Harnessing the Sun
Harnessing the Sun
First-hand info on all things Solar (and a little wind power, too).
We've been living off grid and reliant on solar power and, recently, wind for nearly two years. As we've added on, modified and adjusted, I often question whether large-scale solar or wind power is feasible for whole communities. I'm leaning towards no and I'll explain why.
For those of you considering a solar system, this post is going to be useful. For those of you not considering a solar system, this post is going to be long and probably boring. Consider yourself warned.
My husband, John, designed our system and it was laborious. I remember him hunched at the dining room table on his laptop for hours, jotting down notes and looking perplexed. Personally, my understanding of voltage, wattage and amperage is weak, at best, so all I could do was look on empathetically and make cookies. Building an entire power system to be reliant upon is not only intimidating but expensive. You don't want to make any big mistakes.
Our previous home in the city had a 400 amp capacity, which is double the typical home (200 amps). I'm not sure why it was built that way, but we never had to worry about blowing a circuit.
To put things in perspective, now we have 30 amps. Yes, we went from 400 to 30 amps. But if you came to our home today for a visit, you'd never guess we were running on so little power. Here's how we did it:
The first step in determining the size system we'd need was to take inventory of every appliance we were using and how much draw we were putting on the existing system (back when we were on the city's electrical grid). Typically, anything with its own circuit is drawing a lot of power (most are listed in the breaker box). These will vary from home to home, but here are the most common:
Water heater (220 V)
Range (220 V)
Oven (220 V)
Refrigerator (220V)
Home heat/AC (220 V)
Microwave (110V)
Washer/Dryer (220V)
John and I examined our regular usage and determined where we could scale back or modify. By modify, I mean that any appliance that runs on natural gas can be converted to propane. That allowed us to divert a lot of important conveniences elsewhere, reducing our electric requirements. For instance, we bought a natural gas oven/range and converted it to propane. We opted for a small electric refrigerator (10 cubic ft) but we bought a separate freezer that now runs on propane, so cold storage is no problem. The small fridge is a good size for us, and it doesn't use much power (it's a Summit, made in Mexico, if you're interested).
Of course, John insisted on getting the built-in ice maker and, I must admit, while I balked at first, it's a nice luxury to have for my gin and tonics.
Continuing, we use an instant water heater that also runs on propane, as does our clothes dryer. In the summer, I usually hang laundry out on the line so we're only using the clothes dryer half the year.
So, the only appliances running off our solar system are the oven (because even propane ovens typically use an electric start for the pilot,), our washer (110V), our well pump, and our refrigerator. Obviously, we no longer have the heat pump we had in the city (now we use firewood), and we certainly have no air conditioning. Scaling that list back dramatically reduced the size system we had to buy without sacrificing basic conveniences.
Well, okay, maybe I do miss having air conditioning sometimes...
And John, being John, decided to overbuild our off-grid system so we could add on later, if needed. Turns out, we did need to. For example, we originally thought we'd be using a shallow 24v well pump. That got thrown out the window when we had to deepen our original well... We also started with a 700-amp battery bank, which we expanded to 1100 amps just a few months ago.
Fortunately, the charge controller John purchased originally was designed to handle more capacity than we originally thought we'd need. Now, it's maxed out, but that's okay because it's enough - but we had to learn that through trial and error. If we had to add on at this point, we'd need another charge controller and that's a big expense so, as John says, "Build a system bigger than your needs".
I'm not promoting them, but we bought a lot of our equipment from Backwoods Solar in Idaho and I can't say enough good things about them. Even if you don't buy from them, they have a solar guide and learning center on their website which proved invaluable at helping us determine our needs.
Once we decided what size system we needed, having redirected much of our usage to propane (which I'll get to), we had to decide what kind of equipment we'd use to convert sunlight to usable power, and how.
It's very common to install solar panels on the roof, but there are drawbacks to that. If you get the kind of snow we do, having solar panels on the roof pretty much guarantees they'll be useless much of the year. The same can be said of pole mounts if you can't reach the panels to brush the snow off.
Also, to maximize efficiency, solar panels should be seasonally adjusted 3X a year for maximum exposure to the sun. Similarly, most people's roofs don't face directly South, which is where you want your panels facing, optimally.
When we moved into this house, there was an existing solar pole mount. On it, were eight 50-watt panels that were about 20 years old. I've mentioned before about having to use a lantern to find the bathroom at night when we first moved here... yeah, those panels didn't actually work anymore. I remember John and I taking the whole contraption down and it was pretty scary, unstable, and extremely heavy.
