shown in a typical tracking vs. fixed plot, the difference is seen as a loss when using a fixed array
Tracking versus any other kind of module support is really the first consideration. The first and most efficient method of support is, by default, one that keeps the module facing the sun all day long, automatically. Fixed roof or ground mount, one axis, one axis with backtracking, azimuth rotation with manual tilt, etc., all come up short.
In the chart above the 2 axis tracking array curve predicts a daily production of 46 kWh while the fixed array (with 45 degree tilt) can only produce 37 kWh. The predicted difference is 19 kWh. We call that a (19 kWh / 46 kWh x 100 = ) 41.3% loss of the module efficiency.
​
So, if in this example your new modules are rated at "22% efficient" when purchased it is assumed that one can only get that 22% if the modules face the sun all day. However, if the modules are mounted on the rooftop, south facing with tilt, a 41.3% loss will be sustained, (100% - 41.3%) of 22% is 12.9%. The system must now be rated at 12.9%.
​
Bottom line: the best fixed tilt array in the example turns the new 22% modules into 12.9% modules, the best they could make in 2005! Can you live with that?
these plots are made using pvwatts/sam weather data available at sam.nrel.gov
Becoming a Power Producer
Priorities
When you’re thinking of becoming a power producer, there’s one question you need to consider above all others. And it should inform your decision to invest in one renewable energy technology or another. It’s a question that only those operating electric utilities, producing electricity for the rest of us, have asked for nearly one hundred years. How do we make enough power to satisfy demand at the very moment of that demand? How do we make electricity when people need electricity?
common knowledge: if 2 axis tracking arrays can produce 1Bn kwh, the fixed arrays will leave 300m kwh on the ground.
Load Matching
Most utility companies experience a dip in demand during the middle of the day, so dumping excess energy from fixed arrays onto the grid at noon isn't as helpful as many in the solar industry would like to believe. In fact, in regions with high solar saturation (lots of fixed arrays), electric utilities are using various tools, like Time-Of-Use rate schedules, to discourage excess noon production and avoid over-loading the grid. The only cost effective method to make solar power when demand is high is solar tracking.
Levelized cost of Energy
LCOE is a simple metric that results in surprisingly complex projections. The idea is that if you take the total, lifetime costs of any energy generation system, renewable or fossil, and divide that cost by the total amount of energy the system will produce, the number you get will show you the actual value of the energy produced ($/kWh). This is how utilities determine their rates. And it should be one of the main numbers considered when you are thinking about going solar. High upfront costs are a common reason for people to avoid solar energy and solar tracking, but if we account for the entire lifetime of an array by calculating its LCOE, going solar becomes a great investment in your future.
Energy storage
"Declining costs of both solar photovoltaics (PV) and battery storage have raised interest in the creation of “solar-plus-storage” systems to provide dispatchable energy and reliable capacity. There has been limited deployment of PV-plus-energy storage systems (PV+ESS), and the actual configuration and performance of these systems for dispatchable energy are in the early stages of being defined." NREL
Two-axis solar tracking has the potential to revolutionize the economics of solar energy storage in many parts of the world. Fixed solar arrays paired with battery banks will always result in battery underperformance due to one simple fact. Whenever your panels aren't producing energy, your batteries are draining. This results in more reliance on batteries, shorter battery lifespan and an overall higher LCOE. Two-axis tracking maximizes the amount of time your panels produce energy each day, extending battery life and increasing your system's resilience.
Solar + Tracking + Storage
Join the Club
Join our email list and get access to specials deals exclusive to our subscribers.