Aquion Energy’s saltwater battery has gotten a lot of press in the last couple of years for its unique technology, but I think it deserves even more.
I'm just your average homeowner myself, but I've been following solar technology for years wondering when it would be viable for the general public to start generating and consuming our own power instead buying it all from the grid.
In the past, lack of energy storage was always the downfall for off-grid systems: from small residential to commercial microgrids and nanogrids. There were some options available for large-scale commercial projects like flow battery technology, but those were too expensive for normal homes. Available products for residential customers have still been fairly limited, despite the demand and market growth for energy storage. Compatibility with different inverters and charge controllers has also been an issue.
I was first able to go off-grid some years ago using lead acid batteries on multiple strings, which is not viable for most people and is probably why so few are off-grid now. Even if you know what you're doing and maintain your system at a high standard, it can be difficult to keep things working well. Plus, it's not cheap in any sense.
A typical, off-grid residential energy storage system design.
I wanted to find out for myself if I could live with an off-grid system long term, so I started in my garage to gain experience. My 2000 sq ft garage is slightly larger than my home, but the power usage is much less and more sporadic.The garage also had a separate meter for which we had to pay a monthly fee— whether we used power from the grid or not. That money now stays in our pocket.
We installed 3.5 kw of solar panels and eight, six-volt Trojan batteries in series to power a 48-volt system. I also had a backup generator for in the winter when there was no sun for days or during summer rains with overcast skies.
I worked with that design for three years, but I knew I had a major issue: I was wasting a lot of energy because I couldn't store all the solar power I generated for later use. That can be a frustrating problem with off-grid systems: if you can't store the power you generate because your batteries are full, or if you're not using energy storage at all, then you are wasting energy.
I had heard about saltwater battery technology being developed back around 2011 or so. After a few months of follow-up searching all the flow battery products I could find, I did a chance YouTube search for "saltwater battery".
That's when I found the Aquion saltwater battery, which in fact is not a flow battery, and realized it was already available for order. Then, around the first quarter of 2016, I heard Aquion was also selling a larger capacity module with twelve of their 48S batteries. I had been very anxious to expand my system if I could just find the right energy storage for a decent price. Now, that dream was falling into place.
So, when designing the energy storage system for my house, I decided to go with Aquion batteries. I bought an Aspen 48M module and secured my place in line. Then I just needed a company to design the rest of the system and plan the install.
Luckily, after some extensive searching, I found a local solar installer. At first he wasn't impressed with the idea of doing a residential off-grid system, but was really intrigued when he saw the battery! Here is his video of my system.
Connecting the power from my garage over to the house was really the hardest part of the whole job. But each home will be different depending on where your panels will go, where the inverters and batteries will be placed, and where your house breaker panel is located.
One thing unique to my install is that it is designed as a dual hybrid system. I kept my home meter from the grid which I can use as backup if needed. There's no connection from the grid to the solar system at all and I don't sell my excess power to them. Rather, I installed a commercial transfer switch to handle higher amp demands from the grid side. With this, I can switch the input power feed to my breaker panel. It stays on the solar side unless my battery voltage gets too low and the inverters shut off from the low battery cut-off (LBCO). I could power on my generator at that point if I chose to, or I can switch to grid power until the sun comes up or until whatever the issue may be is resolved.
My system could be better sized for two or even three modules charging in parallel, but I wanted to get my system going, try it for a year or so, and then upgrade once I was satisfied with how everything was working.
David with his off-grid residential system featuring an Aquion 48M.
With just the one module, being mindful of our daily energy usage, it’s possible to get two days of use out of our system without resorting to the generator or the grid. Most of the year, with the 7 kw of panels I have now, I could likely fill up multiple modules, running as many loads as I want without any problems.
If I added two or three more modules, I would never need the generator. Four modules would probably get us through eight days without even cutting back on our use… but when would we even have a week with no sun at all?
Of course, everyone’s usage and system sizing will vary, but the bottom line is going off-grid is not a technology problem. Look at the Aquion saltwater batteries. What can you compare it to across the board? I'm also off-grid for a lot less money than others I know about and I have a more reliable battery than the old lead acid technology.
It's pretty much a plug and play solution for whatever 48vdc inverters or charge controllers you may be using now. Few things are so advanced that they are called disruptive technology. Even though it's only been a few months that I've been off-grid, I think the Aquion fits in that definition!
For more on David's system, you can visit his YouTube channel.