Off-Grid Solar

When we bought our 1200 square foot off-grid house in 2020, it had a small photovoltaic system. The system was designed for a single frugal person back when solar panels were relatively expensive, and consisted of 2.5 kW of solar panels on the roof tilted to capture the winter sun, a 120V Outback inverter, and a new 20 kWh bank of sealed lead-acid batteries.

Actually, why the batteries were new is a story in and of itself. The previous owner had been carefully maintaining his giant lead acid batteries for years past their usual end of life, to the point where the inspector red-tagged them. There were hot spots where some of the batteries were older than the rest, and as they charged, they were emitting clouds of hydrogen sulfide gas, indicating that the electrodes were breaking down. So we asked the seller to replace them with new batteries, and he did, with smaller sealed ones that we could more easily manage.

We went into our first winter with 10 kWh of storage capacity, since lead acid batteries can only be discharged 50%. We found that staying out of the bottom 50% of the battery capacity was tricky, because just understanding where we were involved reading a graph of the battery voltage versus discharge. There were no bars or percent readout like your phone battery. It was more like checking the voltage on rechargeable 1.5 V batteries to judge how charged they are -- not an exact science. Since on a sunny day our 2.4 kW array would generate about 8 kWh of energy, refilling the batteries was pretty quick, but discharging them was discouragingly quick, too. And we discovered that lead acid batteries like to be trickle-charged, even when they are full, so a lot of our generation was just going into "floating" the batteries!

In order to save our batteries, we had to reduce our loads, which involved unplugging the refrigerator and finding alternatives for food storage (more on that in a different article). On several cold nights we found ourselves turning off the main breaker for the house to preserve the batteries, grilling dinner outside in the snow, and then playing board games by lantern light in front of the propane fireplace. Not the modern fuel-free lifestyle we wanted to show was possible in our demonstration project!

We were able to run our electronics to work from home, a few lights and the well pump, but that was about it. Even when the batteries were full, the inverter couldn't handle running multiple loads at once (accidentally turning on the microwave while the well pump was running was enough to flip a breaker), and we wouldn't be able to change to electric cooking, since electric stoves require a 240V system.

We considered connecting to the grid, since there is a power pole on the edge of our property, just 600 ft from the house. But the cost for grid-tying would be $25K, including trenching to the house, meter, etc., not to mention the monthly bills for the rest of our lives. We could buy a lot of solar PV system upgrades for that $25K, we decided, have no power bill, and not participate in the carbon emissions of Xcel Energy's coal-fired power plants!

LED lighting

LED lighting is near and dear to my heart, I'll admit, because I knew graduate students when I was in the PhD program at UC Santa Barbara who were working on the materials science behind blue LASERs and white-light LEDs. The physics and manufacturing of these devices was my specialty, but I still find them magical. A tiny chip a millimeter on a side can convert electric power nearly 100% efficiently into light! It's amazing, even though I understand how it works.

LEDs are nearly 100% efficient, which means that they generate almost no waste heat, and use much less electric power to illuminate a room, so they are far superior in both respects to incandescent lightbulbs. I remember sweating under my desk lamp when I was studying in school in a warm climate, but LEDs produce only light, not heat. They have none of the downsides of fluorescent lights, either -- no flicker, no weird greenish color, no buzz, no blink, no delay in coming on. And they are far more efficient than fluorescent bulbs, while being no more expensive.

One of my favorite features of LED lights is the ability to select the color temperature of the light. In most situations I prefer 4000K light, which is the pure white used in art galleries, to the yellow glow of 3000-3500K bulbs, or the blue cast of 5000K "daylight" LEDs. 4000K LED spotlights make my art "pop," under-cabinet task lights make my food appetizing, bulbs in my closet don't alter the color of my clothing while I'm choosing what to wear, the downlight over the bathroom vanity is flattering to my face, and a track light picks out the controls on the washer in the laundry room. With LED bulbs, I can select the same color temperature for the various fixtures in a room so that everything looks clean and uniformly lit. And, if I'd like to have several moods to choose from, I can strategically place a romantic 3500K bulb in a bedroom lamp, along with 4000K in the closet and reading light.

