A Short Primer on Making Your Own Electricity
Most of us have thought of the dream: A secluded retreat nestled in the woods, off the beaten path, no mortgage, no utility bills, raising our own food, homeschooling our children, spending time with our family, etc. Then we pop back to reality, and try to plan out and prioritize how we make it happen. How do we get from where we are to where we want to be?
Ten seconds of background on me: I have been playing with solar energy for 40 years. I am an Army combat veteran, and have had solar on my own house since 1999. (Anyone remember the Y2K scare?) I have been a professional solar contractor for the last decade. My amazing wife puts up with most of my prepping habits. I bribe her with a new Glock every now and then, let her go to training classes, and equip her with cool toys, like the Harvest Right freeze dryer last Mother’s Day. We raise a lot of our own food, both in the garden and on our acreage, and process all of it at home. My awesome wife can outshoot me with a handgun, take care of our acreage when I am overseas, and still homeschools most of our children. As full disclosure, we still are connected to the electrical utility, but are slowly weaning ourselves off it. We have several battery-based solar systems on our property and add more to it every year.
Okay, let’s get to the meat of our subject. I will not go out of my way to candy coat things here. I will try to be brutally honest. As Americans, we tend to be wasteful of energy. I do a fair amount of work in Third World countries around the world, living and working with people who could survive on just what we waste.
Step 1: Load Analysis
The biggest issue is in figuring out what we actually need for energy. If you live in the Redoubt, or the northern Midwest as I do, you’ll need to heat your living space to be comfortable. Remember the line above about the better half being a better shot? Yes, Ma’am, I will keep the house warm for you and the little ones. The biggest issue with solar energy in northern climates is that we tend to use more energy when we have the least available resource. My particular area gives me close to seven hours of generating sunlight in the summer, but only two in December-January. Obviously, electric heat is not an option (more on that later). It is great for air conditioning in the summer, but when we start needing heat, we do not want to rely on solar PV alone, due to shorter days.
Step 2: Get Efficient
Look at where your loads are being used. Go invest $20 and buy a Kill-A-Watt meter [1], or equivalent. Plug your appliances into it, and it will tell you how much current they actually draw. Keep in mind, something like a refrigerator may use 700-1000 watts, but not all the time. It cycles on and off, directly proportional to the time someone stands in front of it with the door open. Once you figure out the duty cycle, you have real world data that you can plug into your load analysis. Lights are pretty easy, wattage of bulb times hours a day. Use high quality LED bulbs. Cheap ones don’t last long enough to justify their cost. A typical incandescent bulb emits 90% of the inputted energy as heat, 10% as light. Anyone remember growing up and always having a 60- or 100-watt bulb in the well house to keep it from freezing in the winter? I do. An LED is the opposite, 90% light, 10% heat. I know, you don’t like the color. Look at the packaging. They list a color rendering index on them. 6500K blows your eyeballs out of your head, 5000K is going to be bright white, 4000K will be warmer, and 3000 will be a warm almost orange glow.
Lighting can be a big portion of a home’s load during the winter months. I love occupancy sensors to turn lights on and off, but they do consume a small amount of power all the time. Look at anything with a wall wart (transformer on the plug). They use power all the time, whether something is plugged into them or not. [JWR’s Comment: Any gadget with a wall cube transformer is likely to run on 3 to 18 volts DC. Look at the specification markings on the power cube. In many cases you can eliminate the Wall Wart and hook those up to the DC wiring in a house with an alternative power system. Running DC to DC is dramatically more efficient than starting with DC power at your battery bank, inverting it to AC, and then running a wall wart to convert it back into DC!] Same with anything having a remote to turn it on and off. Don’t forget your garage door openers.
I mentioned heating a few times now. We do not want to rely on electric heat as a primary heat source. Depending on how much effort you want to put into it, we can have wood heat at one end of the work spectrum, or LP on the other end. You can use some electric heating for spot heating or opportunity loads, but in the big scheme of things, we do not want to use it when the sun is not shining. If we are “off-grid”, it means we are using batteries, and we don’t want to spend the money to have a large enough battery system to run those loads. If you have that much to spend, contact me, I can set you up. We have done systems this way, and it is doable, but it is not cost effective.
There is presently a federal tax credit available against project cost, provided they are around to pay it. My house system actually does power a little 1500 Watt “milk house heater” in my insulated garage, where the wife’s baby hauler and my “small” service truck are parked. It is plugged into an outlet, which I wired up to a relay, which is controlled by one of my Midnite Classic 150 solar charge controllers. If my batteries are charged, the heater comes on. If the batteries fall below 95%, the heater shuts off. However, I have to be smart enough to remember to unplug it in the summer, go figure. Even in the dead of winter, if it is a clear day, the heater screams, making our vehicles much happier. I have to come clean: I presently have way more PV generation than I have load, but that works better in my climate. I will continue to add more load and PV, and someday, more storage to this system. With a solar and battery system, it is best to stay away from any heating loads to be the most cost effective. That means our cook stove, water heater, clothes dryer, and the like, are good loads to have on LP. With a big enough system, they can be powered, with some creativity.
Step 3: Generators and Fuel Storage
What happens if the sun doesn’t shine? It is best to plan for this up front. Look at solar charts, speak to a recommended professional, or talk to someone in your area to see how their system performs. Depending on your location, wind may be an excellent winter supplement, after all, it can blow all day and night during a storm, when your solar isn’t doing a thing. I would recommend a backup generator if you are trying to be truly stand alone, as it will allow a much smaller battery bank. If you are on a budget, a cheap portable unit can work, but I advise against it if you can. Stay away from cheap, gasoline powered units as well. I will admit that I am a diesel fan, as I can make that at home, it just needs to be in a heated place in order to work in the north.
Southerners, you don’t have these problems. Diesel can store well, if you add a biocide to it in order to keep algae from growing in it. If you are in a cold climate, go LP. The typical off-grid project we do will have a 1000-gallon LP tank (or more) feeding the furnace, clothes dryer, water heater, cook stove, and generator. LP doesn’t go bad over time. You do need to verify occasionally that it doesn’t leak out. If your house is efficient, well insulated, and tightly sealed, a single 1000-gallon tank can last nearly a year and a half, in today’s society and lifestyle. One thing to mention with standby generators is that a lot of them will have electric heaters for the engine block, battery chargers (for the cranking battery), and sometimes plenum heaters on LP units. These are all going to be powered by your solar/wind/battery system, unless you are aware and do something about it.
(To be concluded in Part 2. That will be posted on Friday, February 22, 2019.).