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The Big Advantage of MicroInverters
Feb24

The Big Advantage of MicroInverters

In the old days of solar, all the PV panels used to be connected to a single, large inverter that would convert the direct current (DC) of the sun into the alternating current (AC) we use in outlets around the home. The system acted like one giant solar panel, with its max current rating equivalent to its poorest performing PV unit. That means if one of those connected panels experienced a reduction in energy because it was covered by shade or it failed, the entire system would experience that loss. Similar to the way a string of christmas lights will fail if one goes down, the saying, “you’re only strong as your weakest link” comes to mind when thinking of how these single inverter setups work. Then in 2008 Enhphase released the first commercially successful microinverter. The idea behind the project was to allow each panel to function more autonomously, so if one panel had issues the entire energy output of the system wouldn’t suffer. In order to do this, microinverters are used on every PV panel or every other PV panel, and have become popular in homes, where solar array sizes are small and maximizing the performance of every panel is necessary. Since 2008, microinverters have become increasingly intelligent and companies such as APsystems have innovated technology like a Field Programmable Gate Array chip with software that can be wireless programed to modify each panel’s DC-to-AC conversion to meet the demands of a changing environment without needing to climb up on the roof and replace the hardware. Such residential microinverters like the APsystem’s YC500A allow users to monitor each microinverter unit, giving them a clear overview of the entire system at any time. If a panel fails or is not performing well, it can be quickly identified. Additionally, because every unit functions more independently than the antiquated single inverter system, different models of solar panels can be rigged up to feed into the same power system. This makes it so a homeowner doesn’t have to replace all their PV panels at one time, but can swap out or add new panels as the technology improves. No doubt that when it comes to renewable energy such as PV solar or wind turbines, microinverters offer more flexibility and advantage. Some studies put them at producing 5-25% more power than the single inverter systems. As the solar market continues to expand, we’re going to see these little guys make a huge...

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Solar farms and solar forests
Feb01

Solar farms and solar forests

Think of the sheep. Think of the bees, the birds and the little earthworms. When it comes to solar, sometimes we’ve got our attention so focused on the sky we can overlook what’s there, beneath our feet–the land. However, one of our suppliers, Canadian Solar, has a project-line of solar panels built especially to suit the needs of farmers and those closest to the land. They call it the CS6P-P and the difference is, instead mounting the PV panels on the sleek, metallic basis we’re all used to seeing, it’s mounted on wood.   “So, as far as the goats are concerned, the arrays are very like trees.,” said Eric, one of Canadian Solar’s construction engineers. “They provide good shade, absorb sunlight and convert it to energy without creating CO2 or other greenhouse gas emission. Every solar farm is potentially a unique eco-system that benefits the natural world of which we are all a part”. And faced with global environmental issues like the declining honeybee population as document by the United States Department of Agriculture, structures that create areas with wildflowers to grow and hives to flourish are a good thing. According to Canadian Solar researcher Dr. Shawn Qu, the CS6P-P panels have of a lifespan of 25 years and remain mostly undisturbed by humans after their installation aside from the occasional maintenance. The wooden panel bases equate to about a 5% footprint of the entire structure, allowing room for wildlife to flourish. Canadian Solar was established in 2001 and is currently responsible for generating 9 GW of power, while supplying customers with over 30 million PV modules.   Though the company is the third largest solar companies in the world and has been an industry leader pushing towards a solar-powered future, it has a done a noteworthy job at borrowing inspiration from the sun as well as the trees. So, on behalf of all the sheep,...

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Solar 101: What’s the difference between microinverters and string inverters?
Mar19

Solar 101: What’s the difference between microinverters and string inverters?

