PV Pointer: Find the hidden value in ‘oversizing’ inverters

Fronius oversizing inverters

While inverter oversizing is not new to the solar industry, there are still inverter manufacturers that do not offer an attractive DC:AC ratio for their inverters. This highly impacts cost and profitability of a solar system. Therefore, it’s important for system designers and solar installers to have a closer look on the oversizing capabilities of inverters, and to tap into their hidden power.

Inverter oversizing refers to adding more DC power to an inverter than it is rated for. For example, if you connect 6 kWp of DC power to a 5 kW inverter, you oversize the system by 20%. This makes total sense, because the peak power of 6 kWp will only come up in very few and short moments – so using a 6 kWp inverter (no oversizing) would be unnecessary and therefore a waste of money. In situations where the system actually generates more than 5 kW, the inverter would clip are so rare and so short, that it is negligible. The advantages you gain by oversizing clearly outweigh the effects of clipping.

Modern, high-quality inverters like Fronius SnapINverters can handle DC power of up to 150% of the inverter’s nominal output power, which would be for example 7.5 kWp on a 5 kW inverter, which is a lot of hidden power. Let’s have a closer look on the advantages of oversizing.

Cost savings

A main advantage of oversizing are the initial cost savings. For the price of a 5 kW inverter, you get to support a 7.5 kWp system – benefitting from 2.5 kW of hidden power in your 5 kW inverter (for free). Inverters with a poor DC/AC ratio, or no oversizing capability whatsoever, do not provide this cost saving, increasing the cost per Watt significantly.

In commercial, rooftop or ground mount systems, oversizing reduces the number of inverters needed to support the available array size and its kWp on a given roof. This not only reduces the initial cost, but also the O&M expenses – both resulting in a better return on the investment.

More DC power without an AC panel upgrade

Residential AC panels only allow a certain amount of solar power (AC) being connected to them. For example, 3.8 kW AC is the highest power that is possible on a 100 A service panel, 7.6 kW on a 200 A service panel and 11.4 kW on a 300 A panel. As the cost of upgrading a service panel can be very high, it is useful to fit the largest system possible on the existing AC panel. Inverter oversizing helps to maximize the DC power of your solar system. If you have a 200 A panel and a 7.6 kW AC inverter with 50% oversizing, you can actually get 11.4 kWp of DC power. If you were to choose an inverter without oversizing capability, you would be stuck with only 7.6 kWp, or you would have to invest in an expensive panel upgrade.

Higher yields

While the efficiency of high-quality inverters is quite stable over the whole power range, it’s still getting higher the closer the inverter operates to its nominal power. By oversizing a system, the operating point of the inverter is at a higher power, closer to its AC rating, and reaches its capacity earlier in the morning and stays there until later in the afternoon. This not only improves the inverter’s efficiency, but also maximizes the overall energy yield, while keeping inverter cost low – for maximum return on investment.

Conclusion: Look twice when choosing inverters. Make sure to take their oversizing capabilities into account and to tap into the hidden power of high-quality inverters. Fronius SnapINnverters, for both residential and commercial, are capable of 50% oversizing (DC:AC ratio of 1.5:1) – which is a lot of hidden power, so system designers can really maximize the above advantages of oversizing.

— Solar Builder magazine

NABCEP hat trick: Fronius’ William Burkert first to earn these three PV certifications


After becoming a NABCEP Certified PV System Inspector, William Burkert, Solar Application Engineer of Fronius USA, became the first and only person to be a NABCEP certified PV System Inspector, PV Installation Professional and PV Technical Sales Professional.

“Receiving NABCEP’s PV Solar Inspector Certification is personally very satisfying,” Burkert said. “More important it means I can offer customers the added confidence of knowing that their photovoltaic system installations will be inspected to the highest standards in the solar industry.”

NABCEP is the most well established national certification organization for renewable energy professionals. Designation as a NABCEP PV System Inspector is widely recognized to be the most important and meaningful certification of its kind in the solar industry.

To earn his NABCEP certification, Burkert was required to first document relevant education and experience related to PV system installations. Then he had to pass a rigorous exam that covers the breadth of the multi-craft knowledge, skills, and abilities required to competently design, install, inspect and maintain PV systems. The exam assesses knowledge on subjects as diverse as electrical and mechanical system design, job site safety, the National Electrical Code, roofing and construction techniques, and system maintenance and troubleshooting.

