Is First Solar stalled in innovation and growth? Markus Beck, a thin-film solar expert and former chief technologist at First Solar, provides an industry perspective on the fate of thin-film PV in the United States.

In light of thin-film solar’s very own “House of Cards” (Hanergy) and the recent troubles of companies that are barely hanging on, a closer look at the checkered past of the thin-film solar industry is warranted.

Thin-film solar accounts for less than 5% of the global module supply. Yet, as First Solar has demonstrated, thin-film solar can be 2.5- to 3-times more capital efficient than c-Si, when accounting for the entire process flow from polysilicon through module assembly.

So, why aren’t investors attracted to thin-film solar?

While it may be an uncomfortable answer, the truth is that thin-film solar manufacturers, with the exception of First Solar, have failed to demonstrate economically viable technologies and operations. That single thin-film solar success story is overshadowed by dozens of failures – Abound, Nanosolar, Primestar and Solyndra serve as the most spectacular examples.

Operational excellence

Has China achieved thin-film operational excellence?

It remains to be seen how the Hanergy drama will end – perhaps the Chinese leadership is convinced that their Chinese operations have acquired the skills to continue on their own, no longer requiring the know-how of the German and U.S. operations. If the technology transfer has been successful, Hanergy’s operations in China should demonstrate sustainable manufacturing.

However, given the status of CNBM Group’s Avancis and CTF Solar, as well as CHN Energy’s NICE Solar Energy operations, there is little confidence that Hanergy has mastered thin-film PV manufacturing. Operational excellence is a vastly underestimated element of economically viable manufacturing.

The fact that the processes championed by the above companies are poorly suited for high-volume manufacturing only adds to the problem. Manufacturing approaches rooted in academia and technology of the 1990s or early 2000s are not compatible with today’s, and even less so with future market requirements.

Even if the necessary innovations have been identified, the question remains whether these organizations have the will to implement them or the capital and time available to transition and ramp these highly advanced factories.

Thin-film mistakes

While there are several mistakes for which the individual companies bear sole responsibility, learning from these mistakes seems to be a virtue not exhibited by those in charge. There are a few individuals who understood how to leverage past expertise, capitalize on the lessons learned in both fundamental and applied research, and enable success stories to match that of First Solar. Due to lack of access to sufficient and patient capital, none of these ever saw the light of day.

‘Money makes the world go round’ is a recurring theme, and if we look back at the history of other emerging industries, there always is a gold rush phase giving rise to too many companies. However, what is atypical in the case of thin-film solar is that after about 25 years we are left with just one success – there should have been at least five or six. Why was access to capital such a deciding factor?

In the age of publicly traded companies and quarterly earnings, analysts (sitting in a office without any hands-on experience regarding the industries they evaluate) and investors do not like to invest in manufacturing – in particular as the assets are highly specific to the organization, and therefore next-to-impossible to sell. Asset-less or at least asset-light sectors, on the other hand, continue to see a huge influx of capital. As such the thin-film solar module manufacturing sector was doomed from the get-go, at least in Europe and the United States.

Chinese policy

In comparison, China operates at a far more long-term and strategic level. If the country’s leadership has identified a particular sector as of strategic importance – for example, solar, Li-ion batteries, and electric mobility – it creates a policy environment that encourages massive investment into these sectors. This, in turn, creates a large number of private companies competing with one another for global market dominance.

A high percentage of these companies are ultimately nonviable. The best ones stand out and an entire ecosystem as well as a lot of expertise gets created, all to be fully leveraged by the small number of survivors. Since Europe or the United States have nothing to offer to their industries, the end result is indeed global dominance by the survivors of China’s internal runoff. At this point, the Chinese government rapidly scales back the subsidies and incentives, shifting them to the next industrial sector of strategic importance.

It is, quite frankly, mind-boggling that the West has failed to come up with a strategy to counter the Chinese. How many more sectors are we willing to abandon? Wall Street alone cannot sustain the U.S. economy without manufacturing. Data from the U.S. Department of Commerce shows that the manufacturing sector share of the U.S. economy has fallen to a record low of 11%, steadily declining from 25% in the 1960s.

Are we willing to see the demise of the automotive industry next? Are we willing to sacrifice a clean environment and high-paying manufacturing jobs at the altar of Wall Street and its market indices?

Valuable lessons

It’s not too late for thin-film solar in the United States.

As mentioned in the first paragraph, thin-film solar is superior in its capital efficiency. In addition, thin-film solar has a three to five times lower CO2 footprint and a two to five times higher energy return on energy investment compared to c-Si. Since the financial markets are unlikely to invest in thin-film solar on their own, politicians owe it to their constituents to create a long term industrial policy framework that directs investment into thin-film solar, and in turn creates high-paying jobs.

It is not too late – at present, Europe and the United States still hold technological leadership in thin-film solar. The blueprints for economically viable thin-film module manufacturing exist. The recent insolvency of Calyxo (December 2019), failure of Siva Power (October 2019), and troubles at CNBM, NICE and Solar Frontier are insignificant in the bigger picture, but offer valuable lessons.

