SOLAR PANEL SIZING – WHY BIGGER CAN BE BETTER
The rated power of solar PV panels has climbed steadily over time. This has been driven in large part by innovative new processing techniques for the cells themselves, although improvements to the technology of panel assembly has also played a role. Over the decade from 2010, customers of the panel manufacturers came to expect higher and higher module powers each year.
Because all panels were the same size, the panel power was a good shorthand measure for how advanced the cell technology was. If a panel was rated at 320Wp then it would generate 14% more energy per square metre of space than a 280Wp module.
Squeezing more power (measured in Watt-peak – or Wp per panel) into the same footprint tended to drive down the cost per installed unit of rated power ($/Wp). Since the cost of the glass, frame and other components of the module and all the installation materials remained the same for modules of any power. The inexorable rise in power density of the available cells was a significant factor in helping the industry achieve the amazing feat of cost reductions we have seen over that decade.
However, gains from improving cell powers have reached a plateau. So manufacturers reaching for new ways to keep the story of ever more powerful modules at ever lower cost per Wp going have found a simple answer – just make the cells and the panels bigger.
Breathless excitement from credulous industry commentators as announcement of modules exceeding 400Wp, then 500Wp barriers misses the point. A not-so sleight of hand is evident as soon as you look at the product behind the headline number. Panels are not getting better, they’re just getting bigger.
Today, Trina Solar offers modules with power ranging from 320Wp to 600Wp by offering larger size modules.
Working in standard sizes of solar panel has many advantages:
- In the manufacturing process – greatly reduces the production cost.
- The size of solar panels is more standardized. Easy to design, install and maintain.
- Reduced transportation cost.
A standards war has broken out with Trina Solar, Risen Energy, Canadian Solar and others lining up against Hanwha Q Cells, REC Group, LG on the one hand and Longi, Jinko and others on the other – each calling for the industry to focus on cells of the dimensions they prefer. Will the industry settle on 158.75, 166, 182, or 210mm? At this point nobody knows.
In any case the cell size no longer quite defines the module size. Manufacturers have started slicing up cells into smaller sub-units (half-cut , third cut cells) . There is greater freedom to choose different module sizes. Dizzy with this new found freedom, module designers are expressing their creativity with the results of a a wide range of module sizes now available in the market (see graphic).
About More
Although larger solar modules/solar panels have many benefits and higher efficiency. There are still some cases where we still need smaller power solar panels in applications. For example: solar lights, small charging systems, etc.
There are many more situations that require a combination of voltage, current, and other usage equipment to pick the right solar panel.