Tesla Solar Roof System issued ESR-4074 by ICC Evaluation Services to affirm its compliance with building codes

tesla solar roof

ICC Evaluation Service (ICC-ES), a member of the International Code Council of companies and the experts in building product evaluation and certification, issued ESR-4074 to Tesla, Inc. for their Tesla Solar Roof System. This report provides evidence that the Tesla Solar Roof System is in compliance with code requirements of the International Building Code (IBC) and International Residential Code (IRC) and California Building Code (CBC) and California Residential Code (CRC).

The Tesla Solar Roof System is a complete roof covering system composed of electrically active building-integrated photovoltaic (BIPV) and (inactive) nonBIPV roof tiles, along with flashing and other accessories. The BIPV roof tiles generate electricity from the sun and include photovoltaic modules. The nonBIPV roof tiles are similar to the BIPV roof tiles, except that they do not include photovoltaic cells, and therefore do not generate electricity.

“We are pleased to issue a report to Tesla, a manufacturer of alternative energy systems that relies heavily on ICC-ES’ technical expertise and high-quality reports”, said ICC-ES Senior Staff Engineer Yamil Moya, P.E. “ICC-ES thoroughly examined Tesla’s product information, test reports, quality control methods and other factors to ensure the product is code compliant.”

— Solar Builder magazine

Tesla Solar Roof System issued ESR-4074 by ICC Evaluation Services to affirm its compliance with building codes

tesla solar roof

ICC Evaluation Service (ICC-ES), a member of the International Code Council of companies and the experts in building product evaluation and certification, issued ESR-4074 to Tesla, Inc. for their Tesla Solar Roof System. This report provides evidence that the Tesla Solar Roof System is in compliance with code requirements of the International Building Code (IBC) and International Residential Code (IRC) and California Building Code (CBC) and California Residential Code (CRC).

The Tesla Solar Roof System is a complete roof covering system composed of electrically active building-integrated photovoltaic (BIPV) and (inactive) nonBIPV roof tiles, along with flashing and other accessories. The BIPV roof tiles generate electricity from the sun and include photovoltaic modules. The nonBIPV roof tiles are similar to the BIPV roof tiles, except that they do not include photovoltaic cells, and therefore do not generate electricity.

“We are pleased to issue a report to Tesla, a manufacturer of alternative energy systems that relies heavily on ICC-ES’ technical expertise and high-quality reports”, said ICC-ES Senior Staff Engineer Yamil Moya, P.E. “ICC-ES thoroughly examined Tesla’s product information, test reports, quality control methods and other factors to ensure the product is code compliant.”

— Solar Builder magazine

Tesla drops to third in U.S. Solar Installer Rankings due to its strategy shift

dropping PPA prices

Tesla installed 6.3 percent of U.S. residential solar capacity in the first quarter of 2019, marking the first time the company has fallen to third place since Wood Mackenzie Power & Renewables has been tracking installer market shares in its U.S. PV Leaderboard, dating back to Q1 2013. Vivint Solar reclaimed the number two for the first time since falling to third in Q3 2017.

Meanwhile, Sunrun which overtook Tesla for first place in the second quarter of 2018, gained market share over both Tesla and Vivint Solar. Sunrun installed 11 percent of all home solar capacity installed in the first quarter of the year, notching its highest share ever.

Leading U.S. residential solar installers

Tesla Sunrun market share

Source: Wood Mackenzie Power & Renewables U.S. PV Leaderboard

The top three residential solar installers combined to install 25 percent of all new U.S. residential capacity in the first quarter of the year. This is a significant departure from Tesla’s (then SolarCity’s) peak quarters when it alone accounted for more than a third of the entire U.S. residential solar market.

“Tesla has essentially thrown in the towel on pursuing growth in the residential solar space because it has concluded that acquiring customers is simply too expensive,” writes Austin Perea, Wood Mackenzie Senior Solar Analyst, in a recent report on Tesla’s store closures. “Rather, Tesla will rely on its brand power and low-cost referral methods to keep the solar business afloat until it stabilizes.”

From the same report, Perea writes:

“For Tesla, the installation bleeding lasted into 2018 when its national residential installation volume fell another 41% annually despite other national installers experiencing growth. Vivint and Sunrun’s direct businesses grew 7% and 37%, respectively. But even as other installers grew in 2018, Tesla’s standing continued to have a substantial impact on the national residential solar market.”

