| | Renewable Energy - An Off-Grid Solution of Simple Tricks & No Nonsense
Energy is a force that does something. And we ask a lot from the energies available to us, especially electrical and chemical energies. The electrical energy from the AC power "grid" is obtained primarily from mined, heavily polluting, nonrenewable resources: coal, petroleum in some form, or highly refined uranium-bearing ore. A tiny portion (in the U.S.) of electrical power is supplied by renewable sources: moving water captured by hydroelectric dams turning turbine-coupled generators, moving air powering large wind turbines, sunlight energizing banks of photovoltaic (PV) panels, and geothermal heat powering steam generators.
Chemical energy is often utilized solely for its ability to produce heat, often for a terribly innefficient conversion (about 24%!) into mechanical energy (the internal combustion gasoline engine). Chemical energy for portable power, remote locations, or high volume users is usually supplied by nonrenewable petroleum in the form of natural gas, liquefied petroleum (LP), gasoline, diesel fuel, fuel oil, aviation fuel, or kerosene. Really high volume users who don't need a portable source (like electrical power plants) use coal.
A hundred years ago the scenario was quite different. Electricity, where it could be obtained, was usually from hydroelectric dams, small local steam engine generators, or, a little later, from small wind turbines. It was stored in bulky, heavy, lead-acid batteries that could be charged, discharged, and recharged many times. Chemical energy for direct heating of homes, or for conversion to mechanical energy was obtained mainly from non-renewable coal or renewable trees.
World War II was the impetus for many of the changes we see now. A huge energy appetite and the demands for massive destructive capabilities left us with an enormous civilian chemical products industry and the ability to produce electrical energy from the controlled splitting of uranium atoms. Both industries have left us with huge and ongoing waste disposal problems, neither of which has been adequately resolved. Coal mining continues to be a major polluter of water, a hazard to miners, and, even with decreased noxious emissions from planned "FutureGen" plants, its increasing use exacerbates the global warming scenario of trapped carbon dioxide in the atmosphere. The popular press, influenced no doubt by heavy-handed lobbying, is touting the "carbon neutral" benefits of nukes. But the mining and preparation of uranium fuel rods is a huge source of carbon dioxide, not to mention the water pollution and health hazards associated with uranium mining.
Roughly 76% of all electric power generation goes into building operations! That's about 44% of ALL the energy humans produce. Renewable resources that offer energy with no net CO2 increase are the only intelligent choices in our current situation. But a swelling human population practically guarantees that wise choices won't be made by politicians wanting to remain in office. Still, for those who'd like to take a stab at a semi-sustainable lifestyle, there are some updated versions of the traditional renewable energy sources.
Local electrical power production lost its battle with centralized power way back when Edison's local DC power production scenario was replaced by the Westinghouse-Tesla distributed AC power grid. The main reasons for AC power were the ability to easily transform the energy to a high voltage that could be transported long distances with low loss, and the ability to transform it back to a safer low voltage at its use point. Modern power conversion devices using switching transistors have made locally produced DC power much more efficient, versatile, safe, reliable, and easily obtained. DC to DC converters can transform nearly any voltage to another, either for transport or use. And sine-wave inverters can produce AC power, for conventional appliances, that's often far less "noisy" or "spiky" than grid power (if they are outfitted with on-board or retro-fitted RF filters made by their manufacturers - more on this in a bit).
Our Home Power System (Photovoltaic Solar with Battery Storage - "Off Grid")
 Power can be stored on-site using a variety of battery chemistries including the old lead-acid, deep-cycling variety, improved by better construction, lower maintenance, and longer useful life before recycling. We use four, 375 amp-hour, 6-volt batteries wired in series-parallel configuration to obtain 12 volts and 750 amp-hours. Our previous batteries were Thomas Edison's nickel-iron cells using potassium hydroxide electrolyte, manufactured in the 1920's. They were built for severe-service, industrial use and could be restored by simply changing electrolyte every 10 years. But we switched to lead-acid mainly because it's getting harder to find replacements fo machanically damaged cells or find additional cells. There are Chinese models made now, but the quality is not up to Edison's standards!
