Home Power's System Richard Perez The story of Home Power's energy system is a saga of constant change. Here is a profile of the ever growing photovoltaic (PV) and wind energy system that energizes this magazine and the crew that publishes it. Here are the successes (and failures) in our system's transition from fossil fuel to sunshine. It Grows! Over the last five years, the renewable energy (RE) system producing Home Power has grown, just like the magazine. Five years ago, we started with three PV modules and ran our gasoline fueled generator every other day. Now we use the power produced by 32 modules and a wind generator. We gave away our aged gasoline fueled generator eleven months ago. Our electricity now comes strictly from the sun and wind. Home Power started out with a crew of twoÄKaren and I. We used a single small Macintosh computer. We are now a varying crew of five to eight folks and use three full blown Mac computer systems to produce this magazine. In addition to publishing Home Power, our system also supplies the crew's household power on Agate Flat. Don't look for Agate Flat, Oregon on a map because you won't find it. That's why Karen and I moved here in 1970. We are very rural, located at 3,300 feet elevation in the Siskiyou Mountains of southwestern Oregon. Everyone who works at Home Power Central lives here because the area is too remote for commuting. The nearest town, Hornbrook, is in California. Hornbrook is 22 miles, and one hour's driving time, away. Eight of these miles are unimproved dirt. The rutted dirt roads that claw their way through these mountains test the survivability of the toughest vehicles. We are located eight miles from the nearest grid power outlet. We are six miles from the nearest hardline telephone. If you want to find us on a map our coordinates are 42ø 01' 02" North and 122ø 23' 19" West. Our site on Agate Flat may be far away from it all, but Nature smiles on us none the less. We have abundant dawn-to-dusk sunshine. The wind blows enough here to be a major power source. While we may live and work in the outback, we are happy and content to be here. We give daily thanks and wonder to the renewable energy sources and devices that allow us not only to live in the mountains, but also earn our daily bread here. Our Power Needs Our need for electricity is two fold. We need power to run the computersÄ the primary tools of our publishing business. We need power for our household of six to eight peopleÄthe normal appliances found in most homes. So this is really a saga of two distinct electrical consumers. About 60% of the power we make goes down the gaping maw of the computers and their friends the peripherals. The remaining 40% is used for household hum-drums like keeping cool, cooking, cleaning up, and having fun. Our total systemic power consumption is about 7,000 Watt-hours per average day. One of the problems we have faced in our system is that we rarely have an average day. While our household needs are relatively constant, our business power use is very binge oriented. Just before an issue of Home Power goes to press, the computers run from 16-24 hours per day. After the issue goes to press and its mailing is done, we relax and sometimes don't touch the computers for several days. Here is a breakdown of our power consumers. INSERT CONSUMPTION CHART Our business power usage is dominated by computers. We use a Mac IIcx as the main machine. It is equipped with three large harddrives, a scanner, a two page monochrome monitor, and a 300 dpi printer. The two other Mac SE systems are also equipped with ancillary harddrives and 300 dpi printers. It's not that these computer systems consume so much power, it is that they are operating many hours a day. This long-duration, sustained usage adds up to enough electricity to run two average RE homesteads. Our household usage is dominated by the Sun Frost RF-19 refrigerator/freezer. While Larry Schlussler and the Sun Frost crew make the most efficient refrigerator and freezers in the world, the RF-19 is their largest model. This freezer is big enough to hold a big garden's output, or a quarter of a boned out moose. Our crew is divided 50/50 between veggies and omnivores. Our RF-19 stores the food for the entire crew, and we all like rock-hard ice cream! The evaporative cooler uses a fair amount of power during the summer and none at all during the winter. While strictly not a business appliance, the evaporative cooler has allowed us to work on summer days that would have been too hot for the computers, never mind the sweating humans punching the keyboards. In our low humidity (÷15%) summer environment, the evaporative cooler lowers the air temperature by about 18ø-20øF. It also hydrates the air to a humidity of about 40% and this reduces the static electricity that has plagued our computers. Our lighting is almost all powered by 120 vac from the inverters. We are using the Osram EL series compact fluorescents. These lights are not only efficient and long lasting, but they also produce color-correct, nonflickering light that we can work under for hours without fatigue. Our other household appliances are small-time consumers. We use a variety of power tools including a worm-drive Skiltm saw, various drills, sabre saw, big soldering