Alternate Power Sources

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Home Standby Generator Systems

A home standby generator system is an option when choosing an alternative power source for your home in an emergency. Standby generator systems automatically transfer power to key circuits in your home during an outage, protecting your family and potentially saving you thousands of dollars in property damage. A permanent connection to your power supply via a power transfer switch automatically provides uninterrupted power to your home when the power goes out. The system can be hooked up to natural gas or propane, providing a safe, virtually continuous automatic fuel supply and eliminating the inconvenient connection steps required with portable generators.

The following information has been collected from other sources about Home Standby Generator Systems. We have included this information to help those who have questions or would like to know more about setting up a standby system. This is a compilation of information gathered from other sources, and we in no way accept responsibility or liability for the information contained herein. If you are seriously considered installing a standby generator system, please seek advise and help from a licensed electrician.

How to hook up a standby generator

 

Connecting Your Standby Generator Safely

(Transfer Switches & Code Requirements)

The Double-Throw Switch--An Essential Element*

Adding a standby generator to the electrical system of a home, farm or business requires a suitable transfer switch to disconnect the electric loads from the power supplier's utility grid. This is a requirement of the National Electrical Code (see NEC Article 702-6) and all electric power suppliers, for two very good reasons: (1) it prevents the back flow of current into the utility's lines during an outage, which could electrocute linemen working to restore power; and (2) it prevents damage to the generator when regular electric service has been restored, which can destroy the generator.

For single-phase, 120/240 volt power, the transfer switch should be a double-pole, double-throw type. Double pole means that there are two pairs of wire lugs available for connection of hot conductors (see Fig. 1). The third wire (neutral wire) is continuous through the transfer enclosure, and is typically not switched (NEC Article 230-83). The ground wire also passes through the switch enclosure to provide a safe and continuous ground connection.

A three-phase generator would require a three-pole, double-throw switch. Some electric services use current transformer (CT) metering. This may require the use of a pole-top transfer switch. The operation of these switches is essentially the same, except that an extended manual switch lever is needed to allow the user to operate the switch from ground level.

For small portable generators that serve a single freezer, well pump, or other appliance that plugs directly into the generator, a transfer switch is not necessary. But any time a generator serves loads through the permanent wiring system of the home, farm or business, a suitable transfer switch much be used.

Typically, the transfer switch is located between the utility meter and the loads to be served. It should be within 25 feet or less of the generating unit for convenience and safety. If the location of critical loads are scattered among several outbuildings, the central meter pole may be the best location for both the transfer switch and the generator.

If a critical load is located within a single building, the transfer switch (and generator) can be installed at the service entrance to that particular building.

If only one or two circuits need to be powered during an outage, it is possible to connect only those circuits within a building to the transfer switch as illustrated in Fig. 2.

The size of the transfer switch is determined by the loads to be served. If a central meter pole location is used, the transfer switch rating must be equal to the size of the main service (typically 100, 200 or 400 amperes). If the standby system is designed to supply an individual building, or even a single circuit, the transfer switch will be sized to the total ampere rating of the connected loads.

If an engine-driven generator with automatic start-up is used, the transfer switch is normally built into the automatic controls of the system. In this case, the transfer switch must be large enough to handle all electrical loads, size the switch to match the rating of conductors which supply regular power to the building(s) or farmstead.

*Consult a qualified electrician for assistance, and be sure your "new" wiring is inspected.

All standby generators should be grounded using #6 solid copper wire and an 8-foot ground rod, which must be properly bonded to the electrical grounding system with approved clamp/connections to assure good electrical contact. Cover all generator openings with wire mesh to exclude rodent entry and potential damage. Keep these openings free of debris that might restrict the cooling of the unit.

Other safety features to remember:

• Keep all guards and shields in place to protect the operator from moving parts;

• Never run a generator in a basement or other enclosed area. Fumes that are not easily detected can be lethal to sleeping occupants and others;

• Never shut-off the generator under load;

• Never store fuel near the generator, unless a proper container or fuel tank is used;

• Never re-fuel a generator when hot or while the engine is running;

• Use extreme care under wet conditions; making your body a path to ground can cause a fatal shock;

• On tractor-driven units, always turn off the tractor and PTO control to service the generator. Set the tractor brake before starting the generator.

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Portable Generator Systems

It is simple to determine which generator is right for you. Here are the steps...

1. First determine any special needs or features such as a trailerable unit or an automatic transfer switch, etc.

2. Then determine the wattage of power.

3. Next decide the type of fuel you wish to use.

4. Finally consider durability verses pricing.

 

 

Generators are rated in terms of the amount of power they can produce. This is measured in Watts (W) or Kilowatts (kW). A Kilowatt is equal to 1,000 Watts. Some household items list their power requirement in Watts, such as light bulbs and small appliances. Others only list Amperes (abbreviated A or Amps). Most household electrical loads (including all cord-connected appliances that plug into a standard outlet) run on 120 Volts, and since Watts = Amps X Volts, you can determine Watts by multiplying the amp requirement by 120. Large heating and cooling appliances, and well pumps, sometimes use 240 Volts. This can be determined from the nameplate. For these loads, wattage is determined by multiplying amps by 240.