 Some of what is now used for home energy systems got its start in the military. This is a close-up of the water-saving battery caps we use. Since charging batteries "gas off" some hydrogen and oxygen when they're nearing full charge, various caps have been designed to catalytically recombine the gases to water (HydroCaps, for instance), or simply to condense evaporating water (like these), in systems that don't heavily overcharge. This technology was originally used in WWII submarines which surfaced to quickly diesel-charge their batteries and generated lots of explosive gases in the process.
 We also use a device designed for the military called a "desulfator". It uses a tiny bit of battery power to send a small high-frequency pulse back into the batteries, hampering the growth of large lead sulfate crystals that build up on the lead plates, eventually leading to premature battery failure. This rather cramped photo shows the 2" by 2" device.
On-site power generation using wind turbines, micro-hydroelectric, or PV panels is becoming increasingly popular, especially where you can sell excess power to the AC grid, or, even better, when you can remain off-grid and utilize your excess electrical production for heating, cooling, or whatever else makes sense.
Personally, we prefer not to be grid connected. With monthly connection fees exceeding the cost of the power we actually use, it make no economic sense for us to support this otherwise ugly, dangerous and innefficient infrastructure. And calling the Grid a giant battery is simply nonsense. The Grid exists to generate, not store. A temporary excess of wind or sunshine may make your meter spin in reverse and make you feel like a hero, but that power usually goes into the Grid when it's not really needed.
 Our previous home used both wind and solar electricity, while the current house is solely solar powered. While solar's up-front cost may be the highest of the available alternatives in terms of cost per watt produced, it's the simplest to install, the longest lasting, and the easiest and cheapest to maintain. Plus, our current site is ideal for solar but not the others, and you have to use what your site dictates! These are our sole electric power source: 840 watts of solar power by Kyocera, one of the oldest ceramics companies (and they aren't owned by an oil company!).
 Seen from the back of the panels, the center three panels can be switched to either power the house or charge our G.E. Electrak garden tractor, our cordless electric mower and string trimmer, or our electric-human hybrid trikes (seen on the Transportation Options page).
 This is a close-up of the switch arrangement with the weather cover open. Each toggle controls one panel using a Double-Pole, Center-Off, 20-Amp DC switch. Toggling up runs the three 12-Volt panels in series to run 36-Volt power to the electric tractor and electric-assisted trike. Toggling down puts the panels in parallel to run 12-Volt power to the house.
 Before flowing into the batteries the solar power gets intercepted by this device, a lightning arrestor. It connects to both the positive and negative wires, and shorts to a ground cable if voltage spikes too high.
 The next item in the positive wire is a simple diode on a heat sink. This one-way electrical valve prevents energy from flowing outward from the batteries to the solar panels at night.
 Then the power flows into this DC electrical service box. The left breaker cuts off the batteries. The next controls the Load Diversion Controller (a Trace C-30, seen below). The next controls the solar input. And the final two run the two DC load circuits in our house. We don't use a non-renewable generator for backup power and didn't do so in our previous home either. The solar system is sized to ensure a 2 week supply of electrical power with no solar input. On the worst cloudy days, we still get one-tenth normal power input and an average of half of our days are cloudy. So designing with these factors in mind, we normally have far too much power. To see a free Adobe PDF file of our household loads, just Click Here.
 This is an amp-hour meter. It functions as a battery fuel guage. And even though it consumes a tiny bit of power, and injects a "whiney", high pitched, electrical noise frequency into the batteries, it's still worth its cost (about $200) for peace of mind, especially when you're just starting out in renewables and don't yet have a handle on your power usage vs. input.
 Most solar controllers shut the PV input off when the batteries are fully charged, or, if you are Grid-connected, excess power is sent into the Grid during sunny days and purchased back from non-renewable sources at night. Instead, we use a load diversion controller (Trace C-30) which channels excess power into an "off the shelf" hot water heater and a small chest-type refrigerator. Refrigeration isn't a huge priority in our home since we're not meat or dairy eaters. Still, we do occasionally have left-overs or home-canned condiments that need cooling.