Did I mention LEDs are cool? I'm a fan!

Our house was outfitted with all fluorescent lights when we bought it, because that was the most efficient technology at the time it was built. The fluorescent bulbs cast ugly greenish light, flickered, and used 3 times more energy than LEDs would to produce the same amount of light. So I set about replacing all the fluorescent light fixtures with LEDs. The previous owner had installed electrical wiring above all the windows, with fluorescent fixtures in wooden shadow boxes that illuminated the cathedral ceiling. We removed the wood and the fluorescent fixtures, took them to the building resale depot, and replaced them with simple metal LED fixtures that use less than 1/3 the power. Each LED light bulb in our house uses between 4 and 9 W. We can turn them all on and be using less than the power one incandescent reading lamp required in my childhood home. We refitted the entire house for less than $1000. And the bulbs will last many years longer than incandescent or fluorescent bulbs would, for no more cost.

We also installed solar-powered metal LED landscape lights that shed a soft downward glow on the path from our car to our door, and a solar-powered LED motion-sensor light above our grill. They were inexpensive, simple to install, are fully automatic, and require no power from our house system.

Truly magical!

Switch to electric cooking from burning fuel

When we bought our house, it had several propane appliances (stove, water heater, and fireplace). Our intention has been to move to all-electric primary systems, retaining the propane appliances for backup only.

We removed the propane stove in our house immediately to eliminate the indoor air pollution it produced, and we now use a variety of electric appliances to cook food efficiently with no fuel burning or carbon emissions.

Did you know that you can cook potatoes perfectly in an instant pot in about 10 minutes instead of boiling water on your stove for up to an hour? The pressurized steam gives a nice plump texture to them, even if they were a little dried out and wrinkly going in. Rice also cooks much better under pressure at our altitude. And pressure makes cooking beans and lentils much easier and faster. The instant pot also serves as a pasta pot, quickly boiling a big pot of water, and as a yogurt maker.

Of course, a crock pot is perfect for cooking stews, curries, stock, pulled pork -- anything that benefits from cooking slowly and thoroughly. We already had a crock pot, but the instant pot has a slow cook mode, too, so we can use either one for stews.

A microwave oven is the most efficient way to reheat leftovers or boil water for tea. We also use it to heat warming disks -- they're made for pets, but we use them as modern hot water bottles by our feet on cold nights.

One of our most-loved appliances is a little electric Breville milk frother we bought used from a neighbor. It heats and stirs a pot of chai or coffee to the perfect temperature in no time. It also makes the best hot chocolate and foamy hot milk (or oat "milk," if you're dairy-free).

We've recently bought a small (24" wide) electric stove with a ceramic cooktop and convection oven. We don't use the cooktop often, and we wanted the smaller size range for our small kitchen, so we did not buy the more expensive induction type. When we do cook on our ceramic-topped electric stove, we've found that using very flat-bottomed pots allows the pot to heat up quickly, so we don't keep the burner on very long. We love the ceramic cooktop's ease of cleaning and the fact that we don't get sticky fossil fuel residue on our cabinets, as we used to with a gas stove. The oven pulls very little power since it is small, and once it comes to temperature, the element turns off, and the convection fan circulates the heat. It only takes 15 minutes to cook a frozen pizza to perfection, and it also bakes desserts beautifully.

Our food is just as tasty cooked with these low-power all-electric methods -- but we are using a fraction of the energy and time to prepare it, and, since our electric power is 100% solar, not producing carbon emissions!

We have a propane grill outdoors that we used for cooking whenever we were on backup power our first year living in the house. Since we've increased our PV generation, we have only used it occasionally for fun in the summer, so the electrification of our cooking is complete!