After 12 years of using solar and wind electricity every day as my sole source of power, it still feels like magic. And it keeps me in touch with the daily rhythms of nature’s flow of energy where I live, in Fairfield, Iowa. I’m writing this article on a solar-powered computer.
Okay, so you’ve gotten rid of the old energy-hog fridge, switched to compact fluorescent lighting, put the phantom loads on a switched outlet, and switched to earth tubes for cooling. Like the Isbell family in Vinton, Iowa, you’ve cut your electric bill 75 to 90 percent, to an average of 100 kwh a month for a family of four. You haven’t reduced the quality of your life or the services you get from electricity, you are just smarter in the way that you use energy.
The next step is to generate your own electricity from the abundant and reliable sun (with 100 percent reliability for the last few billion years) and the wind that shakes your home on a cold winter night.
I’ve powered my home with a combination of sun, wind, and the wise use of electricity for the last 12 years, and so have my neighbors. I am an electrical engineer and a bit of a geek. I have a lot of electrical appliances, including three computers, three satellite dishes, high-speed Internet access, a music studio, two large TVs, two vcrs, a dvd player, a well-equipped workshop with lots of high powered tools, a freezer to store the bounty of my gardens, plus many other essentials of modern geek living. The reliability of the wind and solar system that powers all this is very high, and I have power when my neighbors are without due to utility outages.
The technology to power your home with solar electricity is remarkably simple—about the same level of technical difficulty as hooking up a home stereo system, and far less complicated than home computer technology. Any system, large or small, has the same basic components.
PV Panels
Solar electric or photovoltaic (PV) panels are the heart of the system and generate electricity directly from sunlight with no moving parts. Nothing is used up in the process, and PV panels have an indefinite life. Most come with 20-year or longer warranties and will probably continue to generate useful electricity for more than 50 years. PV panels range in size from 10 to 195 watts. Unless you live in a cabin or on a boat, you will require more than one panel. Panels can be connected together to provide as much power as you need. A typical home with a family of four requires 1000 to 2000 watts of PV panels.
It is surprising what you can do with even a small system. One Fairfield family uses less than 300 watts of PV to power their 2000 square foot home, and a well-known reporter in Fairfield has used less than 200 watts of PV to run her office for the last several years. Retail prices for PV panels are $4 to $5 per watt.
Wind Generator
Today’s wind generators have only one or two moving parts. The wind spins a blade, and the blade spins wires or magnets in a generator. Because they have moving parts, wind generators usually require more attention and maintenance than PV panels. The great advantage with a wind generator is that it will fill your battery bank at night. We get far more power from our solar panels than from our wind generator, but the two complement each other nicely.
Inverter
PV panels generate DC (direct current) electricity, and the power that the utility provides is AC (alternating current). An inverter is an electronic device that changes PV-generated DC power to utility-compatible AC power. Some people have adverse health reactions to AC power, and it is possible to power a home with DC without using an inverter. However, most people want the convenience of AC power, and use inverters to get power quality that often exceeds that supplied by a utility company.
Like PV panels, inverters come in many sizes. A house-sized inverter has a capacity of 2000 to 4000 watts and is about the size of a large breadbox. A small inverter capable of running small electronics devices costs as little as $30; a whole-house inverter costs $1500 to $2500.
Batteries
Batteries store energy for nighttime use and to allow you to run large appliances. Lead-acid batteries are the most cost effective. Choose deep-cycle batteries like the ones designed to run electric golf carts and forklift trucks. Battery size needs to be coordinated with PV capacity, because the PV panels need to be able to fully recharge the batteries with a few days of sun. Some systems designed to be connected to the utility grid do not need batteries. Batteries cost $200 to $1000 for typical systems.
Charge Controller
Charge controllers keep the batteries from being overcharged during periods of low energy use. Many new controllers come with peak power tracking, which better matches the output of the panels to the batteries on cold days and when batteries are deeply discharged. Charge controllers cost $100 to $400.
Metering
Meters allow you to monitor your energy use and the flow of sun and wind energy into the system. Some meters act as a “fuel gauge” for the battery bank, allowing you to see at a glance how full or empty the batteries are. It is essential to have some kind of metering and to glance at it daily. At a minimum, you will need a volt meter and an amp meter. Metering costs between $100 and $300.
Back-up Generator
The combination of sun and wind is so reliable in Iowa that you may not need a back-up generator (I have gone for years without using one). You can also hook up to the utility grid for those rare occasions that you need back-up power. At Abundance Ecovillage, we use a biodiesel-fueled back-up generator.
Please feel free to stop by my neighborhood or Abundance Ecovillage to see solar and wind power in action.