“Anyone who makes the considerable effort required to earn NABCEP certification has documented their training and experience as part of the eligibility process,” said Richard Lawrence, Executive Director of NABCEP. “They have also made a very real commitment to upholding high standards of ethical and professional practice. I am delighted to again welcome William Burkert of Fronius to the ranks of the industry’s leading solar professionals.”

To earn his NABCEP PV Technical Sales Professional certification, Bill was required to first document relevant education and experience. Then he had to pass a rigorous exam that covers the breadth of the knowledge, skills, and abilities required to competently perform a solar site assessment, conduct performance and financial analysis, develop a preliminary system design, and prepare a detailed sales proposal for the customer. The exam assesses knowledge on subjects as diverse as financial incentives, utility bills and rate structures, electric load analysis, fundamentals of electrical and mechanical system design, and PV system types and components.

— Solar Builder magazine

Fronius USA announces new President and CEO


Fronius USA, located in Portage, Indiana and leading manufacturer of welding and solar equipment, announces new leadership to serve as both Director of Solar Energy and overall CEO of the company.

During his Fronius career, Adrian Noronho has progressed in various leadership roles since joining the organization 7 years ago.

Prior to signing on with Fronius USA, Noronho held the position of Managing Director of Fronius Australia Pty Ltd, where he earned a reputation for being a transformational business leader helping steer the brand to the number one position in terms of market share and industry-leading service and support across both Australia and New Zealand. More recently he has been based in Austria at Fronius International GmbH as Head of Sales for Solar Energy with a focus on North America, Asia Pacific, Middle East and Central Asia.

Adrian Noronho“I am very grateful to be joining the team at Fronius USA. Our vision for taking on the greatest welding challenges to enable new and better technologies as well as transitioning our world to a 100% renewable energy supply, are missions I am very passionate about and have arguably the greatest potential here in the US. It is very exciting and motivating to think about the immense value we will create here over the next few years.”

Noronho’s empathetic leadership style, engineering background and extensive industry and international market experience will help Fronius USA realize the company’s long term strategic goals.

Sponsored: Top 5 ways to become 24 hours of sun on the new Fronius website

— Solar Builder magazine

What will solar systems look like in 2020? Fronius makes predictions

In just a few years, we will flip the calendar to a new decade. However, in a rapidly evolving industry like solar, a few years can mean significant changes. So what will solar systems look like in 2020? Fronius has some bold predictions they’d like to share, as well as a new website configuration, which you can check out here.

solar predictions

It’s 2020 and Texan solar installer Joe just closed a sale on a residential 5 kWp system. It was an easy sale to a family of four, since solar really became mainstream and customer acquisition costs came way down. Solar and its value proposition have reached the masses! This home owner’s roof is fairly complex in shape, but thanks to smart technologies, this is no longer an issue. There is no need for special designs or installation hassles to mitigate the effects of shading and different roof orientations – making it easier to provide solar to the masses to provide solar to the masses.

Installer Joe sometimes looks back on code changes and how concerned some of his colleagues have been – how can we comply with all this while staying cost effective, they were wondering? Code has always been one of the main drivers for change and strongly impacted how systems are built. Examples are Arc Fault Current Interruption (AFCI), which was introduced in the National Electrical Code (NEC) of 2011, or Rapid Shutdown in NEC 2014 and 2017. But code changes are also a driver for overall innovation, which leads to cost reduction and simplification of systems – letting installer’s concerns vanish.

When module level shutdown came up, new technologies evolved and provided new solutions. Every module in 2020 is a safe or smart module, coming with an integrated chip that replaces the classical bypass diode. These smart modules install like standard modules, but provide all functionality needed: Power Line Communication for rapid shutdown, DC optimization and more reliability. New technology start-ups are flooding the industry, supplying module manufacturers with better and better chips for smart modules, reducing cost and disrupting traditional MLPE. With smart modules based on an open industry standard, add-on boxes such as traditional DC optimizers, micro-inverters or rapid shutdown boxes are no longer needed in 2020.