If you’re a homeowner or an installer doing residential or small scale commercial solar installations, you essentially have three choices for converting the solar system’s DC power into AC power: You can either go with new microinverters or with string inverters—with or without DC power optimizers. All will work, but there are differences, especially in certain situations. String Inverters: The solar industry standard With residential string inverters, all solar modules are connected in a series circuit to a DC electric cable, which is then connected to a single inverter box mounted on a wall by the home’s main AC panel (as well as to any required DC disconnects). So it’s a very centralized system with a limited amount of labor. Modern string inverters not only convert the power from DC to AC, but also use Maximum Point Power Tracking (MPPT) to deliver the maximum amount of power available. This is important, since each solar panel can produce different amounts of power due to manufacturing anomalies, intermittent shading, leaves, dirt, passing clouds, and/or other factors. While a string inverter’s MPPT works fairly well, especially in sunny areas with no obstructions, having all solar modules tied in a series circuit can still be a disadvantage for several reasons: 1)   MPPT technology is essentially drawing the average amount of power available, rather than the full amount available from each module. As a result, the entire solar array can lose 15% to 30% or more of its full potential output because one or more panels in the string are temporarily shaded or have debris. 2)   If you have limited roof space and need two arrays with different sun orientations, each array will need its own string inverter. 3)   Similarly, since module mismatch can cause efficiency issues, you’ll need to use the same brand and panel voltage within each string. 4)   String inverters don’t easily allow for expanding the system in the future unless you purposely oversize the inverter, wiring, and other BOS parts. 5)   While it’s common to have online monitoring with string inverters, the monitors only measure the performance of the entire array. So, if an array isn’t producing the expected power, installers will need to individually test each panel for malfunctions. 6)   String inverters are typically warrantied for 10 years and have an expected lifetime of 12 to 15 years, while solar panels typically last 25 years or longer. Thus, the string inverter will need to be replaced at least once. Adding DC Power Optimizers to String Inverters Adding DC power optimizers to a string inverter system can solve most of the above string inverter challenges. Power optimizers are relatively new...

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Canadian Solar Inc – From Icy Paths to Solar Panels
Mar17

Canadian Solar Inc – From Icy Paths to Solar Panels

Foreward: As a leading retailer for solar products and kits, we’re proud to provide access to the industry’s top manufacturers. But with so many companies, there’s of course, the subtle, but key distinctions between companies, their products, and the people who make them. By shining light on these differences and sharing their stories, we’re aiming to provide a more clear picture to help in your decision making. Canadian Solar Inc., at a Glance Canadian Solar Inc. is one of the largest solar manufacturers in the world. Their story combines global reach and world class financing, expressed through the hard work and humble beginnings of founder and CEO, Dr. Shawn Qu. They maintain their space as leaders in the industry by driving product innovation and in-house R&D; and in 13 years since their founding, they have elevated themselves as a leading company in the solar industry. From Icy Walkways to Sun-Powered Panels Canadian Solar Inc. was founded in 2001 by Dr. Shawn Qu. Qu. As a serial academic/entrepreneur, he received his Bachelor of Science in applied physics from China’s most prestigious school, Tsinghua University. He later graduated with a Masters of Science in physics from the University of Manitoba and went onward to receive his Ph.D in material sciences from the University of Toronto. In an insightful 2010 interview, Dr. Qu recalls the “cold, cold, Winnpeg winter,” as he walked from class to class on icy campus walkways. His story sets an interesting backdrop: The basic beginnings of what would ultimately become the world’s leading solar company. Before founding Canadian Solar Inc., Dr. Qu worked at Ontario Power Generation as a research scientist, then moved into product engineering, business development, and strategy at Automation Tooling Systems, Inc. Here, he was led into the solar industry with Photowatt International S.A. Eventually, he returned to his alma mater Tsinghua University as a visiting professor in 2011. He currently runs Canadian Solar Inc. as CEO and chairman of CSI’s board of directors –  alongside an esteemed lineup of accomplished professionals in corporate finance, law, and nanotechnologies. Leading the Industry Dr. Qu’s multi-discipline background reflects itself within the company’s products and services. They provide a huge range of solar applications (cells, modules, wafers, ingots, panels, etc.) across different verticals and scales (from consumer level to huge solar farm contracts). Their operations are spread across 13 countries worldwide and in more recent news, they were announced as the Nasdaq’s second-best performer with a 687% surge by Q4 of 2013 (hovering around $30/share). As of 2014, their value has grown (once again) by an astounding ~25% to an average of $40 a share with market value...

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What are Building-Integrated Photovoltaics (BIPV)?
Oct11

What are Building-Integrated Photovoltaics (BIPV)?

