Module Evolution: What big-time PV improvements will boost panel efficiency?

Light Bulb Illustration

The solar industry is forever in need of constant innovation and scientific breakthrough. Even now, with PV capacity reaching record highs, prices continuing to fall and efficiencies inching up, more innovation is needed. A lot more. (Not to mention whatever fallout is felt in the module market following the Section 201 trade remedy.)

At Intersolar North America in July, Martin Keller, director of the National Renewable Energy Laboratory (NREL), told attendees that if new materials and new production methods don’t hit the market, solar will never make the impact we all think possible as a distributed energy source.

“What are some new materials we can combine with new manufacturing technologies?” he asks. “If you are really serious about manufacturing on a global scale, we need new methods and new materials.”

If you are reading this, we assume you meet Keller’s “really serious” criteria and thus would like an update on some of those new methods and materials on the horizon. As far off as Keller made 2017 technology seem from where it needs to be, we think there are enough smart people working on stuff right now that this challenge will be met.

Silicon Successors

NREL is at the forefront of renewable research and pushing innovation, and scientists there have developed a new perovskite ink with a long processing window that allows the scalable production of perovskite thin films for high-efficiency solar cells. Keller was excited about it and pointed to a chart that showed a severe uptick in efficiency compared to today’s cells.

The catch is perovskite solar cells have yet to move beyond the laboratory. The crystalline structure of perovskites must be carefully grown upon a substrate, which is normally done by laboratory-scale spin coating — a technology that can’t be scaled to large-scale manufacturing at this time.

“It’s years out from production, but you can see the increase in efficiency is a very steep slope, and then combine that with new technologies like inks and spray ons,” Keller says.

Over at Penn State, researchers are testing a prototype of a new concentrating photovoltaic (CPV) system with embedded microtracking that can produce over 50 percent more energy per day than standard silicon solar cells. CPV focuses sunlight onto smaller but much more efficient solar cells, like those used on satellites, to enable overall efficiencies of 35 to 40 percent. Current CPV systems are large — the size of billboards — and have to rotate to track the sun during the day. These systems work well in open fields with abundant space and lots of direct sun.

“What we’re trying to do is create a high-efficiency CPV system in the form factor of a traditional silicon solar panel,” says Chris Giebink, a Charles K. Etner assistant professor of Electrical Engineering at Penn State.

To do this, the researchers embed tiny multi-junction solar cells, roughly half a millimeter square, into a sheet of glass that slides between a pair of plastic lenslet arrays. The whole arrangement is about 2 centimeters thick and tracking is done by sliding the sheet of solar cells laterally between the lenslet array while the panel remains fixed on the roof. An entire day’s worth of tracking requires about one centimeter of movement.

“Our goal in these recent experiments was to demonstrate the technical feasibility of such a system,” says Giebink. “We put together a prototype with a single microcell and a pair of lenses that concentrated sunlight more than 600 times, took it outdoors and had it automatically track the sun over the course of an entire day.”

The researchers report that the CPV system reached 30 percent efficiency, in contrast to the 17 percent efficiency of the silicon cell. All together over the entire day, the CPV system produced 54 percent more energy than the silicon and could have reached 73 percent if microcell heating from the intense sunlight were avoided.

But (there is always a but) Giebink noted that major challenges still lie ahead in scaling the system to larger areas and proving that it can operate reliably over the long term. Insert sad emoji here.

While we wait for those new markets to scale and develop, there are a bunch of intriguing options that could boost efficiencies and bridge the gap.

Production Disruption

Rayton Solar

Rayton Solar wants to supplant the very way we cut silicon in the first place — a technique that hasn’t changed much since its inception in the 1950s. Cutting silicon with a diamond saw leads to a significant amount of sawdust because the process wasn’t originally concerned with reducing waste for large-scale production.

“We developed a process using ion implantation to cut our very thin pieces of silicon, and there is zero sawdust in the process, so it allows us to increase the yield of the raw silicon and get a 60 percent reduction in the cost to make a solar panel,” says Rayton Solar CEO Andrew Yakub.

Phoenix Nuclear Labs (PNL) has signed a long-term agreement to be the exclusive supplier of high-current proton accelerators to Rayton Solar to produce low cost, high efficiency solar panels. Under the terms of the agreement, PNL will deliver the first system to Rayton at the end of 2017, followed by several additional units in 2018 and 2019.

The Rayton process utilizes high current ion beams produced by the PNL technology to cleave thin layers of silicon with zero waste. The process uses 50-100 times less silicon than the traditional method. Because of this, Rayton can also use a higher quality silicon that is about 10 times as expensive.

