Volume 1 – SOLAR OFF-GRID BASICS
Over the next few months I will discuss with you the topic of off-grid solar systems. The impetus of developing these articles centers around the growing trend of individuals who desire to become less dependent on their utility grid.
There are a number of system types that can be considered when making this move toward energy independence. Some of the questions that you want to start thinking about are:
Do I want my home to be completely off-grid or do I want the ability to have grid power should the need arise?
I have already installed a grid-tied PV system on my home, can I use my existing system and still have the ability to go off-grid?
I’m not sure I’m ready to invest in a battery based system; however, I would like to plan on adding that to my future or existing PV system. What options are there for me?
Now that you have started to think about these questions and which of these applies mostly to your situation we can begin to understand how these relate to the different types of off-grid PV systems.
There are a few basic types of off-grid systems to consider when evaluating the prospect of taking your home off-grid. The types of systems are; PV-Direct, Off-grid and Hybrid. Each of these types have different attributes that define what they are able to do. Each serves a specific purpose and is chosen by the needs that you require.
The PV-Direct system is this simplest of all off-grid systems. It contains the least amount of equipment and is therefore less costly than other off-grid systems types. Essentially the only components that are required are PV modules, disconnects/fuses/breakers, and the load.
The PV-Direct systems are a good consideration if you have devices which are DC powered and are remote. These could be well-pumps, dc-fan motors or any other DC powered device. The limitations to these systems are that they can only be powered when the solar resource is available. This makes them unsuitable for an off-grid home, but can still be considered if your off-grid home is remote and you have a well-pump or perhaps a greenhouse which requires ventilation.
The next type of systems is the Off-grid system. This is the most commonly thought of because it describes a home which is completely isolated from the utility grid by choice or
The next type of systems is the Off-grid system. This is the most commonly thought of because it describes a home which is completely isolated from the utility grid by choice or necessity. These systems contain more components than the PV-Direct system and by extension more energy usability because one of the primary components is energy storage (batteries).
Before I go further, I want to mention here that there are two types of systems that can be considered in an off-grid system. Those may be either DC coupled or AC coupled. I will cover both of these system types in more detail in a later article to help further explain the advantages of each and when they should be employed.
Off-grid systems are most common for homes that are in remote locations or in areas that are too far from a utility service where the cost of running utility service would be cost prohibitive. These circumstances are where off-grid PV systems are a great option to consider when traditionally you would need to rely on some type of fossil fuel or natural gas commodity to run a generator, which can be expensive and not environmentally friendly.
The main components of an off-grid system are the PV modules, charge controller, battery bank, battery management, DC/AC inverter and electrical safety equipment. You can also consider adding or keeping the aforementioned generator if the loads you wish to power require that extra boost, your batteries need an extra charge or you are really conservative and would like to have it just in-case.