gun, and other tools usually found in backwoods homesteads. The microwave oven gets a workout most lunch times. The toaster belongs to HP crew member, Therese Peffer, who is addicted to toast with her breakfast. The entertainment electronics are shared by all and are not used very often because by evening we are mostly too tired to watch the tube. The 12 Volt stereo (an old Mitsubishi component car unit) gets a regularly daily workout and plays on after 14 years on the job. System Parameters We are a 12 Volt, battery based, system. By all rules of PV system design, we should have been a 24 Volt system when our production/consumption exceeded 4,000 Watt-hours per day. But then our system wasn't designed, it just grew. We still use 12 Volts as our battery voltage. We test and review a wide variety of equipment. Some of this gear is only available for 12 Volt input. We still have many 12 Volt appliances (like TVs, and all our Ham radio gear) left over from the early days when reliable inverters were just a dream. Power Sources We use the sun and wind to make over 7,000 Watt-hours of power on an average day. Our all time high production was 11,400 Watt-hours during a single day last winter when the sun shone all day and the wind blew at 45 mph+ all day and all night. This is perhaps the first success story we have to tell you. Photovoltaics and a wind generator are excellent companions. At Agate Flat, when the sun isn't shining, the wind is often blowing. We also have many days, especially during the winter, when the sun shines brightly and the wind blows. Using a combination of renewable energy sources has allowed us to kiss our gasoline powered generator goodbye. Photovoltaics Our system contains a motley assortment of photovoltaic modules. We have been investing in PV modules for the last eight years. You will find virtually every make of PV module somewhere in our system. We divided the modules into different arrays. This makes it easier to measure their power output and to wire them to the system. Array One consists of eight Kyocera J-48 modules, each producing about 3 Amperes at 16 VDC. Array Two consists of eight Kyocera K-51 PV modules mounted on a two- axis Wattsun tracker. Array Three is our "democracy rack" and contains an assortment of modules: Siemens M55, Solarex MSX60, Kyocera K51, Hoxan 4310, ARCO M52 QuadLam, ARCO 16-2000, ARCO M51, Solec S50, and Sovonics R100. While this rack supplies the main battery, its real purpose is on-going testing of PV modules under real life conditions. Each module has its current measured individually, but all provide power at the same voltage, temperature, and solar insolation. This ensures accurate measurement and provides all the modules with an even playing field in a working system. Array Four is just now being installed and consists of eight Kyocera K51 modules mounted on a Zomeworks tracker. Array Five is in the planning stages and will consist of Midway Labs concentrating PV array mounted on a Wattsun tracker. The measured energy output of all our currently installed photovoltaics is roughly equivalent to the output of 32 modulesÄabout 7,000 Watt-hours per average day. Power output is about 1,400 Watts ( ÷92 Amperes at 15.5 VDC). INSERT PV PHOTOS Each of the arrays is wired to the power center with its own cables. These array cables are twisted pairs (one cable for positive and one cable for negative) made from 0 gauge copper wire. The shortest cable is 105 feet (actual round trip wire length) and the longest is 415 feet (once again two- way wire length). Making twisted pairs out of 0 gauge cable is difficult and requires five people. Each person grabs a cable's end and one person stands at the centers of the pairs. The folks holding the ends "skip rope" with the ends and wind the cable into a twisted pair. We were able to get about two twists per foot. Twisting the cables radically reduces the radio interference and magnetic fields surrounding the cables when the arrays are being regulated. When we get Arrays Four and Five wired up to the system, we will have a large (÷3 kWh per day) energy surplus. We are going to use this surplus power to produce hydrogen gas from a water electrolyzer. We are going burn this solar-produced hydrogen in our cook stove which is now fueled by propane. Wind Generator Since September 1991, we have been running an Australian-made wind generator called the Survivor. This wind generator is different from any other design that I have ever seen. It has a very large propeller (11.5 feet in diameter) in proportion to the wind generator's size (9 feet long and weighing in at 132 pounds). The Survivor is optimized to provide substantial power at low wind speeds and still survive high winds. The Survivor uses a permanent magnet alternator rated at 800 Watts. The Survivor produces about 100 Watts at 9 mph, 400 Watts at 13 mph, and 800 Watts at 20 mph. It has survived 60 mph winds here on Agate Flat. Our actual energy production from the Survivor has been an average of 860 Watt-hours per day. But this figure doesn't really tell the tale... INSERT SURVIVOR PHOTO On cloudy, stormy days the wind really blows here. The largest daily energy output we've actually recorded from the Survivor was 4,230 Watt- hours during a storm last December. During this