Some homeowners are turned off by how solar panels affect the appearances of their homes. Building-integrated photovoltaics – basically solar panels incorporated into the construction of new buildings – can eliminate the negative visual impact of traditional solar panels; improve appearance and boost resale value. The installed capacity of building-integrated photovoltaics is expected to boom over the next couple of years. A report by Pike Research, projects that the capacity will grow from 400 MW in 2012 to 2.25 GW in 2017[1] – roughly a five-fold increase worldwide. There are many different categories of BIPV today. Here are the most common ones: Thin-film solar panels integrated with a flexible polymer roofing membrane. Flexible thin-film solar panels integrated into roof shingles/tiles. Thin-film or crystalline-based solar panels mounted on the façade of a building. Semi-transparent solar panels that replace windows and skylights. Solar roof tilesImage credit: US Tile. The SOLÉ Solar Power Tile. Believe it or not, these roof tiles are actually covered in thin-film photovoltaic material. Read our in-depth article Which Solar Panel Type is Best? Mono-, Polycrystalline or Thin Film? to find out which of the various solar panel technologies is best in your situation. Generally, BIPV systems are less efficient and more expensive compared to traditional solar panels. However, if you want to seamlessly integrate solar panels with your home, and have the extra money that is required, building-integrated photovoltaics can be a great solution. Get in touch with our expert advisors at One Block Off the Grid to find out more. Are you eligible for extra incentives? In some places, additional incentives are available for BIPV-systems in addition to the standard feed-in tariff/net metering, rebates and grants. Search DSIRE (Database of State Incentives for Renewables & Efficiency) to see which incentives apply where you live. Although implementing building-integrated photovoltaics in the construction phase of a home makes more sense from a cost perspective, these systems can also be retrofitted into existing buildings. Guest Post by Mathias Aarre Maehlum. Mathias is doing a Masters in Energy and Environmental Engineering. In his spare time he writes about solar power and other sources of renewable energy at his blog Energy Informative....

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Are solar panels tested for hail?
Aug01

Are solar panels tested for hail?

Are solar panels tested for hail, golf balls, or other kinds of impact? If solar panels are broken by some kind of impact, is this damage covered by the solar panel manufacturer’s warranty? If you’re about to drop thousands of dollars on a solar system that’s supposed to last a few decades, you obviously want to be confident that you’re not investing in equipment that could be ruined by one day of extreme weather.  It’s a valid concern. The ambiguity regarding hail resistance and impact testing for solar panels can be frustrating, so I spoke with a claims representative from a major solar panel manufacturer to get some clarification. The short answer is that there’s probably no manufacturer’s warranty that will cover this kind of damage, but any high-quality solar panel will have tempered glass that’s designed to take a beating and tested accordingly. If you’re worried about protecting your investment from this kind of damage, make sure that you pull a permit for the system and consult your property insurance provider.  There should be no problem getting the coverage you need if you go by the books. Back to the question about manufacturer’s warranty-  even though you likely won’t find a manufacturer’s warranty that covers hail damage, any reputable brand will test their solar panels to obtain industry-recognized quality certifications. In North America, these tests are a 5 ft·lbs impact of a 2 inch diameter ball of 1.18 lbs that’s dropped at a distance of 51 inches- no parts of the solar panel can be damaged to acquire this label.  If the solar panel has undergone this standardized testing successfully, you will see something like this in the specifications sheet. Quality Certifications from the Sharp ND-240QCJ specification sheet Because solar panel manufacturers usually sell to markets outside of the United States, modules are often subject to additional testing standards such as Europe’s “IEC.” Quality Certifications from Canadian Solar CS6P-240P specification sheet The European quality certificate specifically for hail is IEC 61215, which is circled in the image above.  Solar panels with this label were shot with frozen ice balls at varying sizes and speeds from an air gun. The most substantial of this IEC impact testing comes at 39.5 m/sec from a 203 gram ice ball.  The solar module must perform at a maximum of 5% degradation with no visible damage. If you live in an area that’s prone to hail storms, you should get solar panels that have been tested for impact and talk with your homeowner’s insurance company about your coverage options. That being said, if your system is going to experience hail that would dwarf...

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