Alternative Energy

ALTERNATIVE ENERGY

The Need:             Electrical power is required for lighting, communications, tools and many other useful devices. A source of back-up electrical power can be very useful in many emergency situations.

                                                                                          Electrical Calculations 

                                              volts x amps = watts                                                           amp hours x volts = watt hours

                                                Examples:             A refrigerator normally runs 10 hours per day and uses 500 watts when it is running. How many amp hours for a 12 volt battery are required to run the refrigerator?

                                               

                                                10 x 500 x 5000 watt hours

                                                5000 watt hours / 12 volts = 417 amp hours

How can a 12 volt 0.5 amp light be operated on a 12 volt 100 amp hour battery? how many watts is the light?

                                                100 amp hours / 0.5 amps =200 hours

                                                12 volts x 0.5 amps = 6 watts

                                                                                                                   

Addressing the Need:

Step 1:   A gasoline or diesel powered generator give the most power per purchase dollar and can handle large loads for a short period of time. Plan on 0.25 gallons of fuel storage per kilowatt hours for gasoline generators and about half that for diesel powered generators. Plan for adequate fuel storage. Honda engines tend to run much longer between rebuilds than other small high rpm gas engines. Low rpm Chinese diesel engines have been know to run over 20,000 hours before a rebuild compared to 500 hours for small gasoline engines. Diesel powered generators cost two to three time more than gasoline generators.

Step 2:   Add a battery charges and batteries so that electrical power can be used when the generator is not running. Large loads such as washing machines and tools could be schedules to be used when the generator is running and some of the power could be stored for used with small loads such as lighting when the generator is not running. Use high quality commercial grade batteries that are made for deep cycle applications. Costs are roughly $1.50 per 12 volt amp hour. The battery bank should be sized to allow for 4 to 7 days of operating planned loads without recharging.

                Proper battery care is critical! The battery should not be cycled too deeply and should reach a full state of charge as often as possible. Electrolyte (water) level should be checked monthly and only distilled water should be added to the battery.

               The batteries should be kept in a well ventilated area and the tops of the batteries should be kept clean. An equalizing charge (overcharge) of the battery should be accomplished once a month if the batteries are in heavy use. For installations in shelters sealed absorbed glass mat  (Gell Cell) batteries should be considered. Hydrocaps (catalytic) can be added to help conserve electrolytes; their use may make water addition a yearly event instead of a monthly event and will help keep the batteries cleaner. Desulfators can prevent sulfation and add life to the batteries. The batteries should not be charged or discharged faster that 1/20^th of their capacity per hour.

An inverter can be added to power AC loads form battery power. AC appliances are much less expensive than SC units and AC appliances are much more common. Large AC load can be operated from a small alternative energy system for short periods. For example; a 1000 watt AC toaster can be operated for a short period of time from a energy stored in batteries that were charged by a solar panel producing only 50 watts. Inverters can have extra features such as an integral battery charge and battery monitoring capability, automatic load switching, or many other features. Inverters can produce power that is either square wave, modified wave, or sine wave. Normal AC power is sine wave. Some equipment won’t operate on square wave but almost everything except for computer printer will run on modified sine wave. Any AC equipment will run on a sine wave inverter but is actually just a 34 step sine wave approximation.

Step 3:   Add photovolatic panels, wind turbines, hydroelectric turbines or other equipment to supplement or almost replace the generator. With a large alternative power source and small enough loads the generator will seldom be needed.

Photovolatic panels are silent and relatively portable.  In this area you can plan on getting an average of 5.5 hours of rated capacity per day. This figure includes cloudy days and seasonal hours of daylight variations. Panels come in rated voltages and two or more panels may be required to charge higher voltage battery banks. Quality of panels and warranties vary significantly between manufactures. New “thin film” panels have yet to be totally proven over time but may contribute to cost reduction in the future.

Wind turbines are somewhat more noisy and less reliable than solar panels. The installation with a tower as such adds to that cost and the turbines are not as portable as panels. The turbine should be mounted at least 30 feet above any obstructions 500 feet away. Recent wind turbines are much more reliable than their predecessors. Output of wind turbines varies significantly with location and some care should be taken in choosing a location. Look at nearby airport data, experience from long time residents of the area or signs of trees being affected by the wind to determine whether your location is suitable. Care should be taken in the design and construction of the tower since wind loads on a tower can be significant.

Hybrid wind and solar panel installations the advantages of more regular power generation since more solar power and less wind power are available in the summer and there is more wind power available in the winter when solar isolation is less available. A hybrid system in this area should have roughly on-third the generating capacity in solar panels and two-thirds in wind generating capacity.

Hydroelectric systems are very site dependent but a suitable locations can be very valuable since power can be generated almost constantly. Several gallons per minute with at least a five foot drop are required for a practical installation.

Alterative energy equipment has been in high demand and some manufactures have up to a six month backlog. This is particularly true with wind turbine manufacturers. Most components can be delivered in a few weeks.

              BECOMING ENERGY LESS DEPENDENT

When considering an alternative energy system it is important to note that for every dollar you spend in reducing your overall energy consumption you will save roughly three dollars in the initial cost of the system. In preparing for emergencies it is also wise to conserve valuable resources such as fuel, clean water and electrical energy.