same storm, all 32 of our PV modules produced less than 450 Watt-hours of energy. This storm occurred before we had attached the linear current booster to the wind generator. Since we have installed the linear current booster, we have seen a peak wattage of 1152 Watts from the Survivor. This amounts to 68 Amperes at 15.5 VDC into our battery. The big news is that when the PVs aren't producing power the Survivor is! We haven't burned a drop of gasoline to make electricity since the Survivor was installed. Instead of using the generator during cloudy periods, the Survivor makes the power instead. What is more, we also get 15 mph+ winds on sunny days. On such days, we have a surplus of energy and can do things like let the woodstove go out and run the 1,500 watt electric heater for a while. The Survivor is mounted atop a 63 foot-tall breakover tower. Our tower is located on a hill about 450 feet from the battery in the main office. The tower design, and all tower hardware (except the 3 inch, schedule 40, steel pipe) are supplied with the Survivor. Karen and I can raise and lower the Survivor in less than 30 minutes with no aid except for our trusty Toyota 4WD truck. The tower uses three levels of four guys per level. We put 2.75 cubic yards of cement into the five tower footings. The Survivor is electrically connected to the rest of the system with about 900 feet of 0 gauge aluminium USE cable. Describing how the Survivor works in words is difficult, although instantly apparent to everyone who sees it working. Imagine a helicopter hanging, by its nose, from the top of the tower. As the wind blows, the helicopter picks up its tail and the machine "flies". Even though the photo here shows the Survivor with its nose in air and its tail to the ground, it becomes almost horizontal in winds over 40 mph. At winds of 20 mph, the boom of the wind generator forms about a 45ø angle with the ground. This concept is called "Infinitely Variable Rotor Area (IVRA)" and is patented. This design presents a decreasing rotor area to the wind as the wind speed increases. It works great! I never thought we had a wind generator site here on Agate Flat. The Survivor proved me wrong. Controls A Heliotrope CC-120C controls the output of our photovoltaic modules. Since we use an alkaline battery, we set this 120 Ampere PV regulator at 16.3 VDC. We control the wind generator with the Bobier LCB-40 which allows us to operate the 24 Volt Survivor at about 30 VDC. The LCB-40 converts the wind generator's extra voltage into current for our 12 Volt battery. See HP29, page 53 for a thorough discussion of the LCB-40. The bottom line is that the LCB-40 improved the performance of the Survivor in our system by about 60%. Battery After twenty-two years of lead-acid battery life, we finally went alkaline. Last December we installed 150 reconditioned NIFE nickel-cadmium cells. Each of these model HIP10 cells stores 100 Ampere-hours at 1.2 VDC. We have these cells connected into series strings of ten, and then 15 of these strings are connected in parallel. The resulting battery has a capacity of 1,500 Ampere-hours at 12 VDC. These nicad cells have a room all to themselves. This insulated, vented, 3.5 foot by 7.5 foot room is equipped with "stair step" racks to hold the cells. This stair step arrangement allows me to see the electrolyte level in every cell without removing the cells' caps. The series strings of nicad cells are connected in parallel with 0.25 inch thick, 1.25 inch wide, copper buss bar. There is over fifty feet of this buss bar inside the battery room and it all runs inside of 1.25 inch diameter plastic conduit. Each series string of cells is connected to the buss bars by two 00 gauge copper cables with soldered connectors. This arrangement was a hell of a lot of work. It took three of us about five working days to cut and fit the buss bars within their conduits. The result is spectacular. We can withdraw hundreds of Amperes from the battery with a voltage difference of less than 0.05 VDC loss in the buss bar system. Our actual measured resistance across the buss system was 0.0003 Ohms. Low resistance bussing assures that each string of series cells is equally charged and discharged. Keeping all the cells at the same state of charge is paramount in any battery. This is best accomplished by allowing series strings of cells an equal resistance path to all incoming and outgoing current. INSERT BATTERY ROOM PHOTOS This battery is large enough to provide energy for three days if all the power inputs (both PV and wind) produce nothing. During the last nine months, we have never had a day where energy production was anywhere near nothing. There is always some sunshine and very often some wind as well. According to our instruments, we have yet to use more than 860 Ampere-hours from the battery before it refilled. Our system is "stand-alone PV & wind" and we no longer have a backup generator. When the battery starts to get low, we just back off on the big power consumers and luxuries. In a day or so, the battery is fully recharged and we can rock-n-roll to our hearts' content. Power Center We use an Ananda Power Center IV to interface our battery with all the power sources and loads. This power center contains all the NEC required safety devices, and