Absent serious competition, First Solar might be next: It took First Solar more than four years to abandon small modules and commit to its Series 6 panels, although the concept had been conceived and proven to be viable. First Solar has not raised its hero-cell efficiency and has reduced its R&D expenditures over the last four years.

Is this the legacy we want to leave? Is this what we want all the excellent thin-film R&D in Europe and the United States to amount to?

Source: PV magazine

A team at the U.S. National Renewable Energy Laboratory has come up with a new process that would reduce the production cost of highly expensive – and highly efficient – gallium arsenide cells.

Image: NASA

Solar researchers on both sides of the Pacific are looking to space for better solar cells. In separate announcements it has emerged Chinese module manufacturer Jinko Solar and the U.S. National Renewable Energy Laboratory (NREL) are both exploring the production of PV technologies used in space to improve solar power returns back on Earth.

At the NREL, researchers claim to have made a breakthrough in III-V cell technology which they say could bring down the costs of the highly efficient – and very expensive – cells quite significantly. The team said it has grown aluminum indium phosphide (AlInP) and aluminum gallium indium phosphide (AlGaInP) in a hydride vapor phase epitaxy reactor.

Referring to the groups of the periodic table in which such materials are found, III-V solar cells are commonly used in space applications, such as to power satellites or the Mars Rover. More efficient than the silicon wafer-based cells used on earth, they are prohibitively expensive.

An epi-taxing problem

The expense is largely bound up in the two-hours-per-cell metalorganic vapor phase epitaxy (MOVPE) production process, which involves several chemical vapors being deposited onto a substrate in a single chamber.

A partial solution was suggested by the NREL with its dynamic hydride vapor phase epitaxy (D-HVPE) process which reduced the time required to less than a minute per cell. However, the inability to incorporate an aluminum content layer meant cell efficiency dropped.

Using D-HVPE, the NREL made solar cells from gallium arsenide (GaAs) and gallium indium phosphide (GaInP) with the latter working as a “window layer” to passivate the front while permitting light to pass through to the GaAs absorber layer. However, the GaInP layer is not as transparent as the AlInP layer which can easily be grown in a MOVPE reactor.

The world efficiency record for MOVPE-grown GaAs solar cells with AlInP window layers is 29.1%. For GaInP alternatives, the maximum figure for HVPE-grown solar cells is estimated to be 27%.

Separate advances

“There’s a decent body of literature that suggests that people would never be able to grow these compounds with hydride vapor phase epitaxy,” said Kevin Schulte, a scientist in the NREL’s Materials Applications & Performance Center and lead author of a paper highlighting the new research. “That’s one of the reasons a lot of the III-V industry has gone with [MOVPE], which is the dominant III-V growth technique.” Referring to the latest development, Schulte added: “This innovation changes things.”

The NREL team said they had been working to improve the economics of GaAs cells by moving the technology forward incrementally. Firstly, the D-HVPE process reduced costs and now aluminum growth means improved efficiency. With aluminum added to the D-HVPE mix, the scientists said they should be able to reach parity with MOVPE solar cells.

The laboratory last year produced a 25.3% efficient GaAs cell using D-HVPE. Kelsey Horowitz, part of the techno economic analysis group at the NREL’s Strategic Energy Analysis Center, suggested D-HVPE cells made at scale could generate electricity at $0.20-0.80/W, with the help of some tweaks and said applications such as electric vehicle integration, systems for roofs not strong enough to support a silicon PV array, and portable or wearable solar panels could be viable at that cost. “There are these intermediate markets where higher prices can be tolerated,” she said.

“The HVPE process is a cheaper process,” said Aaron Ptak, a senior scientist at the NREL’s National Center for Photovoltaics. “Now we’ve shown a pathway to the same efficiency that’s the same as the other guys but with a cheaper technique. Before, we were somewhat less efficient but cheaper. Now there’s the possibility of being exactly as efficient and cheaper.”

Jinko

Across the Pacific, Jinko Solar has signed a memorandum of understanding with the Shanghai Institute of Space Power-Sources to jointly develop high-efficiency solar cell technology. The solar manufacturer said it will use a more robust silicon wafer as the supporting substrate and bottom cell.

Jinko did not provide any further detail regarding cell technology but said its high-efficiency solar tech would take advantage of the cheap availability of silicon wafers and would easily transfer into large scale manufacturing.

“The strategic cooperation with [the] Shanghai Institute of Space Power-Sources has great importance,” said Jin Hao, VP of Jinko Solar. “In the future we will continue to increase technical cooperation, leading our industry in the name of technical innovation and providing more efficient solar panels with a wider range of choices for global customers.”

Jinko predicted the new cell technology would prompt a higher conversion rate than current technologies but said more research was needed.

Source: PV magazine

Thin-film solar panels are made with solar cells that have light-absorbing layers about 350 times smaller than that of a standard silicon panel. Because of their narrow design and the efficient semi-conductor built into their cells, thin-film solar cells are the lightest PV cell you can find while still maintaining strong durability.