According to the report, in 2017 the U.S. residential solar market as a whole fell 15 percent. However, if you were to exclude Tesla from the equation, the market would have only fallen two percent. Similarly, the residential market grew 7 percent in 2018, however excluding Tesla entirely, it would have grown by 15 percent. “Clearly, Tesla had a marked drag on residential solar in 2017 and, to a lesser degree, in 2018,” writes Perea.

“Despite stronger growth from the rest of the market, the growth outlook for 2019 – like 2017 and 2018 – continues to be hampered by Tesla’s decisions to cut back on its customer acquisition channels, though less severely than in previous years,” said Perea.

According to the latest U.S. Solar Market Insight report, Wood Mackenzie forecasts the U.S. residential solar market to grow a modest three percent by the end of this year.

“Tesla stepping away from being a growth driver for solar reaffirms our hypothesis that long-term national growth will continue to be driven by smaller local and regional players and less reliant on national players, though Sunrun and Vivint will remain important,” said Perea. “Indeed, in the long run, it seems that Tesla’s decisions may send a vital message about how solar is sold.”

Additional key findings

• CS Energy (formerly Conti Solar) rose to the top of the commercial solar installer rankings with nearly 48 MW of installations across New York, New Jersey, Minnesota and Rhode Island in Q1 2019.

• Constellation leads the rankings for commercial solar asset ownership this quarter, commanding 5% of the market.

• Both Sunrun and Vivint Solar have now surpassed SolarCity/Tesla as the largest residential solar installers in the US.

• Loanpal leads the financier rankings for the first time ever, less than 1.5 years after entering the solar loan space.

— Solar Builder magazine

Shave and a rate cut: How solar + storage solutions are shaving peaks, saving big bucks

shave and a rate cut

Shaving the peaks off commercial and industrial (C&I) electric bills is the top revenue stream for energy storage systems, and given the trend in increasing utility charges for time-of-use consumption, peak shaving can pay for a system in as little as three years, system providers say.

Just how high the peaks need to be in order to justify the investment in an energy storage system varies with geography and jurisdiction, but in general, demand charges of $15 to $20/kW or more are clear candidates, says John Merritt, the director of applications engineering at Ideal Power.

“The vast majority of converters we sold for storage systems in the past year went to California, with eight out of 10 used in applications for peak shaving,” Merritt says. “With the California incentives and the federal tax break, C&I customers can get a payback in as little as three years and in other cases in four or five years.”

A $15/kW demand charge threshold for economic feasibility also necessitates a 50-kW monthly usage level within the peak charge range, suggests Ellen Howe, VP of marketing and corporate development at JLM Energy, based in Rocklin, Calif. Her colleague, Nate Newsom, VP of enterprise sales, says, “Commercial entities that spend 3 percent or more of their monthly budget on electricity and/or experience 40 percent to 50 percent [higher than normal] demand charges typically are a good fit for energy storage.”

The C&I market is virtually untapped

Analyzing the C&I market for energy storage usefulness, the National Renewable Energy Laboratory in Golden, Colo., started with the assumption that demand charges of $15/kW or higher typically result in favorable economics for energy storage projects. Then, counting rooftops, NREL determined that “Of the nearly 18 million commercial utility customers in the United States, almost 5 million of them are exposed to, or could be exposed to demand charges of $15/kW or higher that would indicate cost-effective opportunities for energy storage.”

While not every potential C&I customer will bite the bullet for a stand-alone energy storage system, aggregation through community solar projects, or virtual power plants (VPP), is increasingly an opportunity.

Tesla is among the storage providers that is now active in community solar, with a high-profile October rollout of its commercial-scale Powerpack system at Puerto Rico’s Hospital del Niño, a children’s hospital in San Juan. As of April, Tesla had provided commercial Powerpacks and residential-scale Powerwalls to over 600 locations, with the count rising daily. The company has been quoted stating a goal of providing up to 40 percent of the island’s power storage needs via community solar system build-outs.

One new provider of VPP services is solar converter maker SolarEdge Technologies, which in May announced a solution for grid services and virtual power plants, thanks to its recent acquisition of Gamatronic Electronic Industries. The solution includes grid services of aggregative control and data reporting that enable the pooling of PV and storage in the cloud for the creation of VPPs.

demand charge example

Fig 1. Example of the steep savings achieved just through shaving peak demand.