a many shunts for current measurements. This power center was not only convenient to install, but it is also efficient and safe. See HP29, page 56 for a detailed report on the Ananda Power Center IV. Inverters We went from a 12 VDC household to an almost all 120 vac household and business because of computers. We could not get the functions we needed out of the 12 VDC computers available back in 1983. So we installed a radical new (back in '83) device that allowed us to convert (actually called "invert") the 12 Volt DC power stored in our battery into 120 vac like "Big Noisy" our gas generator (and the electric company) made. These inverters gave us access to normal everyday appliancesÄ like computers. It didn't take us long to catch on that all appliances didn't have to have cigar lighter plugs anymore. If all the inverters that passed through my life were stacked end to end, the line would reach from Cleveland to Xanadu. Over the years we have owned over a dozen inverters, the ones that work stayed, the rest were junked. Ten years ago, a good inverter lasted six months and barely ran the vacuum cleaner. Things have really changed. Now inverters are reliable, quiet, efficient, and cost about 70› to a buck a watt. Currently we use any one of five inverters: a Heliotrope 2.3 kW PSTT, a Trace 1512, a PowerStar UPG 1300, a Dynamote 2.4 kW sine-wave, and an Exeltech 250 Watt sine-wave inverter. Of particular note is the 2.4 kW (10.6 kW surge!) sine-wave inverter, made by Dynamote, that we are testing now. This inverter (named Brutus by its maker) produces pure sine-wave power. Our computers love it! Time will tell if it lasts and finds a permanent home in our power processing room. The controls, inverters, and power center are housed in their own room located right next to the battery room. This tiny "power processing" room is sound insulated and is 3.5 feet by 4.5 feet. Here the inverters, controls, circuit breakers, fuses, disconnects, distribution panels, and instrumentation are comfy being close to each other, and we humans are comfy not being bathed in their audio noise and electromagnetic fields. Instruments Our business is information about home power. The instruments we use are our eyes into the invisible world of electricity. We have many more instruments than is required to actually operate this system. We are interested in sticking our noses into the esoteric and diverse functions of every piece of equipment in this system. We then report our measurements, ideas, and conclusions to you within these pages. In terms of actual operation, we fly our system using only one instrumentÄthe Cruising Equipment Amp-hour+2 meter. This net reading battery Ampere-hour meter not only acts a "gas gauge" for our battery, but also measures battery voltage and battery amperage. It works and is really all we need. See HP26, page 59 for a report on this fine instrument. Bottom Line Time Well by now you must be thinking that all this hardware must have cost a pile of dough. You're right. But then Home Power's system is big enough to supply three or four country homesteads. We are a large crew who makes our living with tools that eat electricity. So if the $34,000 price tag sounds out of place, then how about 52› per kilowatt-hour? I figure that is what our system produces power for over its estimated 25 year lifespan. And I fully expect the PVs, battery, and some of the power processing equipment to last far beyond twenty-five years. INSERT COST SPREAD Anyhow, the local power company, Pacific Power & Light, wants over $250,000 to run in the lines and for the privilege of paying them a monthly bill. Instead we are energy self-sufficient and can live and work in a beautiful, remote mountain site. We know our power comes from a clean and renewable sourceÄthe sun! Successes Here is a list of things that have worked for us over the years. ù House the battery and the inverters/controls in their own rooms. I thought nothing of sharing a room with a battery until a cell exploded last December. Now I'd rather eat a bug than hang out in the same room with electrochemical cells. Inverters and controls can produce some very intense electromagnetic fields (EMFs). There is no human minimum daily requirement for EMFs, so keep high powered electronic processors out of living spaces. ù Plan on your system growing. We didn't at first and made several expensive false starts such as too small inverters, controls, and wiring. ù Buy the highest quality hardware that you can afford. Cheap prices mean poor design, poor materials, shoddy construction, and early failure. If you can't afford the best, then save until you can. It took Karen and I two years to save up for our second and third PV modules. We're still using their power. Your energy system should last you a lifetime. Make it good enough to will it to your kids. ù Don't rely on that good ole' boy, the engine/generator. I know it makes lotsa power for a small initial investment, but it will eat you up with fuel bills, and maintenance. It will deafen you with it noise and stink you out with its fumes. Burning fossil fuels is part of the problem, not part of the solution. ù Get some help! Our system would have never been a reality without the help of many. Thanks go first to Bob-O Schultze of