Add the normal and/or surge wattage for the following appliances to get your watts required from a generator.

*Some appliances take 3 times the typical wattage for startup (like well pumps, for instance), so buy a generator size based on the startup of your larger appliances.

1000 watts = 1 kilowatt (kW)
Don't forget about surge protectors for your sensitive appliances like TV and computers!

Determining the exact size generator required for a household involves adding up the wattage required by each load, including the starting power required by the largest motor and any others that will be started at the same time. It is difficult to get accurate results since starting current requirements often vary and because nameplate ratings sometimes overstate the power required. If a generator is too small for its load, the voltage will drop. This can cause damage to the generator, the load, or both. Circuit breakers and thermal protectors may trip and prevent damage, but cannot be relied upon. Do not connect loads to the generator that are too large for its capacity. If you only want to run a few critical items, you can use this chart as a guide: Generator size Loads typically supported 1000W or less Lights, radio, battery chargers, clocks, fax, or computer 1500W above items, also small manual defrost freezer or refrigerator 3500W 240V same as 1500W, plus ß H.P. well pump (if 240V)

3500W 120V Most refrigerators and freezers, clothes washer, gas clothes dryer, sump pump, ß H.P. furnace blower, ß H.P. well pump (if 120V), nearly any plug-connected appliance with a standard 120V plug

5000W 240V Same as 3500W, plus most well pumps up to 2 H.P. 15,000 W 240V Will run all the loads in most households including electric water heaters, dryers, well pumps, and ranges; will run many central air conditioning units. Electric heat systems need to be considered case by case as many larger systems use m ore power than even a big generator like this produces.

Determining the size analytically
To determine the size generator required using pencil and paper, you need to add up the power used by everything that you want to operate at the same time. Use the starting power required for the largest motor and for any other motors that will start simultaneously. For small installations, the large motor loads that need to be served determine the size generator that is needed. Induction motors, such as those used in water pumps, sump pumps, washers, dryers, refrigerators, freezers, air conditioners, and furnace blowers require a large amount of power to start. These motors will draw 2-3 times or more their rated amperage for about a second when first started. If the generator cannot produce this number of amps while still maintaining roughly 90% or more of the rated voltage, the motor will not start. Portable hand tools use universal motors still use a lot of power to start, but they are not as sensitive to voltage drop and will usually start anyway even if the voltage drops as much as 50%. Larger motors will list a "code" on the motor nameplate which indicates the starting current required. This applies primarily to industrial and farm equipment, and well pumps, since small household motors do not include the code.

Here's a list of the codes:
Code Starting kW per horsepower A 0-3.15 B 3.15-3.55 C 3.55-4.0 D 4.0-4.5 E 4.5-5.0 F 5.0-5.6 G 5.6-6.3 H 6.3-7.1 J 7.1-8.0 K 8.0-9.0 L 9.0-10.0 M 10.0-11.2 N 11.2-12.5 P 12.5-14.0 R 14.0-16.0 S 16.0-18.0 T 18.0-20.0 U 20.0-22.4 V 22.4 and up If a code is not present, assume that the motor will require at least 3 times its rated amperage to start. Some require much more. Measuring the Load Sometimes it helps to measure the amount of power a particular piece of equipment (or an entire household) uses. This may be the only way to determine power requirements accurately if there is no nameplate listing the power required. Clamp-on ammeters are available at most building supply stores for about $50-$100 that will measure the number of amps flowing through a wire. They usually include an attachment that you can use for cord-and-plug connected devices. More sophisticated ammeters that measure starting current are available but are costly ($400) and require some expertise to use.

Generator Fuel Types and Conversion Kits

Gasoline generators may not be suitable for use during a real emergency. Natural gas or propane is recommended. You can not depend on a gasoline powered emergency backup generator to run during a real emergency. When power outages, ice storms, hurricanes, tornadoes, earthquakes and all other disasters hit, the first commodity to be hoarded is gasoline. Long lines and rationing are a common occurrence during many disasters. If not used often enough, gasoline will gum up the carburetor. Do not get caught with a gummed up engine that can not run or a gasoline generator that you can not get fuel for when you need it the most

Fuels

• Gasoline--The most common choice, but not necessarily the best in all climates. Advantages: Easily available at the gas station, can be carried home in cans, has the most power compared to it's weight, works in most common generators, inexpensive (well, relatively so!). Disadvantages: condensation problems in cold weather, more frequent maintenance required than with propane, smelly to transport unless you have a pickup truck.
• Propane--An -excellent- choice for remote power backup, if the propane trucks have decent access to your location. Advantages--No cold weather starting or condensation problems, maintenance infrequent because of little carbon buildup on cylinder heads, gasoline generators can usually be converted to propane easily at home. (more on this here later) Disadvantages-- 10% less power than gasoline, must be transported in pressurized bottles, more expensive than gasoline.
• Diesel--Another good choice for remote power. Advantages--efficient engine uses less fuel per watt, very low maintenance, can be purchased at most gas stations, can be carried in cans. Disadvantages--Noisy generators, fuel more expensive, more smoke and smell, harder to start in cold weather.