“We are capable of making up to 100 times as many solar panels with the same amount of silicon that our competitors use to make just one panel,” Yakub says.

In a less radical direction, mono passivated emitter rear cells (PERC) have efficiency seekers excited, and advancements keep happening every day. Silicor Materials says that, in its first ever attempt, it has produced p-type mono PERC cells at approximately 20 percent efficiency, using 100 percent of its standard silicon feedstock. Silicor hopes its technology for manufacturing solar grade silicon provides the solar market with a simple solution to manufacturing the highest quality, highest efficiency solar cells of the future at a substantially lower cost than all other solar grade silicon manufacturing technologies on the market.

Sol Voltaics has taken a big step toward commercializing a new efficiency-boosting solar technology. Using its proprietary Aerotaxy process to manufacture PV nanowires, its SolFilm solution could boost solar module performance up to 50 percent at a low cost.

SolFilm consists of billions of gallium arsenide (GaAs) nanowires oriented facing the sun. The nanowires, each of which is a complete solar cell, convert high-energy sunlight directly into power. Gallium arsenide, previously seen in space and concentrated solar projects, has long held great potential for the mainstream solar industry, but its high fabrication costs have prevented economical fabrication of large solar panels.

Manufacturing nanowires with Aerotaxy dramatically reduces the required amount of GaAs and removes the need for a crystalline support wafer, significantly lowering material costs.

“The nanowires are grown such that the top and bottom of the wire have opposite doping profiles. This makes each nanowire a fully functional solar cell, with a pn junction along the length of the wire,” states Erik Smith, CEO of Sol Voltaics. “Whether used by module manufacturers as a single-junction, high-efficiency, low-cost solution or as a boosting technology, we believe SolFilm will usher in a new age of solar power efficiencies.”

Sol Voltaics just closed a record funding round of $21.3 million (following a $17 million investment last year). The new funding will be used to accelerate commercialization of the technology.

You Down with BIPV?

Forward Labs Solar Roof

This is the part of the modules section when we throw an obligatory mention to Tesla and its new, mysterious Solar Roof. Building-integrated PV tiles are not new, but like the cool kid who started wearing bell bottoms to school, Elon Musk has made them trendy again. Any casual conversation I have about the solar industry outside the office always leads to the layperson asking about Tesla’s Solar Roof. So, word is out.

The buzz for the industry is certainly a good thing, but those everyday homeowners might not get the best bang for their buck going with the Tesla Solar Roof. Online solar marketplace EnergySage ran numbers on comparative systems for a 3,000-sq-ft home in Southern California with a $200 monthly electric bill, as an example, and the results speak for themselves:

  • Standard PV system: $26,030; 13,000 kWh annual production
  • Tesla Solar Roof: $50,900; 10,000 kWh annual production

The real hook of the solar roof is how it replaces the roof itself. But if you add in a $20,000 cost for a roof replacement as EnergySage did (based on a Consumer Reports estimate of such a job for that house size), the non-solar roof is still a better value.

Put more simply, GTM Research determined that Tesla Solar Roofs produce about 6 watts per square foot, whereas a high-efficiency module would produce 19 watts per square foot. There is also a potential hang up with applying for ITC credits because not all of the shingles being installed will be solar shingles.

Anyway, we wouldn’t bet against Tesla making this concept happen as the costs become more competitive over time, but a bit more quietly, Palo Alto-based startup Forward Labs entered this space at the same time as Tesla, claiming to be 33 percent cheaper, more efficient and easier to install — 19 watts per square foot of energy density at about $3.25 per watt, installed in two to three days.

“The way we achieved such fantastic cost savings was fairly simple,” Zach Taylor, CEO and product architect of Forward Labs. “We use more affordable materials than our competitors and employ standard manufacturing processes. The roof’s installation process is simple and quick — we can install our system in half the time that other companies can. The benefit to homeowners is a return on their investment that cuts the usual solar payback time in half.”

Forward Labs uses a proprietary five-layer construction. A robust glass panel sits atop an optical layer, which cloaks the underlying black monocrystalline solar cells and enables eight possible color choices. These top layers are embedded over a galvanized metal form-factor that appears nearly identical to the non-solar portions of the roof.

“The colors of solar roofing products have always been muted or limited in choice for the sake of energy production,” says Reid Anthony, former CEO and president of precision optics company Kowa American. “Forward’s embedded optics have overcome these challenges, giving homeowners the freedom to have a solar roof in some of the most desired colors, without increasing the cost or sacrificing energy production. It’s a game-changer for both consumers and the solar industry.”

