October 11, 2008 at 12:00 am #62519madaprakParticipant
I am interested in building a Hybrid energy system that can produce approximately 9000 KWh/yr or 75 KWh/Day. I live on 10 acres in the Oregon City, Oregon Area. We don’t get a lot of sun in the winter months. However, some winter storms can produce wind gusts up to 25 – 30 mph. We have experienced many power outages because of blown down trees over power lines during these storms. Oregon Energy Trust says I need a tower of at least 195′ to capture wind speeds of 10 – 11.5 mph. Most systems I have researched don’t start producing usable power until wind speeds exceed 25 mph. This creates a definite problem. Solar energy appears to be acceptable during the Summer months, but of course during the winter sun is in short supply. So, I would like to design a system that will capture the best of both worlds. I would like to use Deep Cycle batteries in a 24 – 48 vdc configuration. The backup Generator would be used as a last resort and mostly to charge the batteries when the other methods don’t produce enough electricity to keep the batteries charged. As a very last resort, I would have it tied into the Grid in case all else fails. Any help or suggestions would be greatly appreciated. ThanksOctober 26, 2008 at 12:00 am #64139j_pigdenParticipant
Do you have running water nearby?October 29, 2008 at 12:00 am #64151GreenerParticipant
Here are my two cents…i live off grid in Ottawa, Canada – defintely not too sunny here…
Hybrid systems do work for all the reasons you said above (sunny in summer, windy in winter). The question from pigden above is relevant, since if you do have 365 d/yr of running water (with enough power), you don’t even need a generator.
You are building a highly redundant system…solar, wind, possibly water, generator, batteries and grid…if you have the grid, why go off it? It will cost you quite a bit of money to put in the batteries and charge controller, and an inverter to run your home. If you have the grid, use it as your battery. If you are worried about power outages, get a generator.
The type of generator you want for your system is not the same as a backup generator. They are also not “last resorts” for off grid systems, rather, they are integral to the overall health of your batteries. The generator should have an autostart feature, with fuzzy logic – this means that under many different circumstances, it may receive a trigger to turn on – for example – a heavy load with high amp draw, different voltage settings on your batteries, and, most importantly, the generator is used to de-sulfate or “equalize” the batteries every three to six months. My advise is to not cheap out on the generator – it is critical to the health of your batteries.October 30, 2008 at 12:00 am #64152Ana Indie-GreenParticipant
I would STRONGLY suggest you consider Geothermal Energy. Take time to do a thorough search of this energy source. I think you maybe surprised.October 30, 2008 at 12:00 am #64153GreenerParticipant
you cannot run a geothermal system off the grid. well – let me re-phrase that – you can if you have a lot of money. Here is why….
Geothermal requires the use of compressors (similar to an air conditioner unit). Those compressors require 220/240 volt power, which can only be provided with two stacked inverters…not cheap. Further, the amp draw (not peak surge) is at least 30 amps. This equates to 6600 Watts of instantaneous power, every hour they run through a compression cycle. That is just the compressor. Excluded from that equation are the pumps and monitoring systems. Forgetting all the rest of the stuff (like your home), just to run the compressors you will need the following….a battery bank to store 7 kW of energy. Conservatively assume you will allow your batteries to discharge to 50%, which means you need storage of 14,000 Watts per hour to run a geothermal unit. At 24 volts, this equates to an amp-hour rating of 583. We haven’t talked about the rest of your home yet (fridge, tv, lights, radio, computer, etc.). If you want three days of autonomy, and the compressor cycles for three hours a day, the energy needed JUST FOR THE GEOTHERMAL COMPRESSOR UNIT works out to 583 amps x 3 hours/day x 3 days = 5247 amp-hours….a system to hold that much juice will run you well over 100K..that is just the batteries…you need two inverters which run at least $3,500 each, a battery bank of at least 24 to 36 batteries, at least two charge controllers, and we haven’t even got to the solar panels or anything else….
Geothermal is great – just not for off gridders without a lot of money.
tNovember 18, 2008 at 12:00 am #64173JeorgeParticipant
Wind power is such a good growing in U.S. The cost of photovoltaic power can be reduced with organic solar concentrators. These are planar wave guides with a thin-film organic coating on the face and inorganic solar cells attached to the edges.
Here is a link that might be useful:www.lincenergy.us.com/
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