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.

Reducing Peak Demand Charges

Reducing Peak Demand Charges

Unless you have rooftop solar, you’re probably incredibly unhappy about rising electric bills. This misery is even worse for commercial customers since — in addition to energy charges (billed on a kilowatt-hour basis) — they also pay for peak demand charges (billed on the maximum kilowatt demand each month).

For example, let’s say your business uses industrial equipment and a variety of office equipment. Your company uses 50,000 kwh of energy per month; at a rate of $0.15/kwh, your electric bill is $7,500 per month. In addition, your peak demand may be 300 kilowatts in a typical month; at a peak demand rate of $20 per kilowatt, you also pay $6,000 in demand charges every month.

As a conscientious and generous employer, you decide to install 20 EV chargers in your parking lot so your employees can charge up their cars while at work. Each employee may charge up their car with about 10 kwh per day — or $1.50 worth of electricity each, or $600 for all employees each month. A nice employee perk, and not too expensive. However, since 20 employees plug in their cars at about the same time every morning, and each charger draws about 5kw, your extra electricity peak demand will be 100 kw, or an extra $2,000 per month. Ouch!

So for many commercial customers, peak demand charges are a bigger cost than energy charges. Ordinary rooftop solar systems may not have a big impact on demand charges. However, batteries or special control systems in conjunction with rooftop solar can significantly reduce these demand charges.

To learn how your company can reduce peak demand charges, listen to this week’s Energy Show as we speak with John Powers with Extensible Energy. Extensible Energy has software that helps commercial solar buildings to use electricity intelligently and reduce peak demand charges.

Flow Batteries with Matt Harper from Avalon

Flow Batteries with Matt Harper from Avalon


It’s depressing that lithium batteries get almost all of the focus in the energy storage industry. Lithium batteries have a number of advantages, including high energy density, good longevity, declining costs and established integration with electronics, vehicles and stationary energy storage. Although ideal for residential and commercial storage applications, lithium ion chemistries are not great for long term and high capacity energy storage — which are the characteristics that many utility storage installations require. (more…)

Energy Toolbase with Adam Gerza

Energy Toolbase with Adam Gerza

Solar combined with battery storage seems like magic to many residential and commercial customers. With a million and a half systems installed in the U.S., the question is no longer: “does solar work?” Instead, customers want to know how much money they will save with a system. And commercial customers are even more diligent about accurate savings predictions. (more…)

The Commercial Solar Opportunity

The Commercial Solar Opportunity

There are there are three market segment for solar in the U.S.: residential, utility and commercial. Based on some rough math, in 2018 we expect to install 5 to 7 million solar panels on homes in the U.S. In areas with high residential electric rates, paybacks are usually in the range of 4-8 years. But the utility solar segment is much larger: about 20 million solar panels will be installed by utilities in 2018. Utilities realize that it is cheaper to generate power with solar compared to coal or nuclear generation. Moreover, the combination of solar and batteries is projected to be even cheaper than natural gas in a few years. (more…)

Real World Solar Economics with Tom Beach

Real World Solar Economics with Tom Beach

Great solar policy is just as important as great solar technology. Obviously we need the technologies for these products — but we also need the policies so that solar products can be cost-effectively installed. And I’m not just talking about incentives…policies related to net metering, interconnection and permitting are just as important. (more…)