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FREQUENTLY ASKED QUESTIONS

·        Why do other countries use different shaped plugs?

·        Why do outlets have three holes?

·        Why do we have AC electricity?

·        Can we harness lightning as an energy source?

·        Can we have wireless transmission of electricity?

SYSTEM

·        What is electricity?

·        Where does electricity come from?

·        What is the "grid"?

·        How much electricity does a typical household use?

·        Who owns the electric system?

·        Who uses electricity?

·        Where can I find out more about potential careers?

·        How can I improve my energy use?

 

Q: Why do other countries use different shaped plugs?
A: There is not only a physical difference between plugs, but also an issue of electrical incompatibility. There are various voltages as well as frequencies used throughout the world. For instance, in the United States, we use 110-120V (60 Hz), while in many other countries, 220-240V (50 Hz) is used. This is because the electrical standards were originally established by the individual countries and at the time, there was no international standardization. So… if you travel to another country, and you would like to take your favorite electrical device (e.g. digital camera, laptop, mp3 player) then make sure you also have an appropriate converter as well.

 

Q: Why do outlets have three holes?
A: In the United States, standard (120 V) plugs have either two or three prongs. One vertical prong is electrically "hot"; the other (sometimes longer) vertical prong is "neutral". When an appliance or device is plugged into an outlet (or socket) and switched on, an electrical current will flow between the prongs and through the device circuit.

The third prong is the "ground" and is important for ensuring safe operation of the electrical device. It protects the user from dangerous electrical shock if for instance there is an electrical fault involving the appliance’s metal casing.

 

Q: Why do we have AC electricity?
A: At the turn of the century, there was differing opinion (especially between Thomas Edison and George Westinghouse) on whether electricity should be transmitted as alternating current (AC) or direct current (DC). This debate is commonly known as the "War of the Currents". AC had the advantage of being converted via transformers to higher voltages which, at the time, allowed electricity to be transmitted over long distances at lower losses.

Since then, technology improvements especially in the area of power electronics have enabled high voltage direct current (HVDC) applications. HVDC allows controlled transmission of large amounts of power efficiently over very long distances in narrower rights-of-way.

 

Q: Can we harness lightning as an energy source?
A: Lightning is very powerful and very dangerous. But lightning strikes are very brief and infrequent, and therefore the amount of energy that could be gained (and theoretically stored) would be small in comparison to overall electrical needs.

One lightning strike has enough energy (~1500 MJ) to power a 100W light bulb for almost half a year. However, you would need to harness over 58,000 lightning strikes each day to equal the electricity production capability of a large (1GW) power plant.

 

Q: Can we have wireless transmission of electricity?
A: The wireless transmission of electricity is the transmission of electrical energy without wires. Conceptually, transmission of electrical energy is similar to the wireless transmission of information, e.g., radio or microwave. The major difference is that with radio or microwave transmission, you are focused on recovering the information, not all the electrical energy that you originally transmitted. The efficiency losses associated with wireless transmission of electricity would be high, and with current technology would not likely be cost effective.

 

SYSTEM

Q: What is electricity?
A: Electricity is the flow of electrical charge. It is a basic part of nature and one of our most widely used forms of energy. Everyday, we use electricity to do many jobs for us – from lighting and heating/cooling our homes, to powering our televisions and computers. 

 

Q: Where does electricity come from?
A: Electricity is a secondary energy source which means that we get it from the conversion of other sources of energy, like coal, natural gas, oil, nuclear power and other natural sources, which are called primary sources. The energy sources we use to make electricity can be renewable (such as wind or solar) or non-renewable, but electricity itself is neither renewable nor non-renewable.

 

Q: What is the "grid"?
A: The "grid", or transmission system, is the interconnected group of power lines and associated equipment for moving electric energy at high voltage between points of supply and points at which it is delivered to other electric systems or transformed to a lower voltage for delivery to customers.

 

Q: How much electricity does a typical household use?
A: A household's electricity usage varies significantly, throughout both the day and the year. Typically, electricity usage will peak in the summer (due to air conditioning load). During the day, it will tend to be greatest in the late afternoon when people return home from work, they adjust their thermostats, and begin preparing dinner. The amount of electricity a customer uses over time is measured in kilowatt-hours (kWh).

 

Q: Who owns the electric system?
A: The electric system, which includes generation, transmission, and distribution, is owned by a mix of entities. For example, 192 Investor-Owned Utilities (IOUs) account for a significant portion of net generation (38%), transmission (80%), and distribution (50%). About 2,900 publicly-owned utilities and cooperatives account for 15% of net generation, 12% of transmission, and nearly 50% of the nation's electric distribution lines. Approximately 2,800 independent power producers account for 40% of net generation. The Federal Government owns 9 power agencies (including 4 Power Marketing Administrations and TVA) with 7% of net generation and 8% of transmission. And 211 Electric Power Marketers account for approximately 19% of sales to consumers.

 

Q: Who uses electricity?
A: There are over 140 million customers of electricity. They can be divided into 3 categories: residential (122 million customers; 37% electricity sales); commercial (17 million; 35% sales); and industrial (<1 million; 28% sales).

 

Q: Where can I find out more about potential careers?
A: Not all careers in the electric industry require an advanced degree. Lineworkers, for example, are in strong demand.

 

Q: How can I improve my energy use?
A: You have already taken the first step – you are thinking about your energy use and ways that your action can not only save you money but also secure America's energy future. It can be as simple as replacing your old incandescent lightbulb with a compact fluorescent. Additional energy efficiency tips.

 

Reference: Energy.gov | www.energy.gov

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