Thin-film solar panels are typically made with one of the following technologies:

  • Cadmium Telluride (CdTe)
  • Amorphous Silicon (a-Si)
  • Copper Gallium Indium Diselenide (CIGS)
  • Gallium Arsenide (GaAs)
  • Organic photovoltaic

Cadmium Telluride (CdTe) solar panels

Cadmium Telluride (CdTe) solar panel

Cadmium Telluride (CdTe) is the most widely used thin-film technology. CdTe holds roughly 50% of the market share for thin-film solar panels. CdTe thin-film panels are made from several thin layers: one main energy-producing layer made from the compound cadmium telluride, and surrounding layers for electricity conduction and collection. CdTe contains significant amounts of Cadmium – an element with relative toxicity. First Solar is the top innovator and seller in this space.

CdTe is the most common thin-film solar technology, mainly because of First Solar’s utility-scale dominance. In 2016, First Solar hit a CdTe world-record cell efficiency of 22.1%, although its modules average 17%. The Series 6 module should produce 420 W, and its smaller Series 4 modules peaked at about 100 W

Advantages and disadvantages of cadmium telluride solar panels

One of the most exciting benefits of CdTe panels is their ability to absorb sunlight close to an ideal wavelength. Functionally, this means that CdTe solar panels can capture energy at shorter wavelengths than traditional silicon panels can, which matches the natural wavelengths of sunlight closely for optimal sunlight to electricity conversion. Additionally, cadmium telluride panels can be manufactured at low costs, as cadmium is abundant and generated as a by-product of key industrial materials like zinc.

The main concern with CdTe panels is pollution. Cadmium by itself is one of the most toxic materials known, and cadmium telluride also has some toxic properties. Currently, the general opinion on using cadmium telluride is that it is not harmful to humans or the environment in residential or industrial rooftop applications, but disposal of old CdTe panels continues to be a concern.

Amorphous Silicon (a-Si) solar panels

Amorphous Silicon (a-Si) solar panel

Amorphous Silicon (a-Si) is the second most popular thin-film option after CdTe. Amorphous Silicon is the most similar technology to that of a standard silicon wafer panel. Amorphous Silicon is a much better option than its counterparts (CdTe, CIGS) in terms of toxicity and durability, but it is less efficient and is typically used for small load requirements like consumer electronics. The quest for scale is always a hindrance for a-Si.

Amorphous Silicon (a-Si) is the oldest thin-film technology. It uses chemical vapour deposition to place a thin layer of silicon onto the glass, plastic or metal base. It is nontoxic, absorbs a wide range of the light spectrum and performs well in low light but loses efficiency quickly. One layer of silicon on an amorphous solar panel can be as thin as 1 micrometer, which is much thinner than a human hair.

Advantages and disadvantages of amorphous solar panels

Unlike many other thin-film panel options, amorphous silicon panels use minimal toxic materials. When compared mono- or poly-crystalline solar panels, amorphous panels use much less silicon. Amorphous silicon solar panels are also bendable and less subject to cracks than traditional panels constructed from solid wafers of silicon.

The ongoing challenge with amorphous solar panels is their low efficiency. Due to complicated thermodynamics and the degradation of amorphous silicon, among other factors, amorphous solar cells are less than half as efficient as mono- or poly-crystalline solar panels. The highest efficiency on record for a-Si is 13.6%. Attempts to raise the efficiency of amorphous panels by stacking several layers, each in tune to different wavelengths of light, has proven somewhat effective, but the overall efficiency of these types of thin-film panels is low compared to other options.

Copper Gallium Indium Diselenide (CIGS) solar panels

Copper Gallium Indium Diselenide (CIGS) solar panel

Laboratory CIGS cells have reached efficiency highs of 22.4%. However, these performance metrics are not yet possible at scale. The primary manufacturer of CIGS cells was Solyndra (which went bankrupt in 2011). Today, the leader is Solar Frontier. MiaSolé also manufactures CIGS panels in the U.S. and China.

CIGS solar cells are made from a compound called copper gallium indium diselenide sandwiched between conductive layers. This material can be deposited on substrates such as glass, plastic, steel, and aluminum, and when deposited on a flexible backing, the layers are thin enough to allow full-panel flexibility.

Advantages and disadvantages of CIGS solar panels

Unlike most thin-film solar technologies, CIGS solar panels offer a potentially competitive efficiency to traditional silicon panels. Solar Frontier has a 22.9% CIS cell efficiency record, while its full modules average lower and peak at 180 W. MiaSolé’s flexible CIGS thin-film modules average 16.5% efficiency and may peak at 250 W.

CIGS cells also use the toxic chemical cadmium. However, CdTe panels have a higher percentage of cadmium, and CIGS cells are a relatively responsible thin-film option for the environment. Even better, in some models, the cadmium is completely removed in favour of zinc.

The primary disadvantage of CIGS panels are their price. While CIGS solar panels are an exciting option, they are currently very expensive to produce, to the point where they can’t compete with traditional silicon or cadmium telluride panels. Production costs continue to be an issue for the CIGS solar panel market.