Electron Connection for his expertise, sweat, and refusal to do a half-assed job. It is primarily due to Bob-O that Home Power's system meets the National Electric Code's requirements. Also along the way, Dave Wilmeth, Chris Greacen, Barry Brown, Richard "Grizzly Bear" Clark, George Patterson, Dale Hodges, Brian Green, John Pryor, Scott Hening, Ralph Belden, Kenton Lewis, Scott Sayles, Allan Sindelar, Allan Trautman, and many many others. If you get stuck and need info or technical help, give me a call. In that way, maybe I can partially repay the debt I really owe to many many fine and helpful folks who have aided us. We get by with a little help from our friends... Failures The failures we have had are the result of not doing the successful items I have mentioned above. Instead of viewing failure as a specific incident, I see it as a matter of attitude. ù Our biggest source of failure was timidity. We were half-hearted in our initial transition to renewable energy. It was so expensive, it was so unsure, it was so unusual, it was so new, it was so... The list of uncertainties seemed endless in the beginning. ù Our next biggest cause of failure was lack of information. We felt like freshmen at a college not yet invented. Well school is now open and hopefully the pages of this magazine will keep you up to date on all the concepts, devices, and information you need. What a long strange trip it's been... I blame it all on the Grateful Dead. In 1976 I got tired of buying dry cells for our midget tape deck. I established our first system, Ä a single car battery sourced by a homebrew lawnmower engine and junkyard car alternator. I wanted the music, but I wanted it without the waste, cost, and pollution of those throw-away batteries. If if weren't for the Dead, I think we'd still be using kerosene lamps. As soon as my neighbors saw what was going on at our place, they wanted systems too. By 1978 we were in the business designing and installing remote power systems for others. These early systems were based around some batteries, an inverter (which was also a battery charger) and a gasoline (or diesel, or propane) fired engine/generator. These early systems reduced the generator's operating time by 75%. And 120 vac electric power was available 24 hours a day! Around 1985, photovoltaic modules became affordable. We, and our neighbors, started adding PVs to our systems. We watched the gas generators operating time shrink. We liked it! We went back for more! Eleven of the thirteen homesteads within an eight mile radius of Home Power Central are now powered by sunshine. There is only one of our neighbors within this radius connected to commercial electricity and one still using only a fossil fueled generator. Maybe a more amazing statistic is that six of the RE homesteads within eight miles of us also support their owners with work at home businesses. Our neighborhood contains a computer programmer, a full service PV/hydro dealer, a publisher, a financial advisor, and two cattle ranchers. Four of these six businesses would not be here at all if they weren't using renewable energy. In April of 1987, I saw folks clambering for information about practical, effective application of RE power sources. I saw an emerging industry with no place to reach its customers. I saw solar power in all our futures. In November of 1987, the first issue of Home Power Magazine hit the streets and dirt roads. You hold the rest of the saga in your hands at this moment. When we started publishing information about renewable energy we had no idea where it would take us. We, like many, felt that maybe we were the only ones who cared about energy, self-sufficiency and our environment. We now know that RE people are pioneers. What we are doing is novelÄ we make our own power instead of relying on someone else. We have chosen this for many reasonsÄwe wanted to live in the country, our desire to do for ourselves, our concern for our environment, and many other reasons. What we are doing now seems unusual, but our efforts point the way to a livable future we can all share. The resources now commercially used to produce electricity are finite. America is consuming them at an alarming rate. The consequences of unrestricted combustion, tinkering with the atom's interior, and damming our rivers are now apparent. We are looking for something better, something that can provide our power without polluting and bankrupting future generations. Renewable energy users light the way to a better future. So, stand up, give yourself a pat on the back. You deserve it. Thanks for having the courage to look the future (not to mention the power company) in the face and not flinch. In the Grateful Dead's words, "Everybody's dancing the ring around the sun, ain't nobody finished, near even begun." Are we finished yet? You got me. I used to think that Home Power's system would be done someday and I could relax and enjoy our work. Now I realize that I was deluded. We are part of an ongoing, ever changing process. We tuned in during the middle, and we'll tune out before it's done. Access Author: Richard Perez, c/o Home Power, POB 130, Hornbrook, CA 96044 ù 916-475-3179 Wind generator maker: Survivor Energy Systems, POB 244, Melville, Western Australia, Australia, 6156 ù (09) 330 2357