Anyway, modern pole mounts can be adjusted easily, but they also require about 2 yards of concrete for the footing (due to the weight of the panels and pole). In our location, that wasn't happening. No concrete truck is coming up here! We had to think differently.
John designed and built our mounts so they could be installed in the ideal location (facing due South) and adjusted seasonally. We installed our first 6 panels in 2020, and we added three more last April. We also started out with 8 batteries, and now we have 12 (24v system).
Speaking of batteries, there are three basic options: Flooded Lead Acid, Absorbed Glass Mats (AGM), and Lithium Ion. Yet another facet I watched John distress over...more cookies.
After a ton of research, figuring and head-scratching, John decided to go with 6v flooded lead acid batteries (390 Amp each), which has proven to be a good choice. We narrowed our choices thusly:
Aside from being expensive, Lithium Ions are considered a new technology. They weren't around two years ago... would we be able to replace them at the end of their 10-year lifecycle? Not sure. They're a good choice because they don't require maintenance, but the per amp cost comparison just didn't add up for us.
AGMs are in the middle, pricewise. They're becoming more common in vehicles, and they are sealed so they require no maintenance but, again, the issue of availability arose. AGMs have a 7-year expected lifespan, but they still aren't as readily available as lead acid.
Flooded lead acid batteries are the least expensive. Currently, they're industry standard in golf-carts, forklifts and other industrial equipment. They've been around for at least 20 years and will probably be around a lot longer. They do require some regular attention (topping off fluids weekly and monthly equalization (which I'll get to)). Basically, they're old-school. We're old-school, too, so it's a good match.
There are a lot of ways to do solar; this is just our story of what we did and what worked for us (and didn't work). Certainly, do your own research and consider what's right for your situation.
You may be asking yourself the bigger question by now: Batteries, Panels, Mounts... So how do all of these pieces fit together? I'm going to attempt a very basic description of how it all comes together. Here goes:
Basically, our home isn't powered by solar panels. It's powered by batteries. Those batteries are charged by the solar panels. When you see solar panels on the roof of someone's home in town and they are selling power back to the city's grid, they still wouldn't have any power at night if the grid went down because they aren't storing it. They have no batteries. No batteries, no storage. Batteries are key.
Our solar panels take in the sunlight and send the energy to our Charge Controller. The Controller is attached to our Distribution Panel. The Distribution Panel is the main hub that tells everything else what to do.
The batteries also wire into the Distribution Panel, as does our Breaker Box (we have a breaker box just like you'd have in town). The Breaker box (house electricity) is fed by our battery bank. In town, it would be fed by the electric power line, for instance, but we are, in essence, our own power company.
Here come the questions: What happens if there is no sun? Do you have less power in the winter?
Those are good questions...remember when John said to design more than you think you'll need? In the winter, the days are significantly shorter. Summer usable daylight here is from about 6am to 8pm. In winter, it's 9am - 3:30pm. We have a tall mountain to the West so we lose an hour of daylight when the sun goes over the hill. Also in winter, we use more power: more lights are on in the house; the heat trace along the underground water pipes comes on dependent on the temperature. We use other things like a heat lamp (for the chickens) and a heated mattress pad (for us). Basically, we use more power in winter than summer, and there is less sun. That's life. So, we adjust.
Our adjustment involves a 14KW Kohler generator (converted to propane) that lives in its own shed near the house (a shed now shared with the chickens). John programmed the generator come on automatically if the battery bank falls to 23V. The generator will charge the batteries and then automatically shut off.
Of all our appliances that run on propane, the generator is the heaviest user. Fortunately, it's just a back-up and doesn't come on very often. When it does, it takes about 5 hours to completely charge 12 batteries. Many off grid systems use gas generators but gas and diesel can have fuel storage and contamination issues. Propane stores longer and safer and can also be delivered in bulk. For the past two years, having bulk propane delivered here costs about $2.50 a gallon vs. $3.50 per gallon in town. The price hasn't fluctuated much at all - unlike gas and diesel.
By the way, we have a 500-gallon propane tank (and a 250-gallon back-up manifolded to it). So far, our propane usage is about 300 gallons per year.
Although a 14KW generator may seem like overkill, the advantage of having more power is that the generator isn't maxed out charging the batteries, so it should have a longer lifespan. A 20 KW generator is perhaps more popular, but it burns more fuel when running and can burn out faster powering heavy loads.