The solar roof not only weighs the same as a composite shingle roof, its sleek design also vents cool air under the solar cell layer, keeping operating temperatures down while maximizing cell efficiency.

“Although most of the technology has been developed in-house, we’re proud to have developed Forward’s panels with high-quality materials from LG, Valspar and other Fortune 500 companies,” says Taylor. “This will enable Forward to quickly establish a strong network of key supply chain partners.”

Tweaks on the Traditional

panasonic

Current technology still offers a ton of potential, especially with tweaks to traditional panel architecture. Here are four recent developments.

1. Maxim Technology, which we initially reported on to start the year in our Innovations Issue, is gaining momentum with its module optimization technology — a chip that is installed directly into the PV module instead of a diode. The installer can simply wire this system with a string inverter as they normally might and achieve full optimization, MPPT and rapid shutdown compliance.

The Maxim technology, over time, could change the value of high-efficiency modules too. Certain mono PERC modules, for example, are prone to hotspots, which can counteract their added efficiency value. Incorporating cell-level optimization would remove that issue.

2. The two leading thin-film solar manufacturers, First Solar and Solar Frontier, represent a combined manufacturing capacity of 4 GW. While they do not pose a short-term challenge to crystalline silicon players’ market dominance, ongoing innovations will ensure thin-film remains a significant player, according to Lux Research.

Of the two, First Solar is far bigger, with expertise in utility-scale systems and a new large-format module design that will help maintain its GW-scale presence in utility-scale systems, as deployment grows in emerging markets. Solar Frontier has gradually diversified its business away from its home market of Japan and is making steps toward a rooftop BIPV product.

First Solar’s further growth hinges on plant-wide adoption of its Series 6 module and achieving systems costs below $1 per watt. Solar Frontier’s future rests on its ability to move its success in the lab to commercial production, and a partnership with a storage provider to integrate a lithium-ion battery option with its residential systems.

3. In the add-on category there is PLANT PV’s new Silver-on-Aluminum paste. The goal here is providing a 1 percent increase in relative power output for c-Si solar cells via easy implementation with no added investment cost for cell producers. Silver-on-Aluminum paste provides cell manufacturers with the ability to print the paste directly onto dried aluminum film, allowing them to cover the entire back of the wafer with aluminum paste and obtain the beneficial passivation of a continuous aluminum back-surface field.

“For 20 years the industry has had to accept an efficiency loss from printing silver bus bars directly onto solar cells,” stated Craig Peters, CEO of PLANT PV. “Our Silver-on-Aluminum paste has been developed to directly address this problem and enable cell producers to eliminate these unnecessary efficiency losses in all conventional solar cells today.”

4. Incremental efficiency improvements continue from the traditional sources as well. Panasonic Corp. achieved a new leading output temperature coefficient for mass-produced silicon photovoltaic modules, at -0.258 percent /°C. This improves on the previous temperature coefficient by 0.032 points at the mass production level, highlighting the positive temperature characteristics of heterojunction solar cells and further improving Panasonic’s unique heterojunction technology.

Panasonic HIT modules, which boast an improved output temperature coefficient, will nearly halve the decline in the conversion efficiency, significantly increasing performance in high temperature settings.

Chris Crowell is managing editor of Solar Builder.

 

— Solar Builder magazine

Lux Research: Thin-film solar modules could challenge silicon in the coming years

The two leading thin-film solar manufacturers, First Solar and Solar Frontier, represent a combined manufacturing capacity of 4 GW. While they do not pose a short-term challenge to crystalline silicon players’ market dominance, ongoing innovations will ensure thin-film remains a significant player, according to Lux Research.

Of the two, First Solar is far bigger, with expertise in utility-scale systems and a new large-format module design that will help maintain its gigawatt-scale presence in utility-scale systems, as deployment grows in emerging markets. Solar Frontier has gradually diversified its business away from its home market of Japan and is making steps towards a rooftop building-integrated photovoltaic (BIPV) product.

“Both Solar Frontier and First Solar are moving forward to remain competitive with crystalline silicon. While First Solar will remain the thin-film leader, Solar Frontier has exhibited a willingness to form joint ventures to extend its scale,” said Tyler Ogden, Lux Research analyst and lead author of the report titled, “Tier-One Technology Tracker: Charting the Momentum of Thin-Film Leaders Solar Frontier and First Solar.”