Gallium Arsenide (GaAs) solar panels

Gallium Arsenide (GaAs) solar panel

Gallium Arsenide (GaAs) is a costly technology. GaAs holds a world record of 29.1% efficiency for all single-junction solar cells and 31.6% for dual junction solar cells. GaAs is primarily used on spacecrafts and is meant for versatile, mass-scale installments of PV energy in unusual environments.

One of the leading companies in GaAs cells is Alta Devices. Alta Devices solar cells offer an exceptional combination of high efficiency, flexibility, thinness, and low weight. In addition, the product is highly configurable to meet your physical, mechanical and electrical requirements. These attributes make Alta Devices solar ideal for HALE aircraft, allowing them to fly longer, higher, and at more latitudes than competing solar technologies.

Advantages and disadvantages of GaAs cells

The backbone of our entire technology is gallium arsenide (GaAs), which is an III-V semiconductor with a Zinc-Blende crystal structure. GaAs solar cells were first developed in the early 1970s and have several unique advantages. GaAs is naturally robust to moisture and UV radiation, making it very durable. It has a wide and direct bandgap which allows for more efficient photon absorption and high output power density. Finally, it has a low-temperature coefficient and strong low light performance.

Like CIGS solar panels, the most significant disadvantage of GaAs cells is its price. GaAs solutions are costly, which will make them suitable for niche markets like space, HALE and small unmanned planes/drones. Based on its cost, GaAs cells can’t compete with traditional silicon or cadmium telluride panels.

Organic photovoltaic solar panels

Organic photovoltaic solar panel

Organic photovoltaic (OPV) cells use conductive organic polymers or small organic molecules to produce electricity. In an organic photovoltaic cell, several layers of thin organic vapour or solution are deposited and held between two electrodes to carry an electrical current.

Advantages and disadvantages of organic PV cells

The building-integrated photovoltaic (BIPV) market has the most to benefit from OPV cells. Due to the ability to use various absorbers in an organic cell, OPV devices can be coloured in several ways, or even made transparent, which has many applications in unique BIPV solar solutions. The materials needed to build organic solar cells are also abundant, leading to low manufacturing costs and subsequently, low market prices.

Like other thin-film options, organic photovoltaic cells currently operate at relatively low efficiencies. OPVs have been constructed with about 11% efficiency ratings, but scaling module production up while keeping efficiencies high is a problem for the technology. Much of the research currently surrounding OPVs is on how to boost their efficiency.

An additional issue with OPV technology is a shorter lifespan than both other thin-film options and traditional mono-or poly-crystalline panels. Cell degradation that doesn’t occur in inorganic modules is an ongoing struggle for organically-based photovoltaic products.

Efficiency Comparison Thin-film and crystalline silicon modules

Comparatively, a typical 60-cell crystalline silicon (c-Si) module averages a power output between 250 and 350 W with an efficiency between 17 and 18 %, with high-efficiency brands performing even better. One would need more thin-film modules and more area to produce the same power as a smaller group of c-Si. Crystalline silicon modules are just more consistently dependable for the majority of solar markets, and that’s why they are the dominant panel choice.

Efficiency comparison thin-film and crystalline silicon modules

The future of the thin-film market

No single thin-film brand appears to be making a grab for c-Si’s market share in the United States. First Solar is expanding its CdTe manufacturing, but that’s because it has found that utility-scale sweet spot and is dominating globally. Most CIGS and CIS manufacturers market themselves as niche products.

MiaSolé semi-rigid CIGS modules were initially designed for commercial rooftops, but the company has since branched out into emerging markets like transportation and commercial trucks. When it comes to traditional solar applications, MiaSolé’s best play is its lightweight.

A Mia Solé flexible CIGS module

CIGS manufacturer Sunflare also works with nontraditional solar markets like transportation, marine and modular/tiny home applications. The company has been working to improve the manufacturing process at its plants in Sweden and China to increase thin-film adoption.

Source: A+ Solar Solutions / EnergySage / Solar Power World

Solar power is in a constant state of innovation, with new advances in solar panel technology continuously announced. In the past year alone, there have been milestones in solar efficiency, solar energy storage, wearable solar tech, and solar design tech.

There are two main types of solar technology: photovoltaics (PV) and concentrated solar power (CSP). Solar PV technology captures sunlight to generate electric power, and CSP harnesses the sun’s heat and uses it to generate thermal energy that powers heaters or turbines. With these two forms of solar energy comes a wide range of opportunities for technical innovation. Here are some of the latest emerging/further developing solar technologies:

 Solar skin design

One major barrier for the solar industry is the fact that a high percentage of homeowners consider solar panels to be an unsightly home addition. Luckily, one new venture has a solution. Sistine Solar, a Boston-based design firm, is making significant strides with the concept of aesthetic enhancement that allows solar panels to have a customized look. The MIT startup has created a “solar skin” product that makes it possible for solar panels to match the appearance of a roof without interfering with panel efficiency or production.