 This is our previous load diversion controller. It uses PWM, or Pulse-Width Modulation, to divert the exact amount of excessive input power that will keep the batteries at a specified bulk-charge or float-charge voltage. But with precision comes a nasty low-pitched electrical hum from the pulsed DC current sent to the diversion loads. Eventually this had to go in favor of the older C-30 (above), and the house is quieter both in terms of sound and electric fields.
 This photo shows the little wood-covered, and heavily insulated, 15-gallon tank suspended behind the masonry woodstove, where the water can be heated using a spiral of copper pipe around the stove's chimney or by the electric heating element. The stainless steel, 12/24-volt heating element which we purchased to replace the 120-volt element in the water heater can be purchased, among other sources, at Backwoods Solar Electric Systems.
 Since the Trace C-30 isn't large enough to control the 32-37 Amps typically used by the water heater and refrigerator, we use two tiny 40-Amp relays to switch the power. Both are controlled by the relay on the Trace C-30. This diverts excess solar into two very useful assets! Although the refrigerator can run using 120-volt AC or LP gas, we just use the 12-volt DC option, straight from the solar system. When the battery voltage exceeds 14.5 volts, the loads are on. When voltage drops to 12.8 volts, they turn off. This gives us a 30% "duty cycle" yielding cooled foods without freezing anything, and hot water without boiling it.
 Our "critical" electrical devices (water pump, lighting, flour mill, radio) run directly from the batteries on 12-volt DC. Conventional 120 volt appliances run from this Exeltech XP1100 Inverter. Since humans are quite sensitive to AC electrical currents, the inverter is switched on only when AC loads are being operated. We use switched outlets at each appliance location and where a device uses a "black box" or "wall wart" to change voltage or switch from AC to DC current, we use additional labeled wall switches to activate only the intended device. This eliminates "phantom loads," energy sucking, unintended drains on an otherwise intentional, clean, and efficient electrical system.
Many homes that utilize RENEWABLE ENERGY for their electrical needs are wired for both low-voltage DC and standard AC loads. Since electric fields drop as voltage goes down, 12-volt lighting and appliances are an attractive option where low-power, low-amperage devices can be used. In high-amp loads like big motors or water heaters, the increased magnetic fields can offset any gains made from lowering voltage, unless those loads are far from the main living spaces. In our home, all of the lighting is 12-volt DC, although we have a few 12-volt compact fluorescent lamps that convert 12 volts of DC to roughly 10,000 volts of AC in the bulb's "ballast". This creates a moderately-sized electric field "no-man's-land" around the fixtures as a trade-off for one-fifth the energy use. For more detail, check the EMF Hazards page.
Another factor that can reduce or eliminate AC electric/magnetic field exposure is the "sensible" use of an INVERTER in renewably-powered homes. If the home IS NOT connected to the GRID (by using a GRID-INTERTIE INVERTER), the "stand-alone" inverter turns low-voltage DC from storage batteries into "line-voltage" AC for standard appliances. Since many AC loads can be eliminated by using DC devices wherever possible, the inverter often doesn't have to be running all of the time! And if an inverter should break down (unlikely, but there's always a lightning strike!), powering essential loads direct from battery DC is great insurance.
Older and cheaper "square-wave" and "modified sine-wave" inverters rapidly and abruptly switch voltage levels to create a "choppy" sort of AC that only roughly approximates grid-produced AC. The modern "sine-wave" inverter produces a smoother, wave-like pattern of increasing and decreasing AC voltage that most electrical devices prefer. Not only do motors run cooler on sine waves, but the transformers found in many audio-visual devices and "wall warts" no longer hum. Sine-wave inverters can (at least with some modification) actually produce "cleaner" power than what's found on the grid. Grid-produced AC often has voltage spikes, or dips (requiring the use of surge suppressors) and high-frequency "harmonics" (or "hash") and "transients" (or "spikes") that have additional negative health consequences.
