Hydro Electric Power
The first choice for an independent power source is a fast flowing mountain stream. In this system water is diverted to flow through a turbine made from an automobile alternator. The alternator charges deep cycle batteries (Trojan T-105 are recommended). Unfortunately not many have the opportunity to live next to a mountain stream with adequate head pressure and a flow rate sufficient to run a turbine.
Wind power may be an option in some locations that usually have a strong steady breeze. In my location there is rarely enough wind to justify making a significant investment in a wind generator. In locations with intermittent wind conditions it may be practical to invest in a very small and less costly wind turbine to supplement solar energy.
The sun is the most practical source of alternative power for most locations but a change of lifestyle is usually needed to make most solar electric systems affordable. Other solar projects require no life style change at all. Solar power is a very good idea if:
- the cost of commerical electricity is very expensive, or
- there is a significant future currency devaluation, or
- the electric grid becomes intermittent or unavailable.
Many do it yourself projects are described at BuildItSolar.
“Our Simply Solar mission statement is to make all the great benefits of DIY solar easily, inexpensively accessible to everyone. We are about brainstorming and sharing ways to implement solar heat easily, that anyone, regardless of DIY ability, can use to put money back in their pockets, green back in the environment and have a lot of fun along the way!” SimplySolar
My Current Solar System
The cost of my current 24 volt, 450 amp-hr system using 1000 watts of solar panels was:
|8||Kyocera KC125G 12V Solar Panel||$573.00||$4,584.00|
|4||30′ Module interconnections||$32.00||$128.00|
|1||MNPV6 Combiner Box||$91.56||$91.56|
|4||12 Amp Circuit Breakers||$10.92||$43.68|
|1||Trace C60 Charge Controller||$166.00||$166.00|
|1||TM-2020 Trimetric Meter||$135.00||$135.00|
|Shipping for above||$135.00|
|8||Trojan T105 6V Battery||$75.00||$600.00|
|1||Battery Cable Interconnections||$100.00|
|1||400 Amp fuse and holder||$83.00||$83.00|
|1||Xantrex 3624 Inverter||$1,350.00||$1,350.00|
|1||Battery Box (homemade)|
|1||500 Amp Shunt||$28.00|
|1||Aluminum mounts for 8 solar panels||$400.00|
Planning a solar system. What size system is needed?
In a small to medium sized solar electric system, these items will not work:
- Electric hot water heater
- Air conditioning
- Automatic dishwasher
These items need special attention:
- Conventional refrigerator. My refrigerator consumes 25% (250 watt hours) of the total energy captured by the solar panels (1000 watt hours) on a bright summer day. Smaller high efficiency appliances are available such as Sunfrost, Sundanzer and Novacool. Or use a propane powered refrigerator similar to the Dometic (search the site for refrigeration).
- Hot water. An on demand propane water heater is recommended, preheated with a solar hot water system. Other propane powered options will also work.
- Hair dryer. This is useable because it is not used for a significant time duration. However,depending upon the inverter size, it may not work during periods of high demand by a deep well water pump. My experience with a 2000 watt inverter was that a deep well water pump would not start when the hair dryer was being used unless the batteries were fully charged.
- Deep well water pump. A capacitor start motor (3 wires with a control box) is more easily started than an induction start pump motor (2 wires). In the U.S. most deep well pumps are 230 VAC.
- In the U.S. where appliances use either 115 VAC or 230 VAC, an auto-transformer is needed to double the output voltage of the inverter. Some expensive dual inverter systems may not require this. An alternative solution for the well pump is to use a Grundfoss 120 VAC submersible pump. The Grundfoss is designed to start with less current than a conventional well pump.
A very useful device to create an energy survey of appliances currently being used is the P3 International P4400 Kill A Watt Electricity Usage Monitor.
Lessons learned from my previous off grid experience
Two of us (1992 to 1999) lived at Gateway Farm in a 2700 sq ft house not connected to the grid. 700 watts of solar panels (14 solar modules of 50 watts each) provided solar charging power for Trojan T-105 batteries. The batteries provided power to a 12VDC 2400 watt Trace (now Xantrex) DR2412 inverter.
There was no automatic dishwasher or air conditioning. Domestic hot water heater and direct vent space heaters were powered by propane. A generous amount of south facing glass provided free passive solar heating. The washing machine was standard and the clothes dryer used propane for heat and electricity to tumble the clothes. The refrigerator was a high efficiency 12VDC 12 cubic foot Sunfrost RF12 ($2359 plus $50 crating fee).
Peak electric loads occurred while clothes washing, drying clothes and pumping water all at the same time. Without using the generator, the battery-inverter system had enough power to start the submersible water pump while the washing machine and dryer were running and a few fluorescent lights were on, but only if the batteries were not low of charge. A generator was needed to provide power during times of peak power demand. Originally the generator was a 3500 watt Honda. It turned out that it was working near maximum capacity during times of peak power demand: pumping water, running the washer and dryer, and charging the batteries. The small generator was short lived due to stress.
- Pick an adequately sized generator. A 5000 watt generator replaced the stressed out 3500 watt generator after the smaller generator failed.
- Looking back, I would estimate the generator was used an average of 2 or 3 hours per day. That would not be acceptable now considering the price of fuel today. A small cabin would be less demanding of power.
- An electric hair dryer uses a lot of energy for a short period of time, but if there are no complaints it may save your relationship.
- Try not to pump water while the hair dryer is being used.
- Heavy electric loads (vacuum cleaner, etc) should be done when the generator is online.
A system without solar modules could be put together that would provide continuous electric power to the home when commercial electrical power becomes intermittent. Solar modules and other components could be added later with little or no rework. Batteries would be charging whenever grid power was available and batteries would start discharging to power the inverter when the grid was down.
This system allows a house to be powered from either a generator or the grid, or both at different times. A generator could be shut down for long periods of time and still have electric power available from the batteries and inverter when using this configuration.
For those in great physical condition and wannabe’s, pedal power is another option for generating electricity on an extremely small scale. Compare the 130 watt output of a $610 Kyocera solar panel from Wholesale Solar to the price and output of these pedal powered options:
- Windstream Power , 60 watts, $550, Mother Earth News
- Pedal Powered Generator, 150 watts for 30 minutes if you are in great shape, $50 for plans plus $100-$250 for parts you purchase locally.
Wood Gas Conversion
Convert Wood into Charcoal & Electricity: Convert wood into a gas that can be used to power a gasoline engine, and convert wood into charcoal that is superior to commercial charcoal.
More Energy Systems
Generators and Inverters: Building Small Combined Heat and Power Systems for Remote Locations and Emergency Situations