Solar-powered roads

Last summer paved the way for tests of an exciting new PV technology – solar-powered roads. The sidewalks along Route 66, America’s historic interstate highway, were chosen as the testing location for solar-powered pavement tech. These roadways are heralded for their ability to generate clean energy, but they also include LED bulbs that can light roads at night and have the thermal heating capacity to melt snow during winter weather. The next stop following sidewalk tests is to install these roadways on designated segments of Route 66.

Wearable solar

Though wearable solar devices are nothing new (solar-powered watches and other gadgets have been on the market for several years), the past few years saw an innovation in solar textiles: small solar panels can now be stitched into the fabric of clothing. The wearable solar products of the past, like solar-powered watches, have typically been made with hard plastic material. This new textile concept makes it possible for solar to expand into home products like window curtains and dynamic consumer cleantech like heated car seats. This emerging solar technology is credited to textile designer Marianne Fairbanks and chemist Trisha Andrew.

Solar batteries: innovation in solar storage

The concepts of off-grid solar and solar plus storage have gained popularity in U.S. markets, and solar manufacturers have taken notice. The industry-famous Tesla Powerwall, a rechargeable lithium-ion battery product launched in 2015, continues to lead the pack with regard to market share and brand recognition for solar batteries. Tesla offers two storage products, the Powerwall 2.0 for residential use and the Powerpack for commercial use. Solar storage is still a fairly expensive product, but a surge in demand from solar shoppers is expected to bring significantly more efficient and affordable batteries to the market.

Advances in solar energy: the latest solar technology breakthroughs

Solar tracking mounts

As solar starts to reach mainstream status, more and more homeowners are considering solar – even those who have roofs that are less than ideal for panels. Because of this expansion, ground-mounted solar is becoming a viable, clean energy option, thanks in part to tracking mount technology.

Trackers allow solar panels to maximize electricity production by following the sun as it moves across the sky. PV tracking systems tilt and shift the angle of a solar array as the day goes by to best match the location of the sun. Though this panel add-on has been available for some time, solar manufacturers are truly embracing the technology. GTM Research recently unveiled a recent report that shows a significant upward trend in the popularity of tracking systems. GTM projects a 254 percent year-over-year increase for the PV tracking market this year. The report stated that by 2021, almost half of all ground mount arrays would include solar tracking capability.

Advances in solar panel efficiency

The past few years in the solar industry have been a race to the top in terms of solar cell efficiency, and recent times have been no different. Many achievements by various panel manufacturers have brought us to higher and higher maximum efficiencies each year.

The solar cell types used in mainstream markets could also see major improvements in cost per watt – a metric that compares relative affordability of solar panels. Thanks to Swiss and American researchers, Perovskite solar cells (as compared to the silicon cells that are used predominantly today) have seen some major breakthroughs in the past two years. The result will be a solar panel that can generate 20+ percent efficiency while still being one of the lowest cost options on the market.

Of course, the work doesn’t stop there, as MIT researchers reminded us in May when they announced new technology that could double the efficiency of solar cells overall. The MIT lab team revealed a new tech concept that captures and utilizes the waste heat that is usually emitted by solar panels. This typically released and non-harnessed thermal energy is a setback and opportunity for improvement for solar technology, which means this innovation could help the cost of solar to plummet even further.

Solar thermal fuel (STF)

There is little debate when it comes to solar power’s ultimate drawback as an energy source: storage. While the past decade has seen an incredible growth of the PV industry, the path forward for solar involves an affordable storage solution that will make solar a truly sustainable energy source 24 hours a day. Though solar batteries (mentioned above) are a storage option, they are still not economically viable for the mainstream. Luckily, MIT Professor Jeffrey Grossman and his team of researchers have spent much of the past few years developing alternative storage solutions for solar; the best one appears to be solar thermal fuels (STFs).

The technology and process behind STFs is comparable to a typical battery. The STF can harness sunlight energy, store it as a charge and then release it when prompted. The issue with storing solar as heat, according to the team’s findings, is that heat will always dissipate over time, which is why it is crucial that solar storage tech can charge energy rather than capture heat. For Grossman’s team, the latest STF prototype is simply an improvement of a prior design that allowed solar power to be stored as a liquid substance. Recent years saw the invention of a solid-state STF application that could be implemented in windows, windshields, car tops, and other surfaces exposed to sunlight.

Solar water purifiers

Stanford University researchers collaborated with the Department of Energy this year to develop a new solar device that can purify water when exposed to sunlight. The minuscule tablet (roughly half the size of a postage stamp) is not the first solar device to filter water, but it has made significant strides in efficiency compared to past inventions. Prior purifier designs needed to harness UV rays and required hours of sun exposure to purify water fully. By contrast, Stanford’s new product can access visible light and only requires a few minutes to produce reliable drinking water. As the technology behind solar purifiers continues to improve, expect these chiclet-sized devices to come to market with hikers and campers in mind as an ideal consumer audience.

What new solar technology means for homeowners

For those considering solar panels systems, this long list of solar panel technology innovations from recent years is nothing but good news. Efficiency upgrades, storage improvements and equipment capabilities all contribute to more efficient power output for solar panels and lower costs for systems.

