The Myth of Whole House Battery Backup

The Myth of Whole House Battery Backup

Will batteries keep your AC cranking and electric vehicle charged up during an extended blackout? Probably not.

We like to believe the myth of whole house battery backup or the notion that our 21st century lifestyle will continue unabated despite fire hell or high water. The reality is different: Typical battery backup systems work best when they are designed to ration battery capacity and minimize the use of major appliances. These systems must also be integrated with rooftop solar so that the battery can be recharged as soon as the sun comes up.

There are two fundamental engineering limits that make it impractical to run a whole house on battery power alone. First, the energy capacity of typical lithium-ion battery systems is insufficient to power an entire house through a nighttime blackout. Second, battery backup inverters are not powerful enough to start and run many large appliances. Adding multiple batteries and inverters can overcome these engineering limits – but at a very high cost.

Nevertheless, a well-designed solar and whole house battery backup system can provide limited power almost indefinitely. To learn more about the reality of backup power in the event of a blackout or Public Safety Power Shutoff, please listen to this week’s Energy Show.

SolarEdge-Perspective for a Distributed Grid

SolarEdge-Perspective for a Distributed Grid


People talk about solar panels and batteries a lot (at least the people I talk to). The reasons are that solar panels are conspicuous on rooftops — and batteries are what keep the lights on during increasingly frequent blackouts. But the real brains of a solar and battery storage system is the inverter.

With increased global production, solar panels and battery cells have become commodities — differentiated mainly by price and efficiency. For a variety of reasons, inverters are still quite specialized. Initially, inverters simply converted DC current to household AC current. Modern inverters also provide a variety of safety features (rapid shutdown and arc fault protection), monitoring, and grid support services. The next generation of inverters extends beyond solar, providing backup power, EV charging and home energy management capabilities.

Through a combination of great technology, disciplined execution and industry vision, SolarEdge has become the leading inverter company. Based on my experience in the field (and roof), they have the best combination of efficiency, safety, installation ease and overall value. Most importantly, SolarEdge continues to push the technology envelope as they expand into backup power and distributed grid services.

Our guest on this week’s Energy Show is Peter Mathews, General Manager of North America for SolarEdge. He has done a terrific job growing SolarEdge to over a 60% market share in the U.S. Please listen to this week’s Energy Show as Peter shares insights around SolarEdge’s business, how SolarEdge is addressing the power crisis in California, their new commercial products, and the company’s ongoing product vision for a distributed grid.

A Millennial’s Perspective on the Green New Deal

A Millennial’s Perspective on the Green New Deal


The Green New Deal is getting a lot more attention as we get into the 2020 Presidential election. The Green New Deal is a set of proposed economic stimulus programs in the United States with a goal of addressing climate change and economic inequality. The green part refers to renewable energy, energy efficiency, agriculture and related strategies to reduce greenhouse gas emissions. The new deal part refers to social and economic reforms and public works projects, similar to what was undertaken by President Franklin Delano Roosevelt in response to the Great Depression (Civilian Conservation Corp, Civil Works Administration, Social Security Administration, etc.).

Author Thomas Freedman coined the Green New Deal term back in 2007. Taking up where he left off, Representative Alexandria Ocasio-Cortez and Senator Ed Markey released a 14-page resolution for their version of the Green New Deal in February of 2019. Not surprisingly, there are strong political party line differences about the GND. There are even stronger generational differences about the GND. Without mincing words, Millenials see an existential threat to climate change — whereas most Boomers will be dead by then.

OK Boomer, so what should we do? For a youthful perspective, my guest on this week’s show is Kylie Tseng. Kylie is a graduate of NYU and is an activist for the Bay Area Sunrise Movement. Please listen to this week’s Energy Show as Kylie shares a Millennial’s perspective on the Green New Deal, and how everyone can encourage changes that will benefit both our climate and society.

Solar Tracker Systems with Alex Au

Solar Tracker Systems with Alex Au

Whether it’s a residential, commercial or utility solar project, contractors strive to install systems that generate the most energy at the lowest lifecycle cost. Solar panels operate at their peak output when the sun is perpendicular to the panel. So for maximum energy collection, tilting the solar panels at the local latitude (37 degrees here in San Jose) facing south is generally best.

Because of existing building structures, compromises are necessary when installing solar panels. Residential systems are generally installed flush to the roof because tilting the panels is unsightly, and the efficiency benefit of tilting the panels is not worth the additional mounting system costs. Commercial systems on flat roofs are generally installed on racking at a relatively low tilt so that more panels can be installed — but almost never horizontal since flat surfaces collect dirt and debris.

But large-scale solar installations do not need to compromise when it comes to tilt angle and orientation. Systems can be more easily oriented due south and tilted at the angle of the local latitude. Taking things one step further, since the sun moves throughout the day, an additional 10-25% efficiency can be achieved if the panels track the sun.

Single axis solar tracker systems generally towards the east in the morning and west in the afternoon. More complicated dual axis solar tracker systems tilt east-west daily and adjust north-south seasonally. Because of the increase in efficiency, trackers have become a standard feature on large solar farms. Essentially, the added complexity of moving parts is worth the big increase in energy output.

NEXTracker was recently ranked the number one tracker company globally. They provide tracking systems and engineering for large utility scale projects all over the world. My guest on this week’s Energy Show is Alex Au, CTO and co-founder of NEXTracker. Alex was one of the pioneers in the solar industry as a key member of the team that developed the first integrated racking AC solar module, and then developed NEXTracker’s core tracking technology.

Please listen up to this week’s Energy Show as Alex shares his insights on NEXTracker, their technology and their recent work in incorporating flow battery technology to help eliminate the imbalance between peak demand and renewable energy production for utility scale applications.

New Battery Storage Systems

New Battery Storage Systems

The 16th annual Solar Power International show was held this October in Salt Lake City. It’s been quite a growth story since the first show in 2004 in San Francisco, which was held in what is now just a lobby of a downtown skyscraper. Not only has the industry grown, but the range of equipment being exhibited has increased dramatically.

Recently, the biggest change has been towards new battery storage systems. Entire sections of the exhibit halls were dedicated towards energy storage in a periodic table hodge podge of elements: hydrogen, lithium, vanadium, cobalt, nickel, zinc, lead, etc. — everything except my favorite element, Solarium.

To me the real action was with the heart and brains of these battery storage systems: inverters. Pioneers of turnkey residential battery storage prodcuts — Outback, SMA, SolarEdge, Enphase — were joined by just about every company that manufacturers inverters or batteries, including Fronius, Delta, LG Electronics, Q-Cells, Panasonic, Sonnen, Generac and others.

But a nice brochure and fancy booth demos don’t always translate into products that customers can actually install today. Please listen up to this week’s Energy Show as we review the most notable battery storage systems spotted on the floor of Solar Power International 2019.