumination. A variation of the same cell also set the efficiency record under one-sun illumination at 39.2%.

“This device really demonstrates the extraordinary potential of multijunction solar cells,” said John Geisz, a principal scientist in the High-Efficiency Crystalline Photovoltaics Group at NREL and lead author of a new paper on the record-setting cell.

The paper, “Six-junction III-V solar cells with 47.1% conversion efficiency under 143 suns concentration,” appears in the journal Nature Energy. Geisz’s co-authors are NREL scientists Ryan France, Kevin Schulte, Myles Steiner, Andrew Norman, Harvey Guthrey, Matthew Young, Tao Song, and Thomas Moriarty.

To construct the device, NREL researchers relied on III-V materials — so called because of their position on the periodic table — that have a wide range of light absorption properties. Each of the cell’s six junctions (the photoactive layers) is specially designed to capture light from a specific part of the solar spectrum. The device contains about 140 total layers of various III-V materials to support the performance of these junctions, and yet is three times narrower than a human hair. Due to their highly efficient nature and the cost associated with making them, III-V solar cells are most often used to power satellites, which prize III-V’s unmatched performance.

On Earth, however, the six-junction solar cell is well-suited for use in concentrator photovoltaics, said Ryan France, co-author and a scientist in the III-V Multijunctions Group at NREL.

“One way to reduce cost is to reduce the required area,” he said, “and you can do that by using a mirror to capture the light and focus the light down to a point. Then you can get away with a hundredth or even a thousandth of the material, compared to a flat-plate silicon cell. You use a lot less semiconductor material by concentrating the light. An additional advantage is that the efficiency goes up as you concentrate the light.”

France described the potential for the solar cell to exceed 50% efficiency as “actually very achievable” but that 100% efficiency cannot be reached due to the fundamental limits imposed by thermodynamics.

Geisz said that currently the main research hurdle to topping 50% efficiency is to reduce the resistive barriers inside the cell that impede the flow of current. Meanwhile, he notes that NREL is also heavily engaged in reducing the cost of III-V solar cells, enabling new markets for these highly efficient devices.