Why Not Gas Generators?
Like other people here, I care about environmental impacts, but at the same time, I care a lot about human life. In a life-or-death situation, I’d never tell someone to freeze or sweat to death instead of running a generator they have on hand. Even if it’s a really dirty and nasty generator, running it for a few days every few years is preferable to people dying.
But, at the same time, I wouldn’t recommend buying a generator to use once in a blue moon. Over time, an inactive internal combustion engine can develop problems. Fuel lines can corrode or gum up, and fuel in tanks can go bad. Fuel stabilizer only extends the life of fuel, and doesn’t make it last forever in storage. Starters (or a pull starter), spark plugs, distributors, and all sorts of other things can stop working. Rubber seals can dry out and crack, too.
Unless the thing is regularly ran, tested, and maintained, there’s an unacceptable chance that a generator would let you down when you need it the most. Given the demands of daily life and the ease of forgetting about emergency supplies, it’s easy to neglect a generator.
Want some proof that small combustion engines can be a problem? Just think about the times you’ve struggled to start a gas-powered lawnmower, or seen someone else struggle with it. Now, imagine that your life depends on the thing starting.
Unless you live somewhere that doesn’t regularly get sunshine, longer emergencies will be a problem for a generator, even if kept in good working order. If you run out of fuel and the power is still out, you won’t be able to get more gas. But, solar power can be topped up again the next time the sun is out.
Some Basic Concepts For Emergency Solar Power
Now that we’ve established the “why?” of renewable energy in emergencies, let’s get into the things you’ve got to understand to use if effectively.
First off, let’s talk about units of energy. Let’s think about it like water. If you want to save rainwater, you’ll need to collect it from a roof, save it in a barrel, and then put the water out through a hose or a pipe.
Watts are like the flow-rate of the water going into or out of the barrel. More watts means more energy flow. If the amount of water going into a barrel is greater than the amount of water going out, then the barrel will fill up. If the water going out is more than what’s going in, the barrel will be emptied.
Watt-hours (Wh) or kilowatt-hours (kWh) are like the capacity of the barrel. If putting 1000 watts of power into a battery fills it up in an hour, the capacity is 1,000 watt-hours, or 1 kilowatt-hour (the kilo- prefix means x1000).
Before you set out to build or buy a renewable energy system for emergencies, you’ll need to figure out what your power needs are. Figure out what the essential appliances are that you want to run. Then, look up the power consumption on the manufacturers’ websites. Or, use a “Kill A Watt” energy meter to see what the appliance actually uses.
Then, multiply the watts needed by the amount of time you’ll need that many watts each day. That number (in watt-hours or kilowatt-hours) is the amount of energy storage you’ll need. You probably want two or three times that so that you’ll have power if there are a few cloudy days.
Then, for solar power, you’ll want enough power to fill that battery system up in 8 hours or less, and then double it for energy losses and other inefficiencies. So, if you find you need 10 kWh of battery storage, you’ll need 2,500 watts of solar panels.
If you add up your whole home’s energy storage needs, you’re talking about some serious power and battery storage, which in turn means spending some serious money. A really killer system could easily cost over $50,000, but would give you near-absolute home energy security.
What If You Don’t Have The Money?
Not everyone can afford an expensive solar roof, a big bank of batteries, and inverters, other odds and ends, and the labor to put all this in. If you can afford that, awesome! If not, you’ll need to come up with a way to cut your emergency power needs back.
Also, if you’re renting or otherwise can’t get a traditional permanently-installed emergency power system, you’ll need to look at portable or temporary-install options. These systems are usually smaller, but can be had at any price point if you’re able to get by with less electrical power. The smallest systems that can do basic things like charge a phone can be had for well under $100.
There are many ways to conserve power and keep system size/costs down.
When it comes to heat and air conditioning, a heat pump AC for a whole house uses a lot of power. Even a resistive space heater for one room uses almost 1500 watts when it’s running. But, a smaller heater for a smaller room could use only 200 watts. Or, electric blankets could use only a few tens of watts per blanket. Add some sleeping bags or extra normal blankets to trap the heat, and you could get by with a pretty small battery. A small evaporative AC unit isn’t great, but it uses a lot less power than refrigerated air.
There are plenty of other places to save energy. For cooking, consider an inductive cooktop instead of a resistive heating element. For microwaves, use a lower power setting or a smaller microwave. For lighting, be sure to use LED bulbs. For electronic devices, try to use low-power devices during emergencies instead of something power hungry like a gaming computer.
Finally, for transportation, consider using e-bikes or electric scooters.
In other words, you could get by in an emergency on a lot less power than you probably think, and providing for those power needs is probably cheaper than you think.
Personally, I’ve tested a lot of portable solar and battery units, and my favorite two brands are Ecoflow and Jackery. There are some other decent brands out there, but be sure to read reviews before pulling the trigger.
Home-Built Systems and RVs
It’s also possible to build your own battery-solar energy systems. I’ve done it, but I wouldn’t recommend it unless you’ve got some basic low-voltage electrical experience. There are tons of YouTube videos out there discussing building your own system, and I’ll refer you to those.
In short, though, you’ll need panels, a controller, and a battery. For a battery or a bank of batteries, you could use a cheaper lead-acid deep cycle. But, personally, I’d recommend spending more on a lithium-iron (aka LFP or LiFePo4) battery. These are safer, more reliable, and last longer.
Setting Up A Portable System
For permanently-installed systems, you don’t need to worry. If you have a system professionally installed on your roof, the installers will help you figure out how to aim the panels for the best possible output over the course of a day or a year. For vehicle/RV mounted system, the best direction is generally straight up so that you’ll have the best power from different angles.
But, if you have a portable power system, you’ll need to keep it aimed at the sun to get the most power. The simplest way to do this and leave it set up all day would be to aim the panels south and at a 45-degree angle. If you want more output during the day, you might want to re-aim the panels every hour or two and follow the sun. You can use your shadow and the panels’ shadows to get the direction right.
Another important thing to keep in mind with portable systems is to avoid partial shading. Even if most of a panel is getting full sun, a shadow of a branch or leaves going over a small part of it could cut the power down in half or worse. So, try to keep each panel in full sun all the way across the panel whenever possible for maximum power.
Storage Between Uses
One final thing to consider with a portable solar generator setup is that you need to take care of the battery. The panels can probably be stored in a shed or other dry storage space, but it’s best for the long-term life of lithium batteries to keep them at room temperature. So, keep at least the battery part of a power station stored indoors. In most cases, the battery can be kept 100% charged, but the better power systems can be set to limit charge to 80% for even better long-term life.
Featured image by Jennifer Sensiba.