Living Off the Power Grid

For the more intrepid home green power builder, you can always choose to build a system entirely unlinked from the power grid. In this case, you will derive all your power without the assistance of the power company. It can be a scary proposition, but if you have good exposure for a solar array or a lot of wind, it can be viable. If you're lucky enough to have wind, sun, and running water for a micro-hydro system, you're golden.

For the rest of us, though, the main consideration is what to do when the sun isn't shining and the wind isn't blowing. There are generally two answers:

1. Battery Packs
2. Backup Generators

Battery Packs

Battery packs will ultimately get their own section- it's worth it. There are serviceable and non-serviceable batteries, concerns about locating the batteries, different types of batteries, some of which require ventilation, etc. The point here, though, is to say that when you are relying on your green power system to create power for you and you don't have a hookup to the power company, you will need something to store the excess power when the sun shines bright and the wind blows hard. Location will matter- you probably want to run the shortest cables possible between your solar cells and wind turbine and the battery packs, but the main concern is the size of the battery box. Evaluate how much energy you need, the type of battery you will use, how much energy is produced from your green power system on an ideal day, and you will find that you can generally figure out how many batteries you need to have based on realistic weather patterns.

Backup Generator

Notice that I said "realistic" weather patterns? That makes me suspicious when I hear something like the word "realistic" getting thrown around. For example, I usually don't go without seeing the sun for even an entire day- I live in the desert. But I occassionally will come across weeks where it snows consistently. If I was planning on a battery pack that would just get me through an afternoon, I'd be without power.

Thus, if you build off-grid and don't want to be without power for several days in the case of freak weather (and you don't have a consistent micro-hydro system), then you'll need a backup generator. Generally, you will end up with a propoane, gasoline, or diesel generator. Gasoline generators are usually portable, which is a consideration. Also, consider what you want to use it for. If you're using it as a backup source of power, you'll probably get better usage out of a propane or diesel generator.

Also consider size (too much power from one of these is just wasteful), altitude (they become less effective by about 3% per thousand feet of altititude) and noise. The last consideration, noise, can be key if building your off-grid system. It will be a more expensive generator, but the noise produced by these things can be immense. This is another reason to avoid getting a generator that is too large.

In any case, you will have many options when buying a generator, so think through them carefully and talk to your local salesman when you go to buy it.

Other Off-Grid Considerations

Given the added difficulties of this setup, it would seem odd that anyone would choose to rely on solar and wind power without the assistance of the power company. However, there is a satisfaction to never having to pay the power company again. Furthermore, if you have carefully evaluated the wind power potential and solar power potential of your property, there is a serendipitous arrangement in which the wind turbine tends to be most effective under weather conditions that are bad for the solar array. This is yet another level of satisfaction- you have managed to become wholly self-sufficient in all your power needs without sacrificing the amenities of a modern life.