But even the best sine-wave inverters also generate harmonic frequencies and internally-generated switching frequencies. What to do about it? Some inverters constantly check for switched-on loads and turn themselves on only when called for (the Search Mode). And in our home, each cluster of AC outlets has an inverter switch to turn the AC power on only when it's needed. Either way, this eliminates inadvertent AC electric field exposure since no AC is being sent through the wiring most of the time. The Stetzerizer Filters I mention on the EMF Hazards page don't work well on some inverters. A couple of inverters that seem to be unbothered by the capacitive filtration of the Stetzer filters are the Xantrex Pro-Sine series and the Xantrex SW series.
 But by contacting your inverter's manufacturer, the technical staff may be able to build a targeted filter specifically designed to remove the unwanted frequencies the unit generates. We've done this with a call to Exeltech for our XP1100 inverter. This is what they sent. We've wired it into the inverter's output and enclosed it in a metal box to shield its fields. The Exeltech sees the capacitor in a Graham-Stetzer filter as a challenge to put the voltage and amperage back in synch. This makes for a very unhappy inverter. The solution from Exeltech is lots of induction and very little capacitance. This creates a large localized magnetic field, so the filter they sent is enclosed in a heavy steel box that encloses most of the field.
 And this is the final stop for AC current moving from the inverter filter to the AC loads. As you can see, we have only two AC circuits. One goes out to our shed where it powers chargers for an electric mower and a "string trimmer". It also powers an irrigation pump for the garden and an electric rotary tiller for the garden (Mantis brand). Plus it powers various AC shop tools and AC lights, when needed.
Load Management: "Negawatts"
Amory Lovins of the Rocky Mountain Institute coined the term "Negawatts" to describe power that you didn't have to generate because you lowered your power requirements. In our household we call this process "Load Management". It involves the standard conservation methods of turning off unused lights, finding and eliminating "phantom loads", switching to energy-saving lights and appliances, etc. But we also include behavioral changes based on the weather forecast and power system design to maximize overall system efficiency.
The changes in behavior are what give conservation a bad name among those who don't really know how much energy they need to use, who have never been without an unlimited supply, and who aren't interested in following Nature's rhythms. If we know that it's going to be quite cloudy for a week or more, we might delay doing the laundry, hold off temporarily on some big computer project, or watch a DVD on the evening of a sunnier day.
And power use that maximizes direct use of solar energy as it's coming in is our first priority. Direct use eliminates battery storage losses, which are usually at least 10%. Second priority is using DC lights and appliances, powered straight from the batteries. This avoids lost efficiency from inverter-supplied AC power, which normally also exceeds 10%. We keep the solar panels clean, unshaded, and at an optimum tilt angle to capture maximum solar input. The individual solar cells of a solar panel are wired in series to obtain sufficient voltage for charging a battery or powering an inverter. And the flow of current in the panel, or in an array of panels wired in series, is limited to the lowest cell output in the series. Shading even one cell with dirt, leaves, or snow can cut the current flow from the affected panel(s) dramatically. For more details, check out our book, "Peoples' Power Primer" on our Home Page.
Other Concerns
EMF (Electro Magnetic Fields) and "Stray Voltage" (returning neutral ground currents) are causes for concern in any home electrical system. Low voltages generate the smallest electrical fields. But high-powered, low-voltage appliances require a lot of amps, generating large magnetic fields. Electromagnetic fields are easily reduced using two simple wiring options. Closely twisted wires, each with an opposing direction of current flow, cancel each other's magnetic fields to a large extent. And enclosing wire in a spiraling steel ("Greenfield", "MC", or "BX") or solid steel conduit (EMT) that's grounded will shield you from the electric fields. But the best options are Distance and less Duration. Doubling your distance from household wiring gives you one-half to one-fourth the EMF exposure. And turning off an inverter eliminates the time spent soaking up higher-voltage electrical fields from AC wiring and from high-frequency "radio" waves generated by the inverter itself.
Some important web resources:
If you have any questions about EMF, how we've dealt with it in our home, or you'd like help figuring out what to do about your own electrical/geopathic energy situation, check our contact details on the Home Page .
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