Generating your own power is much like growing your own food. The first step is to change your relationship to your power, much like your relationship to food is changed by eating seasonally and locally. Most households use more power than can be efficiently or affordably produced by alternative sources, so the most important thing to do is to reduce and reorganize your power needs. Reducing the first 50% is the easy part, like growing your family's fresh produce needs for the summer. After you bring your power consumption down, somtimes through outright sacrifice, but mostly through a creative process of doing things differently, then you have a chance at going off grid.
After reading reports from the UN lead Intergovernment Panel on Climate Change, and other independent sources, it appears that we should be setting our greenhouse gas emmission reduction goals at 80% or more. That means we need to get extremely creative, and look around at what we can use and afford right now.
We are off grid. We are not fossil fuel free yet, but we are carbon neutral. We have one Sharp 80 watt Solar PV panel, a 1200 watt gas generator, running through a 40 amp battery charger to boost the power, six 6V deep cycle batteries in a 12V configuration, and a 1200 watt moderated sine wave inverter. All of this cost us about $2000. We run the generator an average of 40 minutes a day, and are looking at pracitcal ways to replace it, using 1/2 liter of gas a day (200L or 50Gal a year). With this system we run 1-2 compact flourecent lightbulbs, radio, electric fencer, occational TV and DVD player, charge a laptop, cell phone, ipod, use a fan in the summer, and run kitchen appliances like a cream separator, blender, etc. We do not use electricity to move water, heat water, heat air, cook food or preserve food. Generally speaking there is usually a better source than electricity to provide these domestic needs.
Producing your own power also means looking at what resources you have locally. Wind, sun, water, wood, vegetable oils and human/draft power are all sources of energy, and one or more is bound to be abundant or at least available anywhere on this earth. Generating power is one side of the equation, storing and using the power is on the other side. Below are some things we have learned about renewable energies.
1. Wind power: HAS TO BE in the right location. Look closely at the startup speeds on individual generators to match it to the average wind speed in your area. Get a wind meter and measure your own wind, don't rely on what other locations experience. If the average wind speed is 12 mph then you are going to be on the low end of wind power generation. You need a consistent 12-25mph wind speed to get real economic and efficient use out of any wind generator. Best to be on an open plain or ocean.
2. Solar voltaic PV generation: With PV technology changing in material composition, efficiency and cost within the next 5-10 years, it may be best to wait or take this into account when investing in a PV system. A general search on Photovoltaics will give you more of an idea of what is going on in the industry. Possibly some exciting stuff. Other important factors to take into account regarding PV's are pollution, smog days, contrails, and climate change. We have found that living under a flight path has cut out our power from 6amps to 3.5amps on high flight days. And they don't have to be directly over you, they can spread out from hundreds of miles away.(see The David Suzuki Foundation). For climate change, if you are living in a climate model expected to go dryer or wetter (meaning more or less sun), then take these into your estimates.
3. Draft power: We have looked into the possibilities of using draft animals: oxen, dogs, horses and donkeys. We have come across a few websites that have interesting ideas and working systems, it may be appropriate for many areas or situations, most possibly as as a seasonal, portable standing motor for farmwork, more than a daily home power source. We have a working standard bred horse, and have worked on some designs to power a DC generator, but not one that would be efficient enough in both time and money. Our horse would be better employed to pull in firewood or cultivate the garden than to waste time and energy on generating power at this stage.
4. Steam: We have looked into it as a stable power source, being that we have an abundance of wood. But anything under pressure has it own state regulation and safety issues. Steam has a lot of potential for small scale sustainable carbon neutral generation, especially for community shared power systems.
5. Bio fuels: At this point a controversial issue. Large areas of rainforest are being cleared in Indonesia to grow Europe's demand for biofuels. This is not sustainable or ecological. Biofuels can be grown on the homestead. They would never have sold a tractor if farmers could not run them on their own corn oil or homegrown ethanol. One acre of sugar beets can produce 1000 liters of ethanol, but again state regualtions apply.
8. Pedal power: We are looking into the possibility using a pedal powered generator to replace our gas generator.
9. Geothermal: This is not likely a realistic option for a single household, but on a community or urban scale it may be the best source of power available. It is constant, and can be used to create electricity as well as heat and cool both water and air. Wikipedia gives a good overview of the technology as well as links to more research and working geothermal power stations around the world.
More on batteries next time....