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Introduction To Remote Power Systems
The Cost of a Remote Power System
The cost of a remote power system depends primarily on how much electricity you need. The amount of electricity you need is called your load. If your
remote power system has a back up generator, the size of your load and the size of your remote power system determine how much of the time your generator runs. Asking how much a remote power system costs
is similar to asking how much a car costs. The cost of a remote power system varies all over the place from a few hundred dollars to $50 -$60,000 and more.
Generator only
Cheapest initially, but this option costs the most by far in the long run. One light bulb
will require the generator to be on and to be very inefficient. Generators require frequent maintenance (oil and filter change, check water, etc.) and eventually have high repair costs like a car.
Generators are also very noisy, polluting, and they eventually die. Solar modules will probably last 50 to 100 years!!!!
Generator/Inverter system
A generator with inverter and battery bank. The next least expensive option, but
more expensive in the long run than a mostly, or all, solar system.
Generator with some solar
More expensive initially, but less expensive in the long run than option's A
and B.
Primarily solar with generator backup
Even more expensive initially, but less expensive in the long run.
Solar only
The most expensive initially, but the least expensive in the long run.
Solar DC only
If you have only a few appliances and they are all DC, then you may be able to get by with a
very small solar system and no inverter. But this option is not generally appropriate for most people, since most people have many AC appliances and a fairly large load.
Comparing the Cost of Line Electricity with the Cost of a Remote Power System
When comparing the cost of line electricity to the cost of a remote power system, remember to include not only the cost of bringing in line
electricity but also the cost of monthly electric bills over several years. When comparing the cost of mostly generator systems with a solar only system, remember to include the upward spiraling cost of fuel,
maintenance and eventually a new generator. In contrast to generators, solar electric modules are warranted for 20 to 25 years, they will probably last 50 to 100 years. They require no fuel, little maintenance,
do not pollute our air or put any more stress on our taxed-out environment, and they make no noise.
Reliability and Owning Your Own Utility
Remote power systems, especially solar only systems, have become so reliable that they very seldom are down. Typically owners of remote power systems have
electricity while grid-tied electric customers are in the dark. The owner of a remote power system owns their own electrical power plant. For example, a 10 year economic comparison should consider the fact that
after ten years you still own your own (if solar) very clean and quiet power plant, and it is still warranted for another ten to fifteen years!.
Get Some Solar Now and Add Later?
- You can add more modules later as long as the wiring, disconnects, charge controller and related system items are sized to accommodate more modules
later, so plan ahead.
- Batteries can be added to later, but the entire bank will only function as well as the worst battery in the bank: So adding batteries after a year is
not a good idea.
- Try to buy an inverter that will meet your needs several years from now. Generally speaking it costs a lot more to add an inverter, or an inverter
and modules, later.
High Efficiency Appliances vs Larger Solar System
Frequently thousands of dollars can be saved by spending more money on high efficiency appliances and less on your inverter, solar modules,
batteries, and by reducing the size, wear, and run time on your generator, if one is used.
Load Change Suggestions
(Note: PV stands for photovoltaic. This is basically a more technical and specific way of saying solar electric.)
Fill out a load sheet in order to determine your load size (Available from SWW). It is very common for purchasers
of solar electric systems to go back to their load sheets after finding out the cost of a solar system large enough to supply the electricity demand on their first load sheet. Solar electricity is still initially
much more expensive than line electricity. (However, solar electricity not only enables us to live remotely, but to generate our own electricity without polluting the air, creating nuclear wastes, strip mining coal,
or exploiting national treasures.)
Use a solar, instantaneous propane, or propane hot water heater, a propane or high efficiency electric refrigerator/freezer, propane clothes dryer, and a
gas range in order to reduce the size of your electrical load.
Convert AC and DC incandescent lights to energy efficient compact fluorescent (CF) lights with electronic ballasts. CF lights typically use one-quarter
the energy of an equivalent incandescent light. Phillips and GE CFs are very high in quality and can be run off of a modified sine wave inverter. Ott-Lite Technology makes high-end CFs in various sizes with
full-spectrum lighting for birds, plants.
Eliminate phantom loads (all non-battery clocks, VCR, TV, garage door opener, answer machine, furnace transformer...). Switched outlets can be used
to eliminate most phantom loads. Furnace thermostats can be changed to line voltage, or a relay can be used to keep the furnace transformer from being on all of the time. If the furnace transformer is on
all of the time, this will cause most inverters to be on all of the time, which uses a lot more electricity.
Consider replacing your blower motor with a high efficiency blower motor if you have a forced air furnace. For example, GE makes the ECM Programmable
Motor which can improve your blower efficiency by 1 /3 to 2/3. This motor also has very little surge.
Mounting Methods
Stationary ground mount on a pole, ground rack, or on a roof: A pole mount is the least expensive. A GFCI is required for all residential house roof
mounts; and the entire array will need to be removed and replaced when the roof is reroofed. Stationary mounting should include manual adjusting of modules (4 times per year). Modules should be mounted on theft
resistant racks.
Tracking: passive, single axis, dual axis. We recommend Zomeworks passive trackers or the dual access electronic Wattsun Trackers. (However, even though
the Wattsun Dual Access Trackers are generally reliable, there will eventually be some maintenance required. Some solar companies recommend against Wattsun trackers for this reason.) Using Colorado Springs, Colorado
as an example, the solar electricity gained by using a Wattsun Dual Axis Tracker in stead of a stationary mount (assuming the stationary mount is kept at a tilt angle of 38 degrees all year round) is: December +30%,
July +55%, yearly +38%. Using the same latitude and changing the tilt angle of the stationary mount to 53 degrees, the dual axis advantage is 20% over the stationary during December. (Source: National Renewable
Energy Lab)
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