Most people are surprised to learn that a typical solar photovoltaic (electric) system does not provide power when the utility company electricity goes down. Most solar photovoltaic systems are grid-interconnected, and in a way, grid-dependent. Due to the variable nature of solar panel output, having power during utility outages requires a battery.
Let me say up front that batteries are relatively expensive, dirty, dangerous, short-lived, inefficient, heavy, and big. That’s why I typically don’t recommend battery based solar energy systems. However, I was reminded recently that I should listen to our customers and understand a little better what their goals are. There may be a good application for battery technology in many circumstances. For example, I shouldn’t dismiss a customer who just wants to have their refrigerator powered by solar energy. This may be a great fit for solar energy!
Boats and RVs have been using 12V or 24V DC refrigerators for many years, and some models can be extremely efficient. What if you could have a small refrigerator with one or two solar panels and a few batteries. Perhaps this would fulfill the essential refrigeration functions required during and after a storm. I could be done relatively inexpensively and be made reliable with proper system design.
An expensive part of a battery based solar energy system is the electronics to convert the solar panels’ DC energy to AC energy for household appliances and lighting. System design, engineering, permitting, and wiring (or rewiring) also add substantially to the cost. If you are able to identify clearly what you want to power during an outage, it can make a battery-based solar energy system a much more cost effective and reasonable solution.
You can do just about anything with a battery based solar photovoltaic system – for a price. Once you break it down the the real essentials, the concept becomes a lot more feasible. I’m ready to hear your battery backup needs, and I promise I won’t be so quick to dismiss the idea!