Lux research thin film

Lux Research analysts compared Solar Frontier and First Solar, evaluating the two companies’ varied approaches, strengths and weaknesses. Among their findings:

• First Solar ahead on momentum. In Lux’s momentum analysis, First Solar had a score of 3.7, out of five, moving faster in technology progress and executing a competitive product strategy. Solar Frontier scored 2.9, moving adeptly into new markets through partnerships, while keeping pace in its financial position and manufacturing.

• Solar Frontier capitalizes on niches. Solar Frontier is taking steps toward a BIPV product, with preconfigured systems, flexibility and novel form factors. These are small differentiations in its current rooftop market, but can provide the groundwork for a larger BIPV industry with Solar Frontier at the helm, potentially a huge payoff.

• Challenges lie ahead for both. First Solar’s further growth hinges on plant-wide adoption of its Series 6 module and achieving systems costs below $1.00/W. Solar Frontier’s future rests on its ability to move its success in the lab to commercial production, and a partnership with a storage provider to integrate a lithium-ion battery option with its residential systems.

Thin-Film in 2016: Don’t look now, but thin-film PV is positioned for growth

 

— Solar Builder magazine

First Solar sells Moapa Southern Paiute Solar project to Capital Dynamics

First Solar completed the sale of the cash equity interests in the 250 MW AC Moapa Southern Paiute Solar Project in Nevada to global private asset manager Capital Dynamics. Terms of the deal were not disclosed.

You may recall that this was one of our Projects of the Year for 2016.

Moapa_screws

Minority tax equity interests in the project are shared by GE unit GE Energy Financial Services, and an affiliate of the Goldman Sachs Group.

Located on the Moapa River Indian Reservation approximately 30 miles north of Las Vegas, this facility is the first-ever utility-scale solar power plant to be built on tribal land, and has a long-term power purchase agreement (PPA) with LADWP to bring clean, renewable energy to Los Angeles residents. The solar power plant is capable of generating enough clean energy to power approximately 111,000 homes.

 

First Solar Energy Services will operate and maintain the power plant for Capital Dynamics.

By using renewable energy from the sun, the Moapa Southern Paiute Solar Project will avoid approximately 341,000 metric tons per year of carbon dioxide emissions that would have been produced if the electricity had been generated using fossil fuels – the equivalent of taking nearly 73,000 cars off the road. First Solar’s technology creates no air or water pollution and uses no water to generate electricity.

— Solar Builder magazine

Investor outlook: Four solar companies to watch as the industry matures

The following perspective was shared with us via Financialbuzz.com

Over the course of the last several years the solar industry has finally gone mainstream. A recent research published on December 12, 2016 by The Solar Energy Industries Association (SEIA) shows how much progress has been made. The U.S. installed 4,143 megawatts (MW) of solar PV in the third quarter of 2016 to reach 35.8 gigawatts (GW) of total installed capacity, enough to power 6.5 million American homes. With more than 1 million residential solar installations nationwide and record-breaking growth in the utility-scale sector, the industry is projected to nearly double year-over-year.

Despite the encouraging numbers however, the industry still faces the challenges that are so familiar to businesses reaching maturity – improving efficiency and cutting costs. Thanks to technological innovations, the solar market is combating these challenges. Solarwindow Technologies, Corning Incorporated, Tesla, Canadian Solar, First Solar.

The innovations ahead

Nevada solar utility

Most solar companies today manufacture solar panels using large portions of silicon, called ingots, and cut it into small rectangular shapes. These silicon components account for approximately 40% of the cost of production for solar panels. While some companies have been finding ways to manufacture panels for cheaper using the same materials, the expectations are now somewhat different.

According to a report by Fortune, “today as the industry matures, much more of the expected lowered production costs will come from new components that plug into traditional silicon solar panels, new ways to manage the electrons from panels, or new ways to finance and sell the panels.” In addition, some innovative companies are coming up with entire new techniques to salvage the sun’s energy.

Solarwindow Technologies creates transparent electricity-generating liquid coatings. When applied to glass or plastics, these coatings convert passive windows and other materials into electricity generators under natural, artificial, low, shaded, and even reflected light conditions. Earlier this week, Solarwindow Technologies announced that, “it has been named a winner in the 2017 BIG Innovation Awards presented by the Business Intelligence Group.

Unlike conventional solar photovoltaic (PV) systems, the company’s coatings can be applied to all sides of tall towers, generating electricity using natural and artificial light, as well from diffused and reflected light, and in shaded areas.