Why diesel can be better than other fuels for generators

1) Diesel is safer than gas. Diesel is a less flammable fuel than gasoline and will not ignite in the hot summer sun like gasoline might.

2) Diesel is easier to store than gas as the storage life is longer.

3) Diesel is available as an off road fuel that does not have the tax burden of on road fuel. The off road diesel is tainted with a pink tint.

4) Diesel generators are more reliable than gas. Diesel engines don't have the electronic ignition system, eliminating several dozen parts. The less parts you have the less frequent part failure you have.

5) Diesel generators last far longer than gas generators. To get diesel fuel to burn requires much higher compression than a gasoline engine so the block, crankshaft and cylinder heads of a diesel engine are made heavier than a similarly sized gasoline engine. But despite the higher pressures of a diesel engine, these heavier parts simply last longer.

6) Diesel generators have better fuel consumption than gas. Diesel fuel has a much higher energy content per gallon than gasoline. Given the similar efficiencies of the two engine technologies, the diesel engine burns fewer gallons of fuel for the same power output.

7) Diesel generators can burn "renewable" bio-diesel. But the really exciting prospect of diesel over gasoline is the possibility of eliminating petroleum consumption entirely. Most diesel engines can be coaxed into burning vegetable oil instead of diesel and all of them can burn various processed forms of vegetable oil without loss in live or efficiency.

How The Automatic Power System Works:

The automatic transfer switch monitors incoming voltage from the utility line - around the clock.

When utility power is interrupted, the automatic transfer switch immediately senses the problem and signals the generator to start.

The automatic transfer switch then safely closes off the utility line and simultaneously opens a new power line from the generator.

Within seconds, your generator system begins supplying electricity to the critical emergency circuits of your home or business. The transfer switch continues to monitor the utility line conditions.

When the automatic transfer switch senses the utility line voltage has returned at a steady state, it re-transfers the electrical load back to the utility line and resumes monitoring for subsequent utility loss. The generator will continue to run for an engine cool-down period of several minutes while the entire system stands ready for the next power outage.

Most automatic power systems will have an exerciser to start up and run the generators at timed intervals for test purposes.

 

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Wind Energy

Wind is the fastest-growing energy source in the world. Still there are many advantages and disadvantages of wind energy.

Advantages and Disadvantages of Wind Energy

As oil supplies diminish and prices rise, it is vital that we find alternative energy resources. The advantages of wind energy are making it a popular choice.

· Wind energy is fueled by the wind, so it's a clean fuel source. Wind energy doesn't pollute the air like power plants that rely on combustion of fossil fuels, such as coal or natural gas. Wind turbines don't produce atmospheric emissions that cause acid rain or greenhouse gasses.

· Wind energy is a domestic source of energy, produced in the United States. The nation's wind supply is abundant.

· Wind energy relies on the renewable power of the wind, which can't be used up. Wind is actually a form of solar energy; winds are caused by the heating of the atmosphere by the sun, the rotation of the earth, and the earth's surface irregularities.

· Wind energy is one of the lowest-priced renewable energy technologies available today, costing between 4 and 6 cents per kilowatt-hour, depending upon the wind resource and project financing of the particular project.

· Wind turbines can be built on farms or ranches, thus benefiting the economy in rural areas, where most of the best wind sites are found. Farmers and ranchers can continue to work the land because the wind turbines use only a fraction of the land. Wind power plant owners make rent payments to the farmer or rancher for the use of the land.

While it is cheap, domestic and clean, wind energy production does have some disadvantages:

· Wind power must compete with conventional generation sources on a cost basis. Depending on how energetic a wind site is, the wind farm may or may not be cost competitive.

· Even though the cost of wind power has decreased dramatically in the past 10 years, the technology requires a higher initial investment than fossil-fueled generators.

· The major challenge to using wind as a source of power is that the wind is intermittent and it does not always blow when electricity is needed. Wind energy cannot be stored (unless batteries are used); and not all winds can be harnessed to meet the timing of electricity demands.

· Good wind sites are often located in remote locations, far from cities where the electricity is needed.

· Wind resource development may compete with other uses for the land and those alternative uses may be more highly valued than electricity generation.

· Wind power plants can be somewhat noisy, but much less so when compared to fossil fuel plants.

· Windmills and birds do not mix well. Care has to be given to placing windmills in locations which are not on migration paths.

All and all, the advantages and disadvantages of wind energy certainly favor using it. The only question is how to generate the largest amount of electricity from this simple, clean energy resource.

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