Source: EnergySage

Building-integrated PV (BIPV) has been described as a place where uncompetitive PV products attempt to go to market. But this may be unfair, says Björn Rau, the technology manager and deputy director of PVcomB at the Helmholtz-Zentrum Berlin. Rau argues that the missing link to BIPV deployment lies at the intersection of the architectural community, construction industry, and PV manufacturers.

Multi-family house in Zürich, CH, with integrated, coloured PV in façade and roof designed and planned by Kämpfen für Architektur. Image: Kämpfen für Architektur

PV’s rapid growth over the last decade, to a global market of some 100 GWp installed annually, means some 350 to 400 million solar modules are produced and sold each year. However, their integration into buildings remains a niche market. According to a recent report published by the European Union Horizon 2020 research project PVSITES, only about two percent of the installed PV capacity was integrated into building skins in 2016. This meagre figure is particularly remarkable when it is considered that more than 70% of the energy produced worldwide is consumed in cities, and about 40 to 50% of all greenhouse gas emissions originate from urban areas.

To tackle both this greenhouse gas challenge and to promote on-site electricity generation, the European Parliament and the Council introduced the Directive 2010/31/EU on the energy performance of buildings with the concept of Nearly Zero Energy Buildings (NZEB) in 2010. The directive is applicable to all new buildings to be built from 2021 onwards. For new buildings that are to house public authorities, the directive was applicable already at the start of 2019.

There are no concrete actions specified to reach the Nearly Zero Energy Buildings status. Builder-owners can consider various aspects of energy efficiency such as insulation, heat recovery and electricity saving concepts. But as the overall energy balance of a building is the target of regulation, active energy production with or at the building appears to be indispensable to achieve NZEB standards.

Potential and challenges

The implementation of PV will undoubtedly play an important role in the design of future buildings or the retrofit of the existing building infrastructure. NZEB standards will be one driver of this, but it will not be alone. Building-Integrated PV (BIPV) can be used to activate existing areas or surfaces for the production of electricity. Thus, no additional space is required to bring more PV into urban areas. The potential for clean electricity produced with integrated PV is enormous. As the Becquerel institute found in 2016, the potential share of BIPV power generation in total power demand is more than 30% for Germany and even about 40% for more southern countries like Italy.

But, why do BIPV solutions still play only a marginal role in the solar business? And why are they so seldom considered in construction projects to date?

In order to answer these questions, the German research centre Helmholtz-Zentrum Berlin (HZB) performed a needs analysis by organizing a workshop and engaging with stakeholders from all fields of BIPV last year. And the results show that it is not the technology itself that is lacking.

At the HZB workshop, many from the construction industry, performing both new-build or renovation projects admitted that a knowledge gap in terms of the potential of BIPV and enabling technologies exists.

The majority of architects, planners and builder-owners simply do not have sufficient information about the technical and creative possibilities for the integration of PV into their projects. As a result, there are many reservations about BIPV, such as unalluring designs, high costs and a prohibitive level of complexity.

In order to overcome these apparent misconceptions, the needs of architects and builder-owners must be placed front-and-center and an understanding as to how BIPV is perceived by these stakeholders brought into focus.

Coloured PV modules

Function and style

BIPV is characterized by the fact that a solar module is an integral part of the building’s skin and hence becomes a multifunctional building element. Besides the generation of electricity, the module now has to take over the additional functions of the building’s skin.

Obviously, the best-known alternative to conventional rooftop installations are solar modules that are integrated both functionally and aesthetically directly into the roof. Thus, the modules not only generate electricity, they also act as roofing, protecting against the weather. If they are visible, in the case of a pitched roof, the solar modules also influence the appearance of the building. The diversity of conventional roof elements also requires PV-active elements that have high variability in shape, colour and appearance. Large-area, homogeneous glass-glass modules are needed, as well as small-sized systems like roof tiles, fitting perfectly in shape and colour to conventional roof tiles.

BIPV

Similar criteria are valid for solar modules used as façade elements, but here the aesthetic qualities are particularly important. There are different kinds of PV-active façades. Solar modules installed as a ventilated cold façade can replace conventional elements of ventilated curtain walls quite easily. But solutions as warm façade elements are also possible, for instance directly stuck onto a façade. Besides the protection against weather, heat insulation or insulation against noise are additional attributes that a PV-active façade element can deliver.

BIPV

Regarding the aesthetic function of the façade elements, there are already different concepts on the market. Coloured modules are available ranging from anthracite/black to grey, blue, green, yellow or even “golden”. These colours can be achieved, for instance, by the use of a special front glass that incorporates nano-sized layer structures. Importantly, the power output of this type of module is not prohibitively decreased, with more than 80% of the initial power output achieved when compared with a traditional module with transparent front glass.

BIPV

An alternative to the use of this special front glass is ceramic printing. This technique achieves homogeneous colours along with another feature that architects like: the potential to print almost any structure or picture on top of the module. This feature can actually make the solar cells that comprise the module almost invisible to an observer. Such printing, however, does influence the final power output more strongly. But due to the almost complete invisibility of the solar cells, the technique can also be applied to high powered crystalline modules, and therefore perform as a building element of high aesthetic value and high power.