The best part is that solar installers can choose between a variety of smart module brands, since they are all based on the SunSpec standard, which enables compatibility with any SunSpec based inverter. So customers can chose whatever module brand they like and combine it with whatever inverter they like – eliminating vendor locked-in solutions. Even though solar roof tiles are an option, most customers still prefer not to exchange their existing roof, but go with sleek modules attached to the roof.

The Holistic Home: We peer into the future of home energy generation, usage

Our Texan home owner got an inverter that is just a portion of the size of past inverters, while being more connected than ever. It communicates with smart modules via Power Line Communication and is connected to the web via cellular – the internet of things became a reality. Through this connectivity, data is shared with system owners, O&M providers, grid operators and utilities. The smart home and the smart grid have arrived. And yes, besides all the smart features, the inverter is still converting DC to AC.

Installer Joe had offered several storage and energy management options to the homeowner, but she decided to analyze her family’s energy production and consumption first, and then purchases a tailor-fit solution after a year or so. As an owner of an electrical vehicle, the family is also interested in a smart energy management system to allow charging of the car with solar power, even at night. The available storage options range from high-end solutions based on batteries (both AC and DC coupled versions) to more affordable ways of energy storage such as water heaters controlled in real-time, depending on available solar power. There is no one-fits-all, and customer choice helps the solar and storage industry to grow further.

To summarize, the future of solar is bright. By 2020 the solar industry has settled on open industry standards, enabling industry innovation to drive down cost and allow customer choice. Industry groups, leading technology providers, module and inverter manufacturers come together so that solar customers have access to a variety of cost-effective, simple-to-install and holistic options. Making solar in 2020 smarter, simpler, more affordable – and installers like Joe happier.

— Solar Builder magazine

Details on expanded Fronius Solutions Provider program

Servicing a Fronius inverter

Fronius is expanding its Fronius Solutions Provider (FSP) program, a network of solar installers that are certified and trained directly from the manufacturer. At the upcoming certification training in November, solar installers receive exclusive training to install and field-repair Fronius products, receive NABCEP continuing education credits and have the opportunity to join the recently revamped FSP program. Register now to become part of the leading solar installer program on the market.

Formerly known as Fronius Service Providers, the renamed loyalty and training program offers solar installers the ability to provide the best service to their customers in both installation and service. The Fronius Solutions Provider trainings now also include design and installation aspects of Fronius solutions in the residential and commercial segment. With this qualification, FSPs are able to provide their customers with high-quality solar solutions and can support them seamlessly over the lifetime of a system.

The unique O&M solution of the FSP program eliminates the need for inverter exchanges, which typically causes wait times for the new unit and potential re-wiring and re-inspection. Qualified installers can service inverters directly on site, with only one truck-roll, guaranteeing maximum system uptime as well as satisfied system owners.

In addition to providing better solutions to their customers, FSP certified installers receive a multitude of benefits, including higher reimbursements for warranty work, a direct phone line to Fronius technicians, regular visits from the Fronius team, continuing education and opportunities for beta testing of upcoming products. Fronius also supports FSPs with joint Marketing activities and sales trainings. “We want to grow together with our Solutions Providers and support them and their businesses in the best way possible – making a world of 24 hours of sun a reality together”, says Wolfgang Niedrist, CEO at Fronius USA, “we want solar installers to know that we at Fronius are with them for the long haul”.

Upcoming training at Fronius headquarters in Portage, Ind.

November 13 / Fronius Solutions Provider Legacy product, IG & IG Plus
November 14 / Fronius Solutions Provider Residential Solutions
November 15 / Fronius Solutions Provider Best Practices and Installation
November 16 / Fronius Solutions Provider Commercial Solutions

Solar installers are welcome to register for either all days of training or for specific products only. Course registrants are to arrange their own travel. The cost of the course includes the training, literature, meals, and a portion can be used as a credit towards an FSP spare part kit. The kit is a collection of the most common inverter spare parts and is highly recommended, as it allows the installer to fully utilize the benefits of the FSP program. To register, email pv-training-usa@fronius.com your name, contact information and what days, if not all, you would like to attend.

— Solar Builder magazine