As of now (late June), our generator hasn't run at all in two months. During winter, it ran almost once a week. In December 2021, we added a wind turbine to increase our power intake when it's windy and/or the sun isn't out. It's hard to tell how much it's helping (it doesn't record intake), but often in the morning, the control panel will read "25V" so, it seems to be beneficial.
Solar systems are becoming more popular, especially off-grid, but they can be quickly turn into yard ornaments if you don't take care of them. Our neighbors, for instance, have a pole mount with 6 panels, yet they run their generator every morning from 9-noon, even when it's completely sunny. I think they may have issues. So, what could be the problem?
Probably, batteries. At least with lead acid, if you don't top off the fluids, they can dry out and burn up. We do it weekly because batteries are expensive (they were about $300 each in 2020).
Also, as with all deep cycle batteries, they don't like to be discharged too much. For example, if you let your phone battery wear down to nothing before you recharge it, your battery won't last as long. Same with deep cycle batteries (used in boats, RVs). If the neighbors drained their batteries down too low repeatedly, they have dead batteries. Just speculating.
So, as protection against that, our generator is programmed to start if our batteries drop to 80%. If they were ever to drop to 50%, the whole system would shut down as a safety measure to preserve our batteries until we could figure out what was going wrong. Hasn't happened yet... knock on wood.
Those are pretty basic maintenance requirements for lead acid batteries, but there are a few others, too, like equalization. Equalization is a controlled overcharging of the batteries to clean the plates of stratification/build up. It keeps the batteries healthy. Equalization does produce some out-gassing, so proper ventilation is essential in your storage area. We use both natural ventilation and a powered fan. The term "out-gassing" should be explanation enough why. Our system equalizes once a month; it's programmed into the Charge Controller to do so automatically.
Lastly, the system goes through a process of bulk charging, absorb charging and float charging each day. Bulk is high current, low voltage. Absorb switches to low current, high voltage. Float is lower voltage, lower current (trickle charging). Again, these cycles are programmed into the Charge Controller but it's important to monitor the system and make sure all is running as planned. It really is like having your own little power company. If there were no maintenance happening at your local utility company, things would fall apart pretty quickly. Same here.
I'll mention here our wind turbine that we installed back in December 2021. It's also automatically programmed to shut off if the batteries reach 28.5V to prevent overcharging. And every time I say, "it's programmed", I mean John programmed it (more head scratching and pouring over manuals)...
I've read recently that Chinese solar equipment has been flooding into the US. The prices are attractive, although I can't speak about the quality. We didn't take that road. We spent a little more and went with a US company for all of our equipment.
Amidst all of the head-scratching and questions we had when designing and installing the system, it sure was nice to be able to call the supplier for help. In Idaho. If you're thinking of purchasing equipment from China, just consider the picture below and think: if someone has advanced knowledge of solar systems, they're probably not working in a call center.
Being reliant on 30Amps of nature-powered energy has definitely increased our consumption awareness as we live life. If it's a sunny day, I'll take advantage and vacuum the house! If it's cloudy, I'll sweep instead. Little adjustments like that.
We're learning so much as we go about efficiency, timing, and conservation. And because our activities are directly affected by overcast skies, we're thoughtful about consumption. And this is why I don't believe in large-scale solar or wind farms. It may seem hypocritical since we're dependent on our solar system, but it isn't the same on a large scale.
The difference is proximity. Solar farms are far removed from neighborhoods and towns, as are wind farms. I think of the skinny-jeans wearing hipster smugly charging his Tesla from coal power.... too removed from the source to really understand that he's not actually "saving the planet". Too much of what we're sold regarding alternative energy is hopium. There's a lot of money to be made on the illusion of green energy, when the reality looks more like Texas in February 2021. To make it work large-scale everyone has to be on board, aware, and accountable. And the politicians have to stop lying about what's possible.
The truth is most people will not voluntarily cut back. They won't sweep when there is a vacuum cleaner at hand. The same people who water their lawn at night during a drought will continue to have five televisions turned on in empty rooms, every light in the house on, and the AC set at 65 degrees on a 70-degree day. For these people, there will continue to be forced black-outs, forced brown-outs, and escalating utility bills. They can have it.
Our motive in moving off-grid and creating our own system wasn't to "save the planet". The planet can take care of itself and has been doing so for a long, long time. Our motivation was to eliminate our dependence on the systems which promise to provide everything to everyone with zero accountability. That's a system doomed to fail. It's a Titanic waiting to sink.
Don't wait too long to jump ship.