Storage + trackers (plus pumps, plus…)

A relatively new storage configuration for C&I customers is the use of storage with solar trackers, like the 1.1-MW project at the Maharishi University of Management in Fairfield, Iowa. This project will use the NEXTracker NX Flow integrated solar-plus-storage system, in combination with an Ideal Power SunDial Plus converter and a Vanadium flow battery. The project is NEXTracker’s first large-scale installation of the NX Flow solution.

Another budding C&I application for storage is with water authorities, which can typically generate energy from solar for less than it costs to pump water uphill for a discharge to a generator turbine. The San Diego County Water Authority, for example, won $1 million from the California Public Utilities Commission to install intelligent energy storage that will tap the energy from solar panels already installed at the SDWA’s Twin Oaks Valley Water Treatment Plant.

The SDWA energy storage project, being operated by Santa Clara-based ENGIE, is expected to save an estimated $100,000 per year by storing low-cost power for later use during high-demand periods for peak shaving. The storage will help the plant cope with its highest energy use period, during peak afternoon hours. ENGIE acquired majority control of energy storage management software leader Green Charge in 2016.

RELATED: Solar + Sharing: Connect groups of homeowners, renters via one solar + storage network 

The backbone of storage: data crunching

It is tricky enough to coordinate a community solar or VPP operation, providing power on demand to participants and storing the rest until the utility calls for help. But knowing precisely what times, and advising customers as to when it is most optimal to use grid energy, or substitute with storage, is another matter, thanks to U.S. utility rate mayhem.

NREL notes that “There are almost 3,500 electricity providers in the United States, and each one has their own set of tariff sheets, rate structures and pathways for compensating non-utility-owned energy generation.” Add a dynamic dimension of rate evolution arising from rate cases, and it becomes a bit difficult to keep up with when it is most economic to use how much power.

Here the data crunchers enter the fray. Stem, for example, recently launched its Athena analysis product, which uses artificial intelligence to learn, predict and optimize energy in real time. Athena collects data at a rate of 400 megabytes per minute to continually fine-tune its algorithms. The system also has learned from operating systems for over 5 million hours, from processing nearly 200 million data intervals and from running over 35 million project simulations. As a result, the system decides and tells the battery when to store and to discharge power, responds to demand response opportunities and methodically shaves peak utility rates.

Stem has working relationships with eight utilities thus far and expects that number to grow significantly as the company helps shave peak demand, which is costly on both sides of the transformer. Stem has been dispatching batteries into California’s wholesale energy markets where it responded to more than 600 calls from state grid operator CAISO last year, according to the company.

On top of new legislative challenges, the industry has faced high and growing customer acquisition costs over the past few years. According to GTM Research, customer acquisition costs on average now represent a disproportionate 17 percent of the total system cost. This is where a new service from Urjanet, a global leader in utility data aggregation, comes into play. Its new Utility Data for Solar, a data-as-a-service solution that provides on-demand access to residential and commercial energy usage, cost and location data from more than 900 electric utilities in over 15 countries. Urjanet Utility Data for Solar enables a more cost-effective, customized approach to selling solar systems that allows vendors to effectively focus on the needs, requirements and situation of each residential or commercial buyer.

map of demand charges

Fig 2. Here’s where the harshest demand charges are across the U.S., courtesy of NREL.

Storage as a service emerges

When solar leasing became popular, the common knowledge about actual savings from such arrangements was about 15 percent of a residential utility bill, if that. With C&I customers, the savings opportunities are as high as the sky or at least whatever the utility bill looks like pre-storage.

JLM Energy is one of the latest energy storage solution providers that offers financing for energy storage customers through a $25 million project financing fund. The company uses a lease structure to achieve shared savings on a monthly basis for 20 years, with no upfront cost. JLM owns, maintains and guarantees system performance.

Stem has long been financing storage solutions, and now has a $500 million investment pool from which it can draw to finance a project, thanks to a host of private sector investors, including the Ontario Teachers’ Pension Plan.

Wall Street may not have climbed onto the PV wagon when the industry began to mature, but the storage peak-shaving proposition apparently seems as clear and understandable to such investors as the bottom line of the utility bill.

Charles W. Thurston is a freelance writer covering solar energy from Northern California.

— Solar Builder magazine

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