RELATED: How the cell-optimizer, string inverter combo could change PV systems 

When applied to a 50-story building, SolarWindow could avoid more than two million miles of equivalent carbon dioxide emitted by vehicles on the road, reduce electricity costs by as much as 50 percent per year, provide 15-times the environmental benefits over other roof-top solar PV systems, and according to independently-validated engineering modeling, could achieve a one-year financial payback.”

On Jan. 18, Solarwindow Technologies revealed that the company’s “scientists and engineers recently applied layers of the company’s liquid coatings on to Corning Willow Glass and laminated them under conditions that simulate the high pressure and temperatures of the manufacturing processes used by commercial glass and window producers. The result is a bendable glass ‘veneer’, as thin as a business card, which generates electricity.” The Corning Willow Glass is developed by Corning Incorporated (NYSE: GLW), a company with expertise in specialty glass, ceramics, and optical physics.

American automaker and energy storage company, Tesla Inc., showcased it’s at-home battery, the Powerwall 2, for homes and small businesses that stores the sun’s energy and delivers clean, reliable electricity when the sun isn’t shining. Chief Executive Officer, Elon Musk, emphasizes that homes can capture this free, abundant energy source through rooftop solar tiles, turning sunlight into electricity for immediate use or storage in a Powerwall battery. The new Tesla Powerwall 2 will cost around $5,500, which consist of a built-in inverter and twice the storage capacity of the first ever Powerwall battery. The product is not yet available out in the market.

Canadian Solar Inc. announced that it has completed the sale of the outstanding shares of 3 utility-scale solar farm holding companies, SSM 1 Solar ULC, SSM 2 Solar ULC, and SSM 3 Solar ULC, totaling 59.8 MW AC to Fengate SSM Holdco LP, an affiliate of Fengate Real Asset Investments for over $195.32 Million. Dr. Shawn Qu, Chairman and Chief Executive Officer of Canadian Solar, commented, “We are delighted to announce the successful sale of 3 additional solar power plants. To this point, we have sold all of our operating plants of 100 MWdc in Canada, including the BeamLight and Alfred projects sold in December 2016. We value our partnership with Fengate and look forward to deepening our cooperation while we continue to monetize our solar power plants in other countries.”

First Solar Inc. has been awarded the module supply contract for the 140-megawatt Sun Metals Solar Farm in North Queensland, Australia. The project marks the largest solar initiative by the country and, once constructed, is set to utilize more than 1.16 million First Solar advanced thin-film photovoltaic modules to produce approximately 270,000 megawatt-hours of energy in its first year of operation.

“Large-scale solar is fast becoming one of the most cost-effective sources of energy generation in Australia. This project represents the viability of the commercial and industrial solar market in Australia, and the growing trend of major energy consumers owning and operating renewable energy assets,” said Jack Curtis, First Solar’s regional manager for Asia Pacific.

— Solar Builder magazine

First Solar jumping to Series 6 module production, layoffs forthcoming

First Solar logoFirst Solar is changing things up amid some uncertain times for large, industry leaders like themselves. In terms of production, the company announced the acceleration of its Series 6 modules into 2018, with approximately 3 GW of production expected in 2019. Over the course of 2017 and 2018 the company’s existing production facilities will be converted to Series 6 production and the current Series 4 product will be phased out. As a result of the change in roadmap the Company will cancel its Series 5 product.

“The acceleration of the Series 6 roadmap is an important development for First Solar,” said Mark Widmar, CEO of First Solar. “Following the completion of an internal review process to evaluate the best competitive response to address the current challenging market conditions, we have developed plans that will enable us to more quickly begin production of our Series 6 module. Although the decision to accelerate our Series 6 roadmap requires a restructuring of our current operations, we expect the transition to Series 6 will enable us to maximize the intrinsic cost advantage of CdTe thin-film technology versus crystalline silicon. Recent steep module pricing declines require us to evaluate all components of our cost structure and streamline our business model to best position the Company for long-term success.”

RELATED: First Solar books big utility-scale community solar deployment 

Layoffs on the way

First Solar is also reducing the workforce at its manufacturing facilities both domestically and internationally as a result of the transition from Series 4 to Series 6 production. Additional reductions in administrative and other staff are also planned. The total number of layoffs will be around 1,600 employees.

Resulting from the transition to Series 6 from Series 4 and other competitive factors, the Company expects to incur restructuring and asset impairment charges of $500 to $700 million, which includes a cash impact of $70 to $100 million.

— Solar Builder magazine