I bought a portable solar panel today! I’ve been wondering about solar power for home use for a very long time. We rent, so putting solar panels on the roof isn’t an option without the homeowner’s approval. But, I like the idea of little solar projects, like a grow-light for vegetables or herbs in the winter, or, when camping, charging a laptop or powering a camp stove. I’d also like a small aquaponics set-up at some point in time… the idea of fish swimming around providing nutrition for my salad greens appeals to me!
I thought I’d post about the components of solar panel set-ups and how they function. I’ve noticed that a lot of sites are full of jargon and complex, so I’ve kept it simple.
A solar panel is a collection of solar cells. Each cell consists of at least two layers of silicon, treated so that one side is positively charged & the other negatively charged. This creates a channel from one side of the panel to the other. As photons enter a cell, they knock loose electrons in the silicon. These electrons move along the channel. And that’s electricity! Electricity is nothing more or less than the movement of electrons. So those electrons are collected by a metal plate at the back of the panel, and directed onto wires. Then the wires from every cell are bundled together, so that the electricity from the whole panel is available through one set of wires.
If I was putting my panel on my roof, as part of an array, it would be attached to a secure racking system. Then it’d be connected to the next panel with a simple connector. A homeowner would calculate their electrical power needs BEFORE buying anything. And one should factor in to this equation that the panels will make a bit less power on cloudy and winter days, because it’s better (easier at installation) to install a few more panels extra than it is to add them later. Most homes need between 6 and 10 kiloWatt hours (kWh) per month, or 28 to 34 250 watt panels. The dealer can help you figure your needs. This fabulous Australian site warns: “Avoid any solar energy company that calculates your payback based on 100% self-consumption. Practically no-one has 100% self-consumption. The company is being dishonest in order to get your sale.” Noted!
Next, the electricity goes through an inverter to switch DC (direct current, which is what solar panels produce) to AC, alternating current, which is what powers appliances via outlets. There are string inverters, which mount inside your house and work on the whole system, and microinverters, that sit on the backs of each panel. You can install 33% more panel power than the inverter is rated for. This allows you to make a bit more electricity that you can sell to the electric company. From the inverter, additional wires attach to the electrical meter, then tie in to the grid.
This portable panel I bought is meant to charge up a 12 volt battery. So there would be a gadget called a charge controller between the panel and the battery to prevent the battery from getting overcharged. Then between the battery and the outlet, an inverter. DIY’rs have figured out nice ways to make these systems one unit, such as this example pictured here, where a creative human took the solar cells from dollar store solar lamps and wired them up to a regular electrical outlet to produce a portable electricity generator!
As far as a set-up for a home, batteries are not recommended, because they’re still expensive. The advantage a homeowner would get from being able to store electricity, for use during non-peak generating periods, does not yet outweigh the cost of a large battery. But the cost of batteries really is coming down, just like the cost of solar power did (and this continues). With rebates, government subsidy programs, and the electric company paying generating households for their excess power, homeowners can expect to make back their investment in 5 to 10 years, depending on electricity consumption. Then you are effectively making electricity for free. And getting paid to generate!
I had wondered about the performance of solar panels on cloudy days. But I know that this panel generates electricity on very grey days, because the kit includes a bulb which lights up when the panel is producing electricity. I’d heard manufacturers had made great strides with productivity and quality of solar equipment, but this was reassuring. Solar panels CAN power our homes, folks. I know one homeowner who’s had his set-up for 5 years, and over that period of time, the panels have generated 108% of the electricity he and his family required.
Other cool things I learned about solar include: the environmental footprint that is made during production is paid back after one year of clean energy generation. And, the components are completely recyclable. In addition, a panel will last more than the 25 years its typically guaranteed for. It may not power at 100% of original, but it’s far from useless. They’re incredibly durable. Last, the price has dropped like a rock in the last decade. According to the Lewis model, solar power costs fall by 75% every ten years. There’s NOTHING on this planet increasing in efficiency at that rate!
I have to tell you, when my husband and I first took the panel out of the box, we had strange emotions. Like, who is this strange child we brought home with us? The panel seemed alien and exotic. My husband couldn’t shake the feeling that we needed to “charge it up” somehow to get it functional! Like, we had to boost it with electricity to get it to make electricity! And I kept thinking, surely someone is going to arrive here in 30 seconds and arrest us for making electricity for free. We’re so used to having to pay for our energy! I thought they’d say, “do you really think you’re going to get away with generating your own electricity without having to pay somebody?”
Well, with my new solar panel, folks, that’s exactly what I’m going to do. And what a feeling! It’s so freeing and empowering to know that you can do things that you’ve always been dependent on someone else for. Some corporation. Like, the grocery store, or the utility company, or the government. First, I discovered that I can feed my dirt and make “black gold” compost that makes healthy soil, no fertilizers needed. Then I learned to grow and preserve at least some of my own food. Now, I find out I can actually make power! It turns out that, for me, taking responsibility for how I live in the world is exhilarating in ways I never could have foreseen.