Solar Energy Inverters-
As our second part to our five part series on a solar PV system, you will get a brief overview of how inverters interact in the system and the vital role they play in a system installed in MN, WI, IL, LA, and NC.
The solar energy inverter represents the main functioning electrical component or components (I'll explain later) in making power such that it is usable in your building or home. A solar panel makes DC (Direct Current) electricity, which for most of our homes and buildings is useless, so we must "Invert" the DC energy to AC (Alternating Current), which is almost all our homes and buildings. In all parts of the United States we use AC energy for our electrical needs and appliances, and this piece of equipment helps us do this.
Types of Inverters-
So outside of some complicated systems there are really only 2 categories of main grid tied inverters on the market today. Central Inverters and Micro Inverters dominate the main stream market, and even though there are other options like off grid, battery backup, and optimizers, we will be focusing on the inverters that dominate 99% of the market.
Central Inverters- these inverters are what still represent the largest share of the market and are what has been used by thousands of contractors for more than 15+ years. A central inverter is simply a single device that "inverts" the DC energy of many panels that are tied together electrically.
Pros- they offer a more cost effective installation, simple to replace if needed, low failure points as there are far fewer electronics as compared to other system types, existing technology that has proven durability.
Cons- they can provide more shading effects which limits energy production in heavily shaded areas, they are heavy, typically need an indoor location to mount them on a wall (approximately same size as an electrical panel).
Micro Inverters- these inverters are becoming extremely popular on the residential market in part to their ease of installation, and has gained most of their traction over the last 2-3 years. In a system using these types of inverters each solar energy panel receives its own inverter mounted on the underside of the solar panel and inverts the DC energy to AC outside
Pros- Easy to install, limits shading effects due to the fact each panel has an inverter.
Cons- more failure points, much higher installation costs, expensive to replace as many panels may need to be removed to replace, newer technology and longevity could be an issue.
As with most items in construction, there is always a time and a place for each type of inverter that will provide the best overall "Value" (our favorite word at Able Energy Co.).
Central Inverter- Our Central Inverters offer efficiencies nearing 97% or better and offer warranties up to 20 years. As solar energy experts we strongly suggest Central Inverters to most of our customers that have a shading scenario of less than 10% because a Central inverter will produce the most amount of energy in most of these scenarios, as well as provide a system that offers a much faster return on investment and far less failure points, making it a more durable system.
Micro Inverters- We love micro inverters in the right situation and with inverters in the efficiency range of 96%, they can offer a great return on investment in shaded scenarios or oddly sized electrical systems that a typical string inverter has trouble pairing with. Though the costs are higher for this type of system, when installed in the right application they can far out produce a central inverter and provide a faster ROI in shaded situations that exceed 20%.
Why is Inverter Selection Important?
Like your panels, durability and energy production is the name of the game. Without it a solar energy system is pointless, or shall we say energy less. The right inverter selection in most cases won't make or break your system; it simply is the difference between a faster return on investment and a system that offers maximum durability with the delicate balance of energy production.
What can you do?
A well-qualified solar EPC contractor that also employs an Electrician in house, should be able to indicate when to select a Central inverter and when to select a Micro inverter. If you want to make sure you’re getting the best deal, ask your installer what your shading is, if it is 10% or less, you should be using a central inverter in 90% of cases. If its 20% or more micro inverters are your answer. It is the shading between 10% and 20% that can be tricky and a good installer should be able to select the right inverter option for you. If not, give us a call and we can give you our experienced professional EPC opinion.