A third technique to create coloured BIPV elements is the use of coloured foils. This technology is less costly and, even more importantly, it allows for almost any colour. Because of this feature, researchers from the Swiss Center for Electronics and Microtechnology (CSEM) were able to develop white solar modules. In principle, this development enables the “activation” of huge areas of conventional white façades that are present all over the world.

The integration of solar cells or modules into shading elements is an attractive method to combine sun protection and energy production. This can be achieved for instance by using glass with a very thin, homogeneous coverage of active photovoltaic material. Thin-film techniques like organic semiconductors (OPV), CIGS (Copper-Indium-Gallium-Selenide/Sulphite), or thin-film silicon are well suited for such applications.

Alternatively, semi-transparency can also be realized by the use of crystalline silicon cells if they are arranged in a glass-glass-module as a pattern or with larger gaps between the cells. This concept is used in systems in over-head-installations along with vertical glass façades. And it can also be implemented into movable shading installations which provide a reduction of sunlight at certain times of the day.

All of these approaches demonstrate the way in which BIPV solar modules can deliver additional functionality and address aesthetic concerns, making them more attractive to architects. But they are also accompanied by some level of reduced power output when compared to conventional, yield-optimized modules. Despite the power losses, the aesthetic and functional benefits make them attractive to the construction industry, which places a far lesser emphasis on optimization for power generation. Given this, BIPV elements should be benchmarked with respect to conventional, electrically inactive building elements.

Change of mindset

BIPV is different in many aspects from conventional rooftop solar systems, where neither a multifunctionality is required nor aesthetic aspects considered. Manufacturers need to rethink if they develop products designed for integration into building elements. Architects, builders and also the users of buildings initially expect the fulfilment of the conventional functions in a building skin. From their point of view the generation of electricity is an add-on property. In addition to that, developers of multifunctional BIPV elements have to consider the following aspects:

  • Development of cost-effective, customized solutions for solar-active building elements with variable size, shape, color and transparency;
  • Development of standards, and being attractive in price (ideally usable in the established planning tools, like Building Information Modelling (BIM);
  • Integration of PV elements into novel façade elements by the combination of building materials and energy-producing elements;
  • High resilience against temporary (local) shading;
  • Long-term stability and degradation not only of power output but also with respect to the appearance (e.g. stability in color);
  • Development of concepts for monitoring and maintenance, adapted to the individual situation onsite (considering the height of installation, the exchange of defective modules or façade element);
  • And the compliance with the legal requirements like safety (including fire protection), construction law, energy law etc.

The issue of regulatory compliance is a challenge for all stakeholders. Both construction regulations and those in the energy sector typically depend strongly on local regulations. They are not only different between individual countries, but also deviate often significantly from each other in different states, cities or even local communities. However, it is not only the solar industry that needs to adapt.

The construction industry has to become aware of its responsibility to society as a whole. Both new buildings and renovation projects have to explicitly consider energy consumption and on-site generation. Building designers and those involved with construction have to be willing to work with new materials and elements providing the additional functionality of electricity generation. They also need to accept changes in their conventional planning processes, as electrical aspects have to be considered as early as the conceptual phase.

Closing the gap

The integration of PV into buildings is a challenge for all stakeholders. There is a gap, not only of knowledge about technologies and possibilities but also of cultures. In order to close these gaps, a bridge has to be built between the world of construction and the world of energy. Challenges have to be managed by all: architects and planners; manufacturers of materials and components; and also by R&D departments. These challenges are often new to all involved and influenced by existing prejudices. These are multifaceted challenges that, by their nature, can only be tackled together, and after accepting a change in thinking.

Source: A+ Solar Solutions / PV Magazine

The message from the COP 25 conference in Spain is that the world must rapidly decarbonize or face an existential crisis. No fooling. We have to slash carbon emissions by 55% over the next 10 years or we are all dead ducks. That includes the billionaires who frolic in Davos as well as the migrants who congregate at national borders.

The problem is, everyone talks about climate change but few are doing anything significant about it. Most have absolutely no idea what to do or how to do it. But Mark Jacobson, professor of civil and environmental engineering and director of the Atmosphere/Energy Program at Stanford University, and his research colleagues say they have the answers, not just for the United States or China or Germany but for 143 countries around the world.

“There are a lot of countries that have committed to doing something to counteract the growing impacts of global warming, but they still don’t know exactly what to do,” says Jacobson. “How it would work? How it would keep the lights on? To be honest, many of the policymakers and advocates supporting and promoting the Green New Deal don’t have a good idea of the details of what the actual system looks like or what the impact of a transition is. It’s more an abstract concept. So, we’re trying to quantify it and to pin down what one possible system might look like. This work can help fill that void and give countries guidance.”

Is it gonna be costly? Oh, yeah. The team figures about $73 trillion will be needed to get it done worldwide. But that’s hardly the end of the financial discussion. They say the world can get to 80% renewable energy by 2030 and complete the transition by 2050. And doing so will pay some pretty hefty dividends — money that can be used to offset the cost. Global energy needs would be reduced by 57%. That in turn would reduce the amount of money the world spends on energy each year from $17.7 trillion to $6.6 trillion, a savings of $12.1 trillion a year. But it’s the social cost savings that are truly staggering — you know, things like death and disease caused by pollution from burning fossil fuels. The team pegs those costs at $76 trillion a year now but claims they will be reduced to $6.8 trillion annually by transitioning to 100% clean energy.

Add those two together and you get $80 trillion a year in benefits. Multiply that by the 10 years between now and 2030 and the transition to clean energy could save the world $800 trillion in avoidable costs. And, of course, all the energy generated by renewables won’t be given away. It will be sold at market prices, bringing in trillions more dollars.

But let’s say you’re a skeptic. Okay, cut those estimates in half. You still wind up with more than $400 trillion in savings over a decade on an investment of $76 trillion — more than a 500% return on your investment. What person wouldn’t jump at that deal?

Oh, you can’t put an accurate price on social costs, you say? Fine, ask yourself this question: How much would you pay to give your children, grandchildren, and great grandchildren a sustainable world where they can live long and productive lives free of cognitive impairment, emphysema, cardiovascular disease, and pulmonary issues? If you said “nothing,” stop reading immediately and go order yourself a MAGA hat.

Ready for more? Jacobson and company acknowledge there will be job losses as the result of the transition to 100% zero-emission energy, but their research suggests the transition will lead to the creation of 26.8 million more well paying jobs than the jobs that are lost. In other words, renewable energy will replace those existing jobs and add 26.8 million more worldwide.

The plan creates 3.1 million more U.S. jobs than the business-as-usual case, and saves 63,000 lives from air pollution per year.

Graphic courtesy Mark Z. Jacobson, Mark A. Delucchi, Mary A. Cameron, Stephen J. Coughlin, Catherine A. Hay, Indu Priya Manogaran, Yanbo Shu, Anna-Katharina von Krauland

In the US, the transition would require an upfront investment of $7.8 trillion. That money would pay for the construction of 288,000 new 5 megawatt wind turbines and 16,000 100 megawatt solar farms How much land would all those wind turbines and solar panels take up? Just 1.08% of the total land area of the US. But 85% of that land would be the spacing between wind turbines and could be used as farmland at the same time.

Jacobson’s work deliberately focuses only on wind, water, and solar power and excludes nuclear power, “clean coal,” and biofuels. Nuclear is excluded because it requires 10–19 years between planning and operation. It is also expensive and comes with the ever-present risk of a reactor meltdown, not to mention its role in weapons proliferation, mining, and the inherent risk of its waste products. “Clean coal” and biofuels are not included because they both cause heavy air pollution and still emit over 50 times more carbon per unit of energy than wind, water, or solar power.

This latest study also addresses the intermittent nature of renewable energy. The study finds adding energy storage can solve the intermittency problem. The researchers says electrifying all energy sectors actually creates more flexible demand for energy. For example, an electric car battery can be charged or an electric heat pump water heater can heat water any time of the day or night. Because electrification of all energy sectors creates more flexible demand, matching demand with supply and storage becomes easier in a clean, renewable energy world.

The full report, Impacts of Green New Deal Energy Plans on Grid Stability, Costs, Jobs, Health, and Climate in 143 Countries, One Earth (2019), is available online now at One Earth. It contains all the graphs and footnotes a detail-oriented person could hope for, but the most important point is the research tracks and fully supports the Green New Deal currently before the US Congress. It applies those same principals to 142 other nations which, in conjunction with the United States, consume more than 99% of all the energy used by humanity every year.

The prelude to the report says, “This paper evaluates Green New Deal solutions to global warming, air pollution, and energy insecurity for 143 countries. The solutions involve transitioning energy to 100% clean, renewable wind-water-solar (WWS) energy, efficiency, and storage. WWS energy reduces global energy needs by 57.1%, energy costs by 61%, and social (private plus health plus climate) costs by 91% while avoiding blackouts, creating millions more jobs than lost and requiring little land. Thus, 100% WWS energy is lower, costs less, and creates more jobs than current energy.”

Jacobson points out in comments shared with CleanTechnica that this latest study points to work done by 11 other groups that also found feasible paths to 100% clean, renewable energy. “We’re just trying to lay out one scenario for 143 countries to give people in these and other countries the confidence that yes, this is possible. But there are many solutions and many scenarios that could work. You’re probably not going to predict exactly what’s going to happen, but it’s not like you need to find the needle in the haystack. There are lots of needles in this haystack.”

What the Jacobson study doesn’t do is consider what will be needed to get its recommendations accepted by political leaders. That part is up to us. It is imperative that we elect leaders who will not send delegations to promote coal at global climate conferences and will not put the kibosh on extending EV incentives and investment tax credits for solar and wind power while continuing to shovel hundreds of billions of dollars worth of subsidies to fossil fuel interests.

And the only way to do that is to vote for candidates who have vowed to protect the Earth, not their cronies. The fix has been in for far too long in America and around the world. Whenever you have the chance, vote like your life depends upon it